{"id":330,"date":"2021-12-17T21:41:19","date_gmt":"2021-12-17T21:41:19","guid":{"rendered":"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/4-igneous-processes-and-volcanoes\/"},"modified":"2022-05-18T14:11:26","modified_gmt":"2022-05-18T14:11:26","slug":"4-igneous-processes-and-volcanoes","status":"publish","type":"chapter","link":"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/4-igneous-processes-and-volcanoes\/","title":{"raw":"4 Igneous Processes and Volcanoes","rendered":"4 Igneous Processes and Volcanoes"},"content":{"raw":"[caption id=\"attachment_315\" align=\"aligncenter\" width=\"2031\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/IT-PompeiiVesuvius.jpg\"><img class=\"wp-image-235 size-full\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/12\/IT-PompeiiVesuvius.jpg\" alt=\"The town in Italy is a ruin.\" width=\"2031\" height=\"1355\"><\/a> Mount Vesuvius towers over the ruins of Pompeii, a city destroyed by the eruption in 79 CE.[\/caption]\n<h1>4 Igneous Processes and Volcanoes<\/h1>\n<b>KEY CONCEPTS<\/b>\n\n<strong>By the end of this chapter, students should be able to:<\/strong>\n<ul>\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Explain the origin of [pb_glossary id=\"1750\"]magma[\/pb_glossary] it relates to [pb_glossary id=\"1654\"]plate tectonics[\/pb_glossary]<\/span><\/li>\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Describe how the [pb_glossary id=\"221\"]Bowen\u2019s Reaction Series[\/pb_glossary]\u00a0relates [pb_glossary id=\"1765\"]mineral[\/pb_glossary] [pb_glossary id=\"1752\"]crystallization[\/pb_glossary] and melting temperatures<\/span><\/li>\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Explain how cooling of [pb_glossary id=\"1750\"]magma[\/pb_glossary] leads to rock compositions and textures, and how these are used to classify [pb_glossary id=\"1753\"]igneous[\/pb_glossary] rocks<\/span><\/li>\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Analyze the features of common [pb_glossary id=\"1753\"]igneous[\/pb_glossary] landforms and how they relate to their origin<\/span><\/li>\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Explain [pb_glossary id=\"224\"]partial melting[\/pb_glossary] and [pb_glossary id=\"227\"]fractionation[\/pb_glossary], and how they change [pb_glossary id=\"1750\"]magma[\/pb_glossary] compositions<\/span><\/li>\n \t<li>Describe how silica content affects [pb_glossary id=\"1750\"]magma[\/pb_glossary] [pb_glossary id=\"2446\"]viscosity[\/pb_glossary] and eruptive style of [pb_glossary id=\"228\"]volcanoes[\/pb_glossary]<\/li>\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Describe [pb_glossary id=\"228\"]volcano[\/pb_glossary] types, eruptive styles, [pb_glossary id=\"1909\"]composition[\/pb_glossary], and their [pb_glossary id=\"1669\"]plate[\/pb_glossary] [pb_glossary id=\"1654\"]tectonic[\/pb_glossary] settings<\/span><\/li>\n \t<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Describe [pb_glossary id=\"228\"]volcanic[\/pb_glossary] hazards<\/span><\/li>\n<\/ul>\n<span style=\"font-weight: 400\"><strong>[pb_glossary id=\"1753\"]Igneous[\/pb_glossary]\u00a0rock<\/strong> is\u00a0formed when liquid rock freezes into a solid rock. This molten material is called <strong>[pb_glossary id=\"1750\"]magma[\/pb_glossary]<\/strong>\u00a0when it is in the ground and\u00a0<strong>[pb_glossary id=\"1751\"]lava[\/pb_glossary]<\/strong>\u00a0when it is on the surface. <\/span><span style=\"font-weight: 400\">Only the Earth's [pb_glossary id=\"1673\"]outer core[\/pb_glossary] is liquid; the Earth's [pb_glossary id=\"1664\"]mantle[\/pb_glossary] and [pb_glossary id=\"1658\"]crust[\/pb_glossary] is naturally solid. However, there are<\/span><span style=\"font-weight: 400\">\u00a0a few minor pockets of [pb_glossary id=\"1750\"]magma[\/pb_glossary] that form near the surface where geologic processes cause melting. It is this [pb_glossary id=\"1750\"]magma[\/pb_glossary] that becomes the source for [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] and [pb_glossary id=\"1753\"]igneous rocks[\/pb_glossary]. This chapter will describe the classification of [pb_glossary id=\"1753\"]igneous[\/pb_glossary] rocks, the unique processes that form [pb_glossary id=\"1750\"]magmas[\/pb_glossary], types of [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] and [pb_glossary id=\"228\"]volcanic[\/pb_glossary] processes, [pb_glossary id=\"228\"]volcanic[\/pb_glossary] hazards, and [pb_glossary id=\"1753\"]igneous[\/pb_glossary]\u00a0landforms.\u00a0<\/span>\n\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.1_Pahoehoe_and_Aa_flows_at_Hawaii.jpg\"><img class=\"size-medium wp-image-236\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.1_Pahoehoe_and_Aa_flows_at_Hawaii-300x200.jpg\" alt=\"Pahoehoe lava flow in Hawaii\" width=\"300\" height=\"200\"><\/a> Lava flow in Hawaii[\/caption]\n\n&nbsp;\n\n<span style=\"font-weight: 400\">[pb_glossary id=\"1751\"]Lava[\/pb_glossary] cools quickly on the surface of the earth and forms tiny microscopic crystals. These are known as fine-grained\u00a0<b>[pb_glossary id=\"990\"]extrusive[\/pb_glossary]<\/b>, or [pb_glossary id=\"228\"]volcanic[\/pb_glossary], [pb_glossary id=\"1753\"]igneous[\/pb_glossary] rocks. [pb_glossary id=\"990\"]Extrusive[\/pb_glossary] rocks are often <strong>[pb_glossary id=\"997\"]vesicular[\/pb_glossary]<\/strong>, filled with holes from escaping gas bubbles. <strong>[pb_glossary id=\"228\"]Volcanism[\/pb_glossary]<\/strong> is the process in which [pb_glossary id=\"1751\"]lava[\/pb_glossary] is erupted. Depending on the properties of the [pb_glossary id=\"1751\"]lava[\/pb_glossary] that is erupted, the [pb_glossary id=\"228\"]volcanism[\/pb_glossary] can be drastically different, from smooth and gentle to dangerous and explosive. This leads to different types of [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] and different [pb_glossary id=\"228\"]volcanic[\/pb_glossary] hazards.<\/span>\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Half-Dome-a-granitic-batholith-in-Yosemite.jpg\"><img class=\"size-medium wp-image-237\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Half-Dome-a-granitic-batholith-in-Yosemite-300x257.jpg\" alt=\"An intrusive igneous mass now exposed at the surface by erosion\" width=\"300\" height=\"257\"><\/a> Half Dome, an intrusive igneous batholith in Yosemite National Park[\/caption]\n\n<span style=\"font-weight: 400\">In contrast, [pb_glossary id=\"1750\"]magma[\/pb_glossary] that cools slowly below the earth\u2019s surface forms larger crystals which can be seen with the naked eye. These are known as coarse-grained\u00a0<b>[pb_glossary id=\"991\"]intrusive[\/pb_glossary]<\/b>, or [pb_glossary id=\"991\"]plutonic[\/pb_glossary], [pb_glossary id=\"1753\"]igneous[\/pb_glossary] rocks. This relationship between cooling rates and grain sizes of the solidified [pb_glossary id=\"1765\"]minerals[\/pb_glossary] in [pb_glossary id=\"1753\"]igneous[\/pb_glossary] rocks is important for interpreting the rock\u2019s geologic history.<\/span>\n<h2>\u00a0<span style=\"font-weight: 400\">4.1 Classification of Igneous Rocks<\/span><\/h2>\n<span style=\"font-weight: 400\">[pb_glossary id=\"1753\"]Igneous[\/pb_glossary] rocks are classified based on [pb_glossary id=\"1997\"]texture[\/pb_glossary] and [pb_glossary id=\"1909\"]composition[\/pb_glossary]. [pb_glossary id=\"1997\"]Texture[\/pb_glossary] describes the physical characteristics of the [pb_glossary id=\"1765\"]minerals[\/pb_glossary], such as grain size. This relates to the cooling history of the molten [pb_glossary id=\"1750\"]magma[\/pb_glossary] from which it came. [pb_glossary id=\"1909\"]Composition[\/pb_glossary] refers to the rock's specific mineralogy and chemical [pb_glossary id=\"1909\"]composition[\/pb_glossary]. Cooling history is also related to changes that can occur to the [pb_glossary id=\"1909\"]composition[\/pb_glossary] of [pb_glossary id=\"1753\"]igneous[\/pb_glossary] rocks.<\/span>\n<h3><b>4.1.1 Texture<\/b><\/h3>\n[caption id=\"attachment_315\" align=\"alignright\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Fig-6.3-Granite-vs-Gneiss-e1495050932921.jpg\"><img class=\"size-medium wp-image-238\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Fig-6.3-Granite-vs-Gneiss-e1495050932921-300x271.jpg\" alt=\"Image showing three or four distinct colors of clearly visible minerals.\" width=\"300\" height=\"271\"><\/a> Granite is a classic coarse-grained (phaneritic) intrusive igneous rock. The different colors are unique minerals. The black colors are likely two or three different minerals.[\/caption]\n\nIf [pb_glossary id=\"1750\"]magma[\/pb_glossary] cools slowly, deep within the [pb_glossary id=\"1658\"]crust[\/pb_glossary], the resulting rock is called [pb_glossary id=\"991\"]intrusive[\/pb_glossary] or [pb_glossary id=\"991\"]plutonic[\/pb_glossary]. The slow cooling process allows crystals to grow large, giving [pb_glossary id=\"991\"]intrusive[\/pb_glossary] [pb_glossary id=\"1753\"]igneous rock[\/pb_glossary] a coarse-grained or <strong>[pb_glossary id=\"992\"]phaneritic[\/pb_glossary]<\/strong> [pb_glossary id=\"1997\"]texture[\/pb_glossary]. The individual crystals in [pb_glossary id=\"992\"]phaneritic[\/pb_glossary] [pb_glossary id=\"1997\"]texture[\/pb_glossary] are readily visible to the unaided eye.\n\n&nbsp;\n\n&nbsp;\n\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"284\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/IMG_2623-e1495051966958-scaled.jpg\"><img class=\"size-medium wp-image-2840\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/IMG_2623-e1495051966958-scaled-1.jpg\" alt=\"Show dark rock with no visible minerals except for a few tiny green minerals that are olivine.\" width=\"284\" height=\"300\"><\/a> Basalt is a classic fine-grained extrusive igneous rock. This sample is mostly fine groundmass with a few small green phenocrysts that are the mineral olivine.[\/caption]\n\nWhen [pb_glossary id=\"1751\"]lava[\/pb_glossary] is extruded onto the surface, or intruded into shallow fissures near the surface and cools, the resulting [pb_glossary id=\"1753\"]igneous rock[\/pb_glossary] is called [pb_glossary id=\"990\"]extrusive[\/pb_glossary] or [pb_glossary id=\"228\"]volcanic[\/pb_glossary]. [pb_glossary id=\"990\"]Extrusive[\/pb_glossary] [pb_glossary id=\"1753\"]igneous[\/pb_glossary] rocks have a fine-grained or <strong>[pb_glossary id=\"993\"]aphanitic[\/pb_glossary]<\/strong> [pb_glossary id=\"1997\"]texture[\/pb_glossary], in which the grains are too small to see with the unaided eye. The fine-grained [pb_glossary id=\"1997\"]texture[\/pb_glossary] indicates the quickly cooling [pb_glossary id=\"1751\"]lava[\/pb_glossary] did not have time to grow large crystals. These tiny crystals can be viewed under a petrographic microscope. In some cases, [pb_glossary id=\"990\"]extrusive[\/pb_glossary] [pb_glossary id=\"1751\"]lava[\/pb_glossary] cools so rapidly it does not develop crystals at all. This non-crystalline material is not classified as [pb_glossary id=\"1765\"]minerals[\/pb_glossary], but as [pb_glossary id=\"228\"]volcanic[\/pb_glossary] glass<span style=\"font-weight: 400\">. This is a common component of [pb_glossary id=\"228\"]volcanic[\/pb_glossary] [pb_glossary id=\"1001\"]ash[\/pb_glossary] and rocks like [pb_glossary id=\"999\"]obsidian[\/pb_glossary].<\/span>\n\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.5_Porphyritic_texture.jpg\"><img class=\"size-medium wp-image-240\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.5_Porphyritic_texture-300x223.jpg\" alt=\"Porphyritic teture with large crystals in a finer grained groundmass\" width=\"300\" height=\"223\"><\/a> Porphyritic texture[\/caption]\n\nSome [pb_glossary id=\"1753\"]igneous[\/pb_glossary] rocks have a mix of coarse-grained [pb_glossary id=\"1765\"]minerals[\/pb_glossary] surrounded by a matrix of fine-grained material in a [pb_glossary id=\"1997\"]texture[\/pb_glossary] called <strong>[pb_glossary id=\"994\"]porphyritic[\/pb_glossary]<\/strong>. The large crystals are called <strong>[pb_glossary id=\"995\"]phenocrysts[\/pb_glossary]<\/strong> and the fine-grained matrix is called the <strong>[pb_glossary id=\"1011\"]groundmass[\/pb_glossary]<\/strong> or <strong>matrix<\/strong>. [pb_glossary id=\"994\"]Porphyritic[\/pb_glossary] [pb_glossary id=\"1997\"]texture[\/pb_glossary] indicates the [pb_glossary id=\"1750\"]magma[\/pb_glossary] body underwent a multi-stage cooling history, cooling slowly while deep under the surface and later rising to a shallower depth or the surface where it cooled more quickly.\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.6_We-pegmatite.jpg\"><img class=\"size-medium wp-image-241\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.6_We-pegmatite-300x224.jpg\" alt=\"Pegmatic texture with large grains of minerals, mostly of felsic composition\" width=\"300\" height=\"224\"><\/a> Pegmatitic texture[\/caption]\n\nResidual molten material expelled from [pb_glossary id=\"1753\"]igneous[\/pb_glossary] intrusions may form veins or masses containing very large crystals of [pb_glossary id=\"1765\"]minerals[\/pb_glossary] like [pb_glossary id=\"968\"]feldspar[\/pb_glossary], [pb_glossary id=\"967\"]quartz[\/pb_glossary], beryl, tourmaline, and [pb_glossary id=\"966\"]mica[\/pb_glossary]. This [pb_glossary id=\"1997\"]texture[\/pb_glossary], which indicates a very slow [pb_glossary id=\"1752\"]crystallization[\/pb_glossary], is called <strong>[pb_glossary id=\"996\"]pegmatitic[\/pb_glossary]<\/strong>. A rock that chiefly consists of [pb_glossary id=\"996\"]pegmatitic[\/pb_glossary] [pb_glossary id=\"1997\"]texture[\/pb_glossary] is known as a <strong>[pb_glossary id=\"996\"]pegmatite[\/pb_glossary]<\/strong>. To give an example of how large these crystals can get, transparent cleavage sheets of [pb_glossary id=\"996\"]pegmatitic[\/pb_glossary] [pb_glossary id=\"966\"]muscovite[\/pb_glossary] [pb_glossary id=\"966\"]mica[\/pb_glossary] were used as windows during the Middle Ages.\n\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.7_Scoria_Macro_Digon3-e1495227072616.jpg\"><img class=\"size-medium wp-image-242\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.7_Scoria_Macro_Digon3-e1495227072616-300x286.jpg\" alt=\"A lava rock full of bubbles called scoria\" width=\"300\" height=\"286\"><\/a> Scoria[\/caption]\n\nAll [pb_glossary id=\"1750\"]magmas[\/pb_glossary] contain gases [pb_glossary id=\"1893\"]dissolved[\/pb_glossary] in solution called <strong>[pb_glossary id=\"1684\"]volatiles[\/pb_glossary]<\/strong>. As the [pb_glossary id=\"1750\"]magma[\/pb_glossary] rises to the surface, the drop in pressure causes the [pb_glossary id=\"1893\"]dissolved[\/pb_glossary] [pb_glossary id=\"1684\"]volatiles[\/pb_glossary] to come bubbling out of [pb_glossary id=\"1783\"]solution[\/pb_glossary], like the fizz in an opened bottle of soda. The gas bubbles become trapped in the solidifying [pb_glossary id=\"1751\"]lava[\/pb_glossary] to create a <strong>[pb_glossary id=\"997\"]vesicular[\/pb_glossary]<\/strong> [pb_glossary id=\"1997\"]texture[\/pb_glossary], with the holes specifically called vesicles. The type of [pb_glossary id=\"990\"]volcanic rock[\/pb_glossary] with common vesicles is called <strong>scoria<\/strong>.\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"250\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.9_Pumice_stone-e1495052465796.jpg\"><img class=\"wp-image-243\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.9_Pumice_stone-e1495052465796-298x300.jpg\" alt=\"A pumice stone, a hardened froth of volcanic glass\" width=\"250\" height=\"251\"><\/a> Pumice[\/caption]\n\nAn extreme version of scoria occurs when volatile-rich [pb_glossary id=\"1751\"]lava[\/pb_glossary]\u00a0is very quickly quenched and becomes a meringue-like froth of glass called <b>[pb_glossary id=\"998\"]pumice[\/pb_glossary]<\/b>. Some [pb_glossary id=\"998\"]pumice[\/pb_glossary] is so full of vesicles that the density of the rock drops low enough that it will float.\n\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"200\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.8_Lipari-Obsidienne_5.jpg\"><img class=\"wp-image-244\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.8_Lipari-Obsidienne_5-300x225.jpg\" alt=\"Photo of obsidian, a volcanic glass\" width=\"200\" height=\"150\"><\/a> Obsidian (volcanic glass). Note conchoidal fracture.[\/caption]\n\n&nbsp;\n\n<span style=\"font-weight: 400\">[pb_glossary id=\"1751\"]Lava[\/pb_glossary] that cools extremely quickly may not form crystals at all, even microscopic ones. The resulting rock is called\u00a0<strong>[pb_glossary id=\"228\"]volcanic[\/pb_glossary] glass<\/strong>. <strong>O<\/strong><\/span><b>bsidian<\/b> is a rock consisting of [pb_glossary id=\"228\"]volcanic[\/pb_glossary] glass.\u00a0<span style=\"font-weight: 400\">[pb_glossary id=\"999\"]Obsidian[\/pb_glossary] as a glassy rock shows an excellent example of [pb_glossary id=\"987\"]conchoidal[\/pb_glossary] [pb_glossary id=\"986\"]fracture[\/pb_glossary] similar to the [pb_glossary id=\"1765\"]mineral[\/pb_glossary] [pb_glossary id=\"967\"]quartz[\/pb_glossary] (see <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/3-minerals\/\">Chapter 3<\/a>).<\/span>\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.11_HoleInTheWallTuff.jpg\"><img class=\"size-medium wp-image-245\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.11_HoleInTheWallTuff-300x225.jpg\" alt=\"Tuff showing various size fragments of minerals and ash blown out of a volcano\" width=\"300\" height=\"225\"><\/a> Welded tuff[\/caption]\n\nWhen [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] erupt explosively, vast amounts of [pb_glossary id=\"1751\"]lava[\/pb_glossary], rock, [pb_glossary id=\"1001\"]ash[\/pb_glossary], and gases are thrown into the [pb_glossary id=\"1745\"]atmosphere[\/pb_glossary]. The solid parts, called [pb_glossary id=\"1000\"]tephra[\/pb_glossary], settle back to earth and cool into rocks with <strong>[pb_glossary id=\"1004\"]pyroclastic[\/pb_glossary]<\/strong> textures. <em>Pyro,<\/em> meaning fire, refers to the [pb_glossary id=\"1753\"]igneous[\/pb_glossary] source of the [pb_glossary id=\"1000\"]tephra[\/pb_glossary] and <em>[pb_glossary id=\"1903\"]clastic[\/pb_glossary] <\/em>refers to the rock fragments. [pb_glossary id=\"1000\"]Tephra[\/pb_glossary] fragments are named based on size\u2014<strong>[pb_glossary id=\"1001\"]ash[\/pb_glossary]<\/strong> (&lt;2 mm), <strong>[pb_glossary id=\"1002\"]lapilli[\/pb_glossary]<\/strong> (2-64 mm), and <strong>[pb_glossary id=\"1003\"]bombs[\/pb_glossary] or blocks<\/strong> (&gt;64 mm). [pb_glossary id=\"1004\"]Pyroclastic[\/pb_glossary] [pb_glossary id=\"1997\"]texture[\/pb_glossary] is usually recognized by the chaotic mix of crystals, angular glass shards, and rock fragments. Rock formed from large deposits of [pb_glossary id=\"1000\"]tephra[\/pb_glossary] fragments is called <strong>[pb_glossary id=\"1005\"]tuff[\/pb_glossary]<\/strong>. If the fragments accumulate while still hot, the heat may deform the crystals and weld the mass together, forming a welded [pb_glossary id=\"1005\"]tuff[\/pb_glossary].\n<h3><b>4.1.2 Composition<\/b><\/h3>\n[pb_glossary id=\"1909\"]Composition[\/pb_glossary] refers to a rock\u2019s chemical and [pb_glossary id=\"1765\"]mineral[\/pb_glossary] make-up . For [pb_glossary id=\"1753\"]igneous rock[\/pb_glossary], [pb_glossary id=\"1909\"]composition[\/pb_glossary] is divided into four groups: <strong>[pb_glossary id=\"1006\"]felsic[\/pb_glossary]<\/strong>, <strong>[pb_glossary id=\"1007\"]intermediate[\/pb_glossary]<\/strong>, <strong>[pb_glossary id=\"1008\"]mafic[\/pb_glossary]<\/strong>, and <strong>[pb_glossary id=\"1009\"]ultramafic[\/pb_glossary]<\/strong><em>.<\/em> These groups refer to differing amounts of silica, iron, and magnesium found in the [pb_glossary id=\"1765\"]minerals[\/pb_glossary] that make up the rocks. It is important to realize these groups do not have sharp boundaries in nature, but rather lie on a continuous spectrum with many transitional compositions and names that refer to specific quantities of [pb_glossary id=\"1765\"]minerals[\/pb_glossary].\u00a0<span style=\"font-weight: 400\">As an example, [pb_glossary id=\"1014\"]granite[\/pb_glossary] is a commonly-used term, but has a very specific definition which includes exact quantities of [pb_glossary id=\"1765\"]minerals[\/pb_glossary] like [pb_glossary id=\"968\"]feldspar[\/pb_glossary] and [pb_glossary id=\"967\"]quartz[\/pb_glossary]. Rocks labeled as '[pb_glossary id=\"1014\"]granite[\/pb_glossary]' in laymen applications can be several other rocks, including\u00a0 syenite, tonalite, and monzonite.\u00a0<\/span>To avoid these complications, the following figure presents a simplified version of [pb_glossary id=\"1753\"]igneous rock[\/pb_glossary] nomenclature focusing on the four main groups, which is adequate for an introductory student.\n\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"1672\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Igneous-rock-composition-as-volume-percentages-of-minerals.jpg\"><img class=\"size-full wp-image-246\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Igneous-rock-composition-as-volume-percentages-of-minerals.jpg\" alt=\"Diagram showing the mineral composition of the four classes of igneous rocks, ultramafic, mafic, intermediate, and felsic.\" width=\"1672\" height=\"1182\"><\/a> Mineral composition of common igneous rocks. Percentage of minerals is shown on the vertical axis. Percentage of silica is shown on the horizontal axis. Rock names at the top include a continuous spectrum of compositions grading from one into another.[\/caption]\n\n<b>Fel<\/b><span style=\"font-weight: 400\">sic refers to a predominance of the light-colored ([pb_glossary id=\"1006\"]felsic[\/pb_glossary]) [pb_glossary id=\"1765\"]minerals[\/pb_glossary]\u00a0<\/span><span style=\"text-decoration: underline\"><b>fel<\/b><\/span><span style=\"font-weight: 400\">dspar and <span style=\"text-decoration: underline\"><strong>si<\/strong><\/span>lica in the form of [pb_glossary id=\"967\"]quartz[\/pb_glossary]. These light-colored [pb_glossary id=\"1765\"]minerals[\/pb_glossary] have more silica as a proportion of their overall chemical formula. Minor amounts of dark-colored ([pb_glossary id=\"1008\"]mafic[\/pb_glossary]) [pb_glossary id=\"1765\"]minerals[\/pb_glossary] like [pb_glossary id=\"1791\"]amphibole[\/pb_glossary] and [pb_glossary id=\"4444\"]biotite[\/pb_glossary] [pb_glossary id=\"966\"]mica[\/pb_glossary] may be present as well. [pb_glossary id=\"1006\"]Felsic[\/pb_glossary] [pb_glossary id=\"1753\"]igneous[\/pb_glossary] rocks are rich in silica (in the 65-75% range, meaning the rock would be 65-75% weight percent SiO<sup>2<\/sup>) and poor in iron and magnesium.<\/span>\n\n<b>[pb_glossary id=\"1007\"]Intermediate[\/pb_glossary]<\/b> is a [pb_glossary id=\"1909\"]composition[\/pb_glossary] between [pb_glossary id=\"1006\"]felsic[\/pb_glossary] and [pb_glossary id=\"1008\"]mafic[\/pb_glossary].\u00a0 It usually contains roughly-equal amounts of light and dark [pb_glossary id=\"1765\"]minerals[\/pb_glossary], including light grains of [pb_glossary id=\"968\"]plagioclase[\/pb_glossary] [pb_glossary id=\"968\"]feldspar[\/pb_glossary] and dark [pb_glossary id=\"1765\"]minerals[\/pb_glossary] like amphibole.\u00a0 It is [pb_glossary id=\"1007\"]intermediate[\/pb_glossary] in silica in the 55-60% range.\n\n<b>Maf<\/b><span style=\"font-weight: 400\">ic refers to a abundance of ferromagnesian [pb_glossary id=\"1765\"]minerals[\/pb_glossary] (with magnesium and iron, chemical symbols <\/span><b>M<\/b>g<span style=\"font-weight: 400\">\u00a0and <\/span><b>F<\/b><span style=\"font-weight: 400\">e) plus [pb_glossary id=\"968\"]plagioclase[\/pb_glossary] [pb_glossary id=\"968\"]feldspar[\/pb_glossary]. It is mostly made of dark [pb_glossary id=\"1765\"]minerals[\/pb_glossary] like [pb_glossary id=\"1790\"]pyroxene[\/pb_glossary] and [pb_glossary id=\"1789\"]olivine[\/pb_glossary], which are rich in iron and magnesium and relatively poor in silica. [pb_glossary id=\"1008\"]Mafic[\/pb_glossary] rocks are low in silica, in the 45-50% range.<\/span>\n\n<span style=\"font-weight: 400\"><strong>[pb_glossary id=\"1009\"]Ultramafic[\/pb_glossary]<\/strong> refers to the extremely [pb_glossary id=\"1008\"]mafic[\/pb_glossary] rocks [pb_glossary id=\"1909\"]composed[\/pb_glossary] of mostly [pb_glossary id=\"1789\"]olivine[\/pb_glossary] and some [pb_glossary id=\"1790\"]pyroxene[\/pb_glossary] which have even more magnesium and iron and even less silica. T<\/span><span style=\"font-weight: 400\">hese rocks are rare on the surface, but make up [pb_glossary id=\"1666\"]peridotite[\/pb_glossary], the rock of the upper [pb_glossary id=\"1664\"]mantle[\/pb_glossary]. It is poor in silica, in the 40% or less range.<\/span>\n\n<span style=\"font-weight: 400\">On the figure above, the top row has both [pb_glossary id=\"991\"]plutonic[\/pb_glossary] and [pb_glossary id=\"228\"]volcanic[\/pb_glossary] [pb_glossary id=\"1753\"]igneous[\/pb_glossary] rocks arranged in a continuous spectrum from [pb_glossary id=\"1006\"]felsic[\/pb_glossary] on the left to [pb_glossary id=\"1007\"]intermediate[\/pb_glossary], [pb_glossary id=\"1008\"]mafic[\/pb_glossary], and [pb_glossary id=\"1009\"]ultramafic[\/pb_glossary] toward the right.\u00a0<\/span><b>[pb_glossary id=\"1010\"]Rhyolite[\/pb_glossary]<\/b><span style=\"font-weight: 400\">\u00a0thus refers to the [pb_glossary id=\"228\"]volcanic[\/pb_glossary] and [pb_glossary id=\"1006\"]felsic[\/pb_glossary] [pb_glossary id=\"1753\"]igneous[\/pb_glossary] rocks, and <\/span><b>[pb_glossary id=\"1014\"]granite[\/pb_glossary]<\/b><span style=\"font-weight: 400\"> thus refer to [pb_glossary id=\"991\"]intrusive[\/pb_glossary] and [pb_glossary id=\"1006\"]felsic[\/pb_glossary] [pb_glossary id=\"1753\"]igneous[\/pb_glossary] rocks. <\/span><b>[pb_glossary id=\"1012\"]Andesite[\/pb_glossary]<\/b><span style=\"font-weight: 400\"> and <\/span><b>[pb_glossary id=\"1015\"]diorite[\/pb_glossary]<\/b><span style=\"font-weight: 400\">\u00a0likewise refer to [pb_glossary id=\"990\"]extrusive[\/pb_glossary] and [pb_glossary id=\"991\"]intrusive[\/pb_glossary] [pb_glossary id=\"1007\"]intermediate[\/pb_glossary] rocks (with <\/span>dacite<span style=\"font-weight: 400\"> and <\/span>granodiorite<span style=\"font-weight: 400\"> applying to those rocks with [pb_glossary id=\"1909\"]composition[\/pb_glossary] between [pb_glossary id=\"1006\"]felsic[\/pb_glossary] and [pb_glossary id=\"1007\"]intermediate[\/pb_glossary]).\u00a0<\/span><b>[pb_glossary id=\"1013\"]Basalt[\/pb_glossary]<\/b><span style=\"font-weight: 400\"> and <\/span><b>[pb_glossary id=\"1016\"]gabbro[\/pb_glossary]<\/b><span style=\"font-weight: 400\"> are the [pb_glossary id=\"990\"]extrusive[\/pb_glossary] and [pb_glossary id=\"991\"]intrusive[\/pb_glossary] names for [pb_glossary id=\"1008\"]mafic[\/pb_glossary] [pb_glossary id=\"1753\"]igneous[\/pb_glossary] rocks, and <\/span><b>[pb_glossary id=\"1666\"]peridotite[\/pb_glossary]<\/b><span style=\"font-weight: 400\"> is [pb_glossary id=\"1009\"]ultramafic[\/pb_glossary], with\u00a0<b>komatiite<\/b> as the fine-grained [pb_glossary id=\"990\"]extrusive[\/pb_glossary] equivalent. Komatiite is a rare rock because [pb_glossary id=\"228\"]volcanic[\/pb_glossary] material that comes direct from the [pb_glossary id=\"1664\"]mantle[\/pb_glossary] is not common, although some examples can be found in ancient [pb_glossary id=\"1257\"]Archean[\/pb_glossary] rocks<\/span><span style=\"font-weight: 400\">. Nature rarely has sharp boundaries and the classification and naming of rocks often imposes what appear to be sharp boundary names onto a continuous spectrum.<\/span>\n\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"2048\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Igneous-Classification-cropped-scaled.jpg\"><img class=\"size-full wp-image-2848\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Igneous-Classification-cropped-scaled-1.jpg\" alt=\"Classification table of igneous rock.\" width=\"2048\" height=\"2560\"><\/a> Igneous rock classification table with composition as vertical columns and texture as horizontal rows.[\/caption]\n<h4><strong>Aphanitic\/Phaneritic Rock Types with images<\/strong><\/h4>\n<table style=\"height: 1296px\">\n<tbody>\n<tr style=\"height: 15px\">\n<td style=\"text-align: center;vertical-align: middle;height: 15px;width: 810.062px\" colspan=\"2\">\n<div class=\"mceTemp\"><strong>[pb_glossary id=\"1006\"]Felsic[\/pb_glossary] [pb_glossary id=\"1909\"]Composition[\/pb_glossary]<\/strong><\/div><\/td>\n<\/tr>\n<tr style=\"height: 279px\">\n<td style=\"text-align: center;vertical-align: middle;height: 279px;width: 397.672px\">\n\n[caption id=\"attachment_2849\" align=\"aligncenter\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/550px-Quartz_monzonite_36mw1037.jpg\"><img class=\"size-medium wp-image-248\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/550px-Quartz_monzonite_36mw1037-300x262.jpg\" alt=\"Photograph of cut granite. showing a variety of visible minerals, including quartz and k-feldspar.\" width=\"300\" height=\"262\"><\/a> Granite from Cape Cod, Massachusetts.[\/caption]<\/td>\n<td style=\"text-align: center;vertical-align: middle;height: 279px;width: 399.453px\">\n\n[caption id=\"attachment_2850\" align=\"aligncenter\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/lossy-page1-640px-PinkRhyolite.tif_.jpg\"><img class=\"size-medium wp-image-249\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/lossy-page1-640px-PinkRhyolite.tif_-300x214.jpg\" alt=\"Fine Crystalline rock with larger glassy fragments floating in the groundmass.\" width=\"300\" height=\"214\"><\/a> Rhyolite (source: Michael C. Rygel via Wikimedia Commons)[\/caption]<\/td>\n<\/tr>\n<tr style=\"height: 221px\">\n<td style=\"height: 221px;width: 397.672px\">[pb_glossary id=\"1014\"]Granite[\/pb_glossary] is a course-crystalline [pb_glossary id=\"1006\"]felsic[\/pb_glossary] [pb_glossary id=\"991\"]intrusive[\/pb_glossary] rock. \u00a0The presence of [pb_glossary id=\"967\"]quartz[\/pb_glossary] is a good indicator of [pb_glossary id=\"1014\"]granite[\/pb_glossary]. \u00a0[pb_glossary id=\"1014\"]Granite[\/pb_glossary] commonly has large amounts of salmon pink potassium [pb_glossary id=\"968\"]feldspar[\/pb_glossary] and white [pb_glossary id=\"968\"]plagioclase[\/pb_glossary] crystals that have visible\u00a0cleavage planes. [pb_glossary id=\"1014\"]Granite[\/pb_glossary] is a good approximation for the [pb_glossary id=\"1653\"]continental crust[\/pb_glossary], both in density and [pb_glossary id=\"1909\"]composition[\/pb_glossary].<\/td>\n<td style=\"height: 221px;width: 399.453px\">[pb_glossary id=\"1010\"]Rhyolite[\/pb_glossary]\u00a0is a fine-crystalline [pb_glossary id=\"1006\"]felsic[\/pb_glossary] [pb_glossary id=\"990\"]extrusive[\/pb_glossary] rock. \u00a0[pb_glossary id=\"1010\"]Rhyolite[\/pb_glossary] is commonly pink and will often have glassy [pb_glossary id=\"967\"]quartz[\/pb_glossary] [pb_glossary id=\"995\"]phenocrysts[\/pb_glossary].\u00a0 Because [pb_glossary id=\"1006\"]felsic[\/pb_glossary] lavas are less mobile, it is less common than [pb_glossary id=\"1014\"]granite[\/pb_glossary]. Examples of [pb_glossary id=\"1010\"]rhyolite[\/pb_glossary] include several [pb_glossary id=\"1751\"]lava[\/pb_glossary] flows in Yellowstone National Park and the altered [pb_glossary id=\"1010\"]rhyolite[\/pb_glossary] that makes up the Grand Canyon of the Yellowstone.<\/td>\n<\/tr>\n<tr style=\"height: 15px\">\n<td style=\"text-align: center;height: 15px;width: 810.062px\" colspan=\"2\">\u00a0\u00a0<strong>[pb_glossary id=\"1007\"]Intermediate[\/pb_glossary] [pb_glossary id=\"1909\"]Composition[\/pb_glossary]<\/strong><\/td>\n<\/tr>\n<tr style=\"height: 257px\">\n<td style=\"height: 257px;width: 397.672px\">\n\n[caption id=\"attachment_2851\" align=\"aligncenter\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Diorite_MA-e1496027879779.jpg\"><img class=\"size-medium wp-image-250\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Diorite_MA-e1496027879779-300x225.jpg\" alt=\"Rock with visible black and white crystals.\" width=\"300\" height=\"225\"><\/a> Diorite[\/caption]<\/td>\n<td style=\"height: 257px;width: 399.453px\">\n\n[caption id=\"attachment_2852\" align=\"aligncenter\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Andesite2.tif_.jpg\"><img class=\"size-medium wp-image-251\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Andesite2.tif_-300x240.jpg\" alt=\"Grey rock with fine crystals and black phenocrysts.\" width=\"300\" height=\"240\"><\/a> Andesite[\/caption]<\/td>\n<\/tr>\n<tr style=\"height: 158px\">\n<td style=\"height: 158px;width: 397.672px\">\u00a0[pb_glossary id=\"1015\"]Diorite[\/pb_glossary] is a coarse-crystalline [pb_glossary id=\"1007\"]intermediate[\/pb_glossary] [pb_glossary id=\"991\"]intrusive[\/pb_glossary] [pb_glossary id=\"1753\"]igneous rock[\/pb_glossary]. Diorite is identifiable by it's Dalmatian-like appearance of black hornblende and [pb_glossary id=\"966\"]biotite[\/pb_glossary]\u00a0and white [pb_glossary id=\"968\"]plagioclase[\/pb_glossary] [pb_glossary id=\"968\"]feldspar[\/pb_glossary]. It is found in its namesake, the Andes Mountains as well as the Henry and Abajo mountains of Utah.<\/td>\n<td style=\"height: 158px;width: 399.453px\">\u00a0[pb_glossary id=\"1012\"]Andesite[\/pb_glossary] is a fine crystalline [pb_glossary id=\"1007\"]intermediate[\/pb_glossary] [pb_glossary id=\"990\"]extrusive[\/pb_glossary] rock. \u00a0It is commonly grey and [pb_glossary id=\"994\"]porphyritic[\/pb_glossary]. \u00a0It can be found in the Andes Mountains and in some island arcs (see <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/2-plate-tectonics\/\">Chapter 2<\/a>). It is the fine grained compositional equivalent of [pb_glossary id=\"1015\"]diorite[\/pb_glossary].<\/td>\n<\/tr>\n<tr style=\"height: 15px\">\n<td style=\"text-align: center;height: 15px;width: 810.062px\" colspan=\"2\"><strong>[pb_glossary id=\"1008\"]Mafic[\/pb_glossary] [pb_glossary id=\"1909\"]Composition[\/pb_glossary]<\/strong><\/td>\n<\/tr>\n<tr style=\"height: 242px\">\n<td style=\"height: 242px;width: 397.672px\">\n\n[caption id=\"attachment_2853\" align=\"aligncenter\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/GabbroRockCreek1.jpg\"><img class=\"size-medium wp-image-252\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/GabbroRockCreek1-300x215.jpg\" alt=\"Dark rock with visible crystals.\" width=\"300\" height=\"215\"><\/a> Gabbro[\/caption]<\/td>\n<td style=\"height: 242px;width: 399.453px\">\n\n[caption id=\"attachment_2854\" align=\"aligncenter\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/VessicularBasalt1.jpg\"><img class=\"size-medium wp-image-253\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/VessicularBasalt1-300x225.jpg\" alt=\"Dark grey rock with many visible holes and no visible crystals.\" width=\"300\" height=\"225\"><\/a> Vesicular Basalt[\/caption]<\/td>\n<\/tr>\n<tr style=\"height: 94px\">\n<td style=\"height: 94px;width: 397.672px\">\n<div class=\"mceTemp\">[pb_glossary id=\"1016\"]Gabbro[\/pb_glossary] is a coarse-grained [pb_glossary id=\"1008\"]mafic[\/pb_glossary] [pb_glossary id=\"1753\"]igneous rock[\/pb_glossary], made with mainly [pb_glossary id=\"1008\"]mafic[\/pb_glossary] [pb_glossary id=\"1765\"]minerals[\/pb_glossary] like [pb_glossary id=\"1790\"]pyroxene[\/pb_glossary] and only minor [pb_glossary id=\"968\"]plagioclase[\/pb_glossary]. Because [pb_glossary id=\"1008\"]mafic[\/pb_glossary] [pb_glossary id=\"1751\"]lava[\/pb_glossary] is more mobile, it is less common than [pb_glossary id=\"1013\"]basalt[\/pb_glossary]. [pb_glossary id=\"1016\"]Gabbro[\/pb_glossary] is a major component of the lower [pb_glossary id=\"1659\"]oceanic crust[\/pb_glossary].<\/div><\/td>\n<td style=\"height: 94px;width: 399.453px\">[pb_glossary id=\"1013\"]Basalt[\/pb_glossary] is a fine-grained [pb_glossary id=\"1008\"]mafic[\/pb_glossary] [pb_glossary id=\"1753\"]igneous rock[\/pb_glossary]. It is commonly [pb_glossary id=\"997\"]vesicular[\/pb_glossary] and [pb_glossary id=\"993\"]aphanitic[\/pb_glossary]. When [pb_glossary id=\"994\"]porphyritic[\/pb_glossary], it often has either [pb_glossary id=\"1789\"]olivine[\/pb_glossary] or [pb_glossary id=\"968\"]plagioclase[\/pb_glossary] [pb_glossary id=\"995\"]phenocrysts[\/pb_glossary]. [pb_glossary id=\"1013\"]Basalt[\/pb_glossary] is the main rock which is formed at [pb_glossary id=\"1708\"]mid-ocean ridges[\/pb_glossary], and is therefore the most common rock on the Earth's surface, making up the entirety of the [pb_glossary id=\"1963\"]ocean floor[\/pb_glossary] (except where covered by [pb_glossary id=\"1756\"]sediment[\/pb_glossary]).<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3><b>4.1.3 Igneous Rock Bodies<\/b><\/h3>\n<span style=\"font-weight: 400\">[pb_glossary id=\"1753\"]Igneous[\/pb_glossary] rocks are common in the geologic record, but surprisingly, it is the [pb_glossary id=\"991\"]intrusive[\/pb_glossary] rocks that are more common. [pb_glossary id=\"990\"]Extrusive[\/pb_glossary] rocks, because of their small crystals and glass, are less durable. Plus, they are, by definition, exposed to the [pb_glossary id=\"1778\"]elements[\/pb_glossary] of [pb_glossary id=\"1755\"]erosion[\/pb_glossary] immediately. [pb_glossary id=\"991\"]Intrusive[\/pb_glossary] rocks, forming underground with larger, stronger crystals, are more likely to last. Therefore, most landforms and rock groups that owe their origin to [pb_glossary id=\"1753\"]igneous[\/pb_glossary] rocks are [pb_glossary id=\"991\"]intrusive[\/pb_glossary] bodies. A significant exception to this is active [pb_glossary id=\"228\"]volcanoes[\/pb_glossary], which are discussed in a <a href=\"#4-5Volcanism\">later section on volcanism<\/a>. This section will [pb_glossary id=\"2158\"]focus[\/pb_glossary] on the common [pb_glossary id=\"1753\"]igneous[\/pb_glossary] bodies which are found in many places within the [pb_glossary id=\"1023\"]bedrock[\/pb_glossary] of Earth.<\/span>\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Olivine-gabbro-dike-cuts-across-Baffin-Island-in-the-Canadian-Arctic.jpg\"><img class=\"size-medium wp-image-254\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Olivine-gabbro-dike-cuts-across-Baffin-Island-in-the-Canadian-Arctic-300x201.jpg\" alt=\"Igneous dike cuts across Baffin Island in the Canadian Arctic.\" width=\"300\" height=\"201\"><\/a> Dike of olivine gabbro cuts across Baffin Island in the Canadian Arctic[\/caption]\n\nWhen [pb_glossary id=\"1750\"]magma[\/pb_glossary] intrudes into a weakness like a crack or fissure and solidifies, the resulting cross-cutting feature is called a <strong>[pb_glossary id=\"1021\"]dike[\/pb_glossary]<\/strong>\u00a0(sometimes spelled [pb_glossary id=\"1021\"]dyke[\/pb_glossary])<span style=\"font-weight: 400\">. Because of this, [pb_glossary id=\"1021\"]dikes[\/pb_glossary] are often vertical or at an angle relative to the pre-existing rock layers that they intersect. [pb_glossary id=\"1021\"]Dikes[\/pb_glossary] are therefore discordant intrusions, not following any layering that was present. [pb_glossary id=\"1021\"]Dikes[\/pb_glossary] are important to geologists, not only for the study of [pb_glossary id=\"1753\"]igneous[\/pb_glossary] rocks themselves but also for dating rock sequences and interpreting the geologic history of an area. The [pb_glossary id=\"1021\"]dike[\/pb_glossary] is younger than the rocks it cuts across and, as discussed in the chapter on Geologic Time (<a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/7-geologic-time\/\">Chapter 7<\/a>), may be used to assign actual numeric ages to sedimentary sequences, which are notoriously difficult to age date.\u00a0<\/span>\n\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.14_Horton_Bluff_mid-Carboniferous_sill.jpg\"><img class=\"size-medium wp-image-255\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.14_Horton_Bluff_mid-Carboniferous_sill-300x225.jpg\" alt=\"Igneous sill intruding in between Paleozoic strata in Nova Scotia\" width=\"300\" height=\"225\"><\/a> Igneous sill intruding between Paleozoic strata in Nova Scotia[\/caption]\n\n<strong>[pb_glossary id=\"1022\"]Sills[\/pb_glossary]<\/strong> are another type of [pb_glossary id=\"991\"]intrusive[\/pb_glossary] structure. A [pb_glossary id=\"1022\"]sill[\/pb_glossary] is a concordant intrusion that runs parallel to the sedimentary layers in the [pb_glossary id=\"1023\"]country rock[\/pb_glossary]. They are formed when [pb_glossary id=\"1750\"]magma[\/pb_glossary] exploits a weakness between these layers, shouldering them apart and squeezing between them. As with [pb_glossary id=\"1021\"]dikes[\/pb_glossary], [pb_glossary id=\"1022\"]sills[\/pb_glossary] are younger than the surrounding layers and may be radioactively dated to study the age of sedimentary [pb_glossary id=\"1935\"]strata[\/pb_glossary].\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Cottonwood-Stock-at-mouth-of-Little-Cottonwood-Canyon-Utah.jpg\"><img class=\"size-medium wp-image-256\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Cottonwood-Stock-at-mouth-of-Little-Cottonwood-Canyon-Utah-300x245.jpg\" alt=\"Exposure of Cottonwood Stock in Little Cottonwood Canyon, Utah\" width=\"300\" height=\"245\"><\/a> Cottonwood Stock, a quartz monzonite pluton exposed at the mouth of Little Cottonwood Canyon, Utah[\/caption]\n\n<span style=\"font-weight: 400\">A [pb_glossary id=\"232\"]magma chamber[\/pb_glossary] is a large underground [pb_glossary id=\"2419\"]reservoir[\/pb_glossary] of molten rock. The path of rising [pb_glossary id=\"1750\"]magma[\/pb_glossary] is called a <strong>[pb_glossary id=\"1018\"]diapir[\/pb_glossary]<\/strong>. The processes by which a [pb_glossary id=\"1018\"]diapir[\/pb_glossary] intrudes into the surrounding [pb_glossary id=\"976\"]native[\/pb_glossary] or [pb_glossary id=\"1023\"]country rock[\/pb_glossary] are not well understood and are the subject of ongoing geological inquiry. For example, it is not known what happens to the pre-existing [pb_glossary id=\"1023\"]country rock[\/pb_glossary] as the [pb_glossary id=\"1018\"]diapir[\/pb_glossary] intrudes. One [pb_glossary id=\"1733\"]theory[\/pb_glossary] is the overriding rock gets shouldered aside, displaced by the increased volume of [pb_glossary id=\"1750\"]magma[\/pb_glossary]. Another is the [pb_glossary id=\"976\"]native[\/pb_glossary] rock is melted and consumed into the rising [pb_glossary id=\"1750\"]magma[\/pb_glossary] or broken into pieces that settle into the [pb_glossary id=\"1750\"]magma[\/pb_glossary], a process known as <strong>[pb_glossary id=\"1019\"]stoping[\/pb_glossary]<\/strong>. It has also been proposed that diapirs are not a real phenomenon, but just a series of [pb_glossary id=\"1021\"]dikes[\/pb_glossary] that blend into each other. The [pb_glossary id=\"1021\"]dikes[\/pb_glossary] may be intruding over millions of years, but since they may be made of similar material, they would be appearing to be formed at the same time. Regardless, when a [pb_glossary id=\"1018\"]diapir[\/pb_glossary] cools, it forms an mass of [pb_glossary id=\"991\"]intrusive[\/pb_glossary] rock called a <strong>[pb_glossary id=\"1017\"]pluton[\/pb_glossary]<\/strong>. [pb_glossary id=\"1017\"]Plutons[\/pb_glossary] can have irregular shapes, but can often be somewhat round.<\/span>\n\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.2_Yosemite_Half-Dome.jpg\"><img class=\"size-medium wp-image-257\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.2_Yosemite_Half-Dome-300x225.jpg\" alt=\"View showing an expansive area of a mountain range with exposed white granite in many places.\" width=\"300\" height=\"225\"><\/a> Half-Dome in Yosemite National Park, California, is a part of the Sierra Nevada batholith which is mostly made of granite.[\/caption]\n\n&nbsp;\n\nWhen many [pb_glossary id=\"1017\"]plutons[\/pb_glossary] merge together in an extensive single feature, it is called a <strong>[pb_glossary id=\"1020\"]batholith[\/pb_glossary]<\/strong>. [pb_glossary id=\"1020\"]Batholiths[\/pb_glossary] are found in the cores of many mountain ranges, including the [pb_glossary id=\"1014\"]granite[\/pb_glossary] [pb_glossary id=\"2038\"]formations[\/pb_glossary] of Yosemite National Park in the Sierra Nevada of California. They are typically more than 100 km<sup>2<\/sup> in area, associated with [pb_glossary id=\"1680\"]subduction[\/pb_glossary] zones, and mostly [pb_glossary id=\"1006\"]felsic[\/pb_glossary] in [pb_glossary id=\"1909\"]composition[\/pb_glossary]. A <strong>stock<\/strong> is a type of [pb_glossary id=\"1017\"]pluton[\/pb_glossary] with less surface exposure than a [pb_glossary id=\"1020\"]batholith[\/pb_glossary], and may represent a narrower neck of material emerging from the top of a [pb_glossary id=\"1020\"]batholith[\/pb_glossary]. [pb_glossary id=\"1020\"]Batholiths[\/pb_glossary] and stocks are discordant intrusions that cut across and through surrounding [pb_glossary id=\"1023\"]country rock[\/pb_glossary].\n\n&nbsp;\n\n&nbsp;\n\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"250\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Henry-Mountains-a-laccolith.jpg\"><img class=\"wp-image-258\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Henry-Mountains-a-laccolith-300x198.jpg\" alt=\"Henry Mountains, Utah, interpreted to be a laccolith.\" width=\"250\" height=\"165\"><\/a> The Henry Mountains in Utah are interpreted to be a laccolith, exposed by erosion of the overlying layers.[\/caption]\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"250\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.15_diagram_of_formation_of_laccolith.jpg\"><img class=\"wp-image-259\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.15_diagram_of_formation_of_laccolith-300x225.jpg\" alt=\"Laccolith forms as a blister in between sedimentary layers\" width=\"250\" height=\"188\"><\/a> Laccolith forms as a blister in between sedimentary strata.[\/caption]\n\n<strong>[pb_glossary id=\"219\"]Laccoliths[\/pb_glossary]<\/strong> are blister-like, concordant intrusions of [pb_glossary id=\"1750\"]magma[\/pb_glossary] that form between sedimentary layers. The Henry Mountains of Utah are a famous topographic landform formed by this process. [pb_glossary id=\"219\"]Laccoliths[\/pb_glossary] bulge upwards; a similar downward-bulging intrusion is called a <strong>[pb_glossary id=\"219\"]lopolith[\/pb_glossary]<\/strong>.\n\n&nbsp;\n\n[h5p id=\"23\"]\n\n<em>Click on the plus signs the illustration for descriptions of several [pb_glossary id=\"1753\"]<em>igneous<\/em>[\/pb_glossary] features.<\/em>\n\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"150\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/4.2-Schematic-diagram-of-plutonic-and-volcanic-structures-and-processes-QR-Code.png\"><img class=\"size-thumbnail wp-image-260\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.2-Schematic-diagram-of-plutonic-and-volcanic-structures-and-processes-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a> If you are using the printed version of this OER, access this interactive activity via this QR Code.[\/caption]\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n[h5p id=\"24\"]\n\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"150\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/4.1-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-261\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.1-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a> If you are using the printed version of this OER, access the quiz for section 4.1 via this QR Code.[\/caption]\n<h2><strong><a id=\"4-2BowensReaction\" href=\"\"><\/a>4.2 Bowen's Reaction Series<\/strong><\/h2>\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"696\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.4_Bowens_Reaction_Series.png\"><img class=\"size-full wp-image-262\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.4_Bowens_Reaction_Series.png\" alt=\"Diagram of Bowen's Reaction Series, Y-shpaed with 8 minerals and a temperature scale\" width=\"696\" height=\"369\"><\/a> Bowen's Reaction Series. Higher temperature minerals shown at top (olivine) and lower temperature minerals shown at bottom (quartz). (Source Colivine, modified from Bowen, 1922)[\/caption]\n\n&nbsp;\n\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"150\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Peridot2.jpg\"><img class=\"wp-image-209\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Peridot2-272x300.jpg\" alt=\"The crystal is light green.\" width=\"150\" height=\"165\"><\/a> Olivine, the first mineral to crystallize in a melt.[\/caption]\n\n&nbsp;\n\n<strong>[pb_glossary id=\"221\"]Bowen\u2019s Reaction Series[\/pb_glossary]<\/strong> describes the [pb_glossary id=\"1767\"]temperature[\/pb_glossary] at which [pb_glossary id=\"1765\"]minerals[\/pb_glossary] crystallize when cooled, or melt when heated. The low end of the [pb_glossary id=\"1767\"]temperature[\/pb_glossary] scale where all [pb_glossary id=\"1765\"]minerals[\/pb_glossary] crystallize into solid rock, is approximately 700\u00b0C (1292\u00b0F). The upper end of the range where all [pb_glossary id=\"1765\"]minerals[\/pb_glossary] exist in a molten state, is approximately 1,250\u00b0C (2,282\u00b0F). These numbers reference [pb_glossary id=\"1765\"]minerals[\/pb_glossary] that crystallize at standard sea-level pressure, 1 bar. The values will be different for [pb_glossary id=\"1765\"]minerals[\/pb_glossary] located deep below the Earth\u2019s surface due to the increased pressure, which affects [pb_glossary id=\"1752\"]crystallization[\/pb_glossary] and melting temperatures (see <a href=\"#4-4PartialMelting\">Chapter 4.4<\/a>). However, the order and relationships are maintained.\n\nIn the figure, the righthand column lists the four groups of [pb_glossary id=\"1753\"]igneous rock[\/pb_glossary] from top to bottom: [pb_glossary id=\"1009\"]ultramafic[\/pb_glossary], [pb_glossary id=\"1008\"]mafic[\/pb_glossary], [pb_glossary id=\"1007\"]intermediate[\/pb_glossary], and [pb_glossary id=\"1006\"]felsic[\/pb_glossary]. The down-pointing arrow on the far right shows increasing amounts of silica, sodium, aluminum, and potassium as the [pb_glossary id=\"1765\"]mineral[\/pb_glossary] [pb_glossary id=\"1909\"]composition[\/pb_glossary] goes from [pb_glossary id=\"1009\"]ultramafic[\/pb_glossary] to [pb_glossary id=\"1006\"]felsic[\/pb_glossary]. The up-pointing arrow shows increasing ferromagnesian components, specifically iron, magnesium, and calcium.\u00a0\u00a0 To the far left of the diagram is a [pb_glossary id=\"1767\"]temperature[\/pb_glossary] scale. [pb_glossary id=\"1765\"]Minerals[\/pb_glossary] near the top of diagram, such as olivine and anorthite (a type of plagioclase), crystallize at higher temperatures. Minerals near the bottom, such as [pb_glossary id=\"967\"]quartz[\/pb_glossary] and [pb_glossary id=\"966\"]muscovite[\/pb_glossary], crystalize at lower temperatures.\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"200\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/NormanLBowen_1909.jpg\"><img class=\"size-medium wp-image-263\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/NormanLBowen_1909-200x300.jpg\" alt=\"Photo of Normal L. Bowen in 1909.\" width=\"200\" height=\"300\"><\/a> Normal L. Bowen[\/caption]\n\nThe most important aspect of [pb_glossary id=\"221\"]Bowen's Reaction Series[\/pb_glossary] is to notice the relationships between [pb_glossary id=\"1765\"]minerals[\/pb_glossary] and [pb_glossary id=\"1767\"]temperature[\/pb_glossary]. Norman L. Bowen (1887-1956) was an early 20th Century geologist who studied igneous rocks. He noticed that in [pb_glossary id=\"1753\"]igneous[\/pb_glossary] rocks, certain [pb_glossary id=\"1765\"]minerals[\/pb_glossary] always occur together and these [pb_glossary id=\"1765\"]mineral[\/pb_glossary] assemblages exclude other [pb_glossary id=\"1765\"]minerals[\/pb_glossary]. Curious as to why, and with the\u00a0[pb_glossary id=\"1730\"]hypothesis[\/pb_glossary] in mind that it had to do with the [pb_glossary id=\"1767\"]temperature[\/pb_glossary] at which the rocks cooled, he set about conducting experiments on [pb_glossary id=\"1753\"]igneous[\/pb_glossary] rocks in the early 1900s.\u00a0He conducted experiments on [pb_glossary id=\"1753\"]igneous rock[\/pb_glossary]\u2014grinding combinations of rocks into powder, sealing the powders into metal capsules, heating them to various temperatures, and then cooling them.\n\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"286\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/nlbowenexperimentingsm.jpg\"><img class=\"size-medium wp-image-264\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/nlbowenexperimentingsm-286x300.jpg\" alt=\"Photo of Bowen working over his pertrographic microscope\" width=\"286\" height=\"300\"><\/a> Norman L. Bowen working with his petrographic microscope[\/caption]\n\nWhen he opened the quenched capsules, he found a glass surrounding [pb_glossary id=\"1765\"]mineral[\/pb_glossary] crystals that he could identify under his petrographic microscope. The results of many of these experiments, conducted at different temperatures over a [pb_glossary id=\"1244\"]period[\/pb_glossary] of several years, showed that the common [pb_glossary id=\"1753\"]igneous[\/pb_glossary] [pb_glossary id=\"1765\"]minerals[\/pb_glossary] crystallize from [pb_glossary id=\"1750\"]magma[\/pb_glossary] at different temperatures. He also saw that [pb_glossary id=\"1765\"]minerals[\/pb_glossary] occur together in rocks with others that crystallize within similar [pb_glossary id=\"1767\"]temperature[\/pb_glossary] ranges, and never crystallize with other [pb_glossary id=\"1765\"]minerals[\/pb_glossary]. This relationship can explain the main difference between [pb_glossary id=\"1008\"]mafic[\/pb_glossary] and [pb_glossary id=\"1006\"]felsic[\/pb_glossary] [pb_glossary id=\"1753\"]igneous[\/pb_glossary] rocks. [pb_glossary id=\"1008\"]Mafic[\/pb_glossary] [pb_glossary id=\"1753\"]igneous[\/pb_glossary] rocks contain more [pb_glossary id=\"1008\"]mafic[\/pb_glossary] [pb_glossary id=\"1765\"]minerals[\/pb_glossary], and therefore, crystallize at higher temperatures than [pb_glossary id=\"1006\"]felsic[\/pb_glossary] [pb_glossary id=\"1753\"]igneous[\/pb_glossary] rocks. This is even seen in [pb_glossary id=\"1751\"]lava[\/pb_glossary] flows, with [pb_glossary id=\"1006\"]felsic[\/pb_glossary] lavas erupting hundreds of degrees cooler than their [pb_glossary id=\"1008\"]mafic[\/pb_glossary] counterparts. Bowen\u2019s work laid the foundation for understanding [pb_glossary id=\"1753\"]igneous[\/pb_glossary]<b> [pb_glossary id=\"220\"]petrology[\/pb_glossary]<\/b> (the study of rocks) and resulted in his book, <i>The Evolution of the [pb_glossary id=\"1753\"]Igneous[\/pb_glossary] Rocks<\/i> in 1928.\n<h3><\/h3>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n[h5p id=\"25\"]\n\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"150\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/4.2-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-265\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.2-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a> If you are using the printed version of this OER, access the quiz for section 4.2 via this QR Code.[\/caption]\n<h2><a id=\"4-3MagmaGeneration\" href=\"\"><\/a>4.3 Magma Generation<\/h2>\n[pb_glossary id=\"1750\"]Magma[\/pb_glossary] and [pb_glossary id=\"1751\"]lava[\/pb_glossary] contain three components: melt, solids, and [pb_glossary id=\"1684\"]volatiles[\/pb_glossary]. The melt is made of ions from [pb_glossary id=\"1765\"]minerals[\/pb_glossary] that have liquefied. The solids are made of crystallized [pb_glossary id=\"1765\"]minerals[\/pb_glossary] floating in the liquid melt. These may be [pb_glossary id=\"1765\"]minerals[\/pb_glossary] that have already cooled\u00a0<strong>[pb_glossary id=\"1684\"]Volatiles[\/pb_glossary]<\/strong> are gaseous components\u2014such as water vapor, carbon dioxide, sulfur, and chlorine\u2014[pb_glossary id=\"1893\"]dissolved[\/pb_glossary] in the [pb_glossary id=\"1750\"]magma[\/pb_glossary]. The presence and amount of these three components affect the physical behavior of the [pb_glossary id=\"1750\"]magma[\/pb_glossary] and will be discussed more below.\n<h3>4.3.1 Geothermal Gradient<\/h3>\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.2_Temperature_schematic_of_inner_Earth.jpg\"><img class=\"size-medium wp-image-266\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.2_Temperature_schematic_of_inner_Earth-300x300.jpg\" alt=\"Diagram showing temperature increase with depth in the Earth\" width=\"300\" height=\"300\"><\/a> Geothermal gradient[\/caption]\n\nBelow the surface, the [pb_glossary id=\"1767\"]temperature[\/pb_glossary] of the Earth rises. This heat is caused by residual heat left from the [pb_glossary id=\"2038\"]formation[\/pb_glossary] of Earth and ongoing [pb_glossary id=\"2044\"]radioactive[\/pb_glossary] decay. The rate at which [pb_glossary id=\"1767\"]temperature[\/pb_glossary] increases with depth is called the <strong>[pb_glossary id=\"222\"]geothermal gradient[\/pb_glossary]<\/strong>. The average [pb_glossary id=\"222\"]geothermal gradient[\/pb_glossary] in the upper 100 km (62 mi) of the [pb_glossary id=\"1658\"]crust[\/pb_glossary] is about 25\u00b0C per kilometer of depth. So for every kilometer of depth, the [pb_glossary id=\"1767\"]temperature[\/pb_glossary] increases by about 25\u00b0C.\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"283\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.3_Simple-P-T-Diagram-modified-from-Woudloper.jpg\"><img class=\"size-full wp-image-267\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_Simple-P-T-Diagram-modified-from-Woudloper.jpg\" alt=\"Diagram showing pressures and temperatures of the geothermal gradient increasing deeper in the earth. The solidus line shows that temperatures need to be much higher or pressure needs to be lower in order for rocks to start to melt.\" width=\"283\" height=\"256\"><\/a> Pressure-temperature diagram showing temperature in degrees Celsius on the x-axis and depth below the surface in kilometers (km) on the y-axis. The red line is the geothermal gradient and the green solidus line represents the temperature and pressure regime at which melting begins. Rocks at pressures and temperatures left of the green line are solid. If pressure\/temperature conditions change so that rocks pass to the right of the green line, then they will start to melt. (Source: Woudloper)[\/caption]\n\nThe depth-[pb_glossary id=\"1767\"]temperature[\/pb_glossary] graph (see figure) illustrates the relationship between the [pb_glossary id=\"222\"]geothermal gradient[\/pb_glossary] (geotherm, red line) and the start of rock melting (solidus, green line). The [pb_glossary id=\"222\"]geothermal gradient[\/pb_glossary] changes with depth (which has a direct relationship to pressure) through the [pb_glossary id=\"1658\"]crust[\/pb_glossary] into upper [pb_glossary id=\"1664\"]mantle[\/pb_glossary]. The area to the left of the green line includes solid components; to the right is where liquid components start to form. The increasing [pb_glossary id=\"1767\"]temperature[\/pb_glossary] with depth makes the depth of about 125 kilometers (78 miles) where the natural [pb_glossary id=\"222\"]geothermal gradient[\/pb_glossary] is closest to the solidus.\n\nThe [pb_glossary id=\"1767\"]temperature[\/pb_glossary] at 100 km (62 mi) deep is about 1,200\u00b0C (2,192\u00b0F). At bottom of the [pb_glossary id=\"1658\"]crust[\/pb_glossary], 35 km (22 mi) deep, the pressure is about 10,000 bars. A bar is a measure of pressure, with 1 bar being normal atmospheric pressure at sea level. At these pressures and temperatures, the [pb_glossary id=\"1658\"]crust[\/pb_glossary] and [pb_glossary id=\"1664\"]mantle[\/pb_glossary] are solid. To a depth of 150 km (93 mi), the [pb_glossary id=\"222\"]geothermal gradient[\/pb_glossary] line stays to the left of the solidus line. This relationship continues through the [pb_glossary id=\"1664\"]mantle[\/pb_glossary] to the [pb_glossary id=\"1667\"]core[\/pb_glossary]-[pb_glossary id=\"1664\"]mantle[\/pb_glossary] boundary, at 2,880 km (1,790 mi).\n\nThe solidus line slopes to the right because the melting [pb_glossary id=\"1767\"]temperature[\/pb_glossary] of any substance depends on pressure. The higher pressure created at greater depth increases the [pb_glossary id=\"1767\"]temperature[\/pb_glossary] needed to melt rock. In another example, at sea level with an atmospheric pressure close to 1 bar, water boils at 100\u00b0C. But if the pressure is lowered, as shown on the video below, water boils at a much lower [pb_glossary id=\"1767\"]temperature[\/pb_glossary].\n\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"150\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Boiling-Water-YouTube-QR-Code.png\"><img class=\"size-thumbnail wp-image-268\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Boiling-Water-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a> If you are using the printed version of this OER, access this YouTube video via this QR Code.[\/caption]\n\n[embed]https:\/\/www.youtube.com\/embed\/Ks4VuXTTKmo[\/embed]\n\n&nbsp;\n\nThere are three principal ways rock behavior crosses to the right of the green solidus line to create molten [pb_glossary id=\"1750\"]magma[\/pb_glossary]: 1) [pb_glossary id=\"223\"]decompression melting[\/pb_glossary] caused by lowering the pressure, 2) [pb_glossary id=\"1686\"]flux melting[\/pb_glossary] caused by adding [pb_glossary id=\"1684\"]volatiles[\/pb_glossary] (see more below), and 3) heat-induced melting caused by increasing the [pb_glossary id=\"1767\"]temperature[\/pb_glossary]. The [pb_glossary id=\"221\"]Bowen\u2019s Reaction Series[\/pb_glossary] shows that [pb_glossary id=\"1765\"]minerals[\/pb_glossary] melt at different temperatures. Since [pb_glossary id=\"1750\"]magma[\/pb_glossary] is a mixture of different [pb_glossary id=\"1765\"]minerals[\/pb_glossary], the solidus boundary is more of a fuzzy zone rather than a well-defined line; some [pb_glossary id=\"1765\"]minerals[\/pb_glossary] are melted and some remain solid. This type of rock behavior is called <strong>[pb_glossary id=\"224\"]partial melting[\/pb_glossary]<\/strong> and represents real-world [pb_glossary id=\"1750\"]magmas[\/pb_glossary], which typically contain solid, liquid, and volatile components.\n\n<span style=\"font-weight: 400\">The figure below uses P-T diagrams to show how melting can occur at three different [pb_glossary id=\"1669\"]plate[\/pb_glossary] [pb_glossary id=\"1654\"]tectonic[\/pb_glossary] settings.\u00a0 The green line is called the <strong>solidus<\/strong>, the melting point [pb_glossary id=\"1767\"]temperature[\/pb_glossary] of the rock at that pressure. Setting\u00a0<\/span>A is a situation (called \"normal\") in the middle of a stable [pb_glossary id=\"1669\"]plate[\/pb_glossary] in which no [pb_glossary id=\"1750\"]magma[\/pb_glossary] is generated. In the other three situations, rock at a lettered location with a [pb_glossary id=\"1767\"]temperature[\/pb_glossary] at the [pb_glossary id=\"222\"]geothermal gradient[\/pb_glossary] is moved to a new P-T situation on the diagram. This shift is indicated by the arrow and its [pb_glossary id=\"1767\"]temperature[\/pb_glossary] relative to the solidus is shown by the red line. Partial melting occurs where the red line [pb_glossary id=\"1767\"]temperature[\/pb_glossary] of the rock crosses the green solidus on the diagram. Setting B is at a [pb_glossary id=\"1708\"]mid-ocean ridge[\/pb_glossary] <em>([pb_glossary id=\"223\"]<em>decompression melting<\/em>[\/pb_glossary])<\/em> where reduction of pressure carries the rock at its [pb_glossary id=\"1767\"]temperature[\/pb_glossary] across the solidus. Setting C is a [pb_glossary id=\"1716\"]hotspot[\/pb_glossary] where [pb_glossary id=\"223\"]decompression melting[\/pb_glossary] plus <em>addition of heat<\/em> carries the rock across the solidus, and setting D is a [pb_glossary id=\"1680\"]subduction[\/pb_glossary] zone where a process called <em>[pb_glossary id=\"1686\"]<em>flux melting<\/em>[\/pb_glossary]<\/em> takes place where the solidus (melting point) is actually shifted to below the [pb_glossary id=\"1767\"]temperature[\/pb_glossary] of the rock.\n\nGraphs A-D below, along with the side view of the Earth\u2019s layers in various [pb_glossary id=\"1654\"]tectonic[\/pb_glossary] settings (see figure), show how melting occurs in different situations. Graph A illustrates a normal situation, located in the middle of a stable [pb_glossary id=\"1669\"]plate[\/pb_glossary], where no melted rock can be found. The remaining three graphs illustrate rock behavior relative to shifts in the [pb_glossary id=\"222\"]geothermal gradient[\/pb_glossary] or solidus lines. [pb_glossary id=\"224\"]Partial melting[\/pb_glossary] occurs when the [pb_glossary id=\"222\"]geothermal gradient[\/pb_glossary] line crosses the solidus line. Graph B illustrates behavior of rock located at a [pb_glossary id=\"1708\"]mid-ocean ridge[\/pb_glossary], labeled X in the graph and side view. Reduced pressure shifts the geotherm to the right of the solidus, causing [pb_glossary id=\"223\"]decompression melting[\/pb_glossary]. Graph C and label Y illustrate a [pb_glossary id=\"1716\"]hotspot[\/pb_glossary] situation. [pb_glossary id=\"223\"]Decompression melting[\/pb_glossary], plus an addition of heat, shifts the geotherm across the solidus. Graph D and label Z show a [pb_glossary id=\"1680\"]subduction[\/pb_glossary] zone, where an addition of [pb_glossary id=\"1684\"]volatiles[\/pb_glossary] lowers the melting point, shifting the solidus to the left of the [pb_glossary id=\"222\"]geothermal gradient[\/pb_glossary]. B, C, and D all show different ways the Earth produces intersections of the [pb_glossary id=\"222\"]geothermal gradient[\/pb_glossary] and the solidus, which results in melting each time.\n\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"1024\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.3_P-T-diagrams-in-mantle.jpg\"><img class=\"size-large wp-image-269\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_P-T-diagrams-in-mantle-1024x585.jpg\" alt=\"Pressure-Temperature diagrams showing temperture in the mantle plotted against pressure (depth)\" width=\"1024\" height=\"585\"><\/a> Four P-T diagrams show temperature in degrees Celsius on x-axis and depth below the surface in kilometers (km) on the y-axis. The red line is the geothermal gradient and green solidus line represents at temperature and pressure regime at which melting begins. Each of the four P-T diagrams are associated a tectonic setting as shown by a side-view (cross-section) of the lithosphere and mantle.[\/caption]\n<h3>4.3.2 Decompression Melting<\/h3>\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"212\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Ocean-birth.svg_.png\"><img class=\"size-medium wp-image-2867\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ocean-birth.svg_-1.png\" alt=\"The ocean starts as a valley and then gets wider and wider.\" width=\"212\" height=\"300\"><\/a> Progression from rift to mid-ocean ridge, the divergent boundary types. Note the rising material in the center.[\/caption]\n\n[pb_glossary id=\"1750\"]Magma[\/pb_glossary] is created at [pb_glossary id=\"1708\"]mid-ocean ridges[\/pb_glossary] via <strong>[pb_glossary id=\"223\"]decompression melting[\/pb_glossary]<\/strong>. Strong [pb_glossary id=\"1655\"]convection[\/pb_glossary] currents cause the solid [pb_glossary id=\"1671\"]asthenosphere[\/pb_glossary] to slowly flow beneath the [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary]. The upper part of the [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] ([pb_glossary id=\"1658\"]crust[\/pb_glossary]) is a poor heat conductor, so the [pb_glossary id=\"1767\"]temperature[\/pb_glossary] remains about the same throughout the underlying [pb_glossary id=\"1664\"]mantle[\/pb_glossary] material. Where the [pb_glossary id=\"1655\"]convection[\/pb_glossary] currents cause [pb_glossary id=\"1664\"]mantle[\/pb_glossary] material to rise, the pressure decreases, which causes the melting point to drop. In this situation, the rock at the [pb_glossary id=\"1767\"]temperature[\/pb_glossary] of the [pb_glossary id=\"222\"]geothermal gradient[\/pb_glossary] is rising toward the surface, thus hotter rock is now shallower, at a lower pressure, and the rock, still at the [pb_glossary id=\"1767\"]temperature[\/pb_glossary] of the [pb_glossary id=\"222\"]geothermal gradient[\/pb_glossary] at its old location, shifts past the its melting point (shown as the red line crossing over the solidus or green line in example B in previous figure) and [pb_glossary id=\"224\"]partial melting[\/pb_glossary] starts. As this magma continues to rise, it cools and crystallizes to form new lithospheric [pb_glossary id=\"1658\"]crust[\/pb_glossary].\n<h3>4.3.3 Flux Melting<\/h3>\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"500\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Subduction-en.svg_.png\"><img class=\"wp-image-94\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Subduction-en.svg_-300x147.png\" alt=\"Many features are labeled on the diagram, but the main idea is the ocean plate descending below the continental\" width=\"500\" height=\"244\"><\/a> Diagram of ocean-continent subduction. Note water vapor driven out of hydrated minerals in the descending oceanic slab.[\/caption]\n\n<strong>[pb_glossary id=\"1686\"]Flux melting[\/pb_glossary]<\/strong> or <strong>[pb_glossary id=\"1686\"]fluid-induced melting[\/pb_glossary]<\/strong> occurs in island arcs and [pb_glossary id=\"1680\"]subduction[\/pb_glossary] zones when volatile gases are added to [pb_glossary id=\"1664\"]mantle[\/pb_glossary] material (see figure: graph D, label Z). Flux-melted [pb_glossary id=\"1750\"]magma[\/pb_glossary] produces many of the [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] in the circum-Pacific [pb_glossary id=\"1680\"]subduction[\/pb_glossary] zones, also known as the Ring of Fire. The [pb_glossary id=\"1680\"]subducting[\/pb_glossary] [pb_glossary id=\"1683\"]slab[\/pb_glossary] contains [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] and hydrated [pb_glossary id=\"1765\"]minerals[\/pb_glossary]. As covered in <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/2-plate-tectonics\/\">Chapter 2<\/a>, these hydrated forms are created when water ions [pb_glossary id=\"1781\"]bond[\/pb_glossary] with the crystal structure of [pb_glossary id=\"1787\"]silicate[\/pb_glossary] [pb_glossary id=\"1765\"]minerals[\/pb_glossary]. As the [pb_glossary id=\"1683\"]slab[\/pb_glossary] descends into the hot [pb_glossary id=\"1664\"]mantle[\/pb_glossary], the increased [pb_glossary id=\"1767\"]temperature[\/pb_glossary] causes the hydrated [pb_glossary id=\"1765\"]minerals[\/pb_glossary] to emit water vapor and other volatile gases, which are expelled from the [pb_glossary id=\"1683\"]slab[\/pb_glossary] like water being squeezed out of a sponge. The [pb_glossary id=\"1684\"]volatiles[\/pb_glossary] [pb_glossary id=\"1893\"]dissolve[\/pb_glossary] into the overlying asthenospheric [pb_glossary id=\"1664\"]mantle[\/pb_glossary] and decrease its melting point. In this situation the applied pressure and [pb_glossary id=\"1767\"]temperature[\/pb_glossary] have not changed, the [pb_glossary id=\"1664\"]mantle[\/pb_glossary]'s melting point has been lowered by the addition of volatile substances. The previous figure (graph D) shows the green solidus line shifting to the left of and below the red [pb_glossary id=\"222\"]geothermal gradient[\/pb_glossary] line, and melting begins. This is analogous to adding salt to an icy roadway. The salt lowers the freezing [pb_glossary id=\"1767\"]temperature[\/pb_glossary] of the solid ice so it turns into liquid water.\n<h3>4.3.4 Heat-Induced Melting<\/h3>\n[caption id=\"attachment_315\" align=\"alignright\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/06.2-15-Mt-Blaca-Migmatite-1.jpg\"><img class=\"size-medium wp-image-48\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/06.2-15-Mt-Blaca-Migmatite-1-300x225.jpg\" alt=\"Swirling bands of light and dark minerals.\" width=\"300\" height=\"225\"><\/a> Migmatite, a rock which was partially molten. (Source: Peter Davis)[\/caption]\n\nHeat-induced melting, transforming solid [pb_glossary id=\"1664\"]mantle[\/pb_glossary] into liquid [pb_glossary id=\"1750\"]magma[\/pb_glossary] by simply applying heat, is the least common process for generating [pb_glossary id=\"1750\"]magma[\/pb_glossary] (see figure: graph C, label Y). Heat-induced melting occurs at a [pb_glossary id=\"1664\"]mantle[\/pb_glossary] plumes or [pb_glossary id=\"1716\"]hotspots[\/pb_glossary]. The rock surrounding the plume is exposed to higher temperatures, the [pb_glossary id=\"222\"]geothermal gradient[\/pb_glossary] crosses to the right of the green solidus line, and the rock begins to melt. The [pb_glossary id=\"1717\"]mantle plume[\/pb_glossary] includes rising [pb_glossary id=\"1664\"]mantle[\/pb_glossary] material, meaning some [pb_glossary id=\"223\"]decompression melting[\/pb_glossary] is occurring as well. A small amount of [pb_glossary id=\"1750\"]magma[\/pb_glossary] is also generated by intense [pb_glossary id=\"2024\"]regional metamorphism[\/pb_glossary] (see <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/6-metamorphic-rocks\/\">Chapter 6<\/a>). This [pb_glossary id=\"1750\"]magma[\/pb_glossary] becomes a hybrid [pb_glossary id=\"1992\"]metamorphic[\/pb_glossary]-[pb_glossary id=\"1753\"]igneous rock[\/pb_glossary] called [pb_glossary id=\"2011\"]migmatite[\/pb_glossary].\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n[h5p id=\"26\"]\n\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"150\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/4.3-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-271\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.3-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a> If you are using the printed version of this OER, access the quiz for section 4.3 via this QR Code.[\/caption]\n<h2><b><a id=\"4-4PartialMelting\" href=\"\"><\/a><\/b><strong>4.4<\/strong>\u00a0<b>Partial Melting and Crystallization<\/b><\/h2>\nEven though all [pb_glossary id=\"1750\"]magmas[\/pb_glossary] originate from similar [pb_glossary id=\"1664\"]mantle[\/pb_glossary] rocks, and start out as similar [pb_glossary id=\"1750\"]magma[\/pb_glossary], other things, like\u00a0[pb_glossary id=\"224\"]partial melting[\/pb_glossary] and [pb_glossary id=\"1752\"]crystallization[\/pb_glossary] processes like [pb_glossary id=\"226\"]magmatic differentiation[\/pb_glossary], can change the chemistry of the [pb_glossary id=\"1750\"]magma[\/pb_glossary]. This explains the wide variety of resulting [pb_glossary id=\"1753\"]igneous[\/pb_glossary] rocks that are found all over Earth.\n<h3>4.4.1 Partial Melting<\/h3>\nBecause the [pb_glossary id=\"1664\"]mantle[\/pb_glossary] is [pb_glossary id=\"1909\"]composed[\/pb_glossary] of many different minerals, it does not melt uniformly. As [pb_glossary id=\"1765\"]minerals[\/pb_glossary] with lower melting points turn into liquid [pb_glossary id=\"1750\"]magma[\/pb_glossary], those with higher melting points remain as solid crystals. This is known as [pb_glossary id=\"224\"]partial melting[\/pb_glossary]. As [pb_glossary id=\"1750\"]magma[\/pb_glossary] slowly rises and cools into solid rock, it undergoes physical and chemical changes in a process called [pb_glossary id=\"226\"]magmatic differentiation[\/pb_glossary].\n\nAccording to [pb_glossary id=\"221\"]Bowen\u2019s Reaction Series[\/pb_glossary] (<a href=\"#4-2BowensReaction\">Section 4.2<\/a>), each [pb_glossary id=\"1765\"]mineral[\/pb_glossary] has a unique melting and [pb_glossary id=\"1752\"]crystallization[\/pb_glossary] [pb_glossary id=\"1767\"]temperature[\/pb_glossary]. Since most rocks are made of many different [pb_glossary id=\"1765\"]minerals[\/pb_glossary], when they start to melt, some [pb_glossary id=\"1765\"]minerals[\/pb_glossary] begin melting sooner than others. This is known as [pb_glossary id=\"224\"]partial melting[\/pb_glossary], and creates [pb_glossary id=\"1750\"]magma[\/pb_glossary] with a different [pb_glossary id=\"1909\"]composition[\/pb_glossary] than the original [pb_glossary id=\"1664\"]mantle[\/pb_glossary] material.\n\nThe most important example occurs as [pb_glossary id=\"1750\"]magma[\/pb_glossary] is generated from [pb_glossary id=\"1664\"]mantle[\/pb_glossary] rocks (as discussed in <a href=\"#4-3MagmaGeneration\">Section 4.3<\/a>). The chemistry of [pb_glossary id=\"1664\"]mantle[\/pb_glossary] rock ([pb_glossary id=\"1666\"]peridotite[\/pb_glossary]) is [pb_glossary id=\"1009\"]ultramafic[\/pb_glossary], low in [pb_glossary id=\"1787\"]silicates[\/pb_glossary] and high in iron and magnesium. When [pb_glossary id=\"1666\"]peridotite[\/pb_glossary] begins to melt, the silica-rich portions melt first due to their lower melting point. If this continues, the [pb_glossary id=\"1750\"]magma[\/pb_glossary] becomes increasingly silica-rich, turning [pb_glossary id=\"1009\"]ultramafic[\/pb_glossary] [pb_glossary id=\"1664\"]mantle[\/pb_glossary] into [pb_glossary id=\"1008\"]mafic[\/pb_glossary] [pb_glossary id=\"1750\"]magma[\/pb_glossary], and [pb_glossary id=\"1008\"]mafic[\/pb_glossary] [pb_glossary id=\"1664\"]mantle[\/pb_glossary] into [pb_glossary id=\"1007\"]intermediate[\/pb_glossary] [pb_glossary id=\"1750\"]magma[\/pb_glossary]. The [pb_glossary id=\"1750\"]magma[\/pb_glossary] rises to the surface because it is more buoyant than the [pb_glossary id=\"1664\"]mantle[\/pb_glossary].\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"500\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/CratonGeolProv.jpg\"><img class=\"wp-image-92\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/CratonGeolProv-300x159.jpg\" alt=\"The legend shows shields, platforms, orogens, basins, large igneous provinces, and extended crust.\" width=\"500\" height=\"265\"><\/a> Geologic provinces with the Shield (orange) and Platform (pink) comprising the Craton, the stable interior of continents.[\/caption]\n\n[pb_glossary id=\"224\"]Partial melting[\/pb_glossary] also occurs as existing crustal rocks melt in the presence of heat from [pb_glossary id=\"1750\"]magmas[\/pb_glossary]. In this process, existing rocks melt, allowing the [pb_glossary id=\"1750\"]magma[\/pb_glossary] formed to be more [pb_glossary id=\"1006\"]felsic[\/pb_glossary] and less [pb_glossary id=\"1008\"]mafic[\/pb_glossary] than the pre-existing rock. Early in the Earth\u2019s history when the continents were forming, silica-rich [pb_glossary id=\"1750\"]magmas[\/pb_glossary] formed and rose to the surface and solidified into granitic continents. In the figure, the old granitic cores of the continents, called <strong>[pb_glossary id=\"1259\"]shields[\/pb_glossary]<\/strong>, are shown in orange.\n<h3>4.4.2 Crystallization and Magmatic Differentiation<\/h3>\nLiquid [pb_glossary id=\"1750\"]magma[\/pb_glossary] is less dense than the surrounding solid rock, so it rises through the [pb_glossary id=\"1664\"]mantle[\/pb_glossary] and [pb_glossary id=\"1658\"]crust[\/pb_glossary]. As [pb_glossary id=\"1750\"]magma[\/pb_glossary] begins to cool and crystallize, a process known as <strong>[pb_glossary id=\"226\"]magmatic differentiation[\/pb_glossary]<\/strong> changes the chemistry of the resultant rock towards a more [pb_glossary id=\"1006\"]felsic[\/pb_glossary] [pb_glossary id=\"1909\"]composition[\/pb_glossary]. This happens via two main methods: [pb_glossary id=\"225\"]assimilation[\/pb_glossary] and [pb_glossary id=\"227\"]fractionation[\/pb_glossary].\n\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.16_Xenoliths_Little_Cottonwood_Canyon.jpg\"><img class=\"size-medium wp-image-272\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.16_Xenoliths_Little_Cottonwood_Canyon-300x211.jpg\" alt=\"Xenoliths are bits of surrounding counjtry rock incorporated in intrusive magma and solidified within it.\" width=\"300\" height=\"211\"><\/a> Xenoliths in Little Cottonwood Stock, Utah[\/caption]\n\nDuring <strong>[pb_glossary id=\"225\"]assimilation[\/pb_glossary]<\/strong>, pieces of [pb_glossary id=\"1023\"]country rock[\/pb_glossary] with a different, often more [pb_glossary id=\"1006\"]felsic[\/pb_glossary], [pb_glossary id=\"1909\"]composition[\/pb_glossary] are added to the [pb_glossary id=\"1750\"]magma[\/pb_glossary]. These solid pieces may melt, which changes the composition of the original [pb_glossary id=\"1750\"]magma[\/pb_glossary]. At times, the solid fragments may remain intact within the cooling [pb_glossary id=\"1750\"]magma[\/pb_glossary] and only partially melt. The unmelted country rocks within an [pb_glossary id=\"1753\"]igneous rock[\/pb_glossary] mass are called <strong>[pb_glossary id=\"1665\"]xenoliths[\/pb_glossary]<\/strong>.\n\n[pb_glossary id=\"1665\"]Xenoliths[\/pb_glossary] are also common in the processes of [pb_glossary id=\"1750\"]magma[\/pb_glossary] mixing and rejuvenation, two other processes that can contribute to [pb_glossary id=\"226\"]magmatic differentiation[\/pb_glossary]. [pb_glossary id=\"1750\"]Magma[\/pb_glossary] mixing occurs when two different [pb_glossary id=\"1750\"]magmas[\/pb_glossary] come into contact and mix, though at times, the [pb_glossary id=\"1750\"]magmas[\/pb_glossary] can remain heterogeneous and create [pb_glossary id=\"1665\"]xenoliths[\/pb_glossary], [pb_glossary id=\"1021\"]dikes[\/pb_glossary], and other features. Magmatic rejuvenation happens when a cooled and crystallized body of rock is remelted and pieces of the original rock may remain as [pb_glossary id=\"1665\"]xenoliths[\/pb_glossary].\n\nMuch of the [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] is [pb_glossary id=\"1006\"]felsic[\/pb_glossary] (i.e. granitic), and normally more buoyant than the underlying [pb_glossary id=\"1008\"]mafic[\/pb_glossary]\/[pb_glossary id=\"1009\"]ultramafic[\/pb_glossary] [pb_glossary id=\"1664\"]mantle[\/pb_glossary]. When [pb_glossary id=\"1008\"]mafic[\/pb_glossary] [pb_glossary id=\"1750\"]magma[\/pb_glossary] rises through thick [pb_glossary id=\"1653\"]continental crust[\/pb_glossary], it does so slowly, more slowly than when [pb_glossary id=\"1750\"]magma[\/pb_glossary] rises through [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1669\"]plates[\/pb_glossary]. This gives the [pb_glossary id=\"1750\"]magma[\/pb_glossary] lots of time to react with the surrounding [pb_glossary id=\"1023\"]country rock[\/pb_glossary]. The [pb_glossary id=\"1008\"]mafic[\/pb_glossary] [pb_glossary id=\"1750\"]magma[\/pb_glossary] tends to [pb_glossary id=\"225\"]assimilate[\/pb_glossary] [pb_glossary id=\"1006\"]felsic[\/pb_glossary] rock, becoming more silica-rich as it migrates through the [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] and changing into [pb_glossary id=\"1007\"]intermediate[\/pb_glossary] or [pb_glossary id=\"1006\"]felsic[\/pb_glossary] [pb_glossary id=\"1750\"]magma[\/pb_glossary] by the time it reaches the surface. This is why [pb_glossary id=\"1006\"]felsic[\/pb_glossary] [pb_glossary id=\"1750\"]magmas[\/pb_glossary] are much more common within continents.\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.3_Magmatism_and_volcanism_EN.png\"><img class=\"size-medium wp-image-273\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_Magmatism_and_volcanism_EN-300x235.png\" alt=\"Shows large pools of magma rising from the source in the mantle, up into the crust under a volcano.\" width=\"300\" height=\"235\"><\/a> Rising magma diapirs in mantle and crust. Fractional crystallization assimilation occurs to the diapirs in the crust.[\/caption]\n\n<strong>[pb_glossary id=\"227\"]Fractionation[\/pb_glossary]<\/strong> or <strong>fractional [pb_glossary id=\"1752\"]crystallization[\/pb_glossary]<\/strong> is another process that increase [pb_glossary id=\"1750\"]magma[\/pb_glossary] silica content, making it more [pb_glossary id=\"1006\"]felsic[\/pb_glossary]. As the [pb_glossary id=\"1767\"]temperature[\/pb_glossary] drops within a [pb_glossary id=\"1750\"]magma[\/pb_glossary] [pb_glossary id=\"1018\"]diapir[\/pb_glossary] rising through the [pb_glossary id=\"1658\"]crust[\/pb_glossary], some [pb_glossary id=\"1765\"]minerals[\/pb_glossary] will crystallize and settle to the bottom of the [pb_glossary id=\"232\"]magma\u00a0chamber[\/pb_glossary], leaving the remaining melt depleted of those ions. [pb_glossary id=\"1789\"]Olivine[\/pb_glossary] is a [pb_glossary id=\"1008\"]mafic[\/pb_glossary] [pb_glossary id=\"1765\"]mineral[\/pb_glossary] at the top of the [pb_glossary id=\"221\"]Bowen\u2019s Reaction series[\/pb_glossary] with a high melting point and a smaller percentage of silica verses other common [pb_glossary id=\"1753\"]igneous[\/pb_glossary] [pb_glossary id=\"1765\"]minerals[\/pb_glossary]. When [pb_glossary id=\"1009\"]ultramafic[\/pb_glossary] [pb_glossary id=\"1750\"]magma[\/pb_glossary] cools, the [pb_glossary id=\"1789\"]olivine[\/pb_glossary] crystallizes first and settles to the bottom of the [pb_glossary id=\"232\"]magma chamber[\/pb_glossary] (see figure). This means the remaining melt becomes more silica-rich and [pb_glossary id=\"1006\"]felsic[\/pb_glossary]. As the [pb_glossary id=\"1008\"]mafic[\/pb_glossary] [pb_glossary id=\"1750\"]magma[\/pb_glossary] further cools, the next [pb_glossary id=\"1765\"]minerals[\/pb_glossary] on [pb_glossary id=\"221\"]Bowen's Reaction Series[\/pb_glossary] ([pb_glossary id=\"968\"]plagioclase[\/pb_glossary] and [pb_glossary id=\"1790\"]pyroxene[\/pb_glossary]) crystallize next, removing even more low-silica components from the [pb_glossary id=\"1750\"]magma[\/pb_glossary], making it even more [pb_glossary id=\"1006\"]felsic[\/pb_glossary]. This crystal [pb_glossary id=\"227\"]fractionation[\/pb_glossary] can occur in [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary], but the [pb_glossary id=\"2038\"]formation[\/pb_glossary] of more differentiated, highly evolved [pb_glossary id=\"1006\"]felsic[\/pb_glossary] [pb_glossary id=\"1750\"]magmas[\/pb_glossary] is largely confined to [pb_glossary id=\"1653\"]continental[\/pb_glossary] regions where the longer time to the surface allows more [pb_glossary id=\"227\"]fractionation[\/pb_glossary] to occur.\n\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"750\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.3_Fractional_crystallization.png\"><img class=\"size-full wp-image-274\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_Fractional_crystallization.png\" alt=\"Complicated diagram showing minerals settling out in the magma chamber and thus making the remaining liquid magma (the melt) more silica-rich in composition.\" width=\"750\" height=\"320\"><\/a> Schematic diagram illustrating fractional crystallization. If magma at composition A is ultramafic, as the magma cools it changes composition as different minerals crystallize from the melt and settle to the bottom of the magma chamber. In section 1, olivine crystallizes; section 2: olivine and pyroxene crystallize; section 3: pyroxene and plagioclase crystallize; and section 4: plagioclase crystallizes. The crystals are separated from the melt and the remaining magma (composition B) is more silica-rich. (Source: Woudloper)[\/caption]\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n[h5p id=\"27\"]\n\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"150\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/4.4-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-275\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.4-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a> If you are using the printed version of this OER, access the quiz for section 4.4 via this QR Code.[\/caption]\n<h2><span style=\"font-weight: 400\"><a id=\"4-5Volcanism\" href=\"\"><\/a>4.5 Volcanism<\/span><\/h2>\nWhen [pb_glossary id=\"1750\"]magma[\/pb_glossary] emerges onto the Earth\u2019s surface, the molten rock is called [pb_glossary id=\"1751\"]lava[\/pb_glossary]. A <strong>[pb_glossary id=\"228\"]volcano[\/pb_glossary]<\/strong> is a type of land [pb_glossary id=\"2038\"]formation[\/pb_glossary] created when [pb_glossary id=\"1751\"]lava[\/pb_glossary] solidifies into rock. [pb_glossary id=\"228\"]Volcanoes[\/pb_glossary] have been an important part of human society for centuries, though their understanding has greatly increased as our understanding of [pb_glossary id=\"1654\"]plate tectonics[\/pb_glossary] has made them less mysterious.\u00a0<span style=\"font-weight: 400\">This section\u00a0describes [pb_glossary id=\"228\"]volcano[\/pb_glossary] location, type, hazards, and monitoring.<\/span>\n<h3><b>4.5.1. Distribution and Tectonics<\/b><\/h3>\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"775\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Main-types-of-plate-boundaries.gif\"><img class=\"size-full wp-image-276\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Main-types-of-plate-boundaries.gif\" alt=\"Diagram showing how volcanoes are associated with plate boundaries\" width=\"775\" height=\"429\"><\/a> Association of volcanoes with plate boundaries. (Source: USGS)[\/caption]\n\nMost [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] are [pb_glossary id=\"229\"]interplate[\/pb_glossary] [pb_glossary id=\"228\"]volcanoes[\/pb_glossary]. [pb_glossary id=\"229\"]Interplate[\/pb_glossary] [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] are located at active [pb_glossary id=\"1669\"]plate[\/pb_glossary] boundaries created by [pb_glossary id=\"228\"]volcanism[\/pb_glossary] at [pb_glossary id=\"1708\"]mid-ocean ridges[\/pb_glossary], [pb_glossary id=\"1680\"]subduction[\/pb_glossary] zones, and [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1702\"]rifts[\/pb_glossary]. The prefix \"<em>inter-\"<\/em> means between. Some volcanoes are [pb_glossary id=\"230\"]intraplate[\/pb_glossary] [pb_glossary id=\"228\"]volcanoes[\/pb_glossary]. The prefix \"<em>intra-\"<\/em>\u00a0means within, and intraplate volcanoes are located within [pb_glossary id=\"1654\"]tectonic[\/pb_glossary] [pb_glossary id=\"1669\"]plates[\/pb_glossary], far removed from plate boundaries. Many [pb_glossary id=\"230\"]intraplate[\/pb_glossary] [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] are formed by [pb_glossary id=\"1716\"]hotspots[\/pb_glossary].\n<h4><span style=\"font-weight: 400\">Volcanoes at Mid-Ocean Ridges<\/span><\/h4>\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Spreading_ridges_volcanoes_map-en.svg_.png\"><img class=\"size-medium wp-image-277\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Spreading_ridges_volcanoes_map-en.svg_-300x151.png\" alt=\"Map showing spreading ridges throughout the world. These ridges are all over the world.\" width=\"300\" height=\"151\"><\/a> Map of spreading ridges throughout the world.[\/caption]\n\nMost [pb_glossary id=\"228\"]volcanism[\/pb_glossary] on Earth occurs on the [pb_glossary id=\"1963\"]ocean floor[\/pb_glossary] along [pb_glossary id=\"1708\"]mid-ocean ridges[\/pb_glossary], a type of [pb_glossary id=\"1677\"]divergent[\/pb_glossary] [pb_glossary id=\"1670\"]plate boundary[\/pb_glossary] (see <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/2-plate-tectonics\/\" target=\"_blank\" rel=\"noopener\">Chapter 2<\/a>). These [pb_glossary id=\"229\"]interplate[\/pb_glossary] [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] are also the least observed and famous, since most of them are located under 3,000-4,500 m (10,000-15,000 ft) of ocean and the eruptions are slow, gentle, and oozing. One exception is the [pb_glossary id=\"229\"]interplate[\/pb_glossary] [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] of Iceland. The diverging and thinning [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1654\"]plates[\/pb_glossary] allow hot [pb_glossary id=\"1664\"]mantle[\/pb_glossary] rock to rise, releasing pressure and causing [pb_glossary id=\"223\"]decompression melting[\/pb_glossary]. [pb_glossary id=\"1009\"]Ultramafic[\/pb_glossary] [pb_glossary id=\"1664\"]mantle[\/pb_glossary] rock, consisting largely of [pb_glossary id=\"1666\"]peridotite[\/pb_glossary], partially melts and generates [pb_glossary id=\"1750\"]magma[\/pb_glossary] that is basaltic. Because of this, almost all [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] on the [pb_glossary id=\"1963\"]ocean floor[\/pb_glossary] are basaltic. In fact, most [pb_glossary id=\"1963\"]oceanic[\/pb_glossary] [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] is basaltic near the surface, with [pb_glossary id=\"992\"]phaneritic[\/pb_glossary] [pb_glossary id=\"1016\"]gabbro[\/pb_glossary] and [pb_glossary id=\"1009\"]ultramafic[\/pb_glossary] [pb_glossary id=\"1666\"]peridotite[\/pb_glossary] underneath.\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Pillow-basalt.jpg\"><img class=\"size-medium wp-image-278\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pillow-basalt-300x180.jpg\" alt=\"Pillow basalt on sea floor near Hawaii.\" width=\"300\" height=\"180\"><\/a> Pillow basalt on sea floor near Hawaii.[\/caption]\n\nWhen basaltic [pb_glossary id=\"1751\"]lava[\/pb_glossary] erupts underwater it emerges in small explosions and\/or forms pillow-shaped structures called pillow basalts. These seafloor eruptions enable entire underwater ecosystems to thrive in the deep ocean around [pb_glossary id=\"1708\"]mid-ocean ridges[\/pb_glossary]. This ecosystem exists around tall vents emitting black, hot [pb_glossary id=\"1765\"]mineral[\/pb_glossary]-rich water called deep-sea [pb_glossary id=\"1999\"]hydrothermal[\/pb_glossary] vents, also known as [pb_glossary id=\"2000\"]black smokers[\/pb_glossary].\n\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"133\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/BlackSmoker.jpg\"><img class=\"wp-image-119\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/BlackSmoker-233x300.jpg\" alt=\"There is a large build up of minerals around the vent\" width=\"133\" height=\"171\"><\/a> Black smoker hydrothermal vent with a colony of giant (6'+) tube worms.[\/caption]\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"500\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.16_Distribution_of_hydrothermal_vent_fields.jpg\"><img class=\"wp-image-279\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.16_Distribution_of_hydrothermal_vent_fields-300x178.jpg\" alt=\"Map showing worldwide distgrbution of hydrothermal vent fields;\" width=\"500\" height=\"297\"><\/a> Distribution of hydrothermal vent fields[\/caption]\n\nWithout sunlight to support photosynthesis, these organisms instead utilize a process called <strong>[pb_glossary id=\"231\"]chemosynthesis[\/pb_glossary]<\/strong>. Certain bacteria are able to turn hydrogen [pb_glossary id=\"973\"]sulfide[\/pb_glossary] (H<sub>2<\/sub>S), a gas that smells like rotten eggs, into life-supporting nutrients and water. Larger organisms may eat these bacteria or absorb nutrients and water produced by bacteria living symbiotically inside their bodies. The three videos show some of the ecosystems found around deep-sea [pb_glossary id=\"1999\"]hydrothermal[\/pb_glossary] vents.\n\n[embed]https:\/\/youtu.be\/a5aQ4W9GbpU[\/embed]\n\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"150\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Alvin-Submarine-Part-1-YouTube-QR-Code.png\"><img class=\"size-thumbnail wp-image-280\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-1-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a> If you are using the printed version of this OER, access this YouTube video via this QR Code.[\/caption]\n\n[embed]https:\/\/youtu.be\/dXOQFnU-49k[\/embed]\n\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"150\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Alvin-Submarine-Part-2-YouTube-QR-Code.png\"><img class=\"size-thumbnail wp-image-281\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-2-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a> If you are using the printed version of this OER, access this YouTube video via this QR Code.[\/caption]\n\n[embed]https:\/\/youtu.be\/eUzz_ilsFa0[\/embed]\n\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"150\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Alvin-Submarine-Part-3-YouTube-QR-Code.png\"><img class=\"size-thumbnail wp-image-282\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-3-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a> If you are using the printed version of this OER, access this YouTube video via this QR Code.[\/caption]\n<h4><span style=\"font-weight: 400\">Volcanoes at Subduction Zones<\/span><\/h4>\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"500\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Map_plate_tectonics_world.gif\"><img class=\"wp-image-283\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Map_plate_tectonics_world.gif\" alt=\"Map showing volcanoes follow the edges of tectonic plates.\" width=\"500\" height=\"314\"><\/a> Distribution of volcanoes on the planet. Click here for an <a href=\"https:\/\/maps.ngdc.noaa.gov\/viewers\/hazards\/?layers=3\" target=\"_blank\" rel=\"noopener\">interactive map<\/a>\u00a0of volcano distributions.[\/caption]\n\nThe second most commonly found location for [pb_glossary id=\"228\"]volcanism[\/pb_glossary] is adjacent to [pb_glossary id=\"1680\"]subduction[\/pb_glossary] zones, a type of [pb_glossary id=\"1678\"]convergent[\/pb_glossary] [pb_glossary id=\"1670\"]plate boundary[\/pb_glossary] (see <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/2-plate-tectonics\/\" target=\"_blank\" rel=\"noopener\">Chapter 2<\/a>). The process of [pb_glossary id=\"1680\"]subduction[\/pb_glossary] expels water from hydrated [pb_glossary id=\"1765\"]minerals[\/pb_glossary] in the descending [pb_glossary id=\"1683\"]slab[\/pb_glossary], which causes [pb_glossary id=\"1686\"]flux melting[\/pb_glossary] in the overlying [pb_glossary id=\"1664\"]mantle[\/pb_glossary] rock. Because [pb_glossary id=\"1680\"]subduction[\/pb_glossary] [pb_glossary id=\"228\"]volcanism[\/pb_glossary] occurs in a [pb_glossary id=\"1695\"]volcanic arc[\/pb_glossary], the thickened [pb_glossary id=\"1658\"]crust[\/pb_glossary] promotes [pb_glossary id=\"224\"]partial melting[\/pb_glossary] and [pb_glossary id=\"1750\"]magma[\/pb_glossary] differentiation. These evolve the [pb_glossary id=\"1008\"]mafic[\/pb_glossary] [pb_glossary id=\"1750\"]magma[\/pb_glossary] from the mantle into more silica-rich [pb_glossary id=\"1750\"]magma[\/pb_glossary]. The Ring of Fire surrounding the Pacific Ocean, for example, is dominated by [pb_glossary id=\"1680\"]subduction[\/pb_glossary]-generated eruptions of mostly silica-rich [pb_glossary id=\"1751\"]lava[\/pb_glossary]; the [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] and [pb_glossary id=\"1017\"]plutons[\/pb_glossary] consist largely of [pb_glossary id=\"1007\"]intermediate[\/pb_glossary]-to-[pb_glossary id=\"1006\"]felsic[\/pb_glossary] rock such as [pb_glossary id=\"1012\"]andesite[\/pb_glossary], [pb_glossary id=\"1010\"]rhyolite[\/pb_glossary], [pb_glossary id=\"998\"]pumice[\/pb_glossary], and [pb_glossary id=\"1005\"]tuff[\/pb_glossary].\n<h4><span style=\"font-weight: 400\">Volcanoes at Continental Rifts<\/span><\/h4>\n[caption id=\"attachment_315\" align=\"alignright\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Black_Rock_Desert_volcanic_field.jpg\"><img class=\"size-medium wp-image-284\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Black_Rock_Desert_volcanic_field-300x199.jpg\" alt=\"A barren landscape of lava flows in central Utah.\" width=\"300\" height=\"199\"><\/a> Basaltic cinder cones of the Black Rock Desert near Beaver, Utah.[\/caption]\n\nSome [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] are created at [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1702\"]rifts[\/pb_glossary], where crustal thinning is caused by diverging lithospheric [pb_glossary id=\"1669\"]plates[\/pb_glossary], such as the East African [pb_glossary id=\"1702\"]Rift[\/pb_glossary] [pb_glossary id=\"508\"]Basin[\/pb_glossary] in Africa. [pb_glossary id=\"228\"]Volcanism[\/pb_glossary] caused by crustal thinning without [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1702\"]rifting[\/pb_glossary] is found in the [pb_glossary id=\"1514\"]Basin and Range[\/pb_glossary] Province in North America. In this location, [pb_glossary id=\"228\"]volcanic[\/pb_glossary] activity is produced by rising [pb_glossary id=\"1750\"]magma[\/pb_glossary] that stretches the overlying [pb_glossary id=\"1658\"]crust[\/pb_glossary] (see figure). Lower [pb_glossary id=\"1658\"]crust[\/pb_glossary] or upper [pb_glossary id=\"1664\"]mantle[\/pb_glossary] material rises through the thinned [pb_glossary id=\"1658\"]crust[\/pb_glossary], releases pressure, and undergoes decompression-induced [pb_glossary id=\"224\"]partial melting[\/pb_glossary]. This [pb_glossary id=\"1750\"]magma[\/pb_glossary] is less dense than the surrounding rock and continues to rise through the [pb_glossary id=\"1658\"]crust[\/pb_glossary] to the surface, erupting as basaltic [pb_glossary id=\"1751\"]lava[\/pb_glossary]. These eruptions usually result in [pb_glossary id=\"244\"]flood basalts[\/pb_glossary], [pb_glossary id=\"242\"]cinder[\/pb_glossary] cones, and basaltic [pb_glossary id=\"1751\"]lava[\/pb_glossary] flows (see video). Relatively young [pb_glossary id=\"242\"]cinder[\/pb_glossary] cones of basaltic [pb_glossary id=\"1751\"]lava[\/pb_glossary] can be found in south-central Utah, in the Black Rock Desert [pb_glossary id=\"228\"]Volcanic[\/pb_glossary] Field, which is part of the zone of [pb_glossary id=\"1514\"]Basin and Range[\/pb_glossary] crustal [pb_glossary id=\"492\"]extension[\/pb_glossary]. These Utah [pb_glossary id=\"242\"]cinder[\/pb_glossary] cones and [pb_glossary id=\"1751\"]lava[\/pb_glossary] flows started erupting around 6 million years ago, with the last eruption occurring 720 years ago.\n\n[embed]https:\/\/youtu.be\/4VgMe-JXOAM[\/embed]\n\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"150\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Volcanic-Processes-YouTube-QR-Code.png\"><img class=\"size-thumbnail wp-image-285\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcanic-Processes-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a> If you are using the printed version of this OER, access this YouTube video via this QR Code.[\/caption]\n<h4><span style=\"font-weight: 400\">Hotspots<\/span><\/h4>\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"193\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Hotspotgeology-1.svg_.png\"><img class=\"size-medium wp-image-129\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hotspotgeology-1.svg_-193x300.png\" alt=\"The plate is moving to the left, the magma stays in the center am makes a chain of volcanoes.\" width=\"193\" height=\"300\"><\/a> Diagram showing a non-moving source of magma (mantle plume) and a moving overriding plate.[\/caption]\n\n[pb_glossary id=\"1716\"]Hotspots[\/pb_glossary] are the main source of [pb_glossary id=\"230\"]intraplate[\/pb_glossary] [pb_glossary id=\"228\"]volcanism[\/pb_glossary]. <strong>[pb_glossary id=\"1716\"]Hotspots[\/pb_glossary]<\/strong> occur when lithospheric [pb_glossary id=\"1669\"]plates[\/pb_glossary] glide over a hot [pb_glossary id=\"1717\"]mantle plume[\/pb_glossary], an ascending column of solid heated rock originating from deep within the [pb_glossary id=\"1664\"]mantle[\/pb_glossary]. The [pb_glossary id=\"1717\"]mantle plume[\/pb_glossary] generates melts as material rises, with the [pb_glossary id=\"1750\"]magma[\/pb_glossary] rising even more. When the ascending [pb_glossary id=\"1750\"]magma[\/pb_glossary] reaches the lithospheric crust, it spreads out into a mushroom-shaped head that is tens to hundreds of kilometers across.\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/YellowstoneHotspot.jpg\"><img class=\"size-medium wp-image-133\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/YellowstoneHotspot-300x206.jpg\" alt=\"The hotspot started near the Idaho-Oregon-Nevada boarder, then moved toward its present location neat the Wyoming-Idaho-Montana boarder.\" width=\"300\" height=\"206\"><\/a> The track of the Yellowstone hotspot, which shows the age of different eruptions in millions of years ago.[\/caption]\n\nSince most [pb_glossary id=\"1664\"]mantle[\/pb_glossary] plumes are located beneath the [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary], the early stages of [pb_glossary id=\"230\"]intraplate[\/pb_glossary] [pb_glossary id=\"228\"]volcanism[\/pb_glossary] typically take place underwater. Over time, basaltic [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] may build up from the sea floor into islands, such as the Hawaiian Islands. Where a [pb_glossary id=\"1716\"]hotspot[\/pb_glossary] is found under a [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary], contact with the hot [pb_glossary id=\"1008\"]mafic[\/pb_glossary] magma may cause the overlying [pb_glossary id=\"1006\"]felsic[\/pb_glossary] rock to melt and mix with the mafic material below, forming [pb_glossary id=\"1007\"]intermediate[\/pb_glossary] [pb_glossary id=\"1750\"]magma[\/pb_glossary]. Or the [pb_glossary id=\"1006\"]felsic[\/pb_glossary] [pb_glossary id=\"1750\"]magma[\/pb_glossary] may continue to rise, and cool into a granitic [pb_glossary id=\"1020\"]batholith[\/pb_glossary] or erupt as a [pb_glossary id=\"1006\"]felsic[\/pb_glossary] [pb_glossary id=\"228\"]volcano[\/pb_glossary]. The Yellowstone [pb_glossary id=\"235\"]caldera[\/pb_glossary] is an example of [pb_glossary id=\"1716\"]hotspot[\/pb_glossary] [pb_glossary id=\"228\"]volcanism[\/pb_glossary] that resulted in an explosive eruption.\n\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"296\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Hawaii-Emperor_engl.png\"><img class=\"size-medium wp-image-131\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hawaii-Emperor_engl-296x300.png\" alt=\"There are a series of island and seamounts in the Pacific Ocean, with a bend in the middle.\" width=\"296\" height=\"300\"><\/a> The Hawaii-Emperor seamount and island chain.[\/caption]\n\nA zone of actively erupting [pb_glossary id=\"228\"]volcanism[\/pb_glossary] connected to a chain of [pb_glossary id=\"755\"]extinct[\/pb_glossary] [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] indicates [pb_glossary id=\"230\"]intraplate[\/pb_glossary] [pb_glossary id=\"228\"]volcanism[\/pb_glossary] located over a [pb_glossary id=\"1716\"]hotspot[\/pb_glossary]. These [pb_glossary id=\"228\"]volcanic[\/pb_glossary] chains are created by the overriding [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] slowly moving over a [pb_glossary id=\"1716\"]hotspot[\/pb_glossary] [pb_glossary id=\"1717\"]mantle plume[\/pb_glossary]. These chains are seen on the seafloor and continents and include [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] that have been inactive for millions of years. The Hawaiian Islands on the Pacific [pb_glossary id=\"1659\"]Oceanic[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] are the active end of a long [pb_glossary id=\"228\"]volcanic[\/pb_glossary] chain that extends from the northwest Pacific Ocean to the Emperor [pb_glossary id=\"1977\"]Seamounts[\/pb_glossary], all the way to the to the [pb_glossary id=\"1680\"]subduction[\/pb_glossary] zone beneath the Kamchatka Peninsula. The overriding North American [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] moved across a [pb_glossary id=\"1717\"]mantle plume[\/pb_glossary] [pb_glossary id=\"1716\"]hotspot[\/pb_glossary] for several million years, creating a chain of [pb_glossary id=\"228\"]volcanic[\/pb_glossary] calderas that extends from Southwestern Idaho to the presently active Yellowstone [pb_glossary id=\"235\"]caldera[\/pb_glossary] in Wyoming.\n\n<span style=\"font-weight: 400\">Two three<\/span><span style=\"font-weight: 400\">-minute videos (below)<\/span><span style=\"font-weight: 400\"> illustrates [pb_glossary id=\"1716\"]hotspot[\/pb_glossary] [pb_glossary id=\"228\"]volcanoes[\/pb_glossary].<\/span>\n\n[embed]https:\/\/youtu.be\/AhSaE0omw9o[\/embed]\n\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"150\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/What-is-a-Volcanic-Hotspot-YouTube-QR-Code.png\"><img class=\"size-thumbnail wp-image-286\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/What-is-a-Volcanic-Hotspot-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a> If you are using the printed version of this OER, access this YouTube video via this QR Code.[\/caption]\n\n[embed]https:\/\/youtu.be\/t5go-78gCJU[\/embed]\n\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"150\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Life-of-Hotspot-Volcanic-Island-YouTube-QR-Code.png\"><img class=\"size-thumbnail wp-image-287\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Life-of-Hotspot-Volcanic-Island-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a> If you are using the printed version of this OER, access this YouTube video via this QR Code.[\/caption]\n<h3><b>4.5.2 Volcano Features and Types<\/b><\/h3>\n<span style=\"font-weight: 400\">There are several different types of [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] based on their shape, eruption style, magmatic [pb_glossary id=\"1909\"]composition[\/pb_glossary], and other aspects. <\/span>\n\n<span style=\"font-weight: 400\">[h5p id=\"28\"] <\/span>\n\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"150\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/4.5-Overview-of-volcanic-features-and-landforms-QR-Code.png\"><img class=\"size-thumbnail wp-image-288\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.5-Overview-of-volcanic-features-and-landforms-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a> If you are using the printed version of this OER, access this interactive activity via this QR Code.[\/caption]\n\n<span style=\"font-weight: 400\">The figure shows the main features of a typical [pb_glossary id=\"240\"]stratovolcano[\/pb_glossary]:<\/span><span style=\"font-weight: 400\">\u00a01) <strong>[pb_glossary id=\"232\"]magma chamber[\/pb_glossary]<\/strong>, 2) upper layers of [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary], 3) the<\/span><span style=\"font-weight: 400\">\u00a0<\/span><b>[pb_glossary id=\"233\"]conduit[\/pb_glossary]<\/b><span style=\"font-weight: 400\"> or narrow pipe through which the<\/span><span style=\"font-weight: 400\">\u00a0[pb_glossary id=\"1751\"]lava[\/pb_glossary] erupts, 4) the base or edge of the [pb_glossary id=\"228\"]volcano[\/pb_glossary], 5) a <strong>[pb_glossary id=\"1022\"]sill[\/pb_glossary]<\/strong> of [pb_glossary id=\"1750\"]magma[\/pb_glossary] between layers of the [pb_glossary id=\"228\"]volcano[\/pb_glossary], 6) a <strong>[pb_glossary id=\"1018\"]diapir[\/pb_glossary]<\/strong> or feeder tube to the [pb_glossary id=\"1022\"]sill[\/pb_glossary], 7) layers of <strong>[pb_glossary id=\"1000\"]tephra[\/pb_glossary]<\/strong> ([pb_glossary id=\"1001\"]ash[\/pb_glossary]) from previous eruptions, 8 &amp; 9) layers of [pb_glossary id=\"1751\"]lava[\/pb_glossary] erupting from the [pb_glossary id=\"234\"]vent[\/pb_glossary] and flowing down the sides of the [pb_glossary id=\"228\"]volcano[\/pb_glossary], 10) the <strong>crater<\/strong> at the top of the [pb_glossary id=\"228\"]volcano[\/pb_glossary], 11) layers of [pb_glossary id=\"1751\"]lava[\/pb_glossary] and [pb_glossary id=\"1000\"]tephra[\/pb_glossary] on (12), a [pb_glossary id=\"236\"]parasitic cone[\/pb_glossary]. A\u00a0<b>[pb_glossary id=\"236\"]parasitic cone[\/pb_glossary]<\/b> is a small [pb_glossary id=\"228\"]volcano[\/pb_glossary] located on the flank of a larger volcano such as Shastina on Mount Shasta. Kilauea sitting on the flank of Mauna Loa is not considered a [pb_glossary id=\"236\"]parasitic cone[\/pb_glossary] because it has its own separate [pb_glossary id=\"232\"]magma chamber[\/pb_glossary],\u00a0 13) the <strong>vents<\/strong> of the parasite and the main [pb_glossary id=\"228\"]volcano[\/pb_glossary], 14) the rim of the crater, 15) clouds of [pb_glossary id=\"1001\"]ash[\/pb_glossary] blown into the sky by the eruption; this settles back onto the [pb_glossary id=\"228\"]volcano[\/pb_glossary] and surrounding land.\n<\/span>\n\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Mt.-Shasta-and-Shastina-in-Washington.jpg\"><img class=\"size-medium wp-image-289\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mt.-Shasta-and-Shastina-in-Washington-300x253.jpg\" alt=\"A smaller parasitic cone called Shastina on the flanks of Mt. Shasta in Washington\" width=\"300\" height=\"253\"><\/a> Mt. Shasta in Washington state with Shastina, its parasitic cone[\/caption]\n\n<span style=\"font-weight: 400\">The largest craters are called\u00a0<\/span><b>calderas<\/b><span style=\"font-weight: 400\">, such as the<\/span><span style=\"font-weight: 400\">\u00a0Crater Lake [pb_glossary id=\"235\"]Caldera[\/pb_glossary]<\/span><span style=\"font-weight: 400\">\u00a0in Oregon. <\/span><span style=\"font-weight: 400\">Many [pb_glossary id=\"228\"]volcanic[\/pb_glossary] features are produced by\u00a0<strong>[pb_glossary id=\"2446\"]viscosity[\/pb_glossary]<\/strong>, a basic property of a [pb_glossary id=\"1751\"]lava[\/pb_glossary]. [pb_glossary id=\"2446\"]Viscosity[\/pb_glossary] is the resistance to flowing by a fluid. Low [pb_glossary id=\"2446\"]viscosity[\/pb_glossary] [pb_glossary id=\"1750\"]magma[\/pb_glossary] flows easily more like syrup, the basaltic [pb_glossary id=\"228\"]volcanism[\/pb_glossary] that occurs in Hawaii on [pb_glossary id=\"1259\"]shield[\/pb_glossary] [pb_glossary id=\"228\"]volcanoes[\/pb_glossary].\u00a0High [pb_glossary id=\"2446\"]viscosity[\/pb_glossary] means a thick and sticky [pb_glossary id=\"1750\"]magma[\/pb_glossary], typically [pb_glossary id=\"1006\"]felsic[\/pb_glossary] or [pb_glossary id=\"1007\"]intermediate[\/pb_glossary], that flows slowly, similar to toothpaste.<\/span>\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Crater_lake_oregon-1.jpg\"><img class=\"size-medium wp-image-45\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Crater_lake_oregon-1-300x200.jpg\" alt=\"The mountain has a large hole in the center that is filled with the lake.\" width=\"300\" height=\"200\"><\/a> Oregon's Crater Lake was formed about 7700 years ago after the eruption of Mount Mazama.[\/caption]\n\n&nbsp;\n\n&nbsp;\n\n&nbsp;\n\n&nbsp;\n\n&nbsp;\n<h4><span style=\"font-weight: 400\">Shield Volcano<\/span><\/h4>\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Kilauea_Shield_Volcano_Hawaii_20071209A.jpg\"><img class=\"size-medium wp-image-290\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Kilauea_Shield_Volcano_Hawaii_20071209A-300x200.jpg\" alt=\"The mountain has low-angle flanks\" width=\"300\" height=\"200\"><\/a> Kilauea in Hawai'i.[\/caption]\n\nThe largest [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] are <strong>[pb_glossary id=\"1259\"]shield[\/pb_glossary] [pb_glossary id=\"228\"]volcanoes[\/pb_glossary]<\/strong>. They are characterized by broad low-angle flanks, small vents at the top, and [pb_glossary id=\"1008\"]mafic[\/pb_glossary] [pb_glossary id=\"1750\"]magma[\/pb_glossary] chambers. The name comes from the side view, which resembles a medieval warrior\u2019s [pb_glossary id=\"1259\"]shield[\/pb_glossary]. They are typically associated with [pb_glossary id=\"1716\"]hotspots[\/pb_glossary], [pb_glossary id=\"1708\"]mid-ocean ridges[\/pb_glossary], or [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1702\"]rifts[\/pb_glossary] with rising upper [pb_glossary id=\"1664\"]mantle[\/pb_glossary] material. The low-angle flanks are built up slowly from numerous low-[pb_glossary id=\"2446\"]viscosity[\/pb_glossary] basaltic [pb_glossary id=\"1751\"]lava[\/pb_glossary] flows that spread out over long distances. The basaltic [pb_glossary id=\"1751\"]lava[\/pb_glossary] erupts effusively, meaning the eruptions are small, localized, and predictable.\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Kiluea-eruption-2018.jpg\"><img class=\"size-medium wp-image-291\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Kiluea-eruption-2018-300x223.jpg\" alt=\"Lava from Kiluea destroying road in Hawaii.\" width=\"300\" height=\"223\"><\/a> Eruption of Kiluea in 2018 produced high viscosity lava shown here crossing a road. This eruption caused much property damage[\/caption]\n\nTypically, [pb_glossary id=\"237\"]shield volcano[\/pb_glossary] eruptions are not much of a hazard to human life\u2014although non-explosive eruptions of Kilauea (Hawaii) in 2018 produced uncharacteristically large lavas that damaged roads and structures.\u00a0<span style=\"font-weight: 400\">Mauna Loa (see <a href=\"http:\/\/hvo.wr.usgs.gov\/maunaloa\/\">USGS page<\/a>) and Kilauea (see <a href=\"http:\/\/hvo.wr.usgs.gov\/kilauea\/\">USGS page<\/a>) in Hawaii are examples of [pb_glossary id=\"1259\"]shield[\/pb_glossary] [pb_glossary id=\"228\"]volcanoes[\/pb_glossary]. [pb_glossary id=\"1259\"]Shield[\/pb_glossary] [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] are also found in Iceland, the Galapagos Islands, Northern California, Oregon, and the East African [pb_glossary id=\"1702\"]Rift[\/pb_glossary]<\/span><span style=\"font-weight: 400\">. <\/span>\n\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"215\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Olympus-Mons-on-Mars.jpg\"><img class=\"wp-image-292\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Olympus-Mons-on-Mars-300x278.jpg\" alt=\"\" width=\"215\" height=\"200\"><\/a> Olympus Mons, an enormous shield volcano on Mars, the largest volcano in the solar system, standing about two and a half times higher than Everest is above sea level.[\/caption]\n\nThe largest [pb_glossary id=\"228\"]volcanic[\/pb_glossary] edifice in the [pb_glossary id=\"1253\"]Solar System[\/pb_glossary] is Olympus Mons on Mars. This (possibly [pb_glossary id=\"755\"]extinct[\/pb_glossary]) [pb_glossary id=\"237\"]shield volcano[\/pb_glossary] covers an area the size of the state of Arizona. This may indicate the [pb_glossary id=\"228\"]volcano[\/pb_glossary] erupted over a [pb_glossary id=\"1716\"]hotspot[\/pb_glossary] for millions of years, which means Mars had little, if any, [pb_glossary id=\"1669\"]plate[\/pb_glossary] [pb_glossary id=\"1654\"]tectonic[\/pb_glossary] activity<span style=\"font-weight: 400\">.<\/span>\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/01\/ReU_PtFournaise_Lavastrome.jpg\"><img class=\"size-medium wp-image-293\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ReU_PtFournaise_Lavastrome-300x225.jpg\" alt=\"The lava is ropey\" width=\"300\" height=\"225\"><\/a> Ropey pahoehoe lava[\/caption]\n<p style=\"text-align: left\"><span style=\"font-weight: 400\">Basaltic [pb_glossary id=\"1751\"]lava[\/pb_glossary] forms special landforms based on [pb_glossary id=\"1750\"]magma[\/pb_glossary] [pb_glossary id=\"1767\"]temperature[\/pb_glossary], [pb_glossary id=\"1909\"]composition[\/pb_glossary], and content of [pb_glossary id=\"1893\"]dissolved[\/pb_glossary] gases and water vapor. The two main types of basaltic [pb_glossary id=\"990\"]volcanic rock[\/pb_glossary] have Hawaiian names\u2014<em>[pb_glossary id=\"238\"]<em>pahoehoe<\/em>[\/pb_glossary]<\/em> and <em>[pb_glossary id=\"239\"]<em>aa<\/em>[\/pb_glossary]<\/em>. <strong>[pb_glossary id=\"238\"]Pahoehoe[\/pb_glossary]<\/strong> might come from low-[pb_glossary id=\"2446\"]viscosity[\/pb_glossary] lava that flows easily into ropey strands.<\/span><\/p>\n\n\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Etna_02aa.jpg\"><img class=\"size-medium wp-image-294\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Etna_02aa-300x225.jpg\" alt=\"The lava is sharp and jagged\" width=\"300\" height=\"225\"><\/a> Blocky a'a lava[\/caption]\n<p style=\"text-align: left\"><b>[pb_glossary id=\"239\"]Aa[\/pb_glossary]<\/b><span style=\"font-weight: 400\"> (sometimes spelled a\u2019a or <\/span><span style=\"font-weight: 400\">[pb_glossary id=\"239\"]\u02bba\u02bb\u0101 [\/pb_glossary]and pronounced \"ah-ah\"<\/span><span style=\"font-weight: 400\">) is more [pb_glossary id=\"2446\"]viscous[\/pb_glossary] and has a crumbly blocky appearance. The exact details of what forms the two types of flows are still up for debate. <\/span><span style=\"font-weight: 400\">[pb_glossary id=\"1006\"]Felsic[\/pb_glossary] lavas have lower temperatures and more silica, and thus are higher [pb_glossary id=\"2446\"]viscosity[\/pb_glossary]. These also form [pb_glossary id=\"239\"]aa[\/pb_glossary]-style flows.<\/span><\/p>\n\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Volcano_fissure_tube.jpg\"><img class=\"size-medium wp-image-295\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano_fissure_tube-300x199.jpg\" alt=\"The magma is sputtering outward\" width=\"300\" height=\"199\"><\/a> Volcanic fissure and flow, which could eventually form a lava tube.[\/caption]\n\nLow-[pb_glossary id=\"2446\"]viscosity[\/pb_glossary], fast-flowing basaltic [pb_glossary id=\"1751\"]lava[\/pb_glossary] tends to harden on the outside into a tube and continue to flow internally. Once [pb_glossary id=\"1751\"]lava[\/pb_glossary] flow subsides, the empty outer shell may be left as a [pb_glossary id=\"1751\"]lava[\/pb_glossary] tube. [pb_glossary id=\"1751\"]Lava[\/pb_glossary] tubes, with or without collapsed roofs, make famous caves in Hawaii, Northern California, the Columbia [pb_glossary id=\"2212\"]River[\/pb_glossary] [pb_glossary id=\"1013\"]Basalt[\/pb_glossary] Plateau of Washington and Oregon, El Malpais National Monument in New Mexico, and Craters of the Moon National Monument in Idaho.\n\n<strong>Fissures<\/strong> are cracks that commonly originate from [pb_glossary id=\"1259\"]shield[\/pb_glossary]-style eruptions. [pb_glossary id=\"1751\"]Lava[\/pb_glossary] emerging from fissures is typically [pb_glossary id=\"1008\"]mafic[\/pb_glossary] and very fluid. The 2018 Kiluaea eruption included fissures associated with the [pb_glossary id=\"1751\"]lava[\/pb_glossary] flows. Some fissures are caused by the [pb_glossary id=\"228\"]volcanic[\/pb_glossary] [pb_glossary id=\"2165\"]seismic[\/pb_glossary] activity rather than [pb_glossary id=\"1751\"]lava[\/pb_glossary] flows. Some fissures are influenced by [pb_glossary id=\"1654\"]plate tectonics[\/pb_glossary], such as the common fissures located parallel to the [pb_glossary id=\"1677\"]divergent[\/pb_glossary] boundary in Iceland.\n\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"200\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/DT2-scaled.jpg\"><img class=\"wp-image-2892\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/DT2-scaled-1.jpg\" alt=\"The rock is full of columns\" width=\"200\" height=\"150\"><\/a> Devils Tower in Wyoming has columnar jointing.[\/caption]\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"192\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Columnar-jointing-on-Giants-Causeway-in-Ireland.jpg\"><img class=\"wp-image-297\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Columnar-jointing-on-Giants-Causeway-in-Ireland-288x300.jpg\" alt=\"Columnar jointing on Giant's Causeway in Ireland.\" width=\"192\" height=\"200\"><\/a> Columnar jointing on Giant's Causeway in Ireland.[\/caption]\n\nCooling [pb_glossary id=\"1751\"]lava[\/pb_glossary] can contract into columns with semi-hexagonal cross sections called <strong>columnar jointing<\/strong>. This feature forms the famous Devils Tower in Wyoming, possibly an ancient [pb_glossary id=\"228\"]volcanic[\/pb_glossary] [pb_glossary id=\"234\"]vent[\/pb_glossary] from which the surrounding layers of [pb_glossary id=\"1751\"]lava[\/pb_glossary] and [pb_glossary id=\"1001\"]ash[\/pb_glossary] have been removed by [pb_glossary id=\"1755\"]erosion[\/pb_glossary]. Another well-known exposed example of columnar jointing is the Giant\u2019s Causeway in Ireland.\n<h4><span style=\"font-weight: 400\">Stratovolcano<\/span><\/h4>\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"225\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Mount_Rainier_over_Tacoma.jpg\"><img class=\"wp-image-298\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_Rainier_over_Tacoma-300x200.jpg\" alt=\"The mountain is very tall, and looms over the city\" width=\"225\" height=\"150\"><\/a> Mount Rainier towers over Tacoma, Washington.[\/caption]\n\nA <strong>[pb_glossary id=\"240\"]stratovolcano[\/pb_glossary]<\/strong>, also called a [pb_glossary id=\"240\"]composite cone[\/pb_glossary] [pb_glossary id=\"228\"]volcano[\/pb_glossary], has steep flanks, a symmetrical cone shape, distinct crater, and rises prominently above the surrounding landscape. The term composite refers to the alternating layers of [pb_glossary id=\"1004\"]pyroclastic[\/pb_glossary] fragments like [pb_glossary id=\"1001\"]ash[\/pb_glossary] and [pb_glossary id=\"1003\"]bombs[\/pb_glossary], and solidified [pb_glossary id=\"1751\"]lava[\/pb_glossary] flows of varying [pb_glossary id=\"1909\"]composition[\/pb_glossary]. Examples include Mount Rainier in Washington state and Mount Fuji in Japan.\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"250\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Mt.-Fuji-300x190-1.jpg\"><img class=\"wp-image-299\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mt.-Fuji-300x190-1.jpg\" alt=\"\" width=\"250\" height=\"158\"><\/a> Mt. Fuji in Japan, a typical stratovolcano, symmetrical, increasing slope, visible crater at the top.[\/caption]\n\nStratovolcanoes usually have [pb_glossary id=\"1006\"]felsic[\/pb_glossary] to [pb_glossary id=\"1007\"]intermediate[\/pb_glossary] [pb_glossary id=\"1750\"]magma[\/pb_glossary] chambers, but can even produce [pb_glossary id=\"1008\"]mafic[\/pb_glossary] lavas. Stratovolcanoes have [pb_glossary id=\"2446\"]viscous[\/pb_glossary]\u00a0[pb_glossary id=\"1751\"]lava[\/pb_glossary] flows and [pb_glossary id=\"507\"]domes[\/pb_glossary], punctuated by explosive eruptions. This produces [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] with steep flanks.\n<h4><span style=\"font-weight: 400\">Lava Domes<\/span><\/h4>\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/MSH06_aerial_crater_from_north_high_angle_09-12-06.jpg\"><img class=\"size-medium wp-image-300\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSH06_aerial_crater_from_north_high_angle_09-12-06-300x200.jpg\" alt=\"The mountain has a hole, but the hole has filled in somewhat\" width=\"300\" height=\"200\"><\/a> Lava domes have started the rebuilding process at Mount St. Helens, Washington.[\/caption]\n\n<strong>[pb_glossary id=\"1751\"]Lava[\/pb_glossary] [pb_glossary id=\"507\"]domes[\/pb_glossary]<\/strong> are accumulations of silica-rich [pb_glossary id=\"990\"]volcanic rock[\/pb_glossary], such as [pb_glossary id=\"1010\"]rhyolite[\/pb_glossary] and [pb_glossary id=\"999\"]obsidian[\/pb_glossary]. Too [pb_glossary id=\"2446\"]viscous[\/pb_glossary] to flow easily, the [pb_glossary id=\"1006\"]felsic[\/pb_glossary] [pb_glossary id=\"1751\"]lava[\/pb_glossary] tends to pile up near the [pb_glossary id=\"234\"]vent[\/pb_glossary] in blocky masses. [pb_glossary id=\"1751\"]Lava[\/pb_glossary] [pb_glossary id=\"507\"]domes[\/pb_glossary] often form in a [pb_glossary id=\"234\"]vent[\/pb_glossary] within the collapsed crater of a [pb_glossary id=\"240\"]stratovolcano[\/pb_glossary], and grow by internal expansion. As the [pb_glossary id=\"507\"]dome[\/pb_glossary] expands, the outer surface cools, hardens, and shatters, and spills loose fragments down the sides. Mount Saint Helens has a good example of a [pb_glossary id=\"1751\"]lava[\/pb_glossary] [pb_glossary id=\"507\"]dome[\/pb_glossary] inside of a collapsed [pb_glossary id=\"240\"]stratovolcano[\/pb_glossary] crater. Examples of stand-alone [pb_glossary id=\"1751\"]lava[\/pb_glossary] [pb_glossary id=\"507\"]domes[\/pb_glossary] are Chaiten in Chile and Mammoth Mountain in California.\n<h4><span style=\"font-weight: 400\">Caldera<\/span><\/h4>\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"149\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Mount_Mazama_eruption_timeline.png\"><img class=\"wp-image-301\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_Mazama_eruption_timeline-89x300.png\" alt=\"It shows the eruption forming a caldera.\" width=\"149\" height=\"500\"><\/a> Timeline of events at Mount Mazama.[\/caption]\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"250\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/CL1-scaled.jpg\"><img class=\"wp-image-2898\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/CL1-scaled-1.jpg\" alt=\"The island is forested, as are the flanks\" width=\"250\" height=\"188\"><\/a> Wizard Island sits in the caldera at Crater Lake.[\/caption]\n\n<strong>Calderas<\/strong> are steep-walled, [pb_glossary id=\"508\"]basin[\/pb_glossary]-shaped depressions formed by the collapse of a [pb_glossary id=\"228\"]volcanic[\/pb_glossary] edifice into an empty [pb_glossary id=\"232\"]magma chamber[\/pb_glossary]. Calderas are generally very large, with diameters of up to 25 km (15.5 mi). The term [pb_glossary id=\"235\"]caldera[\/pb_glossary] specifically refers to a [pb_glossary id=\"228\"]volcanic[\/pb_glossary] [pb_glossary id=\"234\"]vent[\/pb_glossary]; however, it is frequently used to describe a [pb_glossary id=\"228\"]volcano[\/pb_glossary] type. [pb_glossary id=\"235\"]Caldera[\/pb_glossary] [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] are\u00a0typically formed by eruptions of high-[pb_glossary id=\"2446\"]viscosity[\/pb_glossary] [pb_glossary id=\"1006\"]felsic[\/pb_glossary] [pb_glossary id=\"1751\"]lava[\/pb_glossary] having high [pb_glossary id=\"1684\"]volatiles[\/pb_glossary] content.\n\nCrater Lake, Yellowstone, and the Long Valley [pb_glossary id=\"235\"]Caldera[\/pb_glossary] are good examples of this type of [pb_glossary id=\"228\"]volcanism[\/pb_glossary]. The [pb_glossary id=\"235\"]caldera[\/pb_glossary] at Crater Lake National Park in Oregon was created about 6,800 years ago when Mount Mazama, a [pb_glossary id=\"240\"]composite volcano[\/pb_glossary], erupted in a huge explosive blast. The [pb_glossary id=\"228\"]volcano[\/pb_glossary] ejected large amounts of [pb_glossary id=\"228\"]volcanic[\/pb_glossary] [pb_glossary id=\"1001\"]ash[\/pb_glossary] and rapidly drained the [pb_glossary id=\"232\"]magma chamber[\/pb_glossary], causing the top to collapse into a large depression that later filled with water. Wizard Island in the middle of the lake is a later resurgent [pb_glossary id=\"241\"]lava dome[\/pb_glossary] that formed within the [pb_glossary id=\"235\"]caldera[\/pb_glossary] [pb_glossary id=\"508\"]basin[\/pb_glossary]<span style=\"font-weight: 400\">.<\/span>\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Yellowstone_Caldera_map2.jpg\"><img class=\"size-medium wp-image-303\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Yellowstone_Caldera_map2-300x242.jpg\" alt=\"The map shows locations of calderas and rocks within Yellowstone\" width=\"300\" height=\"242\"><\/a> Map of calderas and related rocks around Yellowstone.[\/caption]\n\nThe Yellowstone [pb_glossary id=\"228\"]volcanic[\/pb_glossary] [pb_glossary id=\"1742\"]system[\/pb_glossary] erupted three times in the recent geologic past\u20142.1, 1.3, and 0.64 million years ago\u2014leaving behind three [pb_glossary id=\"235\"]caldera[\/pb_glossary] basins. Each eruption created large [pb_glossary id=\"1010\"]rhyolite[\/pb_glossary] [pb_glossary id=\"1751\"]lava[\/pb_glossary] flows as well as [pb_glossary id=\"1004\"]pyroclastic[\/pb_glossary] flows that solidified into [pb_glossary id=\"1005\"]tuff[\/pb_glossary] [pb_glossary id=\"2038\"]formations[\/pb_glossary]. These extra-large eruptions rapidly emptied the [pb_glossary id=\"232\"]magma chamber[\/pb_glossary], causing the roof to collapse and form a [pb_glossary id=\"235\"]caldera[\/pb_glossary]. The youngest of the three calderas contains most of Yellowstone National Park, as well as two resurgent [pb_glossary id=\"1751\"]lava[\/pb_glossary] [pb_glossary id=\"507\"]domes[\/pb_glossary]. The calderas are difficult to see today due to the amount of time since their eruptions and subsequent [pb_glossary id=\"1755\"]erosion[\/pb_glossary] and [pb_glossary id=\"747\"]glaciation[\/pb_glossary].\n\nYellowstone [pb_glossary id=\"228\"]volcanism[\/pb_glossary] started about 17-million years ago as a [pb_glossary id=\"1716\"]hotspot[\/pb_glossary] under the North American lithospheric [pb_glossary id=\"1669\"]plate[\/pb_glossary] near the Oregon\/Nevada border. As the [pb_glossary id=\"1669\"]plate[\/pb_glossary] moved to the southwest over the stationary [pb_glossary id=\"1716\"]hotspot[\/pb_glossary], it left behind a track of past [pb_glossary id=\"228\"]volcanic[\/pb_glossary] activities. Idaho\u2019s Snake [pb_glossary id=\"2212\"]River[\/pb_glossary] Plain was created from [pb_glossary id=\"228\"]volcanism[\/pb_glossary] that produced a series of calderas and [pb_glossary id=\"1751\"]lava[\/pb_glossary] flows. The [pb_glossary id=\"1669\"]plate[\/pb_glossary] eventually arrived at its current location in northwestern Wyoming, where [pb_glossary id=\"1716\"]hotspot[\/pb_glossary] [pb_glossary id=\"228\"]volcanism[\/pb_glossary] formed the Yellowstone calderas<span style=\"font-weight: 400\">.<\/span>\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Yellowstone_volcano_-_ash_beds.jpg\"><img class=\"size-medium wp-image-134\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Yellowstone_volcano_-_ash_beds-300x195.jpg\" alt=\"The eruptions trend eastward due to prevailing winds.\" width=\"300\" height=\"195\"><\/a> Several prominent ash beds found in North America, including three Yellowstone eruptions shaded pink (Mesa Falls, Huckleberry Ridge, and Lava Creek), the Bisho Tuff ash bed (brown dashed line), and the modern May 18th, 1980 ash fall (yellow).[\/caption]\n\nThe Long Valley [pb_glossary id=\"235\"]Caldera[\/pb_glossary] near Mammoth, California, is the result of a large [pb_glossary id=\"228\"]volcanic[\/pb_glossary] eruption that occurred 760,000 years ago. The explosive eruption dumped enormous amounts of [pb_glossary id=\"1001\"]ash[\/pb_glossary] across the United States, in a manner similar to the Yellowstone eruptions. The Bishop [pb_glossary id=\"1005\"]Tuff[\/pb_glossary] deposit near Bishop, California, is made of [pb_glossary id=\"1001\"]ash[\/pb_glossary] from this eruption. The current [pb_glossary id=\"235\"]caldera[\/pb_glossary] [pb_glossary id=\"508\"]basin[\/pb_glossary] is 17 km by 32 km (10 mi by 20 mi), large enough to contain the town of Mammoth Lakes, major ski resort, airport, major highway, resurgent [pb_glossary id=\"507\"]dome[\/pb_glossary], and several hot springs<span style=\"font-weight: 400\">.<\/span>\n<h4><span style=\"font-weight: 400\">Cinder Cone<\/span><\/h4>\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Sunset_Crater10.jpg\"><img class=\"size-medium wp-image-304\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Sunset_Crater10-300x202.jpg\" alt=\"The cone is relatively small and red\" width=\"300\" height=\"202\"><\/a> Sunset Crater, Arizona is a cinder cone.[\/caption]\n\n<strong>[pb_glossary id=\"242\"]Cinder[\/pb_glossary] cones<\/strong> are small [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] with steep sides, and made of [pb_glossary id=\"1004\"]pyroclastic[\/pb_glossary] fragments that have been ejected from a pronounced central [pb_glossary id=\"234\"]vent[\/pb_glossary]. The small fragments are called <strong>[pb_glossary id=\"242\"]cinders[\/pb_glossary]<\/strong> and the largest are <strong>[pb_glossary id=\"228\"]volcanic[\/pb_glossary] [pb_glossary id=\"1003\"]bombs[\/pb_glossary]<\/strong>. The eruptions are usually short-lived events, typically consisting of [pb_glossary id=\"1008\"]mafic[\/pb_glossary] lavas with a high content of [pb_glossary id=\"1684\"]volatiles[\/pb_glossary]. Hot [pb_glossary id=\"1751\"]lava[\/pb_glossary] is ejected into the air, cooling and solidifying into fragments that accumulate on the flank of the [pb_glossary id=\"228\"]volcano[\/pb_glossary]. [pb_glossary id=\"242\"]Cinder[\/pb_glossary] cones are found throughout western North America<span style=\"font-weight: 400\">.<\/span>\n\n&nbsp;\n\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"200\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Paricutin_30_612.jpg\"><img class=\"size-medium wp-image-305\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Paricutin_30_612-200x300.jpg\" alt=\"A person looks at the eruption of ash\" width=\"200\" height=\"300\"><\/a> Soon after the birth of Par\u00edcutin in 1943.[\/caption]\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Paracutin-lava-in-San-Juan-300x224-1.jpg\"><img class=\"size-full wp-image-306\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Paracutin-lava-in-San-Juan-300x224-1.jpg\" alt=\"\" width=\"300\" height=\"224\"><\/a> Lava from Par\u00edcutin covered the local church and destroyed the town of San Juan, Mexico[\/caption]\n\n<span style=\"font-weight: 400\">A recent and striking example of a [pb_glossary id=\"243\"]cinder cone[\/pb_glossary] is the eruption near the village of Par\u00edcutin, Mexico that started in 1943. The [pb_glossary id=\"243\"]cinder cone[\/pb_glossary] started explosively shooting [pb_glossary id=\"242\"]cinders[\/pb_glossary] out of the [pb_glossary id=\"234\"]vent[\/pb_glossary] in the middle of a farmer\u2019s field. The [pb_glossary id=\"228\"]volcanism[\/pb_glossary] quickly built up the cone to a height of over 90 m (300 ft) within a week, and 365 m (1,200 ft) within the first 8 months. After the initial explosive eruption of gases and [pb_glossary id=\"242\"]cinders[\/pb_glossary], basaltic [pb_glossary id=\"1751\"]lava[\/pb_glossary] poured out from the base of the cone. This is a common order of events for [pb_glossary id=\"242\"]cinder[\/pb_glossary] cones: violent eruption, cone and crater [pb_glossary id=\"2038\"]formation[\/pb_glossary], low-[pb_glossary id=\"2446\"]viscosity[\/pb_glossary] [pb_glossary id=\"1751\"]lava[\/pb_glossary] flow from the base. The [pb_glossary id=\"243\"]cinder cone[\/pb_glossary] is not strong enough to support a column of [pb_glossary id=\"1751\"]lava[\/pb_glossary] rising to the top of the crater, so the [pb_glossary id=\"1751\"]lava[\/pb_glossary] breaks through and emerges near the bottom of the [pb_glossary id=\"228\"]volcano[\/pb_glossary]. During nine years of eruption activity, the ashfall covered about 260 km<sup>2<\/sup> (100 mi<sup>2<\/sup>) and destroyed the nearby town of San Juan<\/span><span style=\"font-weight: 400\">.<\/span>\n<h4><span style=\"font-weight: 400\">Flood Basalts<\/span><\/h4>\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"500\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/World-map-or-flood-basalts.jpg\"><img class=\"wp-image-307\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/World-map-or-flood-basalts-300x168.jpg\" alt=\"World map of flood basalts. Note the largest is the Siberian Traps\" width=\"500\" height=\"280\"><\/a> World map of flood basalts. Note the largest is the Siberian Traps[\/caption]\n\nA rare [pb_glossary id=\"228\"]volcanic[\/pb_glossary] eruption type,\u00a0unobserved in modern times, is the\u00a0<strong>[pb_glossary id=\"244\"]flood basalt[\/pb_glossary]<\/strong>. [pb_glossary id=\"244\"]Flood basalts[\/pb_glossary] are some of the largest and lowest [pb_glossary id=\"2446\"]viscosity[\/pb_glossary] types of eruptions known. They are not known from any eruption in human history, so the exact mechanisms of eruption are still mysterious. Some famous examples include the Columbia [pb_glossary id=\"2212\"]River[\/pb_glossary] [pb_glossary id=\"244\"]Flood Basalts[\/pb_glossary] in Washington, Oregon, and Idaho, the Deccan [pb_glossary id=\"2420\"]Traps[\/pb_glossary], which cover about 1\/3 of the country of India, and the Siberian [pb_glossary id=\"2420\"]Traps[\/pb_glossary], which may have been involved in the Earth's largest [pb_glossary id=\"1275\"]mass extinction[\/pb_glossary] (see <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/8-earth-history\/\" target=\"_blank\" rel=\"noopener\">chapter 8<\/a>).\n<h4><span style=\"font-weight: 400\">Carbonatites<\/span><\/h4>\n[caption id=\"attachment_315\" align=\"alignright\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Crater_of_Ol_Doinyo_Lengai_Jan_2011-1.jpg\"><img class=\"size-medium wp-image-3187\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Crater_of_Ol_Doinyo_Lengai_Jan_2011-1-300x169-1.jpg\" alt=\"The crater has white rocks in the walls\" width=\"300\" height=\"169\"><\/a> Crater of Ol Doinyo Lengai in 2011. Note the white carbonatite in the walls of the crater.[\/caption]\n\nArguably the most unusual [pb_glossary id=\"228\"]volcanic[\/pb_glossary] activity are <strong>[pb_glossary id=\"2443\"]carbonatite[\/pb_glossary]<\/strong> eruptions. Only one actively erupting [pb_glossary id=\"2443\"]carbonatite[\/pb_glossary] [pb_glossary id=\"228\"]volcano[\/pb_glossary] exists on Earth today, Ol Doinyo Lengai, in the East African [pb_glossary id=\"1702\"]Rift[\/pb_glossary] Zone of Tanzania. While all other [pb_glossary id=\"228\"]volcanism[\/pb_glossary] on Earth originates from [pb_glossary id=\"1787\"]silicate[\/pb_glossary]-based [pb_glossary id=\"1750\"]magma[\/pb_glossary], [pb_glossary id=\"2443\"]carbonatites[\/pb_glossary] are a product of [pb_glossary id=\"969\"]carbonate[\/pb_glossary]-based [pb_glossary id=\"1750\"]magma[\/pb_glossary] and produce [pb_glossary id=\"228\"]volcanic[\/pb_glossary] rocks containing greater than 50% [pb_glossary id=\"969\"]carbonate[\/pb_glossary] [pb_glossary id=\"1765\"]minerals[\/pb_glossary]. [pb_glossary id=\"2443\"]Carbonatite[\/pb_glossary] lavas are very low [pb_glossary id=\"2446\"]viscosity[\/pb_glossary] and relatively cold for [pb_glossary id=\"1751\"]lava[\/pb_glossary]. The erupting [pb_glossary id=\"1751\"]lava[\/pb_glossary] is black, and solidifies to brown\/grey rock that eventually turns white. These rocks are occasionally found in the geologic record and require special study to distinguish them from [pb_glossary id=\"1992\"]metamorphic[\/pb_glossary] marbles (see <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/6-metamorphic-rocks\/\">Chapter 6<\/a>). They are mostly associated with [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1702\"]rifting[\/pb_glossary].\n\n<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Igneous-e1546649689814.png\"><img class=\"size-full wp-image-309\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Igneous-e1546649689814.png\" alt=\"Table of igneous rocks and related volcano types. Horizontal axis is arranged from low to high silica content (i.e. from ultramafic to felsic). First row shows the extrusive (surface) igneous rocks basalt, andesite, and rhyolite. Second row shows volcano types: mid-ocean ridge, shield, cinder cone, and strato (composite). Third row shows examples of each volcano: mid-atlantic ridge, Mauna Kea (Hawaii), Paricutin, and Mt. St. Helens. Forth row shows intrusive rocks from mafic to felsic: Dunite, gabbro, diorige, granite. Fifth row shows common plate-tectonic settings: divergent oceanic hot spot, and convergent boundaries. Sixth row is typical composition: ultramafic, mafic, intermediate, and felsic.\" width=\"759\" height=\"820\"><\/a>\n<blockquote>\n<p style=\"text-align: left\"><em>[pb_glossary id=\"1753\"]<em>Igneous rock<\/em>[\/pb_glossary] types and related [pb_glossary id=\"228\"]<em>volcano<\/em>[\/pb_glossary] types. [pb_glossary id=\"1708\"]<em>Mid-ocean ridges<\/em>[\/pb_glossary] and [pb_glossary id=\"1259\"]<em>shield<\/em>[\/pb_glossary] [pb_glossary id=\"228\"]<em>volcanoes<\/em>[\/pb_glossary] represent more [pb_glossary id=\"1008\"]<em>mafic<\/em>[\/pb_glossary] compositions, and strato (composite) [pb_glossary id=\"228\"]<em>volcanoes<\/em>[\/pb_glossary] generally represent a more [pb_glossary id=\"1007\"]<em>intermediate<\/em>[\/pb_glossary] or [pb_glossary id=\"1006\"]<em>felsic<\/em>[\/pb_glossary] [pb_glossary id=\"1909\"]<em>composition<\/em>[\/pb_glossary] and a [pb_glossary id=\"1678\"]<em>convergent<\/em>[\/pb_glossary] [pb_glossary id=\"1669\"]<em>plate<\/em>[\/pb_glossary] [pb_glossary id=\"1654\"]<em>tectonic<\/em>[\/pb_glossary] boundary. Note that there are exceptions to this generalized layout of volcano types and [pb_glossary id=\"1753\"]<em>igneous rock<\/em>[\/pb_glossary] [pb_glossary id=\"1909\"]<em>composition<\/em>[\/pb_glossary].<\/em><\/p>\n<\/blockquote>\n<h3><b>4.5.3 Volcanic Hazards and Monitoring<\/b><\/h3>\n[caption id=\"attachment_315\" align=\"alignright\" width=\"258\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Types_of_volcano_hazards_usgs.gif\"><img class=\"wp-image-310 size-medium\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Types_of_volcano_hazards_usgs-258x300.gif\" alt=\"It shows many hazards\" width=\"258\" height=\"300\"><\/a> General diagram of volcanic hazards.[\/caption]\n\nWhile the most obvious [pb_glossary id=\"228\"]volcanic[\/pb_glossary] hazard is [pb_glossary id=\"1751\"]lava[\/pb_glossary], the dangers posed by [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] go far beyond [pb_glossary id=\"1751\"]lava[\/pb_glossary] flows. For example, on May 18, 1980, Mount Saint Helens (Washington, United States) erupted with an explosion and [pb_glossary id=\"246\"]landslide[\/pb_glossary] that removed the upper 400 m (1,300 ft) of the mountain. The initial explosion was immediately followed by a lateral blast, which produced a [pb_glossary id=\"245\"]pyroclastic\u00a0flow[\/pb_glossary] that covered nearly 600 km<sup>2<\/sup> (230 mi<sup>2<\/sup>) of forest with hot [pb_glossary id=\"1001\"]ash[\/pb_glossary] and debris. The pyroclastic flow moved at speeds of 80-130 kph (50-80 mph), flattening trees and ejecting clouds of ash into the air. The USGS video provides an account of this explosive eruption that killed 57 people.\n\n[embed]https:\/\/youtu.be\/Ec30uU0G56U[\/embed]\n\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"150\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Mount-St.-helens-YouTube-QR-Code.png\"><img class=\"size-thumbnail wp-image-311\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount-St.-helens-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a> If you are using the printed version of this OER, access this YouTube video via this QR Code.[\/caption]\n\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"250\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/DSC01727.jpg\"><img class=\"wp-image-312\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/DSC01727-300x225.jpg\" alt=\"The body is outlined with a cast, and the bones are seen.\" width=\"250\" height=\"188\"><\/a> Human remains from the 79 CE eruption of Vesuvius.[\/caption]\n\nIn 79 AD, Mount Vesuvius, located near Naples, Italy, violently erupted sending a [pb_glossary id=\"245\"]pyroclastic flow[\/pb_glossary] over the Roman countryside, including the cities of Herculaneum and Pompeii. The buried towns were discovered in an archeological expedition in the 18th century. Pompeii famously contains the remains ([pb_glossary id=\"1231\"]casts[\/pb_glossary]) of people suffocated by ash and covered by 10 feet (3 m) of [pb_glossary id=\"1001\"]ash[\/pb_glossary], [pb_glossary id=\"998\"]pumice[\/pb_glossary] [pb_glossary id=\"1002\"]lapilli[\/pb_glossary], and collapsed roofs.\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Mount_St._Helens_one_day_before_the_devastating_eruption.jpg\"><img class=\"size-medium wp-image-313\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_St._Helens_one_day_before_the_devastating_eruption-300x203.jpg\" alt=\"The volcano is conical and forested.\" width=\"300\" height=\"203\"><\/a> Mount St. Helens, the day before the May 18th, 1980 eruption.[\/caption]\n\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/MSH80_st_helens_from_johnston_ridge_09-10-80.jpg\"><img class=\"size-medium wp-image-314\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSH80_st_helens_from_johnston_ridge_09-10-80-300x201.jpg\" alt=\"The top of the mountain is gone\" width=\"300\" height=\"201\"><\/a> Picture 4 months after the major eruption of Mount St. Helens.[\/caption]\n\n[caption id=\"attachment_315\" align=\"alignnone\" width=\"1500\"]<img class=\"wp-image-315 size-full\" title=\"By Associated Press, via The Atlantic, https:\/\/www.theatlantic.com\/photo\/2015\/05\/the-eruption-of-mount-st-helens-in-1980\/393557\/\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mt_Saint_Helens_Eruption_main_1500.gif\" alt=\"Series of images showing half of the mountain releasing as a giant landslide and ash billowing out from underneath.\" width=\"1500\" height=\"943\"> Series of still images of the May 18, 1980, eruption of Mt. Saint Helens, Washington showing largest recorded landslide in history and subsequent eruption and pyroclastic flow (By The Associated Press via The Atlantic)[\/caption]\n<h4><span style=\"font-weight: 400\">Pyroclastic flows<\/span><\/h4>\n[caption id=\"attachment_315\" align=\"alignright\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Pyroclastic_flows_at_Mayon_Volcano.jpg\"><img class=\"size-medium wp-image-316\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pyroclastic_flows_at_Mayon_Volcano-300x188.jpg\" alt=\"Most of the material is heading up, but small portions of the eruption column head downward.\" width=\"300\" height=\"188\"><\/a> The material coming down from the eruption column is a pyroclastic flow.[\/caption]\n\n<span style=\"font-weight: 400\">The most dangerous [pb_glossary id=\"228\"]volcanic[\/pb_glossary] hazard are <strong>[pb_glossary id=\"1004\"]pyroclastic[\/pb_glossary] flows<\/strong> (<\/span><a href=\"https:\/\/volcanoes.usgs.gov\/vsc\/movies\/movie_101\/PF_Animation.mp4\"><span style=\"font-weight: 400\">video<\/span><\/a><span style=\"font-weight: 400\">). These flows are a mix of [pb_glossary id=\"1751\"]lava[\/pb_glossary] blocks, [pb_glossary id=\"998\"]pumice[\/pb_glossary], [pb_glossary id=\"1001\"]ash[\/pb_glossary], and hot gases between 200\u00b0C-700\u00b0C (400\u00b0F-1,300\u00b0F). The turbulent cloud of [pb_glossary id=\"1001\"]ash[\/pb_glossary] and gas races down the steep flanks at high speeds up to 193 kph (120 mph) into the valleys around composite [pb_glossary id=\"228\"]volcanoes[\/pb_glossary]<\/span><span style=\"font-weight: 400\">. Most explosive, silica-rich, high [pb_glossary id=\"2446\"]viscosity[\/pb_glossary] [pb_glossary id=\"1750\"]magma[\/pb_glossary] [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] such as composite cones usually have [pb_glossary id=\"1004\"]pyroclastic[\/pb_glossary] flows. The rock <\/span>[pb_glossary id=\"1005\"]tuff[\/pb_glossary] <span style=\"font-weight: 400\">and <\/span>welded [pb_glossary id=\"1005\"]tuff[\/pb_glossary]<span style=\"font-weight: 400\"> is often formed from these [pb_glossary id=\"1004\"]pyroclastic[\/pb_glossary] flows.<\/span>\n\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"256\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Pelee_1902_3.jpg\"><img class=\"size-medium wp-image-317\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pelee_1902_3-256x300.jpg\" alt=\"A man is seen overlooking the destroyed city\" width=\"256\" height=\"300\"><\/a> The remains of St. Pierre.[\/caption]\n\n<span style=\"font-weight: 400\">There are numerous examples of deadly [pb_glossary id=\"1004\"]pyroclastic[\/pb_glossary] flows. In 2014, the Mount Ontake [pb_glossary id=\"245\"]pyroclastic flow[\/pb_glossary] in Japan killed 47 people. The flow was caused by [pb_glossary id=\"1750\"]magma[\/pb_glossary] heating [pb_glossary id=\"2207\"]groundwater[\/pb_glossary] into steam, which then rapidly ejected with [pb_glossary id=\"1001\"]ash[\/pb_glossary] and [pb_glossary id=\"228\"]volcanic[\/pb_glossary] [pb_glossary id=\"1003\"]bombs[\/pb_glossary]. Some were killed by inhalation of toxic gases and hot ash, while others were struck by volcanic bombs<\/span><span style=\"font-weight: 400\">. <\/span><span style=\"font-weight: 400\">Two short videos below document<\/span><span style=\"font-weight: 400\">\u00a0eye-witness video of [pb_glossary id=\"1004\"]pyroclastic[\/pb_glossary] flows. In the early 1990s, Mount Unzen erupted several times with [pb_glossary id=\"1004\"]pyroclastic[\/pb_glossary] flows. The [pb_glossary id=\"245\"]pyroclastic flow[\/pb_glossary]\u00a0shown in this famous <\/span><span style=\"font-weight: 400\">short video<\/span><span style=\"font-weight: 400\"> killed 41 people. In 1902, on the Caribbean Island Martinique, Mount Pelee <\/span><span style=\"font-weight: 400\">erupted with a violent [pb_glossary id=\"245\"]pyroclastic flow[\/pb_glossary] that destroyed the entire town of St. Pierre and killing 28,000 people in moments<\/span><span style=\"font-weight: 400\">.<\/span>\n\n[embed]https:\/\/youtu.be\/3ObsOj9Q2Do[\/embed]\n\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"150\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Japans-Mount-Ontake-YouTube-QR-Code.png\"><img class=\"size-thumbnail wp-image-318\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Japans-Mount-Ontake-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a> If you are using the printed version of this OER, access this YouTube video via this QR Code.[\/caption]\n\n[embed]https:\/\/youtu.be\/Cvjwt9nnwXY[\/embed]\n\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"150\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Dome-collapse-and-pyroclastic-flow-at-Unzen-Volcano-YouTube-QR-Codes.png\"><img class=\"size-thumbnail wp-image-319\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Dome-collapse-and-pyroclastic-flow-at-Unzen-Volcano-YouTube-QR-Codes-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a> If you are using the printed version of this OER, access this YouTube video via this QR Code.[\/caption]\n<h4><span style=\"font-weight: 400\">Landslides and Landslide-Generated Tsunamis<\/span><\/h4>\n[caption id=\"attachment_315\" align=\"alignright\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Msh_may18_sequence.gif\"><img class=\"size-medium wp-image-320\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Msh_may18_sequence-300x197.gif\" alt=\"The landslide opened an area for the eruption\" width=\"300\" height=\"197\"><\/a> Sequence of events for Mount St. Helens, May 18th, 1980. Note that an earthquake caused a landslide, which caused the \"uncorking\" of the mountain and started the eruption.[\/caption]\n\nThe steep and unstable flanks of a [pb_glossary id=\"228\"]volcano[\/pb_glossary] can lead to slope failure and dangerous [pb_glossary id=\"246\"]landslides[\/pb_glossary]. These [pb_glossary id=\"246\"]landslides[\/pb_glossary] can be triggered by [pb_glossary id=\"1750\"]magma[\/pb_glossary] movement, explosive eruptions, large earthquakes, and\/or heavy rainfall. During the 1980 Mount St. Helens eruption, the entire north flank of the [pb_glossary id=\"228\"]volcano[\/pb_glossary] collapsed and released a huge [pb_glossary id=\"246\"]landslide[\/pb_glossary] that moved at speeds of 160-290 kph (100-180 mph).\n\nIf enough [pb_glossary id=\"246\"]landslide[\/pb_glossary] material reaches the ocean, it may cause a [pb_glossary id=\"2272\"]tsunami[\/pb_glossary]. In 1792, a [pb_glossary id=\"246\"]landslide[\/pb_glossary] caused by the Mount Unzen eruption reached the Ariaka Sea, generating a [pb_glossary id=\"2272\"]tsunami[\/pb_glossary] that killed 15,000 people (see <a href=\"http:\/\/volcano.oregonstate.edu\/describe-1883-eruption-krakatau\" target=\"_blank\" rel=\"noopener\">USGS page<\/a>). When Mount Krakatau in Indonesia erupted in 1883, it generated ocean waves that towered 40 m (131 ft) above sea level. The [pb_glossary id=\"2272\"]tsunami[\/pb_glossary] killed 36,000 people and destroyed 165 villages.\n<h4><span style=\"font-weight: 400\">Tephra<\/span><\/h4>\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Ash_in_Yogyakarta_during_the_2014_eruption_of_Kelud_01.jpg\"><img class=\"size-medium wp-image-321\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ash_in_Yogyakarta_during_the_2014_eruption_of_Kelud_01-300x204.jpg\" alt=\"The man is wearing a mask to prevent pneumonoultramicroscopicsilicovolvanoconiosis.\" width=\"300\" height=\"204\"><\/a> Aman sweeps ash from an eruption of Kelud, Indonesia.[\/caption]\n\n<span style=\"font-weight: 400\">[pb_glossary id=\"228\"]Volcanoes[\/pb_glossary], especially composite [pb_glossary id=\"228\"]volcanoes[\/pb_glossary], eject large amounts of <\/span><b>[pb_glossary id=\"1000\"]tephra[\/pb_glossary] <\/b><span style=\"font-weight: 400\">(ejected rock materials), most notably\u00a0<\/span><b>[pb_glossary id=\"1001\"]ash[\/pb_glossary] <\/b><span style=\"font-weight: 400\">([pb_glossary id=\"1000\"]tephra[\/pb_glossary] fragments less than 0.08 inches [2 mm]). Larger [pb_glossary id=\"1000\"]tephra[\/pb_glossary] is heavier and [pb_glossary id=\"2197\"]falls[\/pb_glossary] closer to the [pb_glossary id=\"234\"]vent[\/pb_glossary]. Larger blocks and [pb_glossary id=\"1003\"]bombs[\/pb_glossary] pose hazards to those close to the eruption such as at the 2014 Mount Ontake disaster in Japan discussed earlier.<\/span>\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"250\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Micrograph-of-volcanic-ash-particle.jpg\"><img class=\"size-full wp-image-322\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Micrograph-of-volcanic-ash-particle.jpg\" alt=\"Micrograph of silica particle in volcanic ash. A cloud of these is capable of destroying an aircraft or automobile engine.\" width=\"250\" height=\"183\"><\/a> Micrograph of silica particle in volcanic ash. A cloud of these is capable of destroying an aircraft or automobile engine.[\/caption]\n\nHot [pb_glossary id=\"1001\"]ash[\/pb_glossary] poses an immediate danger to people, animals, plants, machines, roads, and buildings located close to the eruption. [pb_glossary id=\"1001\"]Ash[\/pb_glossary] is fine grained (&lt; 2mm) and can travel airborne long distances away from the eruption site. Heavy accumulations of [pb_glossary id=\"1001\"]ash[\/pb_glossary] can cause buildings to collapse. In people, it may cause respiratory issues like silicosis. [pb_glossary id=\"1001\"]Ash[\/pb_glossary] is destructive to aircraft and automobile engines, which can disrupt transportation and shipping services. In 2010, the Eyjafjallaj\u00f6kull [pb_glossary id=\"228\"]volcano[\/pb_glossary] in Iceland emitted a large [pb_glossary id=\"1001\"]ash[\/pb_glossary] cloud into the upper [pb_glossary id=\"1745\"]atmosphere[\/pb_glossary], causing the largest air-travel disruption in northern Europe since World War II. No one was injured, but the service disruption was estimated to have cost the world economy billions of dollars.\n<h4><span style=\"font-weight: 400\">Volcanic Gases<\/span><\/h4>\nAs [pb_glossary id=\"1750\"]magma[\/pb_glossary] rises to the surface the [pb_glossary id=\"1995\"]confining[\/pb_glossary] pressure decreases, and allows [pb_glossary id=\"1893\"]dissolved[\/pb_glossary] gases to escape into the [pb_glossary id=\"1745\"]atmosphere[\/pb_glossary]. Even [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] that are not actively erupting may emit hazardous gases, such as carbon dioxide (CO<sub>2<\/sub>), sulfur dioxide (SO<sub>2<\/sub>), hydrogen [pb_glossary id=\"973\"]sulfide[\/pb_glossary] (H<sub>2<\/sub>S), and hydrogen [pb_glossary id=\"972\"]halides[\/pb_glossary] (HF, HCl, or HBr).\n\nCarbon dioxide tends to sink and accumulate in depressions and basins. In [pb_glossary id=\"228\"]volcanic[\/pb_glossary] areas known to emit carbon dioxide, low-lying areas may [pb_glossary id=\"2420\"]trap[\/pb_glossary] hazardous concentrations of this colorless and odorless gas. The Mammoth Mountain Ski Resort in California, is located within the Long Valley [pb_glossary id=\"235\"]Caldera[\/pb_glossary], is one such area of carbon dioxide-producing [pb_glossary id=\"228\"]volcanism[\/pb_glossary]. In 2006, three ski patrol members died of suffocation caused by carbon dioxide after falling into a snow depression near a fumarole\u00a0<span style=\"font-weight: 400\">(<\/span><a href=\"http:\/\/volcanoes.usgs.gov\/Imgs\/Jpg\/Unzen\/MayuyamaSlide_caption.html\" target=\"_blank\" rel=\"noopener\"><span style=\"font-weight: 400\">info<\/span><\/a><span style=\"font-weight: 400\">)<\/span>.\n\nIn rare cases, [pb_glossary id=\"228\"]volcanism[\/pb_glossary] may create a sudden emission of gases without warning. Limnic eruptions (<em>limne<\/em> is Greek for lake), occur in crater lakes associated with active [pb_glossary id=\"228\"]volcanism[\/pb_glossary]. The water in these lakes is supercharged with high concentrations of [pb_glossary id=\"1893\"]dissolved[\/pb_glossary] gases. If the water is physically jolted by a [pb_glossary id=\"246\"]landslide[\/pb_glossary] or earthquake, it may [pb_glossary id=\"2195\"]trigger[\/pb_glossary] an immediate and [pb_glossary id=\"985\"]massive[\/pb_glossary] release of gases out of [pb_glossary id=\"1783\"]solution[\/pb_glossary]. An analogous example would be what happens to vigorously shaken bottle of carbonated soda when the cap is opened. An infamous limnic eruption occurred in 1986 at Lake Nyos, Cameroon. Almost 2,000 people were killed by a [pb_glossary id=\"985\"]massive[\/pb_glossary] release of carbon dioxide.\n<h4><span style=\"font-weight: 400\">Lahars<\/span><\/h4>\n[caption id=\"attachment_315\" align=\"alignleft\" width=\"300\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/MSHlahar.jpg\"><img class=\"size-medium wp-image-323\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSHlahar-300x200.jpg\" alt=\"The mud line is far up on the trees\" width=\"300\" height=\"200\"><\/a> Mud line shows the extent of lahars around Mount St. Helens.[\/caption]\n\n<strong>[pb_glossary id=\"247\"]Lahar[\/pb_glossary]<\/strong> is an Indonesian word and is used to describe a [pb_glossary id=\"228\"]volcanic[\/pb_glossary] mudflow that forms from rapidly melting snow or [pb_glossary id=\"1516\"]glaciers[\/pb_glossary]. [pb_glossary id=\"247\"]Lahars[\/pb_glossary] are slurries resembling wet concrete, and consist of water, [pb_glossary id=\"1001\"]ash[\/pb_glossary], rock fragments, and other debris. These mudflows flow down the flanks of [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] or mountains covered with freshly-erupted [pb_glossary id=\"1001\"]ash[\/pb_glossary] and on steep slopes can reach speeds of up to 80 kph (50 mph).\n\n[caption id=\"attachment_315\" align=\"alignright\" width=\"235\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/LaharsRaineer.jpg\"><img class=\"size-medium wp-image-324\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/LaharsRaineer-235x300.jpg\" alt=\"The cities are on top of old lahar deposits\" width=\"235\" height=\"300\"><\/a> Old lahars around Tacoma, Washington.[\/caption]\n\n<span style=\"font-weight: 400\">Several major cities, including Tacoma, are located on prehistoric [pb_glossary id=\"247\"]lahar[\/pb_glossary] flows that extend for many kilometers across the flood plains surrounding Mount Rainier in Washington (see map). A map of Mount Baker in Oregon shows a similar potential hazard for [pb_glossary id=\"247\"]lahar[\/pb_glossary] flows (see map). A tragic scenario played out recently, in 1985, when a [pb_glossary id=\"247\"]lahar[\/pb_glossary] from the Nevado del Ruiz [pb_glossary id=\"228\"]volcano[\/pb_glossary] in Colombia buried the town of Armero and killed an estimated 23,000 people.<\/span>\n<h4><span style=\"font-weight: 400\">Monitoring<\/span><\/h4>\nGeologists use various instruments to detect changes or indications that an eruption is imminent. The three videos show different types of [pb_glossary id=\"228\"]volcanic[\/pb_glossary] monitoring used to predict eruptions 1) earthquake activity; 2) increases in gas emission; and 3) changes in land surface orientation and elevation.\n\nOne video shows how monitoring earthquake frequency, especially special vibrational earthquakes called harmonic tremors, can detect [pb_glossary id=\"1750\"]magma[\/pb_glossary] movement and possible eruption. Another video shows how gas monitoring may be used to predict an eruption. A rapid increase of gas emission may indicate [pb_glossary id=\"1750\"]magma[\/pb_glossary] that is actively rising to surface and releasing [pb_glossary id=\"1893\"]dissolved[\/pb_glossary] gases out of [pb_glossary id=\"1783\"]solution[\/pb_glossary], and that an eruption is imminent. The last video shows how a GPS unit and tiltmeter can detect land surface changes, indicating the [pb_glossary id=\"1750\"]magma[\/pb_glossary] is moving underneath it.\n\nhttps:\/\/youtu.be\/nlo-2JoNHrw\n\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"150\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Volcano-Monitoring-Earthquake-Signals-YouTube-QR-Code.png\"><img class=\"size-thumbnail wp-image-325\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Earthquake-Signals-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a> If you are using the printed version of this OER, access this YouTube video via this QR Code.[\/caption]\n\nhttps:\/\/youtu.be\/owk4fWbw4qM\n\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"150\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Volcano-Monitoring-Measuring-Gas-emmisions-YouTube-QR-Code.png\"><img class=\"size-thumbnail wp-image-326\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Measuring-Gas-emmisions-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a> If you are using the printed version of this OER, access this YouTube video via this QR Code.[\/caption]\n\n&nbsp;\n\nhttps:\/\/youtu.be\/sNYQkxxd_0Q\n\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"150\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Volcano-Monitoring-Deformation-measured-YouTube-QR-Code.png\"><img class=\"size-thumbnail wp-image-327\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Deformation-measured-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a> If you are using the printed version of this OER, access this YouTube video via this QR Code.[\/caption]\n\n&nbsp;\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n[h5p id=\"29\"]\n\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"150\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/4.5-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-328\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.5-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a> If you are using the printed version of this OER, access the quiz for section 4.5 via this QR Code.[\/caption]\n<h2>Summary<\/h2>\n[pb_glossary id=\"1753\"]Igneous rock[\/pb_glossary] is divided into two major groups: [pb_glossary id=\"991\"]intrusive[\/pb_glossary] rock that solidifies from underground [pb_glossary id=\"1750\"]magma[\/pb_glossary], and [pb_glossary id=\"990\"]extrusive[\/pb_glossary] rock formed from [pb_glossary id=\"1751\"]lava[\/pb_glossary] that erupts and cools on the surface. [pb_glossary id=\"1750\"]Magma[\/pb_glossary] is generated from [pb_glossary id=\"1664\"]mantle[\/pb_glossary] material at several [pb_glossary id=\"1669\"]plate[\/pb_glossary] [pb_glossary id=\"1654\"]tectonics[\/pb_glossary] situations by three types of melting: [pb_glossary id=\"223\"]decompression melting[\/pb_glossary], [pb_glossary id=\"1686\"]flux melting[\/pb_glossary], or heat-induced melting. [pb_glossary id=\"1750\"]Magma[\/pb_glossary] [pb_glossary id=\"1909\"]composition[\/pb_glossary] is determined by differences in the melting temperatures of the [pb_glossary id=\"1765\"]mineral[\/pb_glossary] components ([pb_glossary id=\"221\"]Bowen\u2019s Reaction Series[\/pb_glossary]). The processes affecting [pb_glossary id=\"1750\"]magma[\/pb_glossary] [pb_glossary id=\"1909\"]composition[\/pb_glossary] include [pb_glossary id=\"224\"]partial melting[\/pb_glossary], [pb_glossary id=\"226\"]magmatic differentiation[\/pb_glossary], [pb_glossary id=\"225\"]assimilation[\/pb_glossary], and [pb_glossary id=\"1698\"]collision[\/pb_glossary]. [pb_glossary id=\"228\"]Volcanoes[\/pb_glossary] come in a wide variety of shapes and sizes, and are classified by a multiple factors, including [pb_glossary id=\"1750\"]magma[\/pb_glossary] [pb_glossary id=\"1909\"]composition[\/pb_glossary], and [pb_glossary id=\"1669\"]plate[\/pb_glossary] [pb_glossary id=\"1654\"]tectonic[\/pb_glossary] activity. Because [pb_glossary id=\"228\"]volcanism[\/pb_glossary] presents serious hazards to human civilization, geologists carefully monitor [pb_glossary id=\"228\"]volcanic[\/pb_glossary] activity to mitigate or avoid the dangers it presents.\n<h3>Take this quiz to check your comprehension of this Chapter.<\/h3>\n[h5p id=\"30\"]\n\n[caption id=\"attachment_315\" align=\"aligncenter\" width=\"150\"]<a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Ch.4-Review-QR-Code.png\"><img class=\"size-thumbnail wp-image-329\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ch.4-Review-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a> If you are using the printed version of this OER, access the review quiz for Chapter 4 via this QR Code.[\/caption]\n<h2><strong>References<\/strong><\/h2>\n<div class=\"csl-bib-body\">\n<ol>\n \t<li class=\"csl-entry\">Arndt, N.T., 1994, Chapter 1 [pb_glossary id=\"1257\"]Archean[\/pb_glossary] Komatiites, <i>in<\/i> K.C. Condie, editor, Developments in [pb_glossary id=\"1270\"]Precambrian[\/pb_glossary] Geology: Elsevier, p. 11\u201344.<\/li>\n \t<li class=\"csl-entry\">Bateman, P.C., and Chappell, B.W., 1979, [pb_glossary id=\"1752\"]Crystallization[\/pb_glossary], [pb_glossary id=\"227\"]fractionation[\/pb_glossary], and solidification of the Tuolumne [pb_glossary id=\"991\"]Intrusive[\/pb_glossary] Series, Yosemite National Park, California: Geological Society of America Bulletin, v. 90, no. 5, p. 465\u2013482., doi: &lt;a href=\"https:\/\/doi.org\/10.1130\/0016-7606(1979)902.0.CO;2\"&gt;10.1130\/0016-7606(1979)90&lt;465:CFASOT&gt;2.0.CO;2.<\/li>\n \t<li class=\"csl-entry\">Bell, K., and Keller, J., 2012, [pb_glossary id=\"2443\"]Carbonatite[\/pb_glossary] [pb_glossary id=\"228\"]volcanism[\/pb_glossary]: Oldoinyo Lengai and the petrogenesis of natrocarbonatites: Springer Science &amp; Business Media.<\/li>\n \t<li class=\"csl-entry\">Boehler, R., 1996, Melting temperatures of the Earth\u2019s [pb_glossary id=\"1664\"]mantle[\/pb_glossary] and [pb_glossary id=\"1667\"]core[\/pb_glossary]: Earth\u2019s thermal structure: Annual Review of Earth and Planetary Sciences, v. 24, no. 1, p. 15\u201340., doi: <a href=\"https:\/\/doi.org\/10.1146\/annurev.earth.24.1.15\">10.1146\/annurev.earth.24.1.15<\/a>.<\/li>\n \t<li class=\"csl-entry\">Bowen, N.L., 1922, The Reaction Principle in Petrogenesis: J. Geol., v. 30, no. 3, p. 177\u2013198.<\/li>\n \t<li class=\"csl-entry\">Bowen, N.L., 1928, The evolution of the [pb_glossary id=\"1753\"]igneous[\/pb_glossary] rocks: Dover Publications, 334 p.<\/li>\n \t<li class=\"csl-entry\">Carr, M.H., 1975, Geologic map of the Tharsis Quadrangle of Mars: IMAP.<\/li>\n \t<li class=\"csl-entry\">Earle, S., 2015, Physical geology OER textbook: BC Campus OpenEd.<\/li>\n \t<li class=\"csl-entry\">EarthScope, 2014, Mount Ontake [pb_glossary id=\"228\"]Volcanic[\/pb_glossary] Eruption: Online, <a href=\"http:\/\/www.earthscope.org\/science\/geo-events\/mount-ontake-volcanic-eruption\">http:\/\/www.earthscope.org\/science\/geo-events\/mount-ontake-volcanic-eruption<\/a>, accessed July 2016.<\/li>\n \t<li class=\"csl-entry\">Frankel, C., 2005, Worlds on Fire: [pb_glossary id=\"228\"]Volcanoes[\/pb_glossary] on the Earth, the Moon, Mars, Venus and Io: Cambridge University Press, 396 p.<\/li>\n \t<li class=\"csl-entry\">Glazner, A.F., Bartley, J.M., Coleman, D.S., Gray, W., and Taylor, R.Z., 2004, Are [pb_glossary id=\"1017\"]plutons[\/pb_glossary] assembled over millions of years by amalgamation from small [pb_glossary id=\"1750\"]magma[\/pb_glossary] chambers? GSA Today, v. 14, no. 4, p. 4., doi: &lt;a href=\"https:\/\/doi.org\/10.1130\/1052-5173(2004)0142.0.CO;2\"&gt;10.1130\/1052-5173(2004)014&lt;0004:APAOMO&gt;2.0.CO;2.<\/li>\n \t<li class=\"csl-entry\">Luongo, G., Perrotta, A., Scarpati, C., De Carolis, E., Patricelli, G., and Ciarallo, A., 2003, Impact of the AD 79 explosive eruption on Pompeii, II. Causes of death of the inhabitants inferred by [pb_glossary id=\"1937\"]stratigraphic[\/pb_glossary] analysis and areal distribution of the human casualties: J. Volcanol. Geotherm. Res., v. 126, no. 3\u20134, p. 169\u2013200.<\/li>\n \t<li class=\"csl-entry\">Mueller, S., and Phillips, R.J., 1991, On the initiation of [pb_glossary id=\"1680\"]subduction[\/pb_glossary]: J. Geophys. Res. [Solid Earth], v. 96, no. B1, p. 651\u2013665.<\/li>\n \t<li class=\"csl-entry\">Peacock, M.A., 1931, Classification of [pb_glossary id=\"1753\"]Igneous Rock[\/pb_glossary] Series: The Journal of Geology, v. 39, no. 1, p. 54\u201367.<\/li>\n \t<li class=\"csl-entry\">Perkins, S., 2011, 2010\u2019s [pb_glossary id=\"228\"]Volcano[\/pb_glossary]-Induced Air Travel Shutdown Was Justified: Online, <a href=\"http:\/\/www.sciencemag.org\/news\/2011\/04\/2010s-volcano-induced-air-travel-shutdown-was-justified\">http:\/\/www.sciencemag.org\/news\/2011\/04\/2010s-volcano-induced-air-travel-shutdown-was-justified<\/a>, accessed July 2016.<\/li>\n \t<li class=\"csl-entry\">Peterson, D.W., and Tilling, R.I., 1980, Transition of basaltic [pb_glossary id=\"1751\"]lava[\/pb_glossary] from [pb_glossary id=\"238\"]pahoehoe[\/pb_glossary] to [pb_glossary id=\"239\"]aa[\/pb_glossary], Kilauea [pb_glossary id=\"228\"]Volcano[\/pb_glossary], Hawaii: Field observations and key factors - ScienceDirect: J. Volcanol. Geotherm. Res., v. 7, no. 3\u20134, p. 271\u2013293.<\/li>\n \t<li class=\"csl-entry\">Petrini and Podladchikov, 2000, Lithospheric pressure\u2013depth relationship in [pb_glossary id=\"493\"]compressive[\/pb_glossary] regions of thickened [pb_glossary id=\"1658\"]crust[\/pb_glossary]: Journal of [pb_glossary id=\"1992\"]Metamorphic[\/pb_glossary] Geology, v. 18, no. 1, p. 67\u201377., doi: <a href=\"https:\/\/doi.org\/10.1046\/j.1525-1314.2000.00240.x\">10.1046\/j.1525-1314.2000.00240.x<\/a>.<\/li>\n \t<li class=\"csl-entry\">Reid, J.B., Evans, O.C., and Fates, D.G., 1983, [pb_glossary id=\"1750\"]Magma[\/pb_glossary] mixing in granitic rocks of the central Sierra Nevada, California: Earth and Planetary Science Letters, v. 66, p. 243\u2013261., doi: <a href=\"https:\/\/doi.org\/10.1016\/0012-821X(83)90139-5\">10.1016\/0012-821X(83)90139-5<\/a>.<\/li>\n \t<li class=\"csl-entry\">Rhodes, J.M., and Lockwood, J.P., 1995, Mauna Loa Revealed: Structure, [pb_glossary id=\"1909\"]Composition[\/pb_glossary], History, and Hazards: Washington DC American Geophysical Union Geophysical Monograph Series, v. 92.<\/li>\n \t<li class=\"csl-entry\">Scandone, R., Giacomelli, L., and Gasparini, P., 1993, Mount Vesuvius: 2000 years of volcanological observations: Journal of Volcanology and Geothermal Research, v. 58, p. 5\u201325.<\/li>\n \t<li class=\"csl-entry\">Stovall, W.K., Wilkins, A.M., Mandeville, C.W., and Driedger, C.L., 2016, Fact Sheet.:<\/li>\n \t<li class=\"csl-entry\">Thorarinsson, S., 1969, The Lakagigar eruption of 1783: Bull. Volcanol., v. 33, no. 3, p. 910\u2013929.<\/li>\n \t<li class=\"csl-entry\">Tilling, R.I., 2008, The critical role of [pb_glossary id=\"228\"]volcano[\/pb_glossary] monitoring in risk reduction: Adv. Geosci., v. 14, p. 3\u201311.<\/li>\n \t<li class=\"csl-entry\">United States Geological Survey, 1999, Exploring the deep [pb_glossary id=\"1963\"]ocean floor[\/pb_glossary]: Online, <a href=\"http:\/\/pubs.usgs.gov\/gip\/dynamic\/exploring.html\">http:\/\/pubs.usgs.gov\/gip\/dynamic\/exploring.html<\/a>, accessed July 2016.<\/li>\n \t<li class=\"csl-entry\">United States Geological Survey, 2012, Black Rock Desert [pb_glossary id=\"228\"]Volcanic[\/pb_glossary] Field: Online, <a href=\"http:\/\/volcanoes.usgs.gov\/volcanoes\/black_rock_desert\/\">http:\/\/volcanoes.usgs.gov\/volcanoes\/black_rock_desert\/<\/a>, accessed July 2016.<\/li>\n \t<li class=\"csl-entry\">USGS, 2001, Dual [pb_glossary id=\"228\"]volcanic[\/pb_glossary] tragedies in the Caribbean led to founding of HVO: Online, <a href=\"http:\/\/hvo.wr.usgs.gov\/volcanowatch\/archive\/2001\/01_05_03.html\">http:\/\/hvo.wr.usgs.gov\/volcanowatch\/archive\/2001\/01_05_03.html<\/a>, accessed July 2016.<\/li>\n \t<li class=\"csl-entry\">USGS, 2011, [pb_glossary id=\"228\"]Volcanoes[\/pb_glossary]: Principal Types of [pb_glossary id=\"228\"]Volcanoes[\/pb_glossary]: Online, <a href=\"http:\/\/pubs.usgs.gov\/gip\/volc\/types.html\">http:\/\/pubs.usgs.gov\/gip\/volc\/types.html<\/a>, accessed July 2016.<\/li>\n \t<li class=\"csl-entry\">USGS, 2012a, USGS: [pb_glossary id=\"228\"]Volcano[\/pb_glossary] Hazards Program: Online, <a href=\"https:\/\/volcanoes.usgs.gov\/vhp\/hazards.html\">https:\/\/volcanoes.usgs.gov\/vhp\/hazards.html<\/a>, accessed July 2016.<\/li>\n \t<li class=\"csl-entry\">USGS, 2012b, Yellowstone [pb_glossary id=\"228\"]Volcano[\/pb_glossary] Observatory: Online, <a href=\"https:\/\/volcanoes.usgs.gov\/volcanoes\/yellowstone\/yellowstone_geo_hist_52.html\">https:\/\/volcanoes.usgs.gov\/volcanoes\/yellowstone\/yellowstone_geo_hist_52.html<\/a>, accessed July 2016.<\/li>\n \t<li class=\"csl-entry\">USGS, 2016, [pb_glossary id=\"228\"]Volcanoes[\/pb_glossary] General - What are the different types of volcanoes? Online, <a href=\"https:\/\/www2.usgs.gov\/faq\/categories\/9819\/2730\">https:\/\/www2.usgs.gov\/faq\/categories\/9819\/2730<\/a>, accessed March 2017.<\/li>\n \t<li class=\"csl-entry\">USGS, 2017, The Volcanoes of Lewis and Clark - Mount St. Helens: Online, <a href=\"https:\/\/volcanoes.usgs.gov\/observatories\/cvo\/Historical\/LewisClark\/Info\/summary_mount_st_helens.shtml\">https:\/\/volcanoes.usgs.gov\/observatories\/cvo\/Historical\/LewisClark\/Info\/summary_mount_st_helens.shtml<\/a>, accessed March 2017.<\/li>\n \t<li class=\"csl-entry\">Wallace, P.J., 2005, [pb_glossary id=\"1684\"]Volatiles[\/pb_glossary] in [pb_glossary id=\"1680\"]subduction[\/pb_glossary] zone [pb_glossary id=\"1750\"]magmas[\/pb_glossary]: concentrations and fluxes based on melt [pb_glossary id=\"2036\"]inclusion[\/pb_glossary] and [pb_glossary id=\"228\"]volcanic[\/pb_glossary] gas data: Journal of Volcanology and Geothermal Research, v. 140, no. 1\u20133, p. 217\u2013240., doi: <a href=\"https:\/\/doi.org\/10.1016\/j.jvolgeores.2004.07.023\">10.1016\/j.jvolgeores.2004.07.023<\/a>.<\/li>\n \t<li class=\"csl-entry\">Williams, H., 1942, The Geology of Crater Lake National Park, Oregon: With a Reconnaissance of the Cascade Range Southward to Mount Shasta: Carnegie institution.<\/li>\n<\/ol>\n<\/div>","rendered":"<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 2031px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/IT-PompeiiVesuvius.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-235 size-full\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/12\/IT-PompeiiVesuvius.jpg\" alt=\"The town in Italy is a ruin.\" width=\"2031\" height=\"1355\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/12\/IT-PompeiiVesuvius.jpg 2031w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/12\/IT-PompeiiVesuvius-300x200.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/12\/IT-PompeiiVesuvius-1024x683.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/12\/IT-PompeiiVesuvius-768x512.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/12\/IT-PompeiiVesuvius-1536x1025.jpg 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/12\/IT-PompeiiVesuvius-65x43.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/12\/IT-PompeiiVesuvius-225x150.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/12\/IT-PompeiiVesuvius-350x234.jpg 350w\" sizes=\"auto, (max-width: 2031px) 100vw, 2031px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Mount Vesuvius towers over the ruins of Pompeii, a city destroyed by the eruption in 79 CE.<\/figcaption><\/figure>\n<h1>4 Igneous Processes and Volcanoes<\/h1>\n<p><b>KEY CONCEPTS<\/b><\/p>\n<p><strong>By the end of this chapter, students should be able to:<\/strong><\/p>\n<ul>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Explain the origin of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> it relates to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">plate tectonics<\/a><\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Describe how the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_221\">Bowen\u2019s Reaction Series<\/a>\u00a0relates <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1752\">crystallization<\/a> and melting temperatures<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Explain how cooling of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> leads to rock compositions and textures, and how these are used to classify <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Analyze the features of common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> landforms and how they relate to their origin<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Explain <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_224\">partial melting<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_227\">fractionation<\/a>, and how they change <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> compositions<\/span><\/li>\n<li>Describe how silica content affects <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> viscosity and eruptive style of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Describe <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a> types, eruptive styles, composition, and their <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a> settings<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Describe <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> hazards<\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400\"><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">Igneous<\/a>\u00a0rock<\/strong> is\u00a0formed when liquid rock freezes into a solid rock. This molten material is called <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a><\/strong>\u00a0when it is in the ground and\u00a0<strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a><\/strong>\u00a0when it is on the surface. <\/span><span style=\"font-weight: 400\">Only the Earth&rsquo;s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1673\">outer core<\/a> is liquid; the Earth&rsquo;s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a> is naturally solid. However, there are<\/span><span style=\"font-weight: 400\">\u00a0a few minor pockets of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> that form near the surface where geologic processes cause melting. It is this <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> that becomes the source for <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous rocks<\/a>. This chapter will describe the classification of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks, the unique processes that form <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magmas<\/a>, types of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> processes, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> hazards, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a>\u00a0landforms.\u00a0<\/span><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.1_Pahoehoe_and_Aa_flows_at_Hawaii.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-236\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.1_Pahoehoe_and_Aa_flows_at_Hawaii-300x200.jpg\" alt=\"Pahoehoe lava flow in Hawaii\" width=\"300\" height=\"200\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.1_Pahoehoe_and_Aa_flows_at_Hawaii-300x200.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.1_Pahoehoe_and_Aa_flows_at_Hawaii-1024x684.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.1_Pahoehoe_and_Aa_flows_at_Hawaii-768x513.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.1_Pahoehoe_and_Aa_flows_at_Hawaii-1536x1026.jpg 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.1_Pahoehoe_and_Aa_flows_at_Hawaii-65x43.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.1_Pahoehoe_and_Aa_flows_at_Hawaii-225x150.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.1_Pahoehoe_and_Aa_flows_at_Hawaii-350x234.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.1_Pahoehoe_and_Aa_flows_at_Hawaii.jpg 1920w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Lava flow in Hawaii<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">Lava<\/a> cools quickly on the surface of the earth and forms tiny microscopic crystals. These are known as fine-grained\u00a0<b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_990\">extrusive<\/a><\/b>, or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_990\">Extrusive<\/a> rocks are often <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_997\">vesicular<\/a><\/strong>, filled with holes from escaping gas bubbles. <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">Volcanism<\/a><\/strong> is the process in which <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> is erupted. Depending on the properties of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> that is erupted, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> can be drastically different, from smooth and gentle to dangerous and explosive. This leads to different types of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> and different <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> hazards.<\/span><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Half-Dome-a-granitic-batholith-in-Yosemite.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-237\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Half-Dome-a-granitic-batholith-in-Yosemite-300x257.jpg\" alt=\"An intrusive igneous mass now exposed at the surface by erosion\" width=\"300\" height=\"257\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Half-Dome-a-granitic-batholith-in-Yosemite-300x257.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Half-Dome-a-granitic-batholith-in-Yosemite-768x657.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Half-Dome-a-granitic-batholith-in-Yosemite-65x56.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Half-Dome-a-granitic-batholith-in-Yosemite-225x193.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Half-Dome-a-granitic-batholith-in-Yosemite-350x300.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Half-Dome-a-granitic-batholith-in-Yosemite.jpg 784w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Half Dome, an intrusive igneous batholith in Yosemite National Park<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\">In contrast, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> that cools slowly below the earth\u2019s surface forms larger crystals which can be seen with the naked eye. These are known as coarse-grained\u00a0<b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_991\">intrusive<\/a><\/b>, or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_991\">plutonic<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks. This relationship between cooling rates and grain sizes of the solidified <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks is important for interpreting the rock\u2019s geologic history.<\/span><\/p>\n<h2>\u00a0<span style=\"font-weight: 400\">4.1 Classification of Igneous Rocks<\/span><\/h2>\n<p><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">Igneous<\/a> rocks are classified based on texture and composition. Texture describes the physical characteristics of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, such as grain size. This relates to the cooling history of the molten <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> from which it came. Composition refers to the rock&rsquo;s specific mineralogy and chemical composition. Cooling history is also related to changes that can occur to the composition of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks.<\/span><\/p>\n<h3><b>4.1.1 Texture<\/b><\/h3>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Fig-6.3-Granite-vs-Gneiss-e1495050932921.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-238\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Fig-6.3-Granite-vs-Gneiss-e1495050932921-300x271.jpg\" alt=\"Image showing three or four distinct colors of clearly visible minerals.\" width=\"300\" height=\"271\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Fig-6.3-Granite-vs-Gneiss-e1495050932921-300x271.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Fig-6.3-Granite-vs-Gneiss-e1495050932921-65x59.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Fig-6.3-Granite-vs-Gneiss-e1495050932921-225x203.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Fig-6.3-Granite-vs-Gneiss-e1495050932921-350x316.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Fig-6.3-Granite-vs-Gneiss-e1495050932921.jpg 552w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Granite is a classic coarse-grained (phaneritic) intrusive igneous rock. The different colors are unique minerals. The black colors are likely two or three different minerals.<\/figcaption><\/figure>\n<p>If <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> cools slowly, deep within the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a>, the resulting rock is called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_991\">intrusive<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_991\">plutonic<\/a>. The slow cooling process allows crystals to grow large, giving <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_991\">intrusive<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous rock<\/a> a coarse-grained or <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_992\">phaneritic<\/a><\/strong> texture. The individual crystals in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_992\">phaneritic<\/a> texture are readily visible to the unaided eye.<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 284px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/IMG_2623-e1495051966958-scaled.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-2840\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/IMG_2623-e1495051966958-scaled-1.jpg\" alt=\"Show dark rock with no visible minerals except for a few tiny green minerals that are olivine.\" width=\"284\" height=\"300\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Basalt is a classic fine-grained extrusive igneous rock. This sample is mostly fine groundmass with a few small green phenocrysts that are the mineral olivine.<\/figcaption><\/figure>\n<p>When <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> is extruded onto the surface, or intruded into shallow fissures near the surface and cools, the resulting <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous rock<\/a> is called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_990\">extrusive<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_990\">Extrusive<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks have a fine-grained or <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_993\">aphanitic<\/a><\/strong> texture, in which the grains are too small to see with the unaided eye. The fine-grained texture indicates the quickly cooling <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> did not have time to grow large crystals. These tiny crystals can be viewed under a petrographic microscope. In some cases, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_990\">extrusive<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> cools so rapidly it does not develop crystals at all. This non-crystalline material is not classified as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, but as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> glass<span style=\"font-weight: 400\">. This is a common component of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">ash<\/a> and rocks like <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_999\">obsidian<\/a>.<\/span><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.5_Porphyritic_texture.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-240\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.5_Porphyritic_texture-300x223.jpg\" alt=\"Porphyritic teture with large crystals in a finer grained groundmass\" width=\"300\" height=\"223\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.5_Porphyritic_texture-300x223.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.5_Porphyritic_texture-65x48.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.5_Porphyritic_texture-225x168.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.5_Porphyritic_texture-350x261.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.5_Porphyritic_texture.jpg 419w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Porphyritic texture<\/figcaption><\/figure>\n<p>Some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks have a mix of coarse-grained <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> surrounded by a matrix of fine-grained material in a texture called <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_994\">porphyritic<\/a><\/strong>. The large crystals are called <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_995\">phenocrysts<\/a><\/strong> and the fine-grained matrix is called the <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1011\">groundmass<\/a><\/strong> or <strong>matrix<\/strong>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_994\">Porphyritic<\/a> texture indicates the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> body underwent a multi-stage cooling history, cooling slowly while deep under the surface and later rising to a shallower depth or the surface where it cooled more quickly.<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.6_We-pegmatite.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-241\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.6_We-pegmatite-300x224.jpg\" alt=\"Pegmatic texture with large grains of minerals, mostly of felsic composition\" width=\"300\" height=\"224\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.6_We-pegmatite-300x224.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.6_We-pegmatite-768x574.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.6_We-pegmatite-65x49.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.6_We-pegmatite-225x168.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.6_We-pegmatite-350x261.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.6_We-pegmatite.jpg 849w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Pegmatitic texture<\/figcaption><\/figure>\n<p>Residual molten material expelled from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> intrusions may form veins or masses containing very large crystals of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> like <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a>, beryl, tourmaline, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">mica<\/a>. This texture, which indicates a very slow <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1752\">crystallization<\/a>, is called <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_996\">pegmatitic<\/a><\/strong>. A rock that chiefly consists of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_996\">pegmatitic<\/a> texture is known as a <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_996\">pegmatite<\/a><\/strong>. To give an example of how large these crystals can get, transparent cleavage sheets of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_996\">pegmatitic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">muscovite<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">mica<\/a> were used as windows during the Middle Ages.<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.7_Scoria_Macro_Digon3-e1495227072616.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-242\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.7_Scoria_Macro_Digon3-e1495227072616-300x286.jpg\" alt=\"A lava rock full of bubbles called scoria\" width=\"300\" height=\"286\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.7_Scoria_Macro_Digon3-e1495227072616-300x286.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.7_Scoria_Macro_Digon3-e1495227072616-1024x976.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.7_Scoria_Macro_Digon3-e1495227072616-768x732.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.7_Scoria_Macro_Digon3-e1495227072616-65x62.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.7_Scoria_Macro_Digon3-e1495227072616-225x214.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.7_Scoria_Macro_Digon3-e1495227072616-350x334.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.7_Scoria_Macro_Digon3-e1495227072616.jpg 1342w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Scoria<\/figcaption><\/figure>\n<p>All <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magmas<\/a> contain gases dissolved in solution called <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1684\">volatiles<\/a><\/strong>. As the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> rises to the surface, the drop in pressure causes the dissolved <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1684\">volatiles<\/a> to come bubbling out of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a>, like the fizz in an opened bottle of soda. The gas bubbles become trapped in the solidifying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> to create a <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_997\">vesicular<\/a><\/strong> texture, with the holes specifically called vesicles. The type of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_990\">volcanic rock<\/a> with common vesicles is called <strong>scoria<\/strong>.<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 250px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.9_Pumice_stone-e1495052465796.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-243\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.9_Pumice_stone-e1495052465796-298x300.jpg\" alt=\"A pumice stone, a hardened froth of volcanic glass\" width=\"250\" height=\"251\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.9_Pumice_stone-e1495052465796-298x300.jpg 298w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.9_Pumice_stone-e1495052465796-150x150.jpg 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.9_Pumice_stone-e1495052465796-768x772.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.9_Pumice_stone-e1495052465796-65x65.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.9_Pumice_stone-e1495052465796-225x226.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.9_Pumice_stone-e1495052465796-350x352.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.9_Pumice_stone-e1495052465796.jpg 784w\" sizes=\"auto, (max-width: 250px) 100vw, 250px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Pumice<\/figcaption><\/figure>\n<p>An extreme version of scoria occurs when volatile-rich <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a>\u00a0is very quickly quenched and becomes a meringue-like froth of glass called <b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_998\">pumice<\/a><\/b>. Some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_998\">pumice<\/a> is so full of vesicles that the density of the rock drops low enough that it will float.<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 200px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.8_Lipari-Obsidienne_5.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-244\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.8_Lipari-Obsidienne_5-300x225.jpg\" alt=\"Photo of obsidian, a volcanic glass\" width=\"200\" height=\"150\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.8_Lipari-Obsidienne_5-300x225.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.8_Lipari-Obsidienne_5-1024x768.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.8_Lipari-Obsidienne_5-768x576.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.8_Lipari-Obsidienne_5-1536x1152.jpg 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.8_Lipari-Obsidienne_5-65x49.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.8_Lipari-Obsidienne_5-225x169.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.8_Lipari-Obsidienne_5-350x263.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.8_Lipari-Obsidienne_5.jpg 1920w\" sizes=\"auto, (max-width: 200px) 100vw, 200px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Obsidian (volcanic glass). Note conchoidal fracture.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">Lava<\/a> that cools extremely quickly may not form crystals at all, even microscopic ones. The resulting rock is called\u00a0<strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> glass<\/strong>. <strong>O<\/strong><\/span><b>bsidian<\/b> is a rock consisting of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> glass.\u00a0<span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_999\">Obsidian<\/a> as a glassy rock shows an excellent example of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_987\">conchoidal<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_986\">fracture<\/a> similar to the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a> (see <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/3-minerals\/\">Chapter 3<\/a>).<\/span><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.11_HoleInTheWallTuff.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-245\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.11_HoleInTheWallTuff-300x225.jpg\" alt=\"Tuff showing various size fragments of minerals and ash blown out of a volcano\" width=\"300\" height=\"225\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.11_HoleInTheWallTuff-300x225.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.11_HoleInTheWallTuff-1024x768.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.11_HoleInTheWallTuff-768x576.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.11_HoleInTheWallTuff-1536x1152.jpg 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.11_HoleInTheWallTuff-65x49.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.11_HoleInTheWallTuff-225x169.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.11_HoleInTheWallTuff-350x263.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.11_HoleInTheWallTuff.jpg 1920w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Welded tuff<\/figcaption><\/figure>\n<p>When <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> erupt explosively, vast amounts of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a>, rock, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">ash<\/a>, and gases are thrown into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1745\">atmosphere<\/a>. The solid parts, called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1000\">tephra<\/a>, settle back to earth and cool into rocks with <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1004\">pyroclastic<\/a><\/strong> textures. <em>Pyro,<\/em> meaning fire, refers to the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> source of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1000\">tephra<\/a> and <em>clastic <\/em>refers to the rock fragments. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1000\">Tephra<\/a> fragments are named based on size\u2014<strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">ash<\/a><\/strong> (&lt;2 mm), <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1002\">lapilli<\/a><\/strong> (2-64 mm), and <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1003\">bombs<\/a> or blocks<\/strong> (&gt;64 mm). <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1004\">Pyroclastic<\/a> texture is usually recognized by the chaotic mix of crystals, angular glass shards, and rock fragments. Rock formed from large deposits of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1000\">tephra<\/a> fragments is called <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1005\">tuff<\/a><\/strong>. If the fragments accumulate while still hot, the heat may deform the crystals and weld the mass together, forming a welded <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1005\">tuff<\/a>.<\/p>\n<h3><b>4.1.2 Composition<\/b><\/h3>\n<p>Composition refers to a rock\u2019s chemical and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> make-up . For <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous rock<\/a>, composition is divided into four groups: <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a><\/strong>, <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1007\">intermediate<\/a><\/strong>, <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a><\/strong>, and <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1009\">ultramafic<\/a><\/strong><em>.<\/em> These groups refer to differing amounts of silica, iron, and magnesium found in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> that make up the rocks. It is important to realize these groups do not have sharp boundaries in nature, but rather lie on a continuous spectrum with many transitional compositions and names that refer to specific quantities of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>.\u00a0<span style=\"font-weight: 400\">As an example, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1014\">granite<\/a> is a commonly-used term, but has a very specific definition which includes exact quantities of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> like <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a>. Rocks labeled as &lsquo;<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1014\">granite<\/a>&lsquo; in laymen applications can be several other rocks, including\u00a0 syenite, tonalite, and monzonite.\u00a0<\/span>To avoid these complications, the following figure presents a simplified version of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous rock<\/a> nomenclature focusing on the four main groups, which is adequate for an introductory student.<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 1672px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Igneous-rock-composition-as-volume-percentages-of-minerals.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-246\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Igneous-rock-composition-as-volume-percentages-of-minerals.jpg\" alt=\"Diagram showing the mineral composition of the four classes of igneous rocks, ultramafic, mafic, intermediate, and felsic.\" width=\"1672\" height=\"1182\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Igneous-rock-composition-as-volume-percentages-of-minerals.jpg 1672w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Igneous-rock-composition-as-volume-percentages-of-minerals-300x212.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Igneous-rock-composition-as-volume-percentages-of-minerals-1024x724.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Igneous-rock-composition-as-volume-percentages-of-minerals-768x543.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Igneous-rock-composition-as-volume-percentages-of-minerals-1536x1086.jpg 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Igneous-rock-composition-as-volume-percentages-of-minerals-65x46.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Igneous-rock-composition-as-volume-percentages-of-minerals-225x159.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Igneous-rock-composition-as-volume-percentages-of-minerals-350x247.jpg 350w\" sizes=\"auto, (max-width: 1672px) 100vw, 1672px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Mineral composition of common igneous rocks. Percentage of minerals is shown on the vertical axis. Percentage of silica is shown on the horizontal axis. Rock names at the top include a continuous spectrum of compositions grading from one into another.<\/figcaption><\/figure>\n<p><b>Fel<\/b><span style=\"font-weight: 400\">sic refers to a predominance of the light-colored (<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a>) <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>\u00a0<\/span><span style=\"text-decoration: underline\"><b>fel<\/b><\/span><span style=\"font-weight: 400\">dspar and <span style=\"text-decoration: underline\"><strong>si<\/strong><\/span>lica in the form of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a>. These light-colored <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> have more silica as a proportion of their overall chemical formula. Minor amounts of dark-colored (<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a>) <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> like <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1791\">amphibole<\/a> and biotite <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">mica<\/a> may be present as well. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">Felsic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks are rich in silica (in the 65-75% range, meaning the rock would be 65-75% weight percent SiO<sup>2<\/sup>) and poor in iron and magnesium.<\/span><\/p>\n<p><b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1007\">Intermediate<\/a><\/b> is a composition between <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a>.\u00a0 It usually contains roughly-equal amounts of light and dark <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, including light grains of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">plagioclase<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> and dark <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> like amphibole.\u00a0 It is <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1007\">intermediate<\/a> in silica in the 55-60% range.<\/p>\n<p><b>Maf<\/b><span style=\"font-weight: 400\">ic refers to a abundance of ferromagnesian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> (with magnesium and iron, chemical symbols <\/span><b>M<\/b>g<span style=\"font-weight: 400\">\u00a0and <\/span><b>F<\/b><span style=\"font-weight: 400\">e) plus <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">plagioclase<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a>. It is mostly made of dark <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> like <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">pyroxene<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">olivine<\/a>, which are rich in iron and magnesium and relatively poor in silica. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">Mafic<\/a> rocks are low in silica, in the 45-50% range.<\/span><\/p>\n<p><span style=\"font-weight: 400\"><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1009\">Ultramafic<\/a><\/strong> refers to the extremely <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> rocks composed of mostly <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">olivine<\/a> and some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">pyroxene<\/a> which have even more magnesium and iron and even less silica. T<\/span><span style=\"font-weight: 400\">hese rocks are rare on the surface, but make up <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1666\">peridotite<\/a>, the rock of the upper <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a>. It is poor in silica, in the 40% or less range.<\/span><\/p>\n<p><span style=\"font-weight: 400\">On the figure above, the top row has both <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_991\">plutonic<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks arranged in a continuous spectrum from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> on the left to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1007\">intermediate<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1009\">ultramafic<\/a> toward the right.\u00a0<\/span><b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1010\">Rhyolite<\/a><\/b><span style=\"font-weight: 400\">\u00a0thus refers to the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks, and <\/span><b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1014\">granite<\/a><\/b><span style=\"font-weight: 400\"> thus refer to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_991\">intrusive<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks. <\/span><b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1012\">Andesite<\/a><\/b><span style=\"font-weight: 400\"> and <\/span><b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1015\">diorite<\/a><\/b><span style=\"font-weight: 400\">\u00a0likewise refer to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_990\">extrusive<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_991\">intrusive<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1007\">intermediate<\/a> rocks (with <\/span>dacite<span style=\"font-weight: 400\"> and <\/span>granodiorite<span style=\"font-weight: 400\"> applying to those rocks with composition between <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1007\">intermediate<\/a>).\u00a0<\/span><b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1013\">Basalt<\/a><\/b><span style=\"font-weight: 400\"> and <\/span><b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1016\">gabbro<\/a><\/b><span style=\"font-weight: 400\"> are the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_990\">extrusive<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_991\">intrusive<\/a> names for <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks, and <\/span><b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1666\">peridotite<\/a><\/b><span style=\"font-weight: 400\"> is <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1009\">ultramafic<\/a>, with\u00a0<b>komatiite<\/b> as the fine-grained <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_990\">extrusive<\/a> equivalent. Komatiite is a rare rock because <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> material that comes direct from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> is not common, although some examples can be found in ancient <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1257\">Archean<\/a> rocks<\/span><span style=\"font-weight: 400\">. Nature rarely has sharp boundaries and the classification and naming of rocks often imposes what appear to be sharp boundary names onto a continuous spectrum.<\/span><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 2048px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Igneous-Classification-cropped-scaled.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-2848\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Igneous-Classification-cropped-scaled-1.jpg\" alt=\"Classification table of igneous rock.\" width=\"2048\" height=\"2560\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Igneous rock classification table with composition as vertical columns and texture as horizontal rows.<\/figcaption><\/figure>\n<h4><strong>Aphanitic\/Phaneritic Rock Types with images<\/strong><\/h4>\n<table style=\"height: 1296px\">\n<tbody>\n<tr style=\"height: 15px\">\n<td style=\"text-align: center;vertical-align: middle;height: 15px;width: 810.062px\" colspan=\"2\">\n<div class=\"mceTemp\"><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">Felsic<\/a> Composition<\/strong><\/div>\n<\/td>\n<\/tr>\n<tr style=\"height: 279px\">\n<td style=\"text-align: center;vertical-align: middle;height: 279px;width: 397.672px\">\n<figure id=\"attachment_2849\" aria-describedby=\"caption-attachment-2849\" style=\"width: 300px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/550px-Quartz_monzonite_36mw1037.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-248\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/550px-Quartz_monzonite_36mw1037-300x262.jpg\" alt=\"Photograph of cut granite. showing a variety of visible minerals, including quartz and k-feldspar.\" width=\"300\" height=\"262\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/550px-Quartz_monzonite_36mw1037-300x262.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/550px-Quartz_monzonite_36mw1037-65x57.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/550px-Quartz_monzonite_36mw1037-225x196.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/550px-Quartz_monzonite_36mw1037-350x305.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/550px-Quartz_monzonite_36mw1037.jpg 550w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-2849\" class=\"wp-caption-text\">Granite from Cape Cod, Massachusetts.<\/figcaption><\/figure>\n<\/td>\n<td style=\"text-align: center;vertical-align: middle;height: 279px;width: 399.453px\">\n<figure id=\"attachment_2850\" aria-describedby=\"caption-attachment-2850\" style=\"width: 300px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/lossy-page1-640px-PinkRhyolite.tif_.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-249\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/lossy-page1-640px-PinkRhyolite.tif_-300x214.jpg\" alt=\"Fine Crystalline rock with larger glassy fragments floating in the groundmass.\" width=\"300\" height=\"214\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/lossy-page1-640px-PinkRhyolite.tif_-300x214.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/lossy-page1-640px-PinkRhyolite.tif_-65x46.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/lossy-page1-640px-PinkRhyolite.tif_-225x161.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/lossy-page1-640px-PinkRhyolite.tif_-350x250.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/lossy-page1-640px-PinkRhyolite.tif_.jpg 640w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-2850\" class=\"wp-caption-text\">Rhyolite (source: Michael C. Rygel via Wikimedia Commons)<\/figcaption><\/figure>\n<\/td>\n<\/tr>\n<tr style=\"height: 221px\">\n<td style=\"height: 221px;width: 397.672px\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1014\">Granite<\/a> is a course-crystalline <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_991\">intrusive<\/a> rock. \u00a0The presence of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a> is a good indicator of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1014\">granite<\/a>. \u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1014\">Granite<\/a> commonly has large amounts of salmon pink potassium <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> and white <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">plagioclase<\/a> crystals that have visible\u00a0cleavage planes. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1014\">Granite<\/a> is a good approximation for the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental crust<\/a>, both in density and composition.<\/td>\n<td style=\"height: 221px;width: 399.453px\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1010\">Rhyolite<\/a>\u00a0is a fine-crystalline <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_990\">extrusive<\/a> rock. \u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1010\">Rhyolite<\/a> is commonly pink and will often have glassy <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_995\">phenocrysts<\/a>.\u00a0 Because <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> lavas are less mobile, it is less common than <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1014\">granite<\/a>. Examples of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1010\">rhyolite<\/a> include several <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> flows in Yellowstone National Park and the altered <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1010\">rhyolite<\/a> that makes up the Grand Canyon of the Yellowstone.<\/td>\n<\/tr>\n<tr style=\"height: 15px\">\n<td style=\"text-align: center;height: 15px;width: 810.062px\" colspan=\"2\">\u00a0\u00a0<strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1007\">Intermediate<\/a> Composition<\/strong><\/td>\n<\/tr>\n<tr style=\"height: 257px\">\n<td style=\"height: 257px;width: 397.672px\">\n<figure id=\"attachment_2851\" aria-describedby=\"caption-attachment-2851\" style=\"width: 300px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Diorite_MA-e1496027879779.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-250\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Diorite_MA-e1496027879779-300x225.jpg\" alt=\"Rock with visible black and white crystals.\" width=\"300\" height=\"225\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Diorite_MA-e1496027879779-300x225.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Diorite_MA-e1496027879779-768x576.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Diorite_MA-e1496027879779-65x49.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Diorite_MA-e1496027879779-225x169.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Diorite_MA-e1496027879779-350x263.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Diorite_MA-e1496027879779.jpg 808w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-2851\" class=\"wp-caption-text\">Diorite<\/figcaption><\/figure>\n<\/td>\n<td style=\"height: 257px;width: 399.453px\">\n<figure id=\"attachment_2852\" aria-describedby=\"caption-attachment-2852\" style=\"width: 300px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Andesite2.tif_.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-251\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Andesite2.tif_-300x240.jpg\" alt=\"Grey rock with fine crystals and black phenocrysts.\" width=\"300\" height=\"240\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Andesite2.tif_-300x240.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Andesite2.tif_-65x52.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Andesite2.tif_-225x180.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Andesite2.tif_-350x280.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Andesite2.tif_.jpg 600w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-2852\" class=\"wp-caption-text\">Andesite<\/figcaption><\/figure>\n<\/td>\n<\/tr>\n<tr style=\"height: 158px\">\n<td style=\"height: 158px;width: 397.672px\">\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1015\">Diorite<\/a> is a coarse-crystalline <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1007\">intermediate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_991\">intrusive<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous rock<\/a>. Diorite is identifiable by it&rsquo;s Dalmatian-like appearance of black hornblende and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">biotite<\/a>\u00a0and white <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">plagioclase<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a>. It is found in its namesake, the Andes Mountains as well as the Henry and Abajo mountains of Utah.<\/td>\n<td style=\"height: 158px;width: 399.453px\">\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1012\">Andesite<\/a> is a fine crystalline <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1007\">intermediate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_990\">extrusive<\/a> rock. \u00a0It is commonly grey and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_994\">porphyritic<\/a>. \u00a0It can be found in the Andes Mountains and in some island arcs (see <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/2-plate-tectonics\/\">Chapter 2<\/a>). It is the fine grained compositional equivalent of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1015\">diorite<\/a>.<\/td>\n<\/tr>\n<tr style=\"height: 15px\">\n<td style=\"text-align: center;height: 15px;width: 810.062px\" colspan=\"2\"><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">Mafic<\/a> Composition<\/strong><\/td>\n<\/tr>\n<tr style=\"height: 242px\">\n<td style=\"height: 242px;width: 397.672px\">\n<figure id=\"attachment_2853\" aria-describedby=\"caption-attachment-2853\" style=\"width: 300px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/GabbroRockCreek1.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-252\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/GabbroRockCreek1-300x215.jpg\" alt=\"Dark rock with visible crystals.\" width=\"300\" height=\"215\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/GabbroRockCreek1-300x215.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/GabbroRockCreek1-1024x735.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/GabbroRockCreek1-768x551.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/GabbroRockCreek1-1536x1103.jpg 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/GabbroRockCreek1-65x47.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/GabbroRockCreek1-225x162.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/GabbroRockCreek1-350x251.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/GabbroRockCreek1.jpg 2000w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-2853\" class=\"wp-caption-text\">Gabbro<\/figcaption><\/figure>\n<\/td>\n<td style=\"height: 242px;width: 399.453px\">\n<figure id=\"attachment_2854\" aria-describedby=\"caption-attachment-2854\" style=\"width: 300px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/VessicularBasalt1.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-253\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/VessicularBasalt1-300x225.jpg\" alt=\"Dark grey rock with many visible holes and no visible crystals.\" width=\"300\" height=\"225\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/VessicularBasalt1-300x225.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/VessicularBasalt1-65x49.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/VessicularBasalt1-225x169.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/VessicularBasalt1-350x263.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/VessicularBasalt1.jpg 704w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-2854\" class=\"wp-caption-text\">Vesicular Basalt<\/figcaption><\/figure>\n<\/td>\n<\/tr>\n<tr style=\"height: 94px\">\n<td style=\"height: 94px;width: 397.672px\">\n<div class=\"mceTemp\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1016\">Gabbro<\/a> is a coarse-grained <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous rock<\/a>, made with mainly <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> like <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">pyroxene<\/a> and only minor <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">plagioclase<\/a>. Because <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> is more mobile, it is less common than <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1013\">basalt<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1016\">Gabbro<\/a> is a major component of the lower <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic crust<\/a>.<\/div>\n<\/td>\n<td style=\"height: 94px;width: 399.453px\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1013\">Basalt<\/a> is a fine-grained <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous rock<\/a>. It is commonly <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_997\">vesicular<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_993\">aphanitic<\/a>. When <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_994\">porphyritic<\/a>, it often has either <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">olivine<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">plagioclase<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_995\">phenocrysts<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1013\">Basalt<\/a> is the main rock which is formed at <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridges<\/a>, and is therefore the most common rock on the Earth&rsquo;s surface, making up the entirety of the ocean floor (except where covered by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediment<\/a>).<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h3><b>4.1.3 Igneous Rock Bodies<\/b><\/h3>\n<p><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">Igneous<\/a> rocks are common in the geologic record, but surprisingly, it is the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_991\">intrusive<\/a> rocks that are more common. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_990\">Extrusive<\/a> rocks, because of their small crystals and glass, are less durable. Plus, they are, by definition, exposed to the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1755\">erosion<\/a> immediately. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_991\">Intrusive<\/a> rocks, forming underground with larger, stronger crystals, are more likely to last. Therefore, most landforms and rock groups that owe their origin to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks are <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_991\">intrusive<\/a> bodies. A significant exception to this is active <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a>, which are discussed in a <a href=\"#4-5Volcanism\">later section on volcanism<\/a>. This section will focus on the common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> bodies which are found in many places within the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1023\">bedrock<\/a> of Earth.<\/span><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Olivine-gabbro-dike-cuts-across-Baffin-Island-in-the-Canadian-Arctic.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-254\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Olivine-gabbro-dike-cuts-across-Baffin-Island-in-the-Canadian-Arctic-300x201.jpg\" alt=\"Igneous dike cuts across Baffin Island in the Canadian Arctic.\" width=\"300\" height=\"201\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Olivine-gabbro-dike-cuts-across-Baffin-Island-in-the-Canadian-Arctic-300x201.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Olivine-gabbro-dike-cuts-across-Baffin-Island-in-the-Canadian-Arctic-1024x687.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Olivine-gabbro-dike-cuts-across-Baffin-Island-in-the-Canadian-Arctic-768x515.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Olivine-gabbro-dike-cuts-across-Baffin-Island-in-the-Canadian-Arctic-65x44.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Olivine-gabbro-dike-cuts-across-Baffin-Island-in-the-Canadian-Arctic-225x151.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Olivine-gabbro-dike-cuts-across-Baffin-Island-in-the-Canadian-Arctic-350x235.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Olivine-gabbro-dike-cuts-across-Baffin-Island-in-the-Canadian-Arctic.jpg 1394w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Dike of olivine gabbro cuts across Baffin Island in the Canadian Arctic<\/figcaption><\/figure>\n<p>When <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> intrudes into a weakness like a crack or fissure and solidifies, the resulting cross-cutting feature is called a <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1021\">dike<\/a><\/strong>\u00a0(sometimes spelled <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1021\">dyke<\/a>)<span style=\"font-weight: 400\">. Because of this, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1021\">dikes<\/a> are often vertical or at an angle relative to the pre-existing rock layers that they intersect. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1021\">Dikes<\/a> are therefore discordant intrusions, not following any layering that was present. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1021\">Dikes<\/a> are important to geologists, not only for the study of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks themselves but also for dating rock sequences and interpreting the geologic history of an area. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1021\">dike<\/a> is younger than the rocks it cuts across and, as discussed in the chapter on Geologic Time (<a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/7-geologic-time\/\">Chapter 7<\/a>), may be used to assign actual numeric ages to sedimentary sequences, which are notoriously difficult to age date.\u00a0<\/span><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.14_Horton_Bluff_mid-Carboniferous_sill.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-255\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.14_Horton_Bluff_mid-Carboniferous_sill-300x225.jpg\" alt=\"Igneous sill intruding in between Paleozoic strata in Nova Scotia\" width=\"300\" height=\"225\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.14_Horton_Bluff_mid-Carboniferous_sill-300x225.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.14_Horton_Bluff_mid-Carboniferous_sill-1024x768.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.14_Horton_Bluff_mid-Carboniferous_sill-768x576.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.14_Horton_Bluff_mid-Carboniferous_sill-1536x1152.jpg 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.14_Horton_Bluff_mid-Carboniferous_sill-65x49.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.14_Horton_Bluff_mid-Carboniferous_sill-225x169.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.14_Horton_Bluff_mid-Carboniferous_sill-350x263.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.14_Horton_Bluff_mid-Carboniferous_sill.jpg 1920w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Igneous sill intruding between Paleozoic strata in Nova Scotia<\/figcaption><\/figure>\n<p><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1022\">Sills<\/a><\/strong> are another type of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_991\">intrusive<\/a> structure. A <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1022\">sill<\/a> is a concordant intrusion that runs parallel to the sedimentary layers in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1023\">country rock<\/a>. They are formed when <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> exploits a weakness between these layers, shouldering them apart and squeezing between them. As with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1021\">dikes<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1022\">sills<\/a> are younger than the surrounding layers and may be radioactively dated to study the age of sedimentary strata.<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Cottonwood-Stock-at-mouth-of-Little-Cottonwood-Canyon-Utah.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-256\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Cottonwood-Stock-at-mouth-of-Little-Cottonwood-Canyon-Utah-300x245.jpg\" alt=\"Exposure of Cottonwood Stock in Little Cottonwood Canyon, Utah\" width=\"300\" height=\"245\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Cottonwood-Stock-at-mouth-of-Little-Cottonwood-Canyon-Utah-300x245.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Cottonwood-Stock-at-mouth-of-Little-Cottonwood-Canyon-Utah-1024x837.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Cottonwood-Stock-at-mouth-of-Little-Cottonwood-Canyon-Utah-768x627.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Cottonwood-Stock-at-mouth-of-Little-Cottonwood-Canyon-Utah-65x53.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Cottonwood-Stock-at-mouth-of-Little-Cottonwood-Canyon-Utah-225x184.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Cottonwood-Stock-at-mouth-of-Little-Cottonwood-Canyon-Utah-350x286.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Cottonwood-Stock-at-mouth-of-Little-Cottonwood-Canyon-Utah.jpg 1131w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Cottonwood Stock, a quartz monzonite pluton exposed at the mouth of Little Cottonwood Canyon, Utah<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\">A <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_232\">magma chamber<\/a> is a large underground reservoir of molten rock. The path of rising <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> is called a <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1018\">diapir<\/a><\/strong>. The processes by which a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1018\">diapir<\/a> intrudes into the surrounding <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_976\">native<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1023\">country rock<\/a> are not well understood and are the subject of ongoing geological inquiry. For example, it is not known what happens to the pre-existing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1023\">country rock<\/a> as the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1018\">diapir<\/a> intrudes. One <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a> is the overriding rock gets shouldered aside, displaced by the increased volume of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>. Another is the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_976\">native<\/a> rock is melted and consumed into the rising <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> or broken into pieces that settle into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>, a process known as <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1019\">stoping<\/a><\/strong>. It has also been proposed that diapirs are not a real phenomenon, but just a series of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1021\">dikes<\/a> that blend into each other. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1021\">dikes<\/a> may be intruding over millions of years, but since they may be made of similar material, they would be appearing to be formed at the same time. Regardless, when a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1018\">diapir<\/a> cools, it forms an mass of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_991\">intrusive<\/a> rock called a <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1017\">pluton<\/a><\/strong>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1017\">Plutons<\/a> can have irregular shapes, but can often be somewhat round.<\/span><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.2_Yosemite_Half-Dome.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-257\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.2_Yosemite_Half-Dome-300x225.jpg\" alt=\"View showing an expansive area of a mountain range with exposed white granite in many places.\" width=\"300\" height=\"225\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.2_Yosemite_Half-Dome-300x225.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.2_Yosemite_Half-Dome-768x576.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.2_Yosemite_Half-Dome-65x49.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.2_Yosemite_Half-Dome-225x169.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.2_Yosemite_Half-Dome-350x263.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.2_Yosemite_Half-Dome.jpg 1024w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Half-Dome in Yosemite National Park, California, is a part of the Sierra Nevada batholith which is mostly made of granite.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>When many <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1017\">plutons<\/a> merge together in an extensive single feature, it is called a <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1020\">batholith<\/a><\/strong>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1020\">Batholiths<\/a> are found in the cores of many mountain ranges, including the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1014\">granite<\/a> formations of Yosemite National Park in the Sierra Nevada of California. They are typically more than 100 km<sup>2<\/sup> in area, associated with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> zones, and mostly <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> in composition. A <strong>stock<\/strong> is a type of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1017\">pluton<\/a> with less surface exposure than a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1020\">batholith<\/a>, and may represent a narrower neck of material emerging from the top of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1020\">batholith<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1020\">Batholiths<\/a> and stocks are discordant intrusions that cut across and through surrounding <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1023\">country rock<\/a>.<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 250px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Henry-Mountains-a-laccolith.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-258\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Henry-Mountains-a-laccolith-300x198.jpg\" alt=\"Henry Mountains, Utah, interpreted to be a laccolith.\" width=\"250\" height=\"165\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Henry-Mountains-a-laccolith-300x198.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Henry-Mountains-a-laccolith-1024x676.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Henry-Mountains-a-laccolith-768x507.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Henry-Mountains-a-laccolith-65x43.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Henry-Mountains-a-laccolith-225x149.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Henry-Mountains-a-laccolith-350x231.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Henry-Mountains-a-laccolith.jpg 1508w\" sizes=\"auto, (max-width: 250px) 100vw, 250px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">The Henry Mountains in Utah are interpreted to be a laccolith, exposed by erosion of the overlying layers.<\/figcaption><\/figure>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 250px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.15_diagram_of_formation_of_laccolith.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-259\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.15_diagram_of_formation_of_laccolith-300x225.jpg\" alt=\"Laccolith forms as a blister in between sedimentary layers\" width=\"250\" height=\"188\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.15_diagram_of_formation_of_laccolith-300x225.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.15_diagram_of_formation_of_laccolith-65x49.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.15_diagram_of_formation_of_laccolith-225x169.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.15_diagram_of_formation_of_laccolith-350x263.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.15_diagram_of_formation_of_laccolith.jpg 767w\" sizes=\"auto, (max-width: 250px) 100vw, 250px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Laccolith forms as a blister in between sedimentary strata.<\/figcaption><\/figure>\n<p><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_219\">Laccoliths<\/a><\/strong> are blister-like, concordant intrusions of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> that form between sedimentary layers. The Henry Mountains of Utah are a famous topographic landform formed by this process. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_219\">Laccoliths<\/a> bulge upwards; a similar downward-bulging intrusion is called a <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_219\">lopolith<\/a><\/strong>.<\/p>\n<p>&nbsp;<\/p>\n<div id=\"h5p-23\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-23\" class=\"h5p-iframe\" data-content-id=\"23\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"4.2 Schematic diagram of plutonic and volcanic structures and processes (Source: Woudloper).\"><\/iframe><\/div>\n<\/div>\n<p><em>Click on the plus signs the illustration for descriptions of several <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\"><em>igneous<\/em><\/a> features.<\/em><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/4.2-Schematic-diagram-of-plutonic-and-volcanic-structures-and-processes-QR-Code.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-thumbnail wp-image-260\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.2-Schematic-diagram-of-plutonic-and-volcanic-structures-and-processes-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.2-Schematic-diagram-of-plutonic-and-volcanic-structures-and-processes-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.2-Schematic-diagram-of-plutonic-and-volcanic-structures-and-processes-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.2-Schematic-diagram-of-plutonic-and-volcanic-structures-and-processes-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.2-Schematic-diagram-of-plutonic-and-volcanic-structures-and-processes-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.2-Schematic-diagram-of-plutonic-and-volcanic-structures-and-processes-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.2-Schematic-diagram-of-plutonic-and-volcanic-structures-and-processes-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.2-Schematic-diagram-of-plutonic-and-volcanic-structures-and-processes-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.2-Schematic-diagram-of-plutonic-and-volcanic-structures-and-processes-QR-Code.png 1147w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this interactive activity via this QR Code.<\/figcaption><\/figure>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-24\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-24\" class=\"h5p-iframe\" data-content-id=\"24\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"4.1 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/4.1-Did-I-Get-It-QR-Code.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-thumbnail wp-image-261\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.1-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.1-Did-I-Get-It-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.1-Did-I-Get-It-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.1-Did-I-Get-It-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.1-Did-I-Get-It-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.1-Did-I-Get-It-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.1-Did-I-Get-It-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.1-Did-I-Get-It-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.1-Did-I-Get-It-QR-Code.png 1147w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 4.1 via this QR Code.<\/figcaption><\/figure>\n<h2><strong><a id=\"4-2BowensReaction\" href=\"\"><\/a>4.2 Bowen&rsquo;s Reaction Series<\/strong><\/h2>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 696px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.4_Bowens_Reaction_Series.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-262\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.4_Bowens_Reaction_Series.png\" alt=\"Diagram of Bowen's Reaction Series, Y-shpaed with 8 minerals and a temperature scale\" width=\"696\" height=\"369\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.4_Bowens_Reaction_Series.png 696w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.4_Bowens_Reaction_Series-300x159.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.4_Bowens_Reaction_Series-65x34.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.4_Bowens_Reaction_Series-225x119.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.4_Bowens_Reaction_Series-350x186.png 350w\" sizes=\"auto, (max-width: 696px) 100vw, 696px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Bowen&rsquo;s Reaction Series. Higher temperature minerals shown at top (olivine) and lower temperature minerals shown at bottom (quartz). (Source Colivine, modified from Bowen, 1922)<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 150px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Peridot2.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-209\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Peridot2-272x300.jpg\" alt=\"The crystal is light green.\" width=\"150\" height=\"165\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Peridot2-272x300.jpg 272w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Peridot2-929x1024.jpg 929w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Peridot2-768x847.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Peridot2-65x72.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Peridot2-225x248.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Peridot2-350x386.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Peridot2.jpg 1190w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Olivine, the first mineral to crystallize in a melt.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_221\">Bowen\u2019s Reaction Series<\/a><\/strong> describes the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> at which <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> crystallize when cooled, or melt when heated. The low end of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> scale where all <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> crystallize into solid rock, is approximately 700\u00b0C (1292\u00b0F). The upper end of the range where all <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> exist in a molten state, is approximately 1,250\u00b0C (2,282\u00b0F). These numbers reference <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> that crystallize at standard sea-level pressure, 1 bar. The values will be different for <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> located deep below the Earth\u2019s surface due to the increased pressure, which affects <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1752\">crystallization<\/a> and melting temperatures (see <a href=\"#4-4PartialMelting\">Chapter 4.4<\/a>). However, the order and relationships are maintained.<\/p>\n<p>In the figure, the righthand column lists the four groups of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous rock<\/a> from top to bottom: <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1009\">ultramafic<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1007\">intermediate<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a>. The down-pointing arrow on the far right shows increasing amounts of silica, sodium, aluminum, and potassium as the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> composition goes from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1009\">ultramafic<\/a> to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a>. The up-pointing arrow shows increasing ferromagnesian components, specifically iron, magnesium, and calcium.\u00a0\u00a0 To the far left of the diagram is a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> scale. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Minerals<\/a> near the top of diagram, such as olivine and anorthite (a type of plagioclase), crystallize at higher temperatures. Minerals near the bottom, such as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">muscovite<\/a>, crystalize at lower temperatures.<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 200px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/NormanLBowen_1909.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-263\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/NormanLBowen_1909-200x300.jpg\" alt=\"Photo of Normal L. Bowen in 1909.\" width=\"200\" height=\"300\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/NormanLBowen_1909-200x300.jpg 200w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/NormanLBowen_1909-65x98.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/NormanLBowen_1909-225x338.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/NormanLBowen_1909-350x525.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/NormanLBowen_1909.jpg 400w\" sizes=\"auto, (max-width: 200px) 100vw, 200px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Normal L. Bowen<\/figcaption><\/figure>\n<p>The most important aspect of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_221\">Bowen's Reaction Series<\/a> is to notice the relationships between <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a>. Norman L. Bowen (1887-1956) was an early 20th Century geologist who studied igneous rocks. He noticed that in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks, certain <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> always occur together and these <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> assemblages exclude other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. Curious as to why, and with the\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a> in mind that it had to do with the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> at which the rocks cooled, he set about conducting experiments on <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks in the early 1900s.\u00a0He conducted experiments on <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous rock<\/a>\u2014grinding combinations of rocks into powder, sealing the powders into metal capsules, heating them to various temperatures, and then cooling them.<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 286px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/nlbowenexperimentingsm.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-264\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/nlbowenexperimentingsm-286x300.jpg\" alt=\"Photo of Bowen working over his pertrographic microscope\" width=\"286\" height=\"300\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/nlbowenexperimentingsm-286x300.jpg 286w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/nlbowenexperimentingsm-65x68.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/nlbowenexperimentingsm-225x236.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/nlbowenexperimentingsm-350x368.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/nlbowenexperimentingsm.jpg 375w\" sizes=\"auto, (max-width: 286px) 100vw, 286px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Norman L. Bowen working with his petrographic microscope<\/figcaption><\/figure>\n<p>When he opened the quenched capsules, he found a glass surrounding <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> crystals that he could identify under his petrographic microscope. The results of many of these experiments, conducted at different temperatures over a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1244\">period<\/a> of several years, showed that the common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> crystallize from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> at different temperatures. He also saw that <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> occur together in rocks with others that crystallize within similar <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> ranges, and never crystallize with other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. This relationship can explain the main difference between <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">Mafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks contain more <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, and therefore, crystallize at higher temperatures than <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks. This is even seen in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> flows, with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> lavas erupting hundreds of degrees cooler than their <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> counterparts. Bowen\u2019s work laid the foundation for understanding <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a><b> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_220\">petrology<\/a><\/b> (the study of rocks) and resulted in his book, <i>The Evolution of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">Igneous<\/a> Rocks<\/i> in 1928.<\/p>\n<h3><\/h3>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-25\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-25\" class=\"h5p-iframe\" data-content-id=\"25\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"4.2 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/4.2-Did-I-Get-It-QR-Code.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-thumbnail wp-image-265\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.2-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.2-Did-I-Get-It-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.2-Did-I-Get-It-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.2-Did-I-Get-It-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.2-Did-I-Get-It-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.2-Did-I-Get-It-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.2-Did-I-Get-It-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.2-Did-I-Get-It-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.2-Did-I-Get-It-QR-Code.png 1147w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 4.2 via this QR Code.<\/figcaption><\/figure>\n<h2><a id=\"4-3MagmaGeneration\" href=\"\"><\/a>4.3 Magma Generation<\/h2>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">Magma<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> contain three components: melt, solids, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1684\">volatiles<\/a>. The melt is made of ions from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> that have liquefied. The solids are made of crystallized <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> floating in the liquid melt. These may be <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> that have already cooled\u00a0<strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1684\">Volatiles<\/a><\/strong> are gaseous components\u2014such as water vapor, carbon dioxide, sulfur, and chlorine\u2014dissolved in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>. The presence and amount of these three components affect the physical behavior of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> and will be discussed more below.<\/p>\n<h3>4.3.1 Geothermal Gradient<\/h3>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.2_Temperature_schematic_of_inner_Earth.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-266\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.2_Temperature_schematic_of_inner_Earth-300x300.jpg\" alt=\"Diagram showing temperature increase with depth in the Earth\" width=\"300\" height=\"300\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.2_Temperature_schematic_of_inner_Earth-300x300.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.2_Temperature_schematic_of_inner_Earth-150x150.jpg 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.2_Temperature_schematic_of_inner_Earth-65x65.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.2_Temperature_schematic_of_inner_Earth-225x224.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.2_Temperature_schematic_of_inner_Earth-350x349.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.2_Temperature_schematic_of_inner_Earth.jpg 690w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Geothermal gradient<\/figcaption><\/figure>\n<p>Below the surface, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> of the Earth rises. This heat is caused by residual heat left from the formation of Earth and ongoing radioactive decay. The rate at which <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> increases with depth is called the <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_222\">geothermal gradient<\/a><\/strong>. The average <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_222\">geothermal gradient<\/a> in the upper 100 km (62 mi) of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a> is about 25\u00b0C per kilometer of depth. So for every kilometer of depth, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> increases by about 25\u00b0C.<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 283px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.3_Simple-P-T-Diagram-modified-from-Woudloper.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-267\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_Simple-P-T-Diagram-modified-from-Woudloper.jpg\" alt=\"Diagram showing pressures and temperatures of the geothermal gradient increasing deeper in the earth. The solidus line shows that temperatures need to be much higher or pressure needs to be lower in order for rocks to start to melt.\" width=\"283\" height=\"256\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_Simple-P-T-Diagram-modified-from-Woudloper.jpg 283w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_Simple-P-T-Diagram-modified-from-Woudloper-65x59.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_Simple-P-T-Diagram-modified-from-Woudloper-225x204.jpg 225w\" sizes=\"auto, (max-width: 283px) 100vw, 283px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Pressure-temperature diagram showing temperature in degrees Celsius on the x-axis and depth below the surface in kilometers (km) on the y-axis. The red line is the geothermal gradient and the green solidus line represents the temperature and pressure regime at which melting begins. Rocks at pressures and temperatures left of the green line are solid. If pressure\/temperature conditions change so that rocks pass to the right of the green line, then they will start to melt. (Source: Woudloper)<\/figcaption><\/figure>\n<p>The depth-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> graph (see figure) illustrates the relationship between the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_222\">geothermal gradient<\/a> (geotherm, red line) and the start of rock melting (solidus, green line). The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_222\">geothermal gradient<\/a> changes with depth (which has a direct relationship to pressure) through the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a> into upper <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a>. The area to the left of the green line includes solid components; to the right is where liquid components start to form. The increasing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> with depth makes the depth of about 125 kilometers (78 miles) where the natural <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_222\">geothermal gradient<\/a> is closest to the solidus.<\/p>\n<p>The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> at 100 km (62 mi) deep is about 1,200\u00b0C (2,192\u00b0F). At bottom of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a>, 35 km (22 mi) deep, the pressure is about 10,000 bars. A bar is a measure of pressure, with 1 bar being normal atmospheric pressure at sea level. At these pressures and temperatures, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> are solid. To a depth of 150 km (93 mi), the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_222\">geothermal gradient<\/a> line stays to the left of the solidus line. This relationship continues through the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> to the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1667\">core<\/a>&#8211;<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> boundary, at 2,880 km (1,790 mi).<\/p>\n<p>The solidus line slopes to the right because the melting <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> of any substance depends on pressure. The higher pressure created at greater depth increases the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> needed to melt rock. In another example, at sea level with an atmospheric pressure close to 1 bar, water boils at 100\u00b0C. But if the pressure is lowered, as shown on the video below, water boils at a much lower <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a>.<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 150px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Boiling-Water-YouTube-QR-Code.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-thumbnail wp-image-268\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Boiling-Water-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Boiling-Water-YouTube-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Boiling-Water-YouTube-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Boiling-Water-YouTube-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Boiling-Water-YouTube-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Boiling-Water-YouTube-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Boiling-Water-YouTube-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Boiling-Water-YouTube-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Boiling-Water-YouTube-QR-Code.png 1155w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this YouTube video via this QR Code.<\/figcaption><\/figure>\n<p><iframe loading=\"lazy\" id=\"oembed-1\" title=\"Boiling water at room temperature - science experiment\" width=\"500\" height=\"375\" src=\"https:\/\/www.youtube.com\/embed\/Ks4VuXTTKmo?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<p>&nbsp;<\/p>\n<p>There are three principal ways rock behavior crosses to the right of the green solidus line to create molten <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>: 1) <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_223\">decompression melting<\/a> caused by lowering the pressure, 2) <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1686\">flux melting<\/a> caused by adding <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1684\">volatiles<\/a> (see more below), and 3) heat-induced melting caused by increasing the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a>. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_221\">Bowen\u2019s Reaction Series<\/a> shows that <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> melt at different temperatures. Since <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> is a mixture of different <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, the solidus boundary is more of a fuzzy zone rather than a well-defined line; some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are melted and some remain solid. This type of rock behavior is called <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_224\">partial melting<\/a><\/strong> and represents real-world <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magmas<\/a>, which typically contain solid, liquid, and volatile components.<\/p>\n<p><span style=\"font-weight: 400\">The figure below uses P-T diagrams to show how melting can occur at three different <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a> settings.\u00a0 The green line is called the <strong>solidus<\/strong>, the melting point <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> of the rock at that pressure. Setting\u00a0<\/span>A is a situation (called \u00ab\u00a0normal\u00a0\u00bb) in the middle of a stable <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> in which no <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> is generated. In the other three situations, rock at a lettered location with a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> at the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_222\">geothermal gradient<\/a> is moved to a new P-T situation on the diagram. This shift is indicated by the arrow and its <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> relative to the solidus is shown by the red line. Partial melting occurs where the red line <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> of the rock crosses the green solidus on the diagram. Setting B is at a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridge<\/a> <em>(<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_223\"><em>decompression melting<\/em><\/a>)<\/em> where reduction of pressure carries the rock at its <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> across the solidus. Setting C is a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a> where <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_223\">decompression melting<\/a> plus <em>addition of heat<\/em> carries the rock across the solidus, and setting D is a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> zone where a process called <em><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1686\"><em>flux melting<\/em><\/a><\/em> takes place where the solidus (melting point) is actually shifted to below the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> of the rock.<\/p>\n<p>Graphs A-D below, along with the side view of the Earth\u2019s layers in various <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a> settings (see figure), show how melting occurs in different situations. Graph A illustrates a normal situation, located in the middle of a stable <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a>, where no melted rock can be found. The remaining three graphs illustrate rock behavior relative to shifts in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_222\">geothermal gradient<\/a> or solidus lines. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_224\">Partial melting<\/a> occurs when the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_222\">geothermal gradient<\/a> line crosses the solidus line. Graph B illustrates behavior of rock located at a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridge<\/a>, labeled X in the graph and side view. Reduced pressure shifts the geotherm to the right of the solidus, causing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_223\">decompression melting<\/a>. Graph C and label Y illustrate a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a> situation. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_223\">Decompression melting<\/a>, plus an addition of heat, shifts the geotherm across the solidus. Graph D and label Z show a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> zone, where an addition of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1684\">volatiles<\/a> lowers the melting point, shifting the solidus to the left of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_222\">geothermal gradient<\/a>. B, C, and D all show different ways the Earth produces intersections of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_222\">geothermal gradient<\/a> and the solidus, which results in melting each time.<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 1024px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.3_P-T-diagrams-in-mantle.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-large wp-image-269\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_P-T-diagrams-in-mantle-1024x585.jpg\" alt=\"Pressure-Temperature diagrams showing temperture in the mantle plotted against pressure (depth)\" width=\"1024\" height=\"585\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_P-T-diagrams-in-mantle-1024x585.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_P-T-diagrams-in-mantle-300x171.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_P-T-diagrams-in-mantle-768x439.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_P-T-diagrams-in-mantle-65x37.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_P-T-diagrams-in-mantle-225x129.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_P-T-diagrams-in-mantle-350x200.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_P-T-diagrams-in-mantle.jpg 1509w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Four P-T diagrams show temperature in degrees Celsius on x-axis and depth below the surface in kilometers (km) on the y-axis. The red line is the geothermal gradient and green solidus line represents at temperature and pressure regime at which melting begins. Each of the four P-T diagrams are associated a tectonic setting as shown by a side-view (cross-section) of the lithosphere and mantle.<\/figcaption><\/figure>\n<h3>4.3.2 Decompression Melting<\/h3>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 212px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Ocean-birth.svg_.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-2867\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ocean-birth.svg_-1.png\" alt=\"The ocean starts as a valley and then gets wider and wider.\" width=\"212\" height=\"300\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Progression from rift to mid-ocean ridge, the divergent boundary types. Note the rising material in the center.<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">Magma<\/a> is created at <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridges<\/a> via <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_223\">decompression melting<\/a><\/strong>. Strong <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1655\">convection<\/a> currents cause the solid <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1671\">asthenosphere<\/a> to slowly flow beneath the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a>. The upper part of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> (<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a>) is a poor heat conductor, so the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> remains about the same throughout the underlying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> material. Where the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1655\">convection<\/a> currents cause <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> material to rise, the pressure decreases, which causes the melting point to drop. In this situation, the rock at the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_222\">geothermal gradient<\/a> is rising toward the surface, thus hotter rock is now shallower, at a lower pressure, and the rock, still at the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_222\">geothermal gradient<\/a> at its old location, shifts past the its melting point (shown as the red line crossing over the solidus or green line in example B in previous figure) and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_224\">partial melting<\/a> starts. As this magma continues to rise, it cools and crystallizes to form new lithospheric <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a>.<\/p>\n<h3>4.3.3 Flux Melting<\/h3>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 500px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Subduction-en.svg_.png\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-94\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Subduction-en.svg_-300x147.png\" alt=\"Many features are labeled on the diagram, but the main idea is the ocean plate descending below the continental\" width=\"500\" height=\"244\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Subduction-en.svg_-300x147.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Subduction-en.svg_-768x375.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Subduction-en.svg_-65x32.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Subduction-en.svg_-225x110.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Subduction-en.svg_-350x171.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Subduction-en.svg_.png 800w\" sizes=\"auto, (max-width: 500px) 100vw, 500px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Diagram of ocean-continent subduction. Note water vapor driven out of hydrated minerals in the descending oceanic slab.<\/figcaption><\/figure>\n<p><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1686\">Flux melting<\/a><\/strong> or <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1686\">fluid-induced melting<\/a><\/strong> occurs in island arcs and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> zones when volatile gases are added to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> material (see figure: graph D, label Z). Flux-melted <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> produces many of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> in the circum-Pacific <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> zones, also known as the Ring of Fire. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subducting<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1683\">slab<\/a> contains <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> and hydrated <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. As covered in <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/2-plate-tectonics\/\">Chapter 2<\/a>, these hydrated forms are created when water ions <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bond<\/a> with the crystal structure of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. As the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1683\">slab<\/a> descends into the hot <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a>, the increased <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> causes the hydrated <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> to emit water vapor and other volatile gases, which are expelled from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1683\">slab<\/a> like water being squeezed out of a sponge. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1684\">volatiles<\/a> dissolve into the overlying asthenospheric <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> and decrease its melting point. In this situation the applied pressure and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> have not changed, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a>&lsquo;s melting point has been lowered by the addition of volatile substances. The previous figure (graph D) shows the green solidus line shifting to the left of and below the red <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_222\">geothermal gradient<\/a> line, and melting begins. This is analogous to adding salt to an icy roadway. The salt lowers the freezing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> of the solid ice so it turns into liquid water.<\/p>\n<h3>4.3.4 Heat-Induced Melting<\/h3>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/06.2-15-Mt-Blaca-Migmatite-1.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-48\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/06.2-15-Mt-Blaca-Migmatite-1-300x225.jpg\" alt=\"Swirling bands of light and dark minerals.\" width=\"300\" height=\"225\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/06.2-15-Mt-Blaca-Migmatite-1-300x225.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/06.2-15-Mt-Blaca-Migmatite-1-1024x768.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/06.2-15-Mt-Blaca-Migmatite-1-768x576.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/06.2-15-Mt-Blaca-Migmatite-1-1536x1152.jpg 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/06.2-15-Mt-Blaca-Migmatite-1-65x49.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/06.2-15-Mt-Blaca-Migmatite-1-225x169.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/06.2-15-Mt-Blaca-Migmatite-1-350x263.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/06.2-15-Mt-Blaca-Migmatite-1.jpg 1600w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Migmatite, a rock which was partially molten. (Source: Peter Davis)<\/figcaption><\/figure>\n<p>Heat-induced melting, transforming solid <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> into liquid <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> by simply applying heat, is the least common process for generating <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> (see figure: graph C, label Y). Heat-induced melting occurs at a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> plumes or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspots<\/a>. The rock surrounding the plume is exposed to higher temperatures, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_222\">geothermal gradient<\/a> crosses to the right of the green solidus line, and the rock begins to melt. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1717\">mantle plume<\/a> includes rising <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> material, meaning some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_223\">decompression melting<\/a> is occurring as well. A small amount of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> is also generated by intense regional metamorphism (see <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/6-metamorphic-rocks\/\">Chapter 6<\/a>). This <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> becomes a hybrid metamorphic&#8211;<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous rock<\/a> called migmatite.<\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-26\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-26\" class=\"h5p-iframe\" data-content-id=\"26\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"4.3 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/4.3-Did-I-Get-It-QR-Code.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-thumbnail wp-image-271\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.3-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.3-Did-I-Get-It-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.3-Did-I-Get-It-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.3-Did-I-Get-It-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.3-Did-I-Get-It-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.3-Did-I-Get-It-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.3-Did-I-Get-It-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.3-Did-I-Get-It-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.3-Did-I-Get-It-QR-Code.png 1147w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 4.3 via this QR Code.<\/figcaption><\/figure>\n<h2><b><a id=\"4-4PartialMelting\" href=\"\"><\/a><\/b><strong>4.4<\/strong>\u00a0<b>Partial Melting and Crystallization<\/b><\/h2>\n<p>Even though all <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magmas<\/a> originate from similar <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> rocks, and start out as similar <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>, other things, like\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_224\">partial melting<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1752\">crystallization<\/a> processes like <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_226\">magmatic differentiation<\/a>, can change the chemistry of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>. This explains the wide variety of resulting <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks that are found all over Earth.<\/p>\n<h3>4.4.1 Partial Melting<\/h3>\n<p>Because the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> is composed of many different minerals, it does not melt uniformly. As <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> with lower melting points turn into liquid <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>, those with higher melting points remain as solid crystals. This is known as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_224\">partial melting<\/a>. As <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> slowly rises and cools into solid rock, it undergoes physical and chemical changes in a process called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_226\">magmatic differentiation<\/a>.<\/p>\n<p>According to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_221\">Bowen\u2019s Reaction Series<\/a> (<a href=\"#4-2BowensReaction\">Section 4.2<\/a>), each <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> has a unique melting and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1752\">crystallization<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a>. Since most rocks are made of many different <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, when they start to melt, some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> begin melting sooner than others. This is known as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_224\">partial melting<\/a>, and creates <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> with a different composition than the original <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> material.<\/p>\n<p>The most important example occurs as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> is generated from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> rocks (as discussed in <a href=\"#4-3MagmaGeneration\">Section 4.3<\/a>). The chemistry of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> rock (<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1666\">peridotite<\/a>) is <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1009\">ultramafic<\/a>, low in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicates<\/a> and high in iron and magnesium. When <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1666\">peridotite<\/a> begins to melt, the silica-rich portions melt first due to their lower melting point. If this continues, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> becomes increasingly silica-rich, turning <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1009\">ultramafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> into <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> into <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1007\">intermediate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> rises to the surface because it is more buoyant than the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a>.<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 500px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/CratonGeolProv.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-92\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/CratonGeolProv-300x159.jpg\" alt=\"The legend shows shields, platforms, orogens, basins, large igneous provinces, and extended crust.\" width=\"500\" height=\"265\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/CratonGeolProv-300x159.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/CratonGeolProv-1024x544.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/CratonGeolProv-768x408.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/CratonGeolProv-65x35.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/CratonGeolProv-225x119.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/CratonGeolProv-350x186.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/CratonGeolProv.jpg 1200w\" sizes=\"auto, (max-width: 500px) 100vw, 500px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Geologic provinces with the Shield (orange) and Platform (pink) comprising the Craton, the stable interior of continents.<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_224\">Partial melting<\/a> also occurs as existing crustal rocks melt in the presence of heat from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magmas<\/a>. In this process, existing rocks melt, allowing the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> formed to be more <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> and less <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> than the pre-existing rock. Early in the Earth\u2019s history when the continents were forming, silica-rich <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magmas<\/a> formed and rose to the surface and solidified into granitic continents. In the figure, the old granitic cores of the continents, called <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1259\">shields<\/a><\/strong>, are shown in orange.<\/p>\n<h3>4.4.2 Crystallization and Magmatic Differentiation<\/h3>\n<p>Liquid <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> is less dense than the surrounding solid rock, so it rises through the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a>. As <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> begins to cool and crystallize, a process known as <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_226\">magmatic differentiation<\/a><\/strong> changes the chemistry of the resultant rock towards a more <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> composition. This happens via two main methods: <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_225\">assimilation<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_227\">fractionation<\/a>.<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.16_Xenoliths_Little_Cottonwood_Canyon.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-272\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.16_Xenoliths_Little_Cottonwood_Canyon-300x211.jpg\" alt=\"Xenoliths are bits of surrounding counjtry rock incorporated in intrusive magma and solidified within it.\" width=\"300\" height=\"211\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.16_Xenoliths_Little_Cottonwood_Canyon-300x211.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.16_Xenoliths_Little_Cottonwood_Canyon-768x540.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.16_Xenoliths_Little_Cottonwood_Canyon-65x46.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.16_Xenoliths_Little_Cottonwood_Canyon-225x158.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.16_Xenoliths_Little_Cottonwood_Canyon-350x246.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.16_Xenoliths_Little_Cottonwood_Canyon.jpg 847w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Xenoliths in Little Cottonwood Stock, Utah<\/figcaption><\/figure>\n<p>During <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_225\">assimilation<\/a><\/strong>, pieces of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1023\">country rock<\/a> with a different, often more <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a>, composition are added to the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>. These solid pieces may melt, which changes the composition of the original <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>. At times, the solid fragments may remain intact within the cooling <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> and only partially melt. The unmelted country rocks within an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous rock<\/a> mass are called <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1665\">xenoliths<\/a><\/strong>.<\/p>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1665\">Xenoliths<\/a> are also common in the processes of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> mixing and rejuvenation, two other processes that can contribute to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_226\">magmatic differentiation<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">Magma<\/a> mixing occurs when two different <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magmas<\/a> come into contact and mix, though at times, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magmas<\/a> can remain heterogeneous and create <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1665\">xenoliths<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1021\">dikes<\/a>, and other features. Magmatic rejuvenation happens when a cooled and crystallized body of rock is remelted and pieces of the original rock may remain as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1665\">xenoliths<\/a>.<\/p>\n<p>Much of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> is <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> (i.e. granitic), and normally more buoyant than the underlying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a>\/<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1009\">ultramafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a>. When <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> rises through thick <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental crust<\/a>, it does so slowly, more slowly than when <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> rises through <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a>. This gives the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> lots of time to react with the surrounding <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1023\">country rock<\/a>. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> tends to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_225\">assimilate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> rock, becoming more silica-rich as it migrates through the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> and changing into <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1007\">intermediate<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> by the time it reaches the surface. This is why <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magmas<\/a> are much more common within continents.<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.3_Magmatism_and_volcanism_EN.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-273\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_Magmatism_and_volcanism_EN-300x235.png\" alt=\"Shows large pools of magma rising from the source in the mantle, up into the crust under a volcano.\" width=\"300\" height=\"235\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_Magmatism_and_volcanism_EN-300x235.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_Magmatism_and_volcanism_EN-65x51.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_Magmatism_and_volcanism_EN-225x176.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_Magmatism_and_volcanism_EN-350x274.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_Magmatism_and_volcanism_EN.png 766w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Rising magma diapirs in mantle and crust. Fractional crystallization assimilation occurs to the diapirs in the crust.<\/figcaption><\/figure>\n<p><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_227\">Fractionation<\/a><\/strong> or <strong>fractional <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1752\">crystallization<\/a><\/strong> is another process that increase <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> silica content, making it more <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a>. As the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> drops within a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1018\">diapir<\/a> rising through the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a>, some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> will crystallize and settle to the bottom of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_232\">magma\u00a0chamber<\/a>, leaving the remaining melt depleted of those ions. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">Olivine<\/a> is a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> at the top of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_221\">Bowen\u2019s Reaction series<\/a> with a high melting point and a smaller percentage of silica verses other common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. When <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1009\">ultramafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> cools, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">olivine<\/a> crystallizes first and settles to the bottom of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_232\">magma chamber<\/a> (see figure). This means the remaining melt becomes more silica-rich and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a>. As the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> further cools, the next <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> on <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_221\">Bowen's Reaction Series<\/a> (<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">plagioclase<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">pyroxene<\/a>) crystallize next, removing even more low-silica components from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>, making it even more <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a>. This crystal <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_227\">fractionation<\/a> can occur in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a>, but the formation of more differentiated, highly evolved <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magmas<\/a> is largely confined to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> regions where the longer time to the surface allows more <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_227\">fractionation<\/a> to occur.<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 750px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.3_Fractional_crystallization.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-274\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_Fractional_crystallization.png\" alt=\"Complicated diagram showing minerals settling out in the magma chamber and thus making the remaining liquid magma (the melt) more silica-rich in composition.\" width=\"750\" height=\"320\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_Fractional_crystallization.png 750w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_Fractional_crystallization-300x128.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_Fractional_crystallization-65x28.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_Fractional_crystallization-225x96.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.3_Fractional_crystallization-350x149.png 350w\" sizes=\"auto, (max-width: 750px) 100vw, 750px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Schematic diagram illustrating fractional crystallization. If magma at composition A is ultramafic, as the magma cools it changes composition as different minerals crystallize from the melt and settle to the bottom of the magma chamber. In section 1, olivine crystallizes; section 2: olivine and pyroxene crystallize; section 3: pyroxene and plagioclase crystallize; and section 4: plagioclase crystallizes. The crystals are separated from the melt and the remaining magma (composition B) is more silica-rich. (Source: Woudloper)<\/figcaption><\/figure>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-27\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-27\" class=\"h5p-iframe\" data-content-id=\"27\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"4.4 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/4.4-Did-I-Get-It-QR-Code.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-thumbnail wp-image-275\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.4-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.4-Did-I-Get-It-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.4-Did-I-Get-It-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.4-Did-I-Get-It-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.4-Did-I-Get-It-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.4-Did-I-Get-It-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.4-Did-I-Get-It-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.4-Did-I-Get-It-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.4-Did-I-Get-It-QR-Code.png 1147w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 4.4 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-weight: 400\"><a id=\"4-5Volcanism\" href=\"\"><\/a>4.5 Volcanism<\/span><\/h2>\n<p>When <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> emerges onto the Earth\u2019s surface, the molten rock is called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a>. A <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a><\/strong> is a type of land formation created when <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> solidifies into rock. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">Volcanoes<\/a> have been an important part of human society for centuries, though their understanding has greatly increased as our understanding of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">plate tectonics<\/a> has made them less mysterious.\u00a0<span style=\"font-weight: 400\">This section\u00a0describes <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a> location, type, hazards, and monitoring.<\/span><\/p>\n<h3><b>4.5.1. Distribution and Tectonics<\/b><\/h3>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 775px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Main-types-of-plate-boundaries.gif\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-276\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Main-types-of-plate-boundaries.gif\" alt=\"Diagram showing how volcanoes are associated with plate boundaries\" width=\"775\" height=\"429\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Association of volcanoes with plate boundaries. (Source: USGS)<\/figcaption><\/figure>\n<p>Most <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> are <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_229\">interplate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_229\">Interplate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> are located at active <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> boundaries created by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> at <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridges<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> zones, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rifts<\/a>. The prefix \u00ab\u00a0<em>inter-\u00ab\u00a0<\/em> means between. Some volcanoes are <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_230\">intraplate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a>. The prefix \u00ab\u00a0<em>intra-\u00ab\u00a0<\/em>\u00a0means within, and intraplate volcanoes are located within <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a>, far removed from plate boundaries. Many <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_230\">intraplate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> are formed by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspots<\/a>.<\/p>\n<h4><span style=\"font-weight: 400\">Volcanoes at Mid-Ocean Ridges<\/span><\/h4>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Spreading_ridges_volcanoes_map-en.svg_.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-277\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Spreading_ridges_volcanoes_map-en.svg_-300x151.png\" alt=\"Map showing spreading ridges throughout the world. These ridges are all over the world.\" width=\"300\" height=\"151\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Spreading_ridges_volcanoes_map-en.svg_-300x151.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Spreading_ridges_volcanoes_map-en.svg_-768x386.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Spreading_ridges_volcanoes_map-en.svg_-65x33.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Spreading_ridges_volcanoes_map-en.svg_-225x113.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Spreading_ridges_volcanoes_map-en.svg_-350x176.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Spreading_ridges_volcanoes_map-en.svg_.png 1000w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Map of spreading ridges throughout the world.<\/figcaption><\/figure>\n<p>Most <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> on Earth occurs on the ocean floor along <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridges<\/a>, a type of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1677\">divergent<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1670\">plate boundary<\/a> (see <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/2-plate-tectonics\/\" target=\"_blank\" rel=\"noopener\">Chapter 2<\/a>). These <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_229\">interplate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> are also the least observed and famous, since most of them are located under 3,000-4,500 m (10,000-15,000 ft) of ocean and the eruptions are slow, gentle, and oozing. One exception is the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_229\">interplate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> of Iceland. The diverging and thinning <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">plates<\/a> allow hot <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> rock to rise, releasing pressure and causing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_223\">decompression melting<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1009\">Ultramafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> rock, consisting largely of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1666\">peridotite<\/a>, partially melts and generates <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> that is basaltic. Because of this, almost all <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> on the ocean floor are basaltic. In fact, most oceanic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> is basaltic near the surface, with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_992\">phaneritic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1016\">gabbro<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1009\">ultramafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1666\">peridotite<\/a> underneath.<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Pillow-basalt.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-278\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pillow-basalt-300x180.jpg\" alt=\"Pillow basalt on sea floor near Hawaii.\" width=\"300\" height=\"180\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pillow-basalt-300x180.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pillow-basalt-1024x613.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pillow-basalt-768x460.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pillow-basalt-1536x919.jpg 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pillow-basalt-65x39.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pillow-basalt-225x135.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pillow-basalt-350x209.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pillow-basalt.jpg 1669w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Pillow basalt on sea floor near Hawaii.<\/figcaption><\/figure>\n<p>When basaltic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> erupts underwater it emerges in small explosions and\/or forms pillow-shaped structures called pillow basalts. These seafloor eruptions enable entire underwater ecosystems to thrive in the deep ocean around <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridges<\/a>. This ecosystem exists around tall vents emitting black, hot <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>-rich water called deep-sea hydrothermal vents, also known as black smokers.<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 133px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/BlackSmoker.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-119\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/BlackSmoker-233x300.jpg\" alt=\"There is a large build up of minerals around the vent\" width=\"133\" height=\"171\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/BlackSmoker-233x300.jpg 233w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/BlackSmoker-795x1024.jpg 795w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/BlackSmoker-768x990.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/BlackSmoker-65x84.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/BlackSmoker-225x290.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/BlackSmoker-350x451.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/BlackSmoker.jpg 929w\" sizes=\"auto, (max-width: 133px) 100vw, 133px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Black smoker hydrothermal vent with a colony of giant (6&rsquo;+) tube worms.<\/figcaption><\/figure>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 500px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/04.16_Distribution_of_hydrothermal_vent_fields.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-279\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.16_Distribution_of_hydrothermal_vent_fields-300x178.jpg\" alt=\"Map showing worldwide distgrbution of hydrothermal vent fields;\" width=\"500\" height=\"297\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.16_Distribution_of_hydrothermal_vent_fields-300x178.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.16_Distribution_of_hydrothermal_vent_fields-1024x608.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.16_Distribution_of_hydrothermal_vent_fields-768x456.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.16_Distribution_of_hydrothermal_vent_fields-65x39.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.16_Distribution_of_hydrothermal_vent_fields-225x134.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.16_Distribution_of_hydrothermal_vent_fields-350x208.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/04.16_Distribution_of_hydrothermal_vent_fields.jpg 1198w\" sizes=\"auto, (max-width: 500px) 100vw, 500px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Distribution of hydrothermal vent fields<\/figcaption><\/figure>\n<p>Without sunlight to support photosynthesis, these organisms instead utilize a process called <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_231\">chemosynthesis<\/a><\/strong>. Certain bacteria are able to turn hydrogen <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfide<\/a> (H<sub>2<\/sub>S), a gas that smells like rotten eggs, into life-supporting nutrients and water. Larger organisms may eat these bacteria or absorb nutrients and water produced by bacteria living symbiotically inside their bodies. The three videos show some of the ecosystems found around deep-sea hydrothermal vents.<\/p>\n<p><iframe loading=\"lazy\" id=\"oembed-2\" title=\"The Alvin Submarine Part 1: Updating the Deep-Diving Submarine at 50 Years Old - WIRED\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/a5aQ4W9GbpU?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Alvin-Submarine-Part-1-YouTube-QR-Code.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-thumbnail wp-image-280\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-1-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-1-YouTube-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-1-YouTube-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-1-YouTube-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-1-YouTube-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-1-YouTube-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-1-YouTube-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-1-YouTube-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-1-YouTube-QR-Code.png 1155w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this YouTube video via this QR Code.<\/figcaption><\/figure>\n<p><iframe loading=\"lazy\" id=\"oembed-3\" title=\"The Alvin Submarine Part 2: Incredible Views On-Board the Deep-Sea Vessel\u200b\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/dXOQFnU-49k?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Alvin-Submarine-Part-2-YouTube-QR-Code.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-thumbnail wp-image-281\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-2-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-2-YouTube-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-2-YouTube-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-2-YouTube-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-2-YouTube-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-2-YouTube-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-2-YouTube-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-2-YouTube-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-2-YouTube-QR-Code.png 1155w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this YouTube video via this QR Code.<\/figcaption><\/figure>\n<p><iframe loading=\"lazy\" id=\"oembed-4\" title=\"The Alvin Submarine Part 3: Humans vs. Robots and the Future of Deep-Sea Research \u2013 WIRED\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/eUzz_ilsFa0?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Alvin-Submarine-Part-3-YouTube-QR-Code.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-thumbnail wp-image-282\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-3-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-3-YouTube-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-3-YouTube-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-3-YouTube-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-3-YouTube-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-3-YouTube-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-3-YouTube-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-3-YouTube-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alvin-Submarine-Part-3-YouTube-QR-Code.png 1155w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this YouTube video via this QR Code.<\/figcaption><\/figure>\n<h4><span style=\"font-weight: 400\">Volcanoes at Subduction Zones<\/span><\/h4>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 500px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Map_plate_tectonics_world.gif\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-283\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Map_plate_tectonics_world.gif\" alt=\"Map showing volcanoes follow the edges of tectonic plates.\" width=\"500\" height=\"314\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Distribution of volcanoes on the planet. Click here for an <a href=\"https:\/\/maps.ngdc.noaa.gov\/viewers\/hazards\/?layers=3\" target=\"_blank\" rel=\"noopener\">interactive map<\/a>\u00a0of volcano distributions.<\/figcaption><\/figure>\n<p>The second most commonly found location for <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> is adjacent to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> zones, a type of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1678\">convergent<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1670\">plate boundary<\/a> (see <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/2-plate-tectonics\/\" target=\"_blank\" rel=\"noopener\">Chapter 2<\/a>). The process of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> expels water from hydrated <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> in the descending <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1683\">slab<\/a>, which causes <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1686\">flux melting<\/a> in the overlying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> rock. Because <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> occurs in a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1695\">volcanic arc<\/a>, the thickened <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a> promotes <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_224\">partial melting<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> differentiation. These evolve the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> from the mantle into more silica-rich <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>. The Ring of Fire surrounding the Pacific Ocean, for example, is dominated by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a>-generated eruptions of mostly silica-rich <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a>; the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1017\">plutons<\/a> consist largely of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1007\">intermediate<\/a>-to-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> rock such as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1012\">andesite<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1010\">rhyolite<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_998\">pumice<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1005\">tuff<\/a>.<\/p>\n<h4><span style=\"font-weight: 400\">Volcanoes at Continental Rifts<\/span><\/h4>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Black_Rock_Desert_volcanic_field.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-284\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Black_Rock_Desert_volcanic_field-300x199.jpg\" alt=\"A barren landscape of lava flows in central Utah.\" width=\"300\" height=\"199\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Black_Rock_Desert_volcanic_field-300x199.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Black_Rock_Desert_volcanic_field-65x43.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Black_Rock_Desert_volcanic_field-225x149.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Black_Rock_Desert_volcanic_field-350x232.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Black_Rock_Desert_volcanic_field.jpg 640w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Basaltic cinder cones of the Black Rock Desert near Beaver, Utah.<\/figcaption><\/figure>\n<p>Some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> are created at <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rifts<\/a>, where crustal thinning is caused by diverging lithospheric <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a>, such as the East African <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">Rift<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_508\">Basin<\/a> in Africa. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">Volcanism<\/a> caused by crustal thinning without <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rifting<\/a> is found in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1514\">Basin and Range<\/a> Province in North America. In this location, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> activity is produced by rising <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> that stretches the overlying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a> (see figure). Lower <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a> or upper <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> material rises through the thinned <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a>, releases pressure, and undergoes decompression-induced <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_224\">partial melting<\/a>. This <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> is less dense than the surrounding rock and continues to rise through the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a> to the surface, erupting as basaltic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a>. These eruptions usually result in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_244\">flood basalts<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_242\">cinder<\/a> cones, and basaltic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> flows (see video). Relatively young <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_242\">cinder<\/a> cones of basaltic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> can be found in south-central Utah, in the Black Rock Desert <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">Volcanic<\/a> Field, which is part of the zone of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1514\">Basin and Range<\/a> crustal <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_492\">extension<\/a>. These Utah <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_242\">cinder<\/a> cones and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> flows started erupting around 6 million years ago, with the last eruption occurring 720 years ago.<\/p>\n<p><iframe loading=\"lazy\" id=\"oembed-5\" title=\"Basin &amp; Range Volcanic Processes  (Educational)\" width=\"500\" height=\"375\" src=\"https:\/\/www.youtube.com\/embed\/4VgMe-JXOAM?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Volcanic-Processes-YouTube-QR-Code.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-thumbnail wp-image-285\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcanic-Processes-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcanic-Processes-YouTube-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcanic-Processes-YouTube-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcanic-Processes-YouTube-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcanic-Processes-YouTube-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcanic-Processes-YouTube-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcanic-Processes-YouTube-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcanic-Processes-YouTube-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcanic-Processes-YouTube-QR-Code.png 1155w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this YouTube video via this QR Code.<\/figcaption><\/figure>\n<h4><span style=\"font-weight: 400\">Hotspots<\/span><\/h4>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 193px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Hotspotgeology-1.svg_.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-129\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hotspotgeology-1.svg_-193x300.png\" alt=\"The plate is moving to the left, the magma stays in the center am makes a chain of volcanoes.\" width=\"193\" height=\"300\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hotspotgeology-1.svg_-193x300.png 193w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hotspotgeology-1.svg_-660x1024.png 660w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hotspotgeology-1.svg_-768x1192.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hotspotgeology-1.svg_-65x101.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hotspotgeology-1.svg_-225x349.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hotspotgeology-1.svg_-350x543.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hotspotgeology-1.svg_.png 771w\" sizes=\"auto, (max-width: 193px) 100vw, 193px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Diagram showing a non-moving source of magma (mantle plume) and a moving overriding plate.<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">Hotspots<\/a> are the main source of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_230\">intraplate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a>. <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">Hotspots<\/a><\/strong> occur when lithospheric <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> glide over a hot <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1717\">mantle plume<\/a>, an ascending column of solid heated rock originating from deep within the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a>. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1717\">mantle plume<\/a> generates melts as material rises, with the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> rising even more. When the ascending <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> reaches the lithospheric crust, it spreads out into a mushroom-shaped head that is tens to hundreds of kilometers across.<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/YellowstoneHotspot.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-133\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/YellowstoneHotspot-300x206.jpg\" alt=\"The hotspot started near the Idaho-Oregon-Nevada boarder, then moved toward its present location neat the Wyoming-Idaho-Montana boarder.\" width=\"300\" height=\"206\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/YellowstoneHotspot-300x206.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/YellowstoneHotspot-1024x703.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/YellowstoneHotspot-768x527.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/YellowstoneHotspot-65x45.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/YellowstoneHotspot-225x155.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/YellowstoneHotspot-350x240.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/YellowstoneHotspot.jpg 1063w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">The track of the Yellowstone hotspot, which shows the age of different eruptions in millions of years ago.<\/figcaption><\/figure>\n<p>Since most <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> plumes are located beneath the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a>, the early stages of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_230\">intraplate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> typically take place underwater. Over time, basaltic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> may build up from the sea floor into islands, such as the Hawaiian Islands. Where a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a> is found under a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a>, contact with the hot <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> magma may cause the overlying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> rock to melt and mix with the mafic material below, forming <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1007\">intermediate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>. Or the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> may continue to rise, and cool into a granitic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1020\">batholith<\/a> or erupt as a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a>. The Yellowstone <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_235\">caldera<\/a> is an example of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> that resulted in an explosive eruption.<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 296px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Hawaii-Emperor_engl.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-131\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hawaii-Emperor_engl-296x300.png\" alt=\"There are a series of island and seamounts in the Pacific Ocean, with a bend in the middle.\" width=\"296\" height=\"300\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hawaii-Emperor_engl-296x300.png 296w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hawaii-Emperor_engl-1010x1024.png 1010w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hawaii-Emperor_engl-768x778.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hawaii-Emperor_engl-65x66.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hawaii-Emperor_engl-225x228.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hawaii-Emperor_engl-350x355.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hawaii-Emperor_engl.png 1182w\" sizes=\"auto, (max-width: 296px) 100vw, 296px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">The Hawaii-Emperor seamount and island chain.<\/figcaption><\/figure>\n<p>A zone of actively erupting <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> connected to a chain of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_755\">extinct<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> indicates <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_230\">intraplate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> located over a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a>. These <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> chains are created by the overriding <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> slowly moving over a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1717\">mantle plume<\/a>. These chains are seen on the seafloor and continents and include <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> that have been inactive for millions of years. The Hawaiian Islands on the Pacific <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">Oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> are the active end of a long <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> chain that extends from the northwest Pacific Ocean to the Emperor Seamounts, all the way to the to the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> zone beneath the Kamchatka Peninsula. The overriding North American <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> moved across a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1717\">mantle plume<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a> for several million years, creating a chain of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> calderas that extends from Southwestern Idaho to the presently active Yellowstone <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_235\">caldera<\/a> in Wyoming.<\/p>\n<p><span style=\"font-weight: 400\">Two three<\/span><span style=\"font-weight: 400\">-minute videos (below)<\/span><span style=\"font-weight: 400\"> illustrates <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a>.<\/span><\/p>\n<p><iframe loading=\"lazy\" id=\"oembed-6\" title=\"What is a Volcanic Hotspot?    (Educational)\" width=\"500\" height=\"375\" src=\"https:\/\/www.youtube.com\/embed\/AhSaE0omw9o?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/What-is-a-Volcanic-Hotspot-YouTube-QR-Code.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-thumbnail wp-image-286\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/What-is-a-Volcanic-Hotspot-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/What-is-a-Volcanic-Hotspot-YouTube-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/What-is-a-Volcanic-Hotspot-YouTube-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/What-is-a-Volcanic-Hotspot-YouTube-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/What-is-a-Volcanic-Hotspot-YouTube-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/What-is-a-Volcanic-Hotspot-YouTube-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/What-is-a-Volcanic-Hotspot-YouTube-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/What-is-a-Volcanic-Hotspot-YouTube-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/What-is-a-Volcanic-Hotspot-YouTube-QR-Code.png 1155w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this YouTube video via this QR Code.<\/figcaption><\/figure>\n<p><iframe loading=\"lazy\" id=\"oembed-7\" title=\"Life Of Hotspot Volcanic Island (Educational)\" width=\"500\" height=\"375\" src=\"https:\/\/www.youtube.com\/embed\/t5go-78gCJU?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Life-of-Hotspot-Volcanic-Island-YouTube-QR-Code.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-thumbnail wp-image-287\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Life-of-Hotspot-Volcanic-Island-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Life-of-Hotspot-Volcanic-Island-YouTube-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Life-of-Hotspot-Volcanic-Island-YouTube-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Life-of-Hotspot-Volcanic-Island-YouTube-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Life-of-Hotspot-Volcanic-Island-YouTube-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Life-of-Hotspot-Volcanic-Island-YouTube-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Life-of-Hotspot-Volcanic-Island-YouTube-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Life-of-Hotspot-Volcanic-Island-YouTube-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Life-of-Hotspot-Volcanic-Island-YouTube-QR-Code.png 1155w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this YouTube video via this QR Code.<\/figcaption><\/figure>\n<h3><b>4.5.2 Volcano Features and Types<\/b><\/h3>\n<p><span style=\"font-weight: 400\">There are several different types of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> based on their shape, eruption style, magmatic composition, and other aspects. <\/span><\/p>\n<p><span style=\"font-weight: 400\"><\/p>\n<div id=\"h5p-28\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-28\" class=\"h5p-iframe\" data-content-id=\"28\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"4.5 Overview of volcanic features and landforms.\"><\/iframe><\/div>\n<\/div>\n<p> <\/span><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/4.5-Overview-of-volcanic-features-and-landforms-QR-Code.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-thumbnail wp-image-288\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.5-Overview-of-volcanic-features-and-landforms-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.5-Overview-of-volcanic-features-and-landforms-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.5-Overview-of-volcanic-features-and-landforms-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.5-Overview-of-volcanic-features-and-landforms-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.5-Overview-of-volcanic-features-and-landforms-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.5-Overview-of-volcanic-features-and-landforms-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.5-Overview-of-volcanic-features-and-landforms-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.5-Overview-of-volcanic-features-and-landforms-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.5-Overview-of-volcanic-features-and-landforms-QR-Code.png 1147w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this interactive activity via this QR Code.<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\">The figure shows the main features of a typical <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_240\">stratovolcano<\/a>:<\/span><span style=\"font-weight: 400\">\u00a01) <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_232\">magma chamber<\/a><\/strong>, 2) upper layers of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a>, 3) the<\/span><span style=\"font-weight: 400\">\u00a0<\/span><b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_233\">conduit<\/a><\/b><span style=\"font-weight: 400\"> or narrow pipe through which the<\/span><span style=\"font-weight: 400\">\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> erupts, 4) the base or edge of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a>, 5) a <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1022\">sill<\/a><\/strong> of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> between layers of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a>, 6) a <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1018\">diapir<\/a><\/strong> or feeder tube to the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1022\">sill<\/a>, 7) layers of <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1000\">tephra<\/a><\/strong> (<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">ash<\/a>) from previous eruptions, 8 &amp; 9) layers of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> erupting from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_234\">vent<\/a> and flowing down the sides of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a>, 10) the <strong>crater<\/strong> at the top of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a>, 11) layers of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1000\">tephra<\/a> on (12), a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_236\">parasitic cone<\/a>. A\u00a0<b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_236\">parasitic cone<\/a><\/b> is a small <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a> located on the flank of a larger volcano such as Shastina on Mount Shasta. Kilauea sitting on the flank of Mauna Loa is not considered a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_236\">parasitic cone<\/a> because it has its own separate <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_232\">magma chamber<\/a>,\u00a0 13) the <strong>vents<\/strong> of the parasite and the main <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a>, 14) the rim of the crater, 15) clouds of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">ash<\/a> blown into the sky by the eruption; this settles back onto the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a> and surrounding land.<br \/>\n<\/span><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Mt.-Shasta-and-Shastina-in-Washington.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-289\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mt.-Shasta-and-Shastina-in-Washington-300x253.jpg\" alt=\"A smaller parasitic cone called Shastina on the flanks of Mt. Shasta in Washington\" width=\"300\" height=\"253\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mt.-Shasta-and-Shastina-in-Washington-300x253.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mt.-Shasta-and-Shastina-in-Washington-1024x863.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mt.-Shasta-and-Shastina-in-Washington-768x648.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mt.-Shasta-and-Shastina-in-Washington-65x55.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mt.-Shasta-and-Shastina-in-Washington-225x190.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mt.-Shasta-and-Shastina-in-Washington-350x295.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mt.-Shasta-and-Shastina-in-Washington.jpg 1097w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Mt. Shasta in Washington state with Shastina, its parasitic cone<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\">The largest craters are called\u00a0<\/span><b>calderas<\/b><span style=\"font-weight: 400\">, such as the<\/span><span style=\"font-weight: 400\">\u00a0Crater Lake <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_235\">Caldera<\/a><\/span><span style=\"font-weight: 400\">\u00a0in Oregon. <\/span><span style=\"font-weight: 400\">Many <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> features are produced by\u00a0<strong>viscosity<\/strong>, a basic property of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a>. Viscosity is the resistance to flowing by a fluid. Low viscosity <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> flows easily more like syrup, the basaltic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> that occurs in Hawaii on <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1259\">shield<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a>.\u00a0High viscosity means a thick and sticky <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>, typically <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1007\">intermediate<\/a>, that flows slowly, similar to toothpaste.<\/span><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Crater_lake_oregon-1.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-45\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Crater_lake_oregon-1-300x200.jpg\" alt=\"The mountain has a large hole in the center that is filled with the lake.\" width=\"300\" height=\"200\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Crater_lake_oregon-1-300x200.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Crater_lake_oregon-1-65x43.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Crater_lake_oregon-1-225x150.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Crater_lake_oregon-1-350x233.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Crater_lake_oregon-1.jpg 623w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Oregon&rsquo;s Crater Lake was formed about 7700 years ago after the eruption of Mount Mazama.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<h4><span style=\"font-weight: 400\">Shield Volcano<\/span><\/h4>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Kilauea_Shield_Volcano_Hawaii_20071209A.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-290\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Kilauea_Shield_Volcano_Hawaii_20071209A-300x200.jpg\" alt=\"The mountain has low-angle flanks\" width=\"300\" height=\"200\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Kilauea_Shield_Volcano_Hawaii_20071209A-300x200.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Kilauea_Shield_Volcano_Hawaii_20071209A-1024x683.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Kilauea_Shield_Volcano_Hawaii_20071209A-768x512.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Kilauea_Shield_Volcano_Hawaii_20071209A-1536x1024.jpg 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Kilauea_Shield_Volcano_Hawaii_20071209A-65x43.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Kilauea_Shield_Volcano_Hawaii_20071209A-225x150.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Kilauea_Shield_Volcano_Hawaii_20071209A-350x233.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Kilauea_Shield_Volcano_Hawaii_20071209A.jpg 1599w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Kilauea in Hawai&rsquo;i.<\/figcaption><\/figure>\n<p>The largest <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> are <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1259\">shield<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a><\/strong>. They are characterized by broad low-angle flanks, small vents at the top, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> chambers. The name comes from the side view, which resembles a medieval warrior\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1259\">shield<\/a>. They are typically associated with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspots<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridges<\/a>, or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rifts<\/a> with rising upper <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> material. The low-angle flanks are built up slowly from numerous low-viscosity basaltic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> flows that spread out over long distances. The basaltic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> erupts effusively, meaning the eruptions are small, localized, and predictable.<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Kiluea-eruption-2018.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-291\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Kiluea-eruption-2018-300x223.jpg\" alt=\"Lava from Kiluea destroying road in Hawaii.\" width=\"300\" height=\"223\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Kiluea-eruption-2018-300x223.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Kiluea-eruption-2018-1024x761.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Kiluea-eruption-2018-768x571.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Kiluea-eruption-2018-65x48.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Kiluea-eruption-2018-225x167.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Kiluea-eruption-2018-350x260.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Kiluea-eruption-2018.jpg 1414w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Eruption of Kiluea in 2018 produced high viscosity lava shown here crossing a road. This eruption caused much property damage<\/figcaption><\/figure>\n<p>Typically, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_237\">shield volcano<\/a> eruptions are not much of a hazard to human life\u2014although non-explosive eruptions of Kilauea (Hawaii) in 2018 produced uncharacteristically large lavas that damaged roads and structures.\u00a0<span style=\"font-weight: 400\">Mauna Loa (see <a href=\"http:\/\/hvo.wr.usgs.gov\/maunaloa\/\">USGS page<\/a>) and Kilauea (see <a href=\"http:\/\/hvo.wr.usgs.gov\/kilauea\/\">USGS page<\/a>) in Hawaii are examples of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1259\">shield<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1259\">Shield<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> are also found in Iceland, the Galapagos Islands, Northern California, Oregon, and the East African <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">Rift<\/a><\/span><span style=\"font-weight: 400\">. <\/span><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 215px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Olympus-Mons-on-Mars.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-292\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Olympus-Mons-on-Mars-300x278.jpg\" alt=\"\" width=\"215\" height=\"200\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Olympus-Mons-on-Mars-300x278.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Olympus-Mons-on-Mars-1024x950.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Olympus-Mons-on-Mars-768x713.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Olympus-Mons-on-Mars-65x60.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Olympus-Mons-on-Mars-225x209.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Olympus-Mons-on-Mars-350x325.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Olympus-Mons-on-Mars.jpg 1043w\" sizes=\"auto, (max-width: 215px) 100vw, 215px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Olympus Mons, an enormous shield volcano on Mars, the largest volcano in the solar system, standing about two and a half times higher than Everest is above sea level.<\/figcaption><\/figure>\n<p>The largest <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> edifice in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1253\">Solar System<\/a> is Olympus Mons on Mars. This (possibly <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_755\">extinct<\/a>) <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_237\">shield volcano<\/a> covers an area the size of the state of Arizona. This may indicate the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a> erupted over a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a> for millions of years, which means Mars had little, if any, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a> activity<span style=\"font-weight: 400\">.<\/span><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/01\/ReU_PtFournaise_Lavastrome.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-293\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ReU_PtFournaise_Lavastrome-300x225.jpg\" alt=\"The lava is ropey\" width=\"300\" height=\"225\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ReU_PtFournaise_Lavastrome-300x225.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ReU_PtFournaise_Lavastrome-1024x768.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ReU_PtFournaise_Lavastrome-768x576.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ReU_PtFournaise_Lavastrome-65x49.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ReU_PtFournaise_Lavastrome-225x169.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ReU_PtFournaise_Lavastrome-350x263.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ReU_PtFournaise_Lavastrome.jpg 1276w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Ropey pahoehoe lava<\/figcaption><\/figure>\n<p style=\"text-align: left\"><span style=\"font-weight: 400\">Basaltic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> forms special landforms based on <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a>, composition, and content of dissolved gases and water vapor. The two main types of basaltic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_990\">volcanic rock<\/a> have Hawaiian names\u2014<em><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_238\"><em>pahoehoe<\/em><\/a><\/em> and <em><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_239\"><em>aa<\/em><\/a><\/em>. <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_238\">Pahoehoe<\/a><\/strong> might come from low-viscosity lava that flows easily into ropey strands.<\/span><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Etna_02aa.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-294\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Etna_02aa-300x225.jpg\" alt=\"The lava is sharp and jagged\" width=\"300\" height=\"225\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Etna_02aa-300x225.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Etna_02aa-1024x768.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Etna_02aa-768x576.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Etna_02aa-65x49.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Etna_02aa-225x169.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Etna_02aa-350x263.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Etna_02aa.jpg 1200w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Blocky a&rsquo;a lava<\/figcaption><\/figure>\n<p style=\"text-align: left\"><b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_239\">Aa<\/a><\/b><span style=\"font-weight: 400\"> (sometimes spelled a\u2019a or <\/span><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_239\">\u02bba\u02bb\u0101 <\/a>and pronounced \u00ab\u00a0ah-ah\u00a0\u00bb<\/span><span style=\"font-weight: 400\">) is more viscous and has a crumbly blocky appearance. The exact details of what forms the two types of flows are still up for debate. <\/span><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">Felsic<\/a> lavas have lower temperatures and more silica, and thus are higher viscosity. These also form <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_239\">aa<\/a>-style flows.<\/span><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Volcano_fissure_tube.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-295\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano_fissure_tube-300x199.jpg\" alt=\"The magma is sputtering outward\" width=\"300\" height=\"199\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano_fissure_tube-300x199.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano_fissure_tube-65x43.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano_fissure_tube-225x149.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano_fissure_tube-350x232.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano_fissure_tube.jpg 678w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Volcanic fissure and flow, which could eventually form a lava tube.<\/figcaption><\/figure>\n<p>Low-viscosity, fast-flowing basaltic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> tends to harden on the outside into a tube and continue to flow internally. Once <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> flow subsides, the empty outer shell may be left as a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> tube. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">Lava<\/a> tubes, with or without collapsed roofs, make famous caves in Hawaii, Northern California, the Columbia River <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1013\">Basalt<\/a> Plateau of Washington and Oregon, El Malpais National Monument in New Mexico, and Craters of the Moon National Monument in Idaho.<\/p>\n<p><strong>Fissures<\/strong> are cracks that commonly originate from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1259\">shield<\/a>-style eruptions. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">Lava<\/a> emerging from fissures is typically <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> and very fluid. The 2018 Kiluaea eruption included fissures associated with the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> flows. Some fissures are caused by the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> seismic activity rather than <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> flows. Some fissures are influenced by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">plate tectonics<\/a>, such as the common fissures located parallel to the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1677\">divergent<\/a> boundary in Iceland.<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 200px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/DT2-scaled.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-2892\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/DT2-scaled-1.jpg\" alt=\"The rock is full of columns\" width=\"200\" height=\"150\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Devils Tower in Wyoming has columnar jointing.<\/figcaption><\/figure>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 192px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Columnar-jointing-on-Giants-Causeway-in-Ireland.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-297\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Columnar-jointing-on-Giants-Causeway-in-Ireland-288x300.jpg\" alt=\"Columnar jointing on Giant's Causeway in Ireland.\" width=\"192\" height=\"200\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Columnar-jointing-on-Giants-Causeway-in-Ireland-288x300.jpg 288w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Columnar-jointing-on-Giants-Causeway-in-Ireland-982x1024.jpg 982w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Columnar-jointing-on-Giants-Causeway-in-Ireland-768x800.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Columnar-jointing-on-Giants-Causeway-in-Ireland-65x68.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Columnar-jointing-on-Giants-Causeway-in-Ireland-225x235.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Columnar-jointing-on-Giants-Causeway-in-Ireland-350x365.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Columnar-jointing-on-Giants-Causeway-in-Ireland.jpg 1017w\" sizes=\"auto, (max-width: 192px) 100vw, 192px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Columnar jointing on Giant&rsquo;s Causeway in Ireland.<\/figcaption><\/figure>\n<p>Cooling <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> can contract into columns with semi-hexagonal cross sections called <strong>columnar jointing<\/strong>. This feature forms the famous Devils Tower in Wyoming, possibly an ancient <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_234\">vent<\/a> from which the surrounding layers of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">ash<\/a> have been removed by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1755\">erosion<\/a>. Another well-known exposed example of columnar jointing is the Giant\u2019s Causeway in Ireland.<\/p>\n<h4><span style=\"font-weight: 400\">Stratovolcano<\/span><\/h4>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 225px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Mount_Rainier_over_Tacoma.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-298\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_Rainier_over_Tacoma-300x200.jpg\" alt=\"The mountain is very tall, and looms over the city\" width=\"225\" height=\"150\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_Rainier_over_Tacoma-300x200.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_Rainier_over_Tacoma-1024x683.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_Rainier_over_Tacoma-768x512.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_Rainier_over_Tacoma-1536x1024.jpg 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_Rainier_over_Tacoma-65x43.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_Rainier_over_Tacoma-225x150.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_Rainier_over_Tacoma-350x233.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_Rainier_over_Tacoma.jpg 1600w\" sizes=\"auto, (max-width: 225px) 100vw, 225px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Mount Rainier towers over Tacoma, Washington.<\/figcaption><\/figure>\n<p>A <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_240\">stratovolcano<\/a><\/strong>, also called a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_240\">composite cone<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a>, has steep flanks, a symmetrical cone shape, distinct crater, and rises prominently above the surrounding landscape. The term composite refers to the alternating layers of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1004\">pyroclastic<\/a> fragments like <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">ash<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1003\">bombs<\/a>, and solidified <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> flows of varying composition. Examples include Mount Rainier in Washington state and Mount Fuji in Japan.<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 250px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Mt.-Fuji-300x190-1.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-299\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mt.-Fuji-300x190-1.jpg\" alt=\"\" width=\"250\" height=\"158\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mt.-Fuji-300x190-1.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mt.-Fuji-300x190-1-65x41.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mt.-Fuji-300x190-1-225x143.jpg 225w\" sizes=\"auto, (max-width: 250px) 100vw, 250px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Mt. Fuji in Japan, a typical stratovolcano, symmetrical, increasing slope, visible crater at the top.<\/figcaption><\/figure>\n<p>Stratovolcanoes usually have <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1007\">intermediate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> chambers, but can even produce <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> lavas. Stratovolcanoes have viscous\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> flows and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_507\">domes<\/a>, punctuated by explosive eruptions. This produces <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> with steep flanks.<\/p>\n<h4><span style=\"font-weight: 400\">Lava Domes<\/span><\/h4>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/MSH06_aerial_crater_from_north_high_angle_09-12-06.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-300\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSH06_aerial_crater_from_north_high_angle_09-12-06-300x200.jpg\" alt=\"The mountain has a hole, but the hole has filled in somewhat\" width=\"300\" height=\"200\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSH06_aerial_crater_from_north_high_angle_09-12-06-300x200.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSH06_aerial_crater_from_north_high_angle_09-12-06-1024x681.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSH06_aerial_crater_from_north_high_angle_09-12-06-768x511.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSH06_aerial_crater_from_north_high_angle_09-12-06-1536x1022.jpg 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSH06_aerial_crater_from_north_high_angle_09-12-06-65x43.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSH06_aerial_crater_from_north_high_angle_09-12-06-225x150.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSH06_aerial_crater_from_north_high_angle_09-12-06-350x233.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSH06_aerial_crater_from_north_high_angle_09-12-06.jpg 2048w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Lava domes have started the rebuilding process at Mount St. Helens, Washington.<\/figcaption><\/figure>\n<p><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">Lava<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_507\">domes<\/a><\/strong> are accumulations of silica-rich <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_990\">volcanic rock<\/a>, such as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1010\">rhyolite<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_999\">obsidian<\/a>. Too viscous to flow easily, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> tends to pile up near the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_234\">vent<\/a> in blocky masses. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">Lava<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_507\">domes<\/a> often form in a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_234\">vent<\/a> within the collapsed crater of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_240\">stratovolcano<\/a>, and grow by internal expansion. As the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_507\">dome<\/a> expands, the outer surface cools, hardens, and shatters, and spills loose fragments down the sides. Mount Saint Helens has a good example of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_507\">dome<\/a> inside of a collapsed <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_240\">stratovolcano<\/a> crater. Examples of stand-alone <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_507\">domes<\/a> are Chaiten in Chile and Mammoth Mountain in California.<\/p>\n<h4><span style=\"font-weight: 400\">Caldera<\/span><\/h4>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 149px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Mount_Mazama_eruption_timeline.png\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-301\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_Mazama_eruption_timeline-89x300.png\" alt=\"It shows the eruption forming a caldera.\" width=\"149\" height=\"500\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_Mazama_eruption_timeline-89x300.png 89w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_Mazama_eruption_timeline-65x219.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_Mazama_eruption_timeline-225x757.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_Mazama_eruption_timeline.png 250w\" sizes=\"auto, (max-width: 149px) 100vw, 149px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Timeline of events at Mount Mazama.<\/figcaption><\/figure>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 250px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/CL1-scaled.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-2898\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/CL1-scaled-1.jpg\" alt=\"The island is forested, as are the flanks\" width=\"250\" height=\"188\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Wizard Island sits in the caldera at Crater Lake.<\/figcaption><\/figure>\n<p><strong>Calderas<\/strong> are steep-walled, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_508\">basin<\/a>-shaped depressions formed by the collapse of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> edifice into an empty <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_232\">magma chamber<\/a>. Calderas are generally very large, with diameters of up to 25 km (15.5 mi). The term <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_235\">caldera<\/a> specifically refers to a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_234\">vent<\/a>; however, it is frequently used to describe a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a> type. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_235\">Caldera<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> are\u00a0typically formed by eruptions of high-viscosity <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> having high <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1684\">volatiles<\/a> content.<\/p>\n<p>Crater Lake, Yellowstone, and the Long Valley <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_235\">Caldera<\/a> are good examples of this type of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a>. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_235\">caldera<\/a> at Crater Lake National Park in Oregon was created about 6,800 years ago when Mount Mazama, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_240\">composite volcano<\/a>, erupted in a huge explosive blast. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a> ejected large amounts of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">ash<\/a> and rapidly drained the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_232\">magma chamber<\/a>, causing the top to collapse into a large depression that later filled with water. Wizard Island in the middle of the lake is a later resurgent <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_241\">lava dome<\/a> that formed within the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_235\">caldera<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_508\">basin<\/a><span style=\"font-weight: 400\">.<\/span><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Yellowstone_Caldera_map2.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-303\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Yellowstone_Caldera_map2-300x242.jpg\" alt=\"The map shows locations of calderas and rocks within Yellowstone\" width=\"300\" height=\"242\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Yellowstone_Caldera_map2-300x242.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Yellowstone_Caldera_map2-1024x826.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Yellowstone_Caldera_map2-768x620.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Yellowstone_Caldera_map2-65x52.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Yellowstone_Caldera_map2-225x182.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Yellowstone_Caldera_map2-350x282.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Yellowstone_Caldera_map2.jpg 1486w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Map of calderas and related rocks around Yellowstone.<\/figcaption><\/figure>\n<p>The Yellowstone <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1742\">system<\/a> erupted three times in the recent geologic past\u20142.1, 1.3, and 0.64 million years ago\u2014leaving behind three <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_235\">caldera<\/a> basins. Each eruption created large <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1010\">rhyolite<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> flows as well as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1004\">pyroclastic<\/a> flows that solidified into <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1005\">tuff<\/a> formations. These extra-large eruptions rapidly emptied the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_232\">magma chamber<\/a>, causing the roof to collapse and form a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_235\">caldera<\/a>. The youngest of the three calderas contains most of Yellowstone National Park, as well as two resurgent <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_507\">domes<\/a>. The calderas are difficult to see today due to the amount of time since their eruptions and subsequent <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1755\">erosion<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_747\">glaciation<\/a>.<\/p>\n<p>Yellowstone <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> started about 17-million years ago as a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a> under the North American lithospheric <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> near the Oregon\/Nevada border. As the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> moved to the southwest over the stationary <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a>, it left behind a track of past <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> activities. Idaho\u2019s Snake River Plain was created from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> that produced a series of calderas and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> flows. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> eventually arrived at its current location in northwestern Wyoming, where <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> formed the Yellowstone calderas<span style=\"font-weight: 400\">.<\/span><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Yellowstone_volcano_-_ash_beds.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-134\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Yellowstone_volcano_-_ash_beds-300x195.jpg\" alt=\"The eruptions trend eastward due to prevailing winds.\" width=\"300\" height=\"195\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Yellowstone_volcano_-_ash_beds-300x195.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Yellowstone_volcano_-_ash_beds-65x42.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Yellowstone_volcano_-_ash_beds-225x146.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Yellowstone_volcano_-_ash_beds-350x228.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Yellowstone_volcano_-_ash_beds.jpg 580w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Several prominent ash beds found in North America, including three Yellowstone eruptions shaded pink (Mesa Falls, Huckleberry Ridge, and Lava Creek), the Bisho Tuff ash bed (brown dashed line), and the modern May 18th, 1980 ash fall (yellow).<\/figcaption><\/figure>\n<p>The Long Valley <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_235\">Caldera<\/a> near Mammoth, California, is the result of a large <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> eruption that occurred 760,000 years ago. The explosive eruption dumped enormous amounts of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">ash<\/a> across the United States, in a manner similar to the Yellowstone eruptions. The Bishop <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1005\">Tuff<\/a> deposit near Bishop, California, is made of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">ash<\/a> from this eruption. The current <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_235\">caldera<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_508\">basin<\/a> is 17 km by 32 km (10 mi by 20 mi), large enough to contain the town of Mammoth Lakes, major ski resort, airport, major highway, resurgent <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_507\">dome<\/a>, and several hot springs<span style=\"font-weight: 400\">.<\/span><\/p>\n<h4><span style=\"font-weight: 400\">Cinder Cone<\/span><\/h4>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Sunset_Crater10.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-304\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Sunset_Crater10-300x202.jpg\" alt=\"The cone is relatively small and red\" width=\"300\" height=\"202\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Sunset_Crater10-300x202.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Sunset_Crater10-1024x688.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Sunset_Crater10-768x516.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Sunset_Crater10-1536x1032.jpg 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Sunset_Crater10-65x44.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Sunset_Crater10-225x151.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Sunset_Crater10-350x235.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Sunset_Crater10.jpg 1599w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Sunset Crater, Arizona is a cinder cone.<\/figcaption><\/figure>\n<p><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_242\">Cinder<\/a> cones<\/strong> are small <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> with steep sides, and made of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1004\">pyroclastic<\/a> fragments that have been ejected from a pronounced central <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_234\">vent<\/a>. The small fragments are called <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_242\">cinders<\/a><\/strong> and the largest are <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1003\">bombs<\/a><\/strong>. The eruptions are usually short-lived events, typically consisting of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> lavas with a high content of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1684\">volatiles<\/a>. Hot <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> is ejected into the air, cooling and solidifying into fragments that accumulate on the flank of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_242\">Cinder<\/a> cones are found throughout western North America<span style=\"font-weight: 400\">.<\/span><\/p>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 200px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Paricutin_30_612.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-305\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Paricutin_30_612-200x300.jpg\" alt=\"A person looks at the eruption of ash\" width=\"200\" height=\"300\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Paricutin_30_612-200x300.jpg 200w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Paricutin_30_612-65x97.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Paricutin_30_612-225x337.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Paricutin_30_612-350x525.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Paricutin_30_612.jpg 667w\" sizes=\"auto, (max-width: 200px) 100vw, 200px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Soon after the birth of Par\u00edcutin in 1943.<\/figcaption><\/figure>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Paracutin-lava-in-San-Juan-300x224-1.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-306\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Paracutin-lava-in-San-Juan-300x224-1.jpg\" alt=\"\" width=\"300\" height=\"224\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Paracutin-lava-in-San-Juan-300x224-1.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Paracutin-lava-in-San-Juan-300x224-1-65x49.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Paracutin-lava-in-San-Juan-300x224-1-225x168.jpg 225w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Lava from Par\u00edcutin covered the local church and destroyed the town of San Juan, Mexico<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\">A recent and striking example of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_243\">cinder cone<\/a> is the eruption near the village of Par\u00edcutin, Mexico that started in 1943. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_243\">cinder cone<\/a> started explosively shooting <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_242\">cinders<\/a> out of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_234\">vent<\/a> in the middle of a farmer\u2019s field. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> quickly built up the cone to a height of over 90 m (300 ft) within a week, and 365 m (1,200 ft) within the first 8 months. After the initial explosive eruption of gases and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_242\">cinders<\/a>, basaltic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> poured out from the base of the cone. This is a common order of events for <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_242\">cinder<\/a> cones: violent eruption, cone and crater formation, low-viscosity <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> flow from the base. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_243\">cinder cone<\/a> is not strong enough to support a column of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> rising to the top of the crater, so the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> breaks through and emerges near the bottom of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a>. During nine years of eruption activity, the ashfall covered about 260 km<sup>2<\/sup> (100 mi<sup>2<\/sup>) and destroyed the nearby town of San Juan<\/span><span style=\"font-weight: 400\">.<\/span><\/p>\n<h4><span style=\"font-weight: 400\">Flood Basalts<\/span><\/h4>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 500px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/World-map-or-flood-basalts.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-307\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/World-map-or-flood-basalts-300x168.jpg\" alt=\"World map of flood basalts. Note the largest is the Siberian Traps\" width=\"500\" height=\"280\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/World-map-or-flood-basalts-300x168.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/World-map-or-flood-basalts-1024x573.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/World-map-or-flood-basalts-768x430.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/World-map-or-flood-basalts-1536x860.jpg 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/World-map-or-flood-basalts-65x36.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/World-map-or-flood-basalts-225x126.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/World-map-or-flood-basalts-350x196.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/World-map-or-flood-basalts.jpg 1703w\" sizes=\"auto, (max-width: 500px) 100vw, 500px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">World map of flood basalts. Note the largest is the Siberian Traps<\/figcaption><\/figure>\n<p>A rare <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> eruption type,\u00a0unobserved in modern times, is the\u00a0<strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_244\">flood basalt<\/a><\/strong>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_244\">Flood basalts<\/a> are some of the largest and lowest viscosity types of eruptions known. They are not known from any eruption in human history, so the exact mechanisms of eruption are still mysterious. Some famous examples include the Columbia River <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_244\">Flood Basalts<\/a> in Washington, Oregon, and Idaho, the Deccan Traps, which cover about 1\/3 of the country of India, and the Siberian Traps, which may have been involved in the Earth&rsquo;s largest <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1275\">mass extinction<\/a> (see <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/8-earth-history\/\" target=\"_blank\" rel=\"noopener\">chapter 8<\/a>).<\/p>\n<h4><span style=\"font-weight: 400\">Carbonatites<\/span><\/h4>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Crater_of_Ol_Doinyo_Lengai_Jan_2011-1.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-3187\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Crater_of_Ol_Doinyo_Lengai_Jan_2011-1-300x169-1.jpg\" alt=\"The crater has white rocks in the walls\" width=\"300\" height=\"169\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Crater of Ol Doinyo Lengai in 2011. Note the white carbonatite in the walls of the crater.<\/figcaption><\/figure>\n<p>Arguably the most unusual <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> activity are <strong>carbonatite<\/strong> eruptions. Only one actively erupting carbonatite <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a> exists on Earth today, Ol Doinyo Lengai, in the East African <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">Rift<\/a> Zone of Tanzania. While all other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> on Earth originates from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a>-based <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>, carbonatites are a product of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a>-based <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> and produce <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> rocks containing greater than 50% <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. Carbonatite lavas are very low viscosity and relatively cold for <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a>. The erupting <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> is black, and solidifies to brown\/grey rock that eventually turns white. These rocks are occasionally found in the geologic record and require special study to distinguish them from metamorphic marbles (see <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/6-metamorphic-rocks\/\">Chapter 6<\/a>). They are mostly associated with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rifting<\/a>.<\/p>\n<p><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Igneous-e1546649689814.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-309\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Igneous-e1546649689814.png\" alt=\"Table of igneous rocks and related volcano types. Horizontal axis is arranged from low to high silica content (i.e. from ultramafic to felsic). First row shows the extrusive (surface) igneous rocks basalt, andesite, and rhyolite. Second row shows volcano types: mid-ocean ridge, shield, cinder cone, and strato (composite). Third row shows examples of each volcano: mid-atlantic ridge, Mauna Kea (Hawaii), Paricutin, and Mt. St. Helens. Forth row shows intrusive rocks from mafic to felsic: Dunite, gabbro, diorige, granite. Fifth row shows common plate-tectonic settings: divergent oceanic hot spot, and convergent boundaries. Sixth row is typical composition: ultramafic, mafic, intermediate, and felsic.\" width=\"759\" height=\"820\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Igneous-e1546649689814.png 759w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Igneous-e1546649689814-278x300.png 278w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Igneous-e1546649689814-65x70.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Igneous-e1546649689814-225x243.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Igneous-e1546649689814-350x378.png 350w\" sizes=\"auto, (max-width: 759px) 100vw, 759px\" \/><\/a><\/p>\n<blockquote>\n<p style=\"text-align: left\"><em><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\"><em>Igneous rock<\/em><\/a> types and related <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\"><em>volcano<\/em><\/a> types. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\"><em>Mid-ocean ridges<\/em><\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1259\"><em>shield<\/em><\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\"><em>volcanoes<\/em><\/a> represent more <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\"><em>mafic<\/em><\/a> compositions, and strato (composite) <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\"><em>volcanoes<\/em><\/a> generally represent a more <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1007\"><em>intermediate<\/em><\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\"><em>felsic<\/em><\/a> <em>composition<\/em> and a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1678\"><em>convergent<\/em><\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\"><em>plate<\/em><\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\"><em>tectonic<\/em><\/a> boundary. Note that there are exceptions to this generalized layout of volcano types and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\"><em>igneous rock<\/em><\/a> <em>composition<\/em>.<\/em><\/p>\n<\/blockquote>\n<h3><b>4.5.3 Volcanic Hazards and Monitoring<\/b><\/h3>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 258px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Types_of_volcano_hazards_usgs.gif\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-310 size-medium\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Types_of_volcano_hazards_usgs-258x300.gif\" alt=\"It shows many hazards\" width=\"258\" height=\"300\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Types_of_volcano_hazards_usgs-258x300.gif 258w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Types_of_volcano_hazards_usgs-65x76.gif 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Types_of_volcano_hazards_usgs-225x262.gif 225w\" sizes=\"auto, (max-width: 258px) 100vw, 258px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">General diagram of volcanic hazards.<\/figcaption><\/figure>\n<p>While the most obvious <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> hazard is <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a>, the dangers posed by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> go far beyond <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> flows. For example, on May 18, 1980, Mount Saint Helens (Washington, United States) erupted with an explosion and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_246\">landslide<\/a> that removed the upper 400 m (1,300 ft) of the mountain. The initial explosion was immediately followed by a lateral blast, which produced a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_245\">pyroclastic\u00a0flow<\/a> that covered nearly 600 km<sup>2<\/sup> (230 mi<sup>2<\/sup>) of forest with hot <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">ash<\/a> and debris. The pyroclastic flow moved at speeds of 80-130 kph (50-80 mph), flattening trees and ejecting clouds of ash into the air. The USGS video provides an account of this explosive eruption that killed 57 people.<\/p>\n<p><iframe loading=\"lazy\" id=\"oembed-8\" title=\"Mount St. Helens: May 18, 1980\" width=\"500\" height=\"375\" src=\"https:\/\/www.youtube.com\/embed\/Ec30uU0G56U?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Mount-St.-helens-YouTube-QR-Code.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-thumbnail wp-image-311\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount-St.-helens-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount-St.-helens-YouTube-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount-St.-helens-YouTube-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount-St.-helens-YouTube-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount-St.-helens-YouTube-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount-St.-helens-YouTube-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount-St.-helens-YouTube-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount-St.-helens-YouTube-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount-St.-helens-YouTube-QR-Code.png 1155w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this YouTube video via this QR Code.<\/figcaption><\/figure>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 250px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/DSC01727.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-312\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/DSC01727-300x225.jpg\" alt=\"The body is outlined with a cast, and the bones are seen.\" width=\"250\" height=\"188\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/DSC01727-300x225.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/DSC01727-1024x768.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/DSC01727-768x576.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/DSC01727-1536x1152.jpg 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/DSC01727-65x49.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/DSC01727-225x169.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/DSC01727-350x263.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/DSC01727.jpg 2048w\" sizes=\"auto, (max-width: 250px) 100vw, 250px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Human remains from the 79 CE eruption of Vesuvius.<\/figcaption><\/figure>\n<p>In 79 AD, Mount Vesuvius, located near Naples, Italy, violently erupted sending a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_245\">pyroclastic flow<\/a> over the Roman countryside, including the cities of Herculaneum and Pompeii. The buried towns were discovered in an archeological expedition in the 18th century. Pompeii famously contains the remains (<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1231\">casts<\/a>) of people suffocated by ash and covered by 10 feet (3 m) of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">ash<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_998\">pumice<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1002\">lapilli<\/a>, and collapsed roofs.<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Mount_St._Helens_one_day_before_the_devastating_eruption.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-313\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_St._Helens_one_day_before_the_devastating_eruption-300x203.jpg\" alt=\"The volcano is conical and forested.\" width=\"300\" height=\"203\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_St._Helens_one_day_before_the_devastating_eruption-300x203.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_St._Helens_one_day_before_the_devastating_eruption-1024x692.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_St._Helens_one_day_before_the_devastating_eruption-768x519.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_St._Helens_one_day_before_the_devastating_eruption-1536x1038.jpg 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_St._Helens_one_day_before_the_devastating_eruption-65x44.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_St._Helens_one_day_before_the_devastating_eruption-225x152.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_St._Helens_one_day_before_the_devastating_eruption-350x237.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mount_St._Helens_one_day_before_the_devastating_eruption.jpg 2048w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Mount St. Helens, the day before the May 18th, 1980 eruption.<\/figcaption><\/figure>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/MSH80_st_helens_from_johnston_ridge_09-10-80.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-314\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSH80_st_helens_from_johnston_ridge_09-10-80-300x201.jpg\" alt=\"The top of the mountain is gone\" width=\"300\" height=\"201\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSH80_st_helens_from_johnston_ridge_09-10-80-300x201.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSH80_st_helens_from_johnston_ridge_09-10-80-1024x687.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSH80_st_helens_from_johnston_ridge_09-10-80-768x515.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSH80_st_helens_from_johnston_ridge_09-10-80-1536x1031.jpg 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSH80_st_helens_from_johnston_ridge_09-10-80-65x44.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSH80_st_helens_from_johnston_ridge_09-10-80-225x151.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSH80_st_helens_from_johnston_ridge_09-10-80-350x235.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSH80_st_helens_from_johnston_ridge_09-10-80.jpg 2048w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Picture 4 months after the major eruption of Mount St. Helens.<\/figcaption><\/figure>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 1500px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-315 size-full\" title=\"By Associated Press, via The Atlantic, https:\/\/www.theatlantic.com\/photo\/2015\/05\/the-eruption-of-mount-st-helens-in-1980\/393557\/\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mt_Saint_Helens_Eruption_main_1500.gif\" alt=\"Series of images showing half of the mountain releasing as a giant landslide and ash billowing out from underneath.\" width=\"1500\" height=\"943\" \/><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Series of still images of the May 18, 1980, eruption of Mt. Saint Helens, Washington showing largest recorded landslide in history and subsequent eruption and pyroclastic flow (By The Associated Press via The Atlantic)<\/figcaption><\/figure>\n<h4><span style=\"font-weight: 400\">Pyroclastic flows<\/span><\/h4>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Pyroclastic_flows_at_Mayon_Volcano.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-316\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pyroclastic_flows_at_Mayon_Volcano-300x188.jpg\" alt=\"Most of the material is heading up, but small portions of the eruption column head downward.\" width=\"300\" height=\"188\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pyroclastic_flows_at_Mayon_Volcano-300x188.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pyroclastic_flows_at_Mayon_Volcano-768x480.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pyroclastic_flows_at_Mayon_Volcano-65x41.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pyroclastic_flows_at_Mayon_Volcano-225x141.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pyroclastic_flows_at_Mayon_Volcano-350x219.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pyroclastic_flows_at_Mayon_Volcano.jpg 800w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">The material coming down from the eruption column is a pyroclastic flow.<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\">The most dangerous <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> hazard are <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1004\">pyroclastic<\/a> flows<\/strong> (<\/span><a href=\"https:\/\/volcanoes.usgs.gov\/vsc\/movies\/movie_101\/PF_Animation.mp4\"><span style=\"font-weight: 400\">video<\/span><\/a><span style=\"font-weight: 400\">). These flows are a mix of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> blocks, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_998\">pumice<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">ash<\/a>, and hot gases between 200\u00b0C-700\u00b0C (400\u00b0F-1,300\u00b0F). The turbulent cloud of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">ash<\/a> and gas races down the steep flanks at high speeds up to 193 kph (120 mph) into the valleys around composite <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a><\/span><span style=\"font-weight: 400\">. Most explosive, silica-rich, high viscosity <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> such as composite cones usually have <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1004\">pyroclastic<\/a> flows. The rock <\/span><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1005\">tuff<\/a> <span style=\"font-weight: 400\">and <\/span>welded <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1005\">tuff<\/a><span style=\"font-weight: 400\"> is often formed from these <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1004\">pyroclastic<\/a> flows.<\/span><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 256px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Pelee_1902_3.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-317\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pelee_1902_3-256x300.jpg\" alt=\"A man is seen overlooking the destroyed city\" width=\"256\" height=\"300\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pelee_1902_3-256x300.jpg 256w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pelee_1902_3-65x76.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pelee_1902_3-225x264.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pelee_1902_3.jpg 322w\" sizes=\"auto, (max-width: 256px) 100vw, 256px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">The remains of St. Pierre.<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\">There are numerous examples of deadly <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1004\">pyroclastic<\/a> flows. In 2014, the Mount Ontake <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_245\">pyroclastic flow<\/a> in Japan killed 47 people. The flow was caused by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> heating groundwater into steam, which then rapidly ejected with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">ash<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1003\">bombs<\/a>. Some were killed by inhalation of toxic gases and hot ash, while others were struck by volcanic bombs<\/span><span style=\"font-weight: 400\">. <\/span><span style=\"font-weight: 400\">Two short videos below document<\/span><span style=\"font-weight: 400\">\u00a0eye-witness video of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1004\">pyroclastic<\/a> flows. In the early 1990s, Mount Unzen erupted several times with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1004\">pyroclastic<\/a> flows. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_245\">pyroclastic flow<\/a>\u00a0shown in this famous <\/span><span style=\"font-weight: 400\">short video<\/span><span style=\"font-weight: 400\"> killed 41 people. In 1902, on the Caribbean Island Martinique, Mount Pelee <\/span><span style=\"font-weight: 400\">erupted with a violent <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_245\">pyroclastic flow<\/a> that destroyed the entire town of St. Pierre and killing 28,000 people in moments<\/span><span style=\"font-weight: 400\">.<\/span><\/p>\n<p><iframe loading=\"lazy\" id=\"oembed-9\" title=\"Japan&#39;s Mount Ontake volcano erupted\/eruption, killing 34 people, report BBC (corrected aspect)\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/3ObsOj9Q2Do?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Japans-Mount-Ontake-YouTube-QR-Code.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-thumbnail wp-image-318\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Japans-Mount-Ontake-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Japans-Mount-Ontake-YouTube-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Japans-Mount-Ontake-YouTube-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Japans-Mount-Ontake-YouTube-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Japans-Mount-Ontake-YouTube-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Japans-Mount-Ontake-YouTube-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Japans-Mount-Ontake-YouTube-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Japans-Mount-Ontake-YouTube-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Japans-Mount-Ontake-YouTube-QR-Code.png 1155w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this YouTube video via this QR Code.<\/figcaption><\/figure>\n<p><iframe loading=\"lazy\" id=\"oembed-10\" title=\"Dome collapse and pyroclastic flow at Unzen Volcano\" width=\"500\" height=\"375\" src=\"https:\/\/www.youtube.com\/embed\/Cvjwt9nnwXY?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Dome-collapse-and-pyroclastic-flow-at-Unzen-Volcano-YouTube-QR-Codes.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-thumbnail wp-image-319\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Dome-collapse-and-pyroclastic-flow-at-Unzen-Volcano-YouTube-QR-Codes-150x150.png\" alt=\"\" width=\"150\" height=\"150\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Dome-collapse-and-pyroclastic-flow-at-Unzen-Volcano-YouTube-QR-Codes-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Dome-collapse-and-pyroclastic-flow-at-Unzen-Volcano-YouTube-QR-Codes-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Dome-collapse-and-pyroclastic-flow-at-Unzen-Volcano-YouTube-QR-Codes-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Dome-collapse-and-pyroclastic-flow-at-Unzen-Volcano-YouTube-QR-Codes-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Dome-collapse-and-pyroclastic-flow-at-Unzen-Volcano-YouTube-QR-Codes-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Dome-collapse-and-pyroclastic-flow-at-Unzen-Volcano-YouTube-QR-Codes-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Dome-collapse-and-pyroclastic-flow-at-Unzen-Volcano-YouTube-QR-Codes-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Dome-collapse-and-pyroclastic-flow-at-Unzen-Volcano-YouTube-QR-Codes.png 1155w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this YouTube video via this QR Code.<\/figcaption><\/figure>\n<h4><span style=\"font-weight: 400\">Landslides and Landslide-Generated Tsunamis<\/span><\/h4>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Msh_may18_sequence.gif\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-320\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Msh_may18_sequence-300x197.gif\" alt=\"The landslide opened an area for the eruption\" width=\"300\" height=\"197\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Msh_may18_sequence-300x197.gif 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Msh_may18_sequence-65x43.gif 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Msh_may18_sequence-225x147.gif 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Msh_may18_sequence-350x229.gif 350w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Sequence of events for Mount St. Helens, May 18th, 1980. Note that an earthquake caused a landslide, which caused the \u00ab\u00a0uncorking\u00a0\u00bb of the mountain and started the eruption.<\/figcaption><\/figure>\n<p>The steep and unstable flanks of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a> can lead to slope failure and dangerous <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_246\">landslides<\/a>. These <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_246\">landslides<\/a> can be triggered by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> movement, explosive eruptions, large earthquakes, and\/or heavy rainfall. During the 1980 Mount St. Helens eruption, the entire north flank of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a> collapsed and released a huge <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_246\">landslide<\/a> that moved at speeds of 160-290 kph (100-180 mph).<\/p>\n<p>If enough <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_246\">landslide<\/a> material reaches the ocean, it may cause a tsunami. In 1792, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_246\">landslide<\/a> caused by the Mount Unzen eruption reached the Ariaka Sea, generating a tsunami that killed 15,000 people (see <a href=\"http:\/\/volcano.oregonstate.edu\/describe-1883-eruption-krakatau\" target=\"_blank\" rel=\"noopener\">USGS page<\/a>). When Mount Krakatau in Indonesia erupted in 1883, it generated ocean waves that towered 40 m (131 ft) above sea level. The tsunami killed 36,000 people and destroyed 165 villages.<\/p>\n<h4><span style=\"font-weight: 400\">Tephra<\/span><\/h4>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Ash_in_Yogyakarta_during_the_2014_eruption_of_Kelud_01.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-321\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ash_in_Yogyakarta_during_the_2014_eruption_of_Kelud_01-300x204.jpg\" alt=\"The man is wearing a mask to prevent pneumonoultramicroscopicsilicovolvanoconiosis.\" width=\"300\" height=\"204\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ash_in_Yogyakarta_during_the_2014_eruption_of_Kelud_01-300x204.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ash_in_Yogyakarta_during_the_2014_eruption_of_Kelud_01-1024x695.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ash_in_Yogyakarta_during_the_2014_eruption_of_Kelud_01-768x521.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ash_in_Yogyakarta_during_the_2014_eruption_of_Kelud_01-1536x1043.jpg 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ash_in_Yogyakarta_during_the_2014_eruption_of_Kelud_01-65x44.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ash_in_Yogyakarta_during_the_2014_eruption_of_Kelud_01-225x153.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ash_in_Yogyakarta_during_the_2014_eruption_of_Kelud_01-350x238.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ash_in_Yogyakarta_during_the_2014_eruption_of_Kelud_01.jpg 2048w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Aman sweeps ash from an eruption of Kelud, Indonesia.<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">Volcanoes<\/a>, especially composite <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a>, eject large amounts of <\/span><b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1000\">tephra<\/a> <\/b><span style=\"font-weight: 400\">(ejected rock materials), most notably\u00a0<\/span><b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">ash<\/a> <\/b><span style=\"font-weight: 400\">(<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1000\">tephra<\/a> fragments less than 0.08 inches [2 mm]). Larger <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1000\">tephra<\/a> is heavier and falls closer to the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_234\">vent<\/a>. Larger blocks and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1003\">bombs<\/a> pose hazards to those close to the eruption such as at the 2014 Mount Ontake disaster in Japan discussed earlier.<\/span><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 250px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Micrograph-of-volcanic-ash-particle.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-322\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Micrograph-of-volcanic-ash-particle.jpg\" alt=\"Micrograph of silica particle in volcanic ash. A cloud of these is capable of destroying an aircraft or automobile engine.\" width=\"250\" height=\"183\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Micrograph-of-volcanic-ash-particle.jpg 250w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Micrograph-of-volcanic-ash-particle-65x48.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Micrograph-of-volcanic-ash-particle-225x165.jpg 225w\" sizes=\"auto, (max-width: 250px) 100vw, 250px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Micrograph of silica particle in volcanic ash. A cloud of these is capable of destroying an aircraft or automobile engine.<\/figcaption><\/figure>\n<p>Hot <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">ash<\/a> poses an immediate danger to people, animals, plants, machines, roads, and buildings located close to the eruption. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">Ash<\/a> is fine grained (&lt; 2mm) and can travel airborne long distances away from the eruption site. Heavy accumulations of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">ash<\/a> can cause buildings to collapse. In people, it may cause respiratory issues like silicosis. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">Ash<\/a> is destructive to aircraft and automobile engines, which can disrupt transportation and shipping services. In 2010, the Eyjafjallaj\u00f6kull <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a> in Iceland emitted a large <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">ash<\/a> cloud into the upper <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1745\">atmosphere<\/a>, causing the largest air-travel disruption in northern Europe since World War II. No one was injured, but the service disruption was estimated to have cost the world economy billions of dollars.<\/p>\n<h4><span style=\"font-weight: 400\">Volcanic Gases<\/span><\/h4>\n<p>As <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> rises to the surface the confining pressure decreases, and allows dissolved gases to escape into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1745\">atmosphere<\/a>. Even <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> that are not actively erupting may emit hazardous gases, such as carbon dioxide (CO<sub>2<\/sub>), sulfur dioxide (SO<sub>2<\/sub>), hydrogen <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfide<\/a> (H<sub>2<\/sub>S), and hydrogen <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_972\">halides<\/a> (HF, HCl, or HBr).<\/p>\n<p>Carbon dioxide tends to sink and accumulate in depressions and basins. In <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> areas known to emit carbon dioxide, low-lying areas may trap hazardous concentrations of this colorless and odorless gas. The Mammoth Mountain Ski Resort in California, is located within the Long Valley <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_235\">Caldera<\/a>, is one such area of carbon dioxide-producing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a>. In 2006, three ski patrol members died of suffocation caused by carbon dioxide after falling into a snow depression near a fumarole\u00a0<span style=\"font-weight: 400\">(<\/span><a href=\"http:\/\/volcanoes.usgs.gov\/Imgs\/Jpg\/Unzen\/MayuyamaSlide_caption.html\" target=\"_blank\" rel=\"noopener\"><span style=\"font-weight: 400\">info<\/span><\/a><span style=\"font-weight: 400\">)<\/span>.<\/p>\n<p>In rare cases, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> may create a sudden emission of gases without warning. Limnic eruptions (<em>limne<\/em> is Greek for lake), occur in crater lakes associated with active <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a>. The water in these lakes is supercharged with high concentrations of dissolved gases. If the water is physically jolted by a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_246\">landslide<\/a> or earthquake, it may trigger an immediate and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_985\">massive<\/a> release of gases out of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a>. An analogous example would be what happens to vigorously shaken bottle of carbonated soda when the cap is opened. An infamous limnic eruption occurred in 1986 at Lake Nyos, Cameroon. Almost 2,000 people were killed by a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_985\">massive<\/a> release of carbon dioxide.<\/p>\n<h4><span style=\"font-weight: 400\">Lahars<\/span><\/h4>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/MSHlahar.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-323\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSHlahar-300x200.jpg\" alt=\"The mud line is far up on the trees\" width=\"300\" height=\"200\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSHlahar-300x200.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSHlahar-65x43.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSHlahar-225x150.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSHlahar-350x234.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSHlahar.jpg 400w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Mud line shows the extent of lahars around Mount St. Helens.<\/figcaption><\/figure>\n<p><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_247\">Lahar<\/a><\/strong> is an Indonesian word and is used to describe a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> mudflow that forms from rapidly melting snow or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1516\">glaciers<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_247\">Lahars<\/a> are slurries resembling wet concrete, and consist of water, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">ash<\/a>, rock fragments, and other debris. These mudflows flow down the flanks of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> or mountains covered with freshly-erupted <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">ash<\/a> and on steep slopes can reach speeds of up to 80 kph (50 mph).<\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 235px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/LaharsRaineer.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"size-medium wp-image-324\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/LaharsRaineer-235x300.jpg\" alt=\"The cities are on top of old lahar deposits\" width=\"235\" height=\"300\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/LaharsRaineer-235x300.jpg 235w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/LaharsRaineer-65x83.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/LaharsRaineer-225x287.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/LaharsRaineer-350x446.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/LaharsRaineer.jpg 450w\" sizes=\"auto, (max-width: 235px) 100vw, 235px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">Old lahars around Tacoma, Washington.<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\">Several major cities, including Tacoma, are located on prehistoric <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_247\">lahar<\/a> flows that extend for many kilometers across the flood plains surrounding Mount Rainier in Washington (see map). A map of Mount Baker in Oregon shows a similar potential hazard for <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_247\">lahar<\/a> flows (see map). A tragic scenario played out recently, in 1985, when a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_247\">lahar<\/a> from the Nevado del Ruiz <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a> in Colombia buried the town of Armero and killed an estimated 23,000 people.<\/span><\/p>\n<h4><span style=\"font-weight: 400\">Monitoring<\/span><\/h4>\n<p>Geologists use various instruments to detect changes or indications that an eruption is imminent. The three videos show different types of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> monitoring used to predict eruptions 1) earthquake activity; 2) increases in gas emission; and 3) changes in land surface orientation and elevation.<\/p>\n<p>One video shows how monitoring earthquake frequency, especially special vibrational earthquakes called harmonic tremors, can detect <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> movement and possible eruption. Another video shows how gas monitoring may be used to predict an eruption. A rapid increase of gas emission may indicate <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> that is actively rising to surface and releasing dissolved gases out of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a>, and that an eruption is imminent. The last video shows how a GPS unit and tiltmeter can detect land surface changes, indicating the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> is moving underneath it.<\/p>\n<p><iframe loading=\"lazy\" id=\"oembed-11\" title=\"Volcano Monitoring\u2014Earthquake signals (educational)\" width=\"500\" height=\"375\" src=\"https:\/\/www.youtube.com\/embed\/nlo-2JoNHrw?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Volcano-Monitoring-Earthquake-Signals-YouTube-QR-Code.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-thumbnail wp-image-325\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Earthquake-Signals-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Earthquake-Signals-YouTube-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Earthquake-Signals-YouTube-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Earthquake-Signals-YouTube-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Earthquake-Signals-YouTube-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Earthquake-Signals-YouTube-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Earthquake-Signals-YouTube-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Earthquake-Signals-YouTube-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Earthquake-Signals-YouTube-QR-Code.png 1155w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this YouTube video via this QR Code.<\/figcaption><\/figure>\n<p><iframe loading=\"lazy\" id=\"oembed-12\" title=\"Volcano Monitoring\u2014Measuring Gas emmisions\" width=\"500\" height=\"375\" src=\"https:\/\/www.youtube.com\/embed\/owk4fWbw4qM?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Volcano-Monitoring-Measuring-Gas-emmisions-YouTube-QR-Code.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-thumbnail wp-image-326\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Measuring-Gas-emmisions-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Measuring-Gas-emmisions-YouTube-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Measuring-Gas-emmisions-YouTube-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Measuring-Gas-emmisions-YouTube-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Measuring-Gas-emmisions-YouTube-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Measuring-Gas-emmisions-YouTube-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Measuring-Gas-emmisions-YouTube-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Measuring-Gas-emmisions-YouTube-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Measuring-Gas-emmisions-YouTube-QR-Code.png 1155w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this YouTube video via this QR Code.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p><iframe loading=\"lazy\" id=\"oembed-13\" title=\"Volcano Monitoring_Deformation measured with tilt meter and GPS\" width=\"500\" height=\"375\" src=\"https:\/\/www.youtube.com\/embed\/sNYQkxxd_0Q?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Volcano-Monitoring-Deformation-measured-YouTube-QR-Code.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-thumbnail wp-image-327\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Deformation-measured-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Deformation-measured-YouTube-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Deformation-measured-YouTube-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Deformation-measured-YouTube-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Deformation-measured-YouTube-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Deformation-measured-YouTube-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Deformation-measured-YouTube-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Deformation-measured-YouTube-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Volcano-Monitoring-Deformation-measured-YouTube-QR-Code.png 1155w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this YouTube video via this QR Code.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-29\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-29\" class=\"h5p-iframe\" data-content-id=\"29\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"4.5 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/4.5-Did-I-Get-It-QR-Code.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-thumbnail wp-image-328\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.5-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.5-Did-I-Get-It-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.5-Did-I-Get-It-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.5-Did-I-Get-It-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.5-Did-I-Get-It-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.5-Did-I-Get-It-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.5-Did-I-Get-It-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.5-Did-I-Get-It-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4.5-Did-I-Get-It-QR-Code.png 1147w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 4.5 via this QR Code.<\/figcaption><\/figure>\n<h2>Summary<\/h2>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">Igneous rock<\/a> is divided into two major groups: <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_991\">intrusive<\/a> rock that solidifies from underground <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_990\">extrusive<\/a> rock formed from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> that erupts and cools on the surface. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">Magma<\/a> is generated from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> material at several <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonics<\/a> situations by three types of melting: <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_223\">decompression melting<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1686\">flux melting<\/a>, or heat-induced melting. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">Magma<\/a> composition is determined by differences in the melting temperatures of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> components (<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_221\">Bowen\u2019s Reaction Series<\/a>). The processes affecting <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> composition include <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_224\">partial melting<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_226\">magmatic differentiation<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_225\">assimilation<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1698\">collision<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">Volcanoes<\/a> come in a wide variety of shapes and sizes, and are classified by a multiple factors, including <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> composition, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a> activity. Because <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> presents serious hazards to human civilization, geologists carefully monitor <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> activity to mitigate or avoid the dangers it presents.<\/p>\n<h3>Take this quiz to check your comprehension of this Chapter.<\/h3>\n<div id=\"h5p-30\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-30\" class=\"h5p-iframe\" data-content-id=\"30\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Chapter 4 Review\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_315\" aria-describedby=\"caption-attachment-315\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Ch.4-Review-QR-Code.png\"><img loading=\"lazy\" decoding=\"async\" class=\"size-thumbnail wp-image-329\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ch.4-Review-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ch.4-Review-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ch.4-Review-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ch.4-Review-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ch.4-Review-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ch.4-Review-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ch.4-Review-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ch.4-Review-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ch.4-Review-QR-Code.png 1147w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/a><figcaption id=\"caption-attachment-315\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the review quiz for Chapter 4 via this QR Code.<\/figcaption><\/figure>\n<h2><strong>References<\/strong><\/h2>\n<div class=\"csl-bib-body\">\n<ol>\n<li class=\"csl-entry\">Arndt, N.T., 1994, Chapter 1 <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1257\">Archean<\/a> Komatiites, <i>in<\/i> K.C. Condie, editor, Developments in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1270\">Precambrian<\/a> Geology: Elsevier, p. 11\u201344.<\/li>\n<li class=\"csl-entry\">Bateman, P.C., and Chappell, B.W., 1979, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1752\">Crystallization<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_227\">fractionation<\/a>, and solidification of the Tuolumne <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_991\">Intrusive<\/a> Series, Yosemite National Park, California: Geological Society of America Bulletin, v. 90, no. 5, p. 465\u2013482., doi: &lt;a href=\u00a0\u00bbhttps:\/\/doi.org\/10.1130\/0016-7606(1979)902.0.CO;2&Prime;&gt;10.1130\/0016-7606(1979)90&lt;465:CFASOT&gt;2.0.CO;2.<\/li>\n<li class=\"csl-entry\">Bell, K., and Keller, J., 2012, Carbonatite <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a>: Oldoinyo Lengai and the petrogenesis of natrocarbonatites: Springer Science &amp; Business Media.<\/li>\n<li class=\"csl-entry\">Boehler, R., 1996, Melting temperatures of the Earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1667\">core<\/a>: Earth\u2019s thermal structure: Annual Review of Earth and Planetary Sciences, v. 24, no. 1, p. 15\u201340., doi: <a href=\"https:\/\/doi.org\/10.1146\/annurev.earth.24.1.15\">10.1146\/annurev.earth.24.1.15<\/a>.<\/li>\n<li class=\"csl-entry\">Bowen, N.L., 1922, The Reaction Principle in Petrogenesis: J. Geol., v. 30, no. 3, p. 177\u2013198.<\/li>\n<li class=\"csl-entry\">Bowen, N.L., 1928, The evolution of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks: Dover Publications, 334 p.<\/li>\n<li class=\"csl-entry\">Carr, M.H., 1975, Geologic map of the Tharsis Quadrangle of Mars: IMAP.<\/li>\n<li class=\"csl-entry\">Earle, S., 2015, Physical geology OER textbook: BC Campus OpenEd.<\/li>\n<li class=\"csl-entry\">EarthScope, 2014, Mount Ontake <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">Volcanic<\/a> Eruption: Online, <a href=\"http:\/\/www.earthscope.org\/science\/geo-events\/mount-ontake-volcanic-eruption\">http:\/\/www.earthscope.org\/science\/geo-events\/mount-ontake-volcanic-eruption<\/a>, accessed July 2016.<\/li>\n<li class=\"csl-entry\">Frankel, C., 2005, Worlds on Fire: <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">Volcanoes<\/a> on the Earth, the Moon, Mars, Venus and Io: Cambridge University Press, 396 p.<\/li>\n<li class=\"csl-entry\">Glazner, A.F., Bartley, J.M., Coleman, D.S., Gray, W., and Taylor, R.Z., 2004, Are <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1017\">plutons<\/a> assembled over millions of years by amalgamation from small <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> chambers? GSA Today, v. 14, no. 4, p. 4., doi: &lt;a href=\u00a0\u00bbhttps:\/\/doi.org\/10.1130\/1052-5173(2004)0142.0.CO;2&Prime;&gt;10.1130\/1052-5173(2004)014&lt;0004:APAOMO&gt;2.0.CO;2.<\/li>\n<li class=\"csl-entry\">Luongo, G., Perrotta, A., Scarpati, C., De Carolis, E., Patricelli, G., and Ciarallo, A., 2003, Impact of the AD 79 explosive eruption on Pompeii, II. Causes of death of the inhabitants inferred by stratigraphic analysis and areal distribution of the human casualties: J. Volcanol. Geotherm. Res., v. 126, no. 3\u20134, p. 169\u2013200.<\/li>\n<li class=\"csl-entry\">Mueller, S., and Phillips, R.J., 1991, On the initiation of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a>: J. Geophys. Res. [Solid Earth], v. 96, no. B1, p. 651\u2013665.<\/li>\n<li class=\"csl-entry\">Peacock, M.A., 1931, Classification of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">Igneous Rock<\/a> Series: The Journal of Geology, v. 39, no. 1, p. 54\u201367.<\/li>\n<li class=\"csl-entry\">Perkins, S., 2011, 2010\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">Volcano<\/a>-Induced Air Travel Shutdown Was Justified: Online, <a href=\"http:\/\/www.sciencemag.org\/news\/2011\/04\/2010s-volcano-induced-air-travel-shutdown-was-justified\">http:\/\/www.sciencemag.org\/news\/2011\/04\/2010s-volcano-induced-air-travel-shutdown-was-justified<\/a>, accessed July 2016.<\/li>\n<li class=\"csl-entry\">Peterson, D.W., and Tilling, R.I., 1980, Transition of basaltic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_238\">pahoehoe<\/a> to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_239\">aa<\/a>, Kilauea <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">Volcano<\/a>, Hawaii: Field observations and key factors &#8211; ScienceDirect: J. Volcanol. Geotherm. Res., v. 7, no. 3\u20134, p. 271\u2013293.<\/li>\n<li class=\"csl-entry\">Petrini and Podladchikov, 2000, Lithospheric pressure\u2013depth relationship in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_493\">compressive<\/a> regions of thickened <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a>: Journal of Metamorphic Geology, v. 18, no. 1, p. 67\u201377., doi: <a href=\"https:\/\/doi.org\/10.1046\/j.1525-1314.2000.00240.x\">10.1046\/j.1525-1314.2000.00240.x<\/a>.<\/li>\n<li class=\"csl-entry\">Reid, J.B., Evans, O.C., and Fates, D.G., 1983, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">Magma<\/a> mixing in granitic rocks of the central Sierra Nevada, California: Earth and Planetary Science Letters, v. 66, p. 243\u2013261., doi: <a href=\"https:\/\/doi.org\/10.1016\/0012-821X(83)90139-5\">10.1016\/0012-821X(83)90139-5<\/a>.<\/li>\n<li class=\"csl-entry\">Rhodes, J.M., and Lockwood, J.P., 1995, Mauna Loa Revealed: Structure, Composition, History, and Hazards: Washington DC American Geophysical Union Geophysical Monograph Series, v. 92.<\/li>\n<li class=\"csl-entry\">Scandone, R., Giacomelli, L., and Gasparini, P., 1993, Mount Vesuvius: 2000 years of volcanological observations: Journal of Volcanology and Geothermal Research, v. 58, p. 5\u201325.<\/li>\n<li class=\"csl-entry\">Stovall, W.K., Wilkins, A.M., Mandeville, C.W., and Driedger, C.L., 2016, Fact Sheet.:<\/li>\n<li class=\"csl-entry\">Thorarinsson, S., 1969, The Lakagigar eruption of 1783: Bull. Volcanol., v. 33, no. 3, p. 910\u2013929.<\/li>\n<li class=\"csl-entry\">Tilling, R.I., 2008, The critical role of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a> monitoring in risk reduction: Adv. Geosci., v. 14, p. 3\u201311.<\/li>\n<li class=\"csl-entry\">United States Geological Survey, 1999, Exploring the deep ocean floor: Online, <a href=\"http:\/\/pubs.usgs.gov\/gip\/dynamic\/exploring.html\">http:\/\/pubs.usgs.gov\/gip\/dynamic\/exploring.html<\/a>, accessed July 2016.<\/li>\n<li class=\"csl-entry\">United States Geological Survey, 2012, Black Rock Desert <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">Volcanic<\/a> Field: Online, <a href=\"http:\/\/volcanoes.usgs.gov\/volcanoes\/black_rock_desert\/\">http:\/\/volcanoes.usgs.gov\/volcanoes\/black_rock_desert\/<\/a>, accessed July 2016.<\/li>\n<li class=\"csl-entry\">USGS, 2001, Dual <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> tragedies in the Caribbean led to founding of HVO: Online, <a href=\"http:\/\/hvo.wr.usgs.gov\/volcanowatch\/archive\/2001\/01_05_03.html\">http:\/\/hvo.wr.usgs.gov\/volcanowatch\/archive\/2001\/01_05_03.html<\/a>, accessed July 2016.<\/li>\n<li class=\"csl-entry\">USGS, 2011, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">Volcanoes<\/a>: Principal Types of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">Volcanoes<\/a>: Online, <a href=\"http:\/\/pubs.usgs.gov\/gip\/volc\/types.html\">http:\/\/pubs.usgs.gov\/gip\/volc\/types.html<\/a>, accessed July 2016.<\/li>\n<li class=\"csl-entry\">USGS, 2012a, USGS: <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">Volcano<\/a> Hazards Program: Online, <a href=\"https:\/\/volcanoes.usgs.gov\/vhp\/hazards.html\">https:\/\/volcanoes.usgs.gov\/vhp\/hazards.html<\/a>, accessed July 2016.<\/li>\n<li class=\"csl-entry\">USGS, 2012b, Yellowstone <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">Volcano<\/a> Observatory: Online, <a href=\"https:\/\/volcanoes.usgs.gov\/volcanoes\/yellowstone\/yellowstone_geo_hist_52.html\">https:\/\/volcanoes.usgs.gov\/volcanoes\/yellowstone\/yellowstone_geo_hist_52.html<\/a>, accessed July 2016.<\/li>\n<li class=\"csl-entry\">USGS, 2016, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">Volcanoes<\/a> General &#8211; What are the different types of volcanoes? Online, <a href=\"https:\/\/www2.usgs.gov\/faq\/categories\/9819\/2730\">https:\/\/www2.usgs.gov\/faq\/categories\/9819\/2730<\/a>, accessed March 2017.<\/li>\n<li class=\"csl-entry\">USGS, 2017, The Volcanoes of Lewis and Clark &#8211; Mount St. Helens: Online, <a href=\"https:\/\/volcanoes.usgs.gov\/observatories\/cvo\/Historical\/LewisClark\/Info\/summary_mount_st_helens.shtml\">https:\/\/volcanoes.usgs.gov\/observatories\/cvo\/Historical\/LewisClark\/Info\/summary_mount_st_helens.shtml<\/a>, accessed March 2017.<\/li>\n<li class=\"csl-entry\">Wallace, P.J., 2005, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1684\">Volatiles<\/a> in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> zone <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magmas<\/a>: concentrations and fluxes based on melt inclusion and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> gas data: Journal of Volcanology and Geothermal Research, v. 140, no. 1\u20133, p. 217\u2013240., doi: <a href=\"https:\/\/doi.org\/10.1016\/j.jvolgeores.2004.07.023\">10.1016\/j.jvolgeores.2004.07.023<\/a>.<\/li>\n<li class=\"csl-entry\">Williams, H., 1942, The Geology of Crater Lake National Park, Oregon: With a Reconnaissance of the Cascade Range Southward to Mount Shasta: Carnegie institution.<\/li>\n<\/ol>\n<\/div>\n<div class=\"media-attributions clear\" prefix:cc=\"http:\/\/creativecommons.org\/ns#\" prefix:dc=\"http:\/\/purl.org\/dc\/terms\/\"><h2>Mention de la source du contenu multim\u00e9dia<\/h2><ul><li >Pompeii&amp;Vesuvius       <\/li><li >P\u0101hoehoe and Aa flows at Hawaii       <\/li><li >Yosemite 20 bg 090404       <\/li><li >04.2_Granite       <\/li><li >Olearyandesite       <\/li><li >We-pegmatite       <\/li><li >Scoria Macro Digon3       <\/li><li >Pomice di veglia       <\/li><li >Lipari-Obsidienne (5)       <\/li><li >HoleInTheWallTuff       <\/li><li >Mineralogy igneous rocks EN       <\/li><li >Quartz monzonite 36mw1037       <\/li><li >PinkRhyolite.tif       <\/li><li >Diorite MA       <\/li><li >Andesite2.tif       <\/li><li >GabbroRockCreek1       <\/li><li >VesicularBasalt1       <\/li><li >Franklin dike on northwestern Baffin Island       <\/li><li >Horton Bluff mid-Carboniferous sill       <\/li><li >Little Cottonwood Canyon Oct 2008       <\/li><li >Yosemite_Half-Dome       <\/li><li >Henry Mountains, a laccolith       <\/li><li >Laccolith       <\/li><li >4.2 Schematic diagram of plutonic and volcanic structures and processes QR Code       <\/li><li >4.1 Did I Get It QR Code       <\/li><li >Bowen&rsquo;s Reaction Series       <\/li><li >Peridot2       <\/li><li >NormanLBowen_1909       <\/li><li >nlbowenexperimentingsm       <\/li><li >4.2 Did I Get It QR Code       <\/li><li >Temperature schematic of inner Earth       <\/li><li >Partial melting asthenosphere EN       <\/li><li >Boiling Water YouTube QR Code       <\/li><li >Partial melting asthenosphere EN       <\/li><li >Subduction-en       <\/li><li >Migmatite       <\/li><li >4.3 Did I Get It QR Code       <\/li><li >World geologic provinces       <\/li><li >Xenoliths Little Cottonwood Canyon       <\/li><li >Magmatism and volcanism EN       <\/li><li >Fractional crystallization       <\/li><li >4.4 Did I Get It QR Code       <\/li><li >Main types of plate boundaries       <\/li><li >Spreading ridges volcanoes map-en       <\/li><li >Pillow basalt crop l       <\/li><li >BlackSmoker       <\/li><li >Distribution of hydrothermal vent fields       <\/li><li >Alvin Submarine Part 1 YouTube QR Code       <\/li><li >Alvin Submarine Part 2 YouTube QR Code       <\/li><li >Alvin Submarine Part 3 YouTube QR Code       <\/li><li >Map_plate_tectonics_world       <\/li><li >Black Rock Desert volcanic field       <\/li><li >Volcanic Processes YouTube QR Code       <\/li><li >Hotspot(geology)-1       <\/li><li >HotspotsSRP update2013       <\/li><li >Hawaii-Emperor engl       <\/li><li >What is a Volcanic Hotspot YouTube QR Code       <\/li><li >Life of Hotspot Volcanic Island YouTube QR Code       <\/li><li >4.5 Overview of volcanic features and landforms QR Code       <\/li><li >Mt. Shasta &#8211; Mt. Shastina, CA 8-28-13a (10070662374)       <\/li><li >Crater lake oregon       <\/li><li >Kilauea Shield Volcano Hawaii 20071209A       <\/li><li >USGS K\u012blauea multimediaFile-1955       <\/li><li >Olympus Mons alt.jpg       <\/li><li >ReU PtFournaise Lavastr\u00f6me.jpg       <\/li><li >Etna 02.jpg       <\/li><li >Volcano_fissure_tube       <\/li><li >Giant&rsquo;s Causeway 2006 08       <\/li><li >Mount Rainier over Tacoma       <\/li><li >Mt.-Fuji-300&#215;190-1       <\/li><li >MSH06 aerial crater from north high angle 09-12-06       <\/li><li >Mount Mazama eruption timeline       <\/li><li >Yellowstone_Caldera_map       <\/li><li >Yellowstone volcano-ash beds       <\/li><li >Sunset_Crater10       <\/li><li >Paricutin 30 612       <\/li><li >Paricutin2       <\/li><li >Flood Basalt Map       <\/li><li >Igneous       <\/li><li >Types_of_volcano_hazards_usgs       <\/li><li >Mount St. Helens YouTube QR Code       <\/li><li >DSC01727       <\/li><li >Mount St. Helens, one day before the devastating eruption       <\/li><li >MSH80 st helens from johnston ridge 09-10-80       <\/li><li >Mt_Saint_Helens_Eruption_main_1500       <\/li><li >Pyroclastic_flows_at_Mayon_Volcano       <\/li><li >Pelee 1902 3       <\/li><li >Japans Mount Ontake YouTube QR Code       <\/li><li >Dome collapse and pyroclastic flow at Unzen Volcano YouTube QR Codes       <\/li><li >Msh may18 sequence       <\/li><li >Ash in Yogyakarta during the 2014 eruption of Kelud 01       <\/li><li >Micrograph of volcanic ash particle       <\/li><li >MSHlahar       <\/li><li >LaharsRaineer       <\/li><li >Volcano Monitoring-Earthquake Signals YouTube QR Code       <\/li><li >Volcano Monitoring-Measuring Gas emmisions YouTube QR Code       <\/li><li >Volcano Monitoring-Deformation measured YouTube QR Code       <\/li><li >4.5 Did I Get It QR Code       <\/li><li >Ch.4 Review QR Code       <\/li><\/ul><\/div><div class=\"glossary\"><span class=\"screen-reader-text\" id=\"definition\">d\u00e9finition<\/span><template id=\"term_330_1750\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1750\"><div tabindex=\"-1\"><p>Minerals that have a luster that is not similar to metal, and typically do not contain valuable metals like copper, lead, zinc, tin, etc.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1654\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1654\"><div tabindex=\"-1\"><p>Rock with abraded surfaces formed in deserts.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_221\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_221\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1765\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1765\"><div tabindex=\"-1\"><p>A rule that says the outer valence shell of electrons is complete when it contains 8 electrons.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1752\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1752\"><div tabindex=\"-1\"><p>An ultramafic rock from deep volcanic vents that can contain diamonds.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1753\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1753\"><div tabindex=\"-1\"><p>Metallic mineral deposit which forms near mid-ocean ridges.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_224\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_224\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_227\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_227\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_2446\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_2446\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_228\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_228\"><div tabindex=\"-1\"><p>QR Code generated with QRCode Monkey. All generated QR Codes are 100% free and can be used for whatever you want. This includes all commercial purposes.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1909\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1909\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1669\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1669\"><div tabindex=\"-1\"><p>Glaciers that form in cool or mountainous areas.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1751\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1751\"><div tabindex=\"-1\"><p>Metallic mineral deposit consisting of mafic plutonic rocks, typically containing platinum-group elements, chromium, copper, nickel, etc.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1673\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1673\"><div tabindex=\"-1\"><p>Cracks that form with glacial movement in the upper, brittle part of the glacier.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1664\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1664\"><div tabindex=\"-1\"><p>Dunes that form semicircular shapes due to anchoring vegetation.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1658\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1658\"><div tabindex=\"-1\"><p>Dangerous flooding that occurs in arid regions.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_990\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_990\"><div tabindex=\"-1\"><p>Middle chemical layer of the Earth, made of mainly iron and magnesium silicates. It is generally denser than the crust (except for older oceanic crust) and less dense than the core.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_997\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_997\"><div tabindex=\"-1\"><p>A ductile physical layer of the Earth, below the lithosphere. Movement within the asthenosphere is the main driver of plate motion, as the overriding lithosphere is pushed by this.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_991\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_991\"><div tabindex=\"-1\"><p>A piece of foreign rock that has been incorporated into a magma body. This can be a different type of magma, or a mantle xenolith, a rock from the mantle brought up near the surface.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1997\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1997\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_992\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_992\"><div tabindex=\"-1\"><p>An intrusive ultramafic rock, which is the main component of the mantle. The minerals in peridotite are typically olivine with some pyroxene.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_993\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_993\"><div tabindex=\"-1\"><p>The innermost chemical layer of the Earth, made chiefly of iron and nickel. It has both liquid and solid components.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1001\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1001\"><div tabindex=\"-1\"><p>A boundary between continental and oceanic plates that has relative movement, making it a plate boundary.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_999\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_999\"><div tabindex=\"-1\"><p>The outer physical&nbsp;layer of the core, which is liquid. Movement within the outer core is believed to be responsible for Earth's magnetic field and flips of the magnetic field.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_994\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_994\"><div tabindex=\"-1\"><p>The outermost physical layer of the Earth, made of the entire crust and upper mantle. It is brittle and broken into a series of plates, and these plates move in various ways (relative to one another), causing the features of the theory of plate tectonics.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_995\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_995\"><div tabindex=\"-1\"><p>A solid part&nbsp;of the lithosphere which moves as a unit, i.e. the entire plate generally moves the same direction at the same speed.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1011\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1011\"><div tabindex=\"-1\"><p>The area of the mantle where volatiles rise from the slab, causing flux melting and volcanism.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_968\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_968\"><div tabindex=\"-1\"><p>By Matt Affolter(QFL247) (talk) (Transferred by Citypeek\/Original uploaded by Matt Affolter(QFL247)) [<a href=\"http:\/\/creativecommons.org\/licenses\/by-sa\/3.0\">CC BY-SA 3.0<\/a> or <a href=\"http:\/\/www.gnu.org\/copyleft\/fdl.html\">GFDL<\/a>], <a href=\"https:\/\/commons.wikimedia.org\/wiki\/File%3AHanksite.JPG\">via Wikimedia Commons<\/a><\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_967\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_967\"><div tabindex=\"-1\"><p>By Hermann Luyken (Own work) [<a href=\"http:\/\/creativecommons.org\/publicdomain\/zero\/1.0\/deed.en\">CC0<\/a>], <a href=\"https:\/\/commons.wikimedia.org\/wiki\/File%3A2012.10.02.111543_Bonneville_Salt_Flats_Utah.jpg\">via Wikimedia Commons<\/a><\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_966\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_966\"><div tabindex=\"-1\"><p>By Michele Buzzi, Studio Cicero. [<a href=\"http:\/\/www.gnu.org\/copyleft\/fdl.html\">GFDL<\/a>, <a href=\"http:\/\/creativecommons.org\/licenses\/by-sa\/3.0\/\">CC-BY-SA-3.0<\/a> or <a href=\"http:\/\/creativecommons.org\/licenses\/by\/2.5\">CC BY 2.5<\/a>], <a href=\"https:\/\/commons.wikimedia.org\/wiki\/File%3AMarblequarry.JPG\">via Wikimedia Commons<\/a><\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_996\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_996\"><div tabindex=\"-1\"><p>Location where two plates are in contact, allowing a relative motion between the two plates. These are the locations where&nbsp;most earthquakes and volcanoes are found.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1893\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1893\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1684\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1684\"><div tabindex=\"-1\"><p>Low point within an&nbsp;ar\u00eate.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1783\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1783\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_998\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_998\"><div tabindex=\"-1\"><p>Also called lower mantle, a solid, more brittle physical layer&nbsp;of the Earth, below the asthenosphere.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_987\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_987\"><div tabindex=\"-1\"><p>A property of solids in which a force applied to an object causes the object to fracture, break, or snap. Most rocks, at low temperatures, are brittle.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_986\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_986\"><div tabindex=\"-1\"><p>A property of a solid, such that when a force is applied, the solid flows, stretches, or bends along with the force, instead of cracking or breaking. For example, many plastics are ductile.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1745\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1745\"><div tabindex=\"-1\"><p>Rocks which allow petroleum resources to collect or move.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1000\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1000\"><div tabindex=\"-1\"><p>The innermost physical layer of the Earth, which is solid.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1004\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1004\"><div tabindex=\"-1\"><p>Place where two plates come together, casing subduction or collision.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1903\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1903\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1002\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1002\"><div tabindex=\"-1\"><p>A boundary between continental and oceanic plates that has no relative movement, making it a place where an oceanic plate is connected to a continental plate, but it is not a plate boundary.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1003\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1003\"><div tabindex=\"-1\"><p>Place where two plates are moving apart, creating either a rift (continental lithosphere) or a mid-ocean ridge (oceanic lithosphere).<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1005\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1005\"><div tabindex=\"-1\"><p>Place where two plates slide past each other, creating strike slip faults.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1006\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1006\"><div tabindex=\"-1\"><p>A process where an oceanic plate descends bellow a less dense plate, causing the removal of the plate from the surface. Subduction causes the largest earthquakes possible, as the subducting plate can lock as it goes down. Volcanism is also caused as the plate releases volatiles into the mantle, causing melting.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1007\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1007\"><div tabindex=\"-1\"><p>Deepest part of the ocean where a subducting plate dives below the overriding plate.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1008\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1008\"><div tabindex=\"-1\"><p>Mix of sediments that form as a subducting plate descends and the overriding plate scrapes material and material is added.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1009\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1009\"><div tabindex=\"-1\"><p>Name given to the subducting plate, where volatiles are driven out at depth, causing volcanism.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1014\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1014\"><div tabindex=\"-1\"><p>Area behind the arc, which can be subject to compressional (causing thrusted mountain belts) or extensional (causing back-arc basins) forces.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1791\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1791\"><div tabindex=\"-1\"><figure id=\"attachment_2498\" aria-describedby=\"caption-attachment-2498\" style=\"width: 2048px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/MT3.jpg\"><img class=\"wp-image-67 size-full\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/09\/MT3.jpg\" alt=\"The rock is getting thinner farther away.\" width=\"2048\" height=\"1536\"><\/a><figcaption id=\"caption-attachment-2498\" class=\"wp-caption-text\">A layer of shallow ocean limestone (white) has been brought to the top of a mountain by the convergent forces of the Sevier Orogeny. Near Sun River Canyon, Montana.<\/figcaption><\/figure>\n<h1>2 Plate Tectonics<\/h1>\n<p><b>KEY CONCEPTS<\/b><\/p>\n<p><b>At the end of this chapter, students should be able to:<\/b><\/p>\n<ul>\n<li>Describe how the ideas behind <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">plate tectonics<\/a> started with Alfred Wegener\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a> of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a>\u00a0drift<\/li>\n<li>Describe the physical and chemical layers of the Earth and how they affect <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> movement<\/li>\n<li>Explain how movement at the three types of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> boundaries causes earthquakes, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a>, and mountain building<\/li>\n<li>Identify <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1678\">convergent<\/a> boundaries, including <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> and collisions, as places where <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a>\u00a0come together<\/li>\n<li>Identify <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1677\">divergent<\/a> boundaries, including <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rifts<\/a>\u00a0and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridges<\/a>, as places where <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> separate<\/li>\n<li>Explain <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1679\">transform<\/a> boundaries as places where adjacent <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_494\">shear<\/a> past each other<\/li>\n<li>Describe the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1715\">Wilson Cycle<\/a>, beginning with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rifting<\/a>, ocean <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_508\">basin<\/a> creation, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a>, and ending with ocean <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_508\">basin<\/a> closure<\/li>\n<li>Explain how the tracks of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspots<\/a>, places that have continually rising <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>, is used to calculate <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> motion<\/li>\n<\/ul>\n<figure id=\"attachment_2499\" aria-describedby=\"caption-attachment-2499\" style=\"width: 4898px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Tectonic_plates_boundaries_detailed-en.svg_.png\"><img class=\"size-full wp-image-68\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tectonic_plates_boundaries_detailed-en.svg_.png\" alt=\"The map shows many plates.\" width=\"4898\" height=\"2461\"><\/a><figcaption id=\"caption-attachment-2499\" class=\"wp-caption-text\">Detailed map of all known plates, their boundaries, and movements.<\/figcaption><\/figure>\n<p>Revolution is a word usually reserved for significant political or social changes. Several of these idea revolutions forced scientists to re-examine their entire field, triggering a paradigm shift that shook up their conventionally held knowledge. Charles Darwin\u2019s book on evolution, <em>On the Origin of Species<\/em>, published in 1859; Gregor Mendel\u2019s discovery of the genetic principles of inheritance in 1866; and James Watson, Francis Crick, and Rosalind Franklin\u2019s model for the structure of DNA in 1953 did that for biology. Albert Einstein\u2019s relativity and quantum mechanics concepts in the early twentieth century did the same for Newtonian physics.<\/p>\n<p>The concept of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">plate tectonics<\/a> was just as revolutionary for geology. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a> of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">plate tectonics<\/a> attributes the movement of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_985\">massive<\/a> sections of the Earth\u2019s outer layers with creating earthquakes, mountains, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a>. Many earth processes make more sense when viewed through the lens of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">plate tectonics<\/a>. Because it is so important in understanding how the world works, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">plate tectonics<\/a> is the first topic of discussion in this textbook.<\/p>\n<h2><span style=\"font-weight: 400;\">2.1 Alfred Wegener\u2019s Continental Drift Hypothesis<\/span><\/h2>\n<figure id=\"attachment_2500\" aria-describedby=\"caption-attachment-2500\" style=\"width: 195px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Alfred_Wegener_ca.1924-30-2.jpg\"><img class=\"size-full wp-image-28\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alfred_Wegener_ca.1924-30-2.jpg\" alt=\"He is a male in a suit.\" width=\"195\" height=\"240\"><\/a><figcaption id=\"caption-attachment-2500\" class=\"wp-caption-text\">Wegener later in his life, ca. 1924-1930.<\/figcaption><\/figure>\n<p>Alfred Wegener (1880-1930) was a German scientist who specialized in meteorology and climatology. His knack for questioning accepted ideas started in 1910 when he disagreed with the explanation that the Bering Land Bridge was formed by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_753\">isostasy<\/a>, and that similar land bridges once connected the continents. After reviewing the scientific literature, he published a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a> stating the continents were originally connected, and then drifted apart. While he did not have the precise mechanism worked out, his <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a> was backed up by a long list of evidence.<\/p>\n<h3><\/h3>\n<h3><b>2.1.1 Early Evidence for Continental Drift Hypothesis<\/b><\/h3>\n<figure id=\"attachment_2501\" aria-describedby=\"caption-attachment-2501\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Antonio_Snider-Pellegrini_Opening_of_the_Atlantic.jpg\"><img class=\"size-medium wp-image-69\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Antonio_Snider-Pellegrini_Opening_of_the_Atlantic-300x177.jpg\" alt=\"It shows South America and Africa connected, then apart.\" width=\"300\" height=\"177\"><\/a><figcaption id=\"caption-attachment-2501\" class=\"wp-caption-text\">Snider-Pellegrini's map showing the continental fit and separation, 1858.<\/figcaption><\/figure>\n<p>Wegener\u2019s first piece of evidence was that the coastlines of some continents fit together like pieces of a jigsaw puzzle. People noticed the similarities in the coastlines of South America and Africa on the first world maps, and some suggested the continents had been ripped apart. Antonio Snider-Pellegrini did preliminary work on <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> separation and matching <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1228\">fossils<\/a> in 1858.<\/p>\n<figure id=\"attachment_2502\" aria-describedby=\"caption-attachment-2502\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/ElevationWorld.jpg\"><img class=\"size-medium wp-image-70\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ElevationWorld-300x150.jpg\" alt=\"The shape of the continents is different than what is seen by just coastlines.\" width=\"300\" height=\"150\"><\/a><figcaption id=\"caption-attachment-2502\" class=\"wp-caption-text\">Map of world elevations. Note the light blue, which are continental shelves flooded by shallow ocean water. These show the true shapes of the continents.<\/figcaption><\/figure>\n<p>What Wegener did differently was synthesize a large amount of data in one place. He used true edges of the continents, based on the shapes of the continental shelves. This resulted in a better fit than previous efforts that traced the existing coastlines.<\/p>\n<figure id=\"attachment_3259\" aria-describedby=\"caption-attachment-3259\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Wegener_fossil_map.svg_.png\"><img class=\"size-medium wp-image-71\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Wegener_fossil_map.svg_-300x231.png\" alt=\"There are four different fossil organisms that connect South America, Africa, India, Antartica, and Australia.\" width=\"300\" height=\"231\"><\/a><figcaption id=\"caption-attachment-3259\" class=\"wp-caption-text\">Image showing fossils that connect the continents of Gondwana (the southern continents of Pangea).<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>Wegener also compiled evidence by comparing similar rocks, mountains, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1228\">fossils<\/a>, and glacial formations across oceans. For example, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1228\">fossils<\/a> of the primitive aquatic reptile <em>Mesosaurus<\/em> were found on the separate coastlines of Africa and South America. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1228\">Fossils<\/a> of another reptile, <em>Lystrosaurus,<\/em> were found on Africa, India, and Antarctica. He pointed out these were land-dwelling creatures could not have swum across an entire ocean.<\/p>\n<p>Opponents of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> drift insisted trans-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic <\/a> land bridges allowed animals and plants to move between continents. The land bridges eventually eroded away, leaving the continents permanently separated. The problem with this <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a> is the improbability of a land bridge being tall and long enough to stretch across a broad, deep ocean.<\/p>\n<p>More support for <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> drift came from the puzzling evidence that <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1516\">glaciers<\/a> once existed in normally very warm areas in southern Africa, India, Australia, and Arabia. These <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_757\">climate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_765\">anomalies<\/a> could not be explained by land bridges. Wegener found similar evidence when he discovered tropical plant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1228\">fossils<\/a> in the frozen region of the Arctic Circle. As Wegener collected more data, he realized the explanation that best fit all the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_757\">climate<\/a>, rock, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1228\">fossil<\/a> observations involved moving continents.<\/p>\n<h3><b>2.1.2 Proposed Mechanism for Continental Drift<\/b><\/h3>\n<figure id=\"attachment_2504\" aria-describedby=\"caption-attachment-2504\" style=\"width: 400px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Convection.gif\"><img class=\"wp-image-72 size-full\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Convection.gif\" alt=\"The rising material is drawn red. The cool material is blue.\" width=\"400\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2504\" class=\"wp-caption-text\">Animation of the basic idea of convection: an uneven heat source in a fluid causes rising material next to the heat and sinking material far from the heat.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>Wegener\u2019s work was considered a fringe science <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a> for his entire life. One of the biggest flaws in his <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a> was an inability to provide a mechanism for how the continents moved. Obviously, the continents did not appear to move, and changing the conservative minds of the scientific community would require exceptional evidence that supported a credible mechanism. Other pro-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> drift followers used expansion, contraction, or even the moon\u2019s origin to explain how the continents moved. Wegener used centrifugal forces and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_749\">precession<\/a>, but this model was proven wrong. He also speculated about seafloor spreading, with hints of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1655\">convection<\/a>, but could not substantiate these proposals. As it turns out, current scientific knowledge reveals <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1655\">convection<\/a> is one the major forces in driving <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> movements, along with gravity and density.<\/p>\n<h3><b>2.1.3 Development of Plate Tectonic Theory<\/b><\/h3>\n<figure id=\"attachment_2505\" aria-describedby=\"caption-attachment-2505\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Global_plate_motion_2008-04-17.jpg\"><img class=\"size-medium wp-image-73\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Global_plate_motion_2008-04-17-300x212.jpg\" alt=\"The map shows many data points all over the world.\" width=\"300\" height=\"212\"><\/a><figcaption id=\"caption-attachment-2505\" class=\"wp-caption-text\">GPS measurements of plate motions.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>Wegener died in 1930 on an expedition in Greenland. Poorly respected in his lifetime, Wegener and his ideas about moving continents seemed destined to be lost in history as fringe science. However, in the 1950s, evidence started to trickle in that made <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> drift a more viable idea. By the 1960s, scientists had amassed enough evidence to support the missing mechanism\u2014namely, seafloor spreading\u2014for Wegener\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a> of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> drift to be accepted as the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a> of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">plate tectonics<\/a>. Ongoing GPS and earthquake data analyses continue to support this <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a>. The next section provides the pieces of evidence that helped <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1679\">transform<\/a> one man\u2019s wild notion into a scientific <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a>.<\/p>\n<h4><span style=\"font-weight: 400;\">Mapping of the Ocean Floors<\/span><\/h4>\n<figure id=\"attachment_2506\" aria-describedby=\"caption-attachment-2506\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Deep_sea_vent_chemistry_diagram.jpg\"><img class=\"size-medium wp-image-74\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Deep_sea_vent_chemistry_diagram-300x174.jpg\" alt=\"The diagram shows water going into the ground and coming out, with many different reactions.\" width=\"300\" height=\"174\"><\/a><figcaption id=\"caption-attachment-2506\" class=\"wp-caption-text\">The complex chemistry around mid-ocean ridges.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>In 1947 researchers started using an adaptation of SONAR to map a region in the middle of the Atlantic Ocean with poorly-understood topographic and thermal properties. Using this information, Bruce Heezen and Marie Tharp created the first detailed map of the ocean floor to reveal the Mid-Atlantic Ridge, a basaltic mountain range that spanned the length of the Atlantic Ocean, with rock chemistry and dimensions unlike the mountains found on the continents. Initially scientists thought the ridge was part of a mechanism that explained the expanding Earth or ocean-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_508\">basin<\/a> growth <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypotheses<\/a>. In 1959, Harry Hess proposed the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a> of seafloor spreading \u2013 that the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridges<\/a> represented <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> factories, where new <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> was issuing from these long <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> ridges. Scientists later included <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1679\">transform<\/a> faults perpendicular to the ridges to better account for varying rates of movement between the newly formed <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a>. When earthquake epicenters were discovered along the ridges, the idea that earthquakes were linked to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> movement took hold.<\/p>\n<div style=\"height: 0; padding-bottom: 56.25%;\">\n<\/div>\n<figure id=\"attachment_3739\" aria-describedby=\"caption-attachment-3739\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Marie-Tharp-YouTube-QR-Code.png\"><img class=\"size-thumbnail wp-image-75\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Marie-Tharp-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3739\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this YouTube video via this QR Code.<\/figcaption><\/figure>\n<p>Seafloor <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediment<\/a>, measured by dredging and drilling, provided another clue. Scientists once believed <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediment<\/a> accumulated on the ocean floors over a very long time in a static environment. When some studies showed less <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediment<\/a> than expected, these results were initially used to argue against <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> movement. With more time, researchers discovered these thinner <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediment<\/a> layers were located close to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridges<\/a>, indicating the ridges were younger than the surrounding ocean floor. This finding supported the idea that the sea floor was not fixed in one place.<\/p>\n<h4><span style=\"font-weight: 400;\">Paleomagnetism<\/span><\/h4>\n<figure id=\"attachment_2507\" aria-describedby=\"caption-attachment-2507\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Earths_magnetic_field_schematic.svg_.png\"><img class=\"size-medium wp-image-76\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Earths_magnetic_field_schematic.svg_-300x250.png\" alt=\"The north end of the magnet is south topographically, and vice versa.\" width=\"300\" height=\"250\"><\/a><figcaption id=\"caption-attachment-2507\" class=\"wp-caption-text\">The magnetic field of Earth, simplified as a bar magnet.<\/figcaption><\/figure>\n<p>The seafloor was also mapped magnetically. Scientists had long known of strange magnetic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_765\">anomalies<\/a> that formed a striped pattern of symmetrical rows on both sides of mid-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> ridges. What made these features unusual was the north and south magnetic poles within each stripe was reversed in alternating rows. By 1963, Harry Hess and other scientists used these magnetic reversal patterns to support their model for seafloor spreading (see also Lawrence W. Morley).<\/p>\n<figure id=\"attachment_2508\" aria-describedby=\"caption-attachment-2508\" style=\"width: 351px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Earth_Magnetic_Field_Declination_from_1590_to_1990.gif\"><img class=\"wp-image-77 size-full\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Earth_Magnetic_Field_Declination_from_1590_to_1990.gif\" alt=\"The poles shift slightly every year.\" width=\"351\" height=\"293\"><\/a><figcaption id=\"caption-attachment-2508\" class=\"wp-caption-text\">This animation shows how the magnetic poles have moved over 400 years.<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1657\">Paleomagnetism<\/a> is the study of magnetic fields frozen within rocks, basically a fossilized compass. In fact, the first hard evidence to support <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> motion came from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1657\">paleomagnetism<\/a>.<\/p>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">Igneous<\/a> rocks containing magnetic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> like magnetite typically provide the most useful data. In their liquid state as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a>, the magnetic poles of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> align themselves with the Earth\u2019s magnetic field. When the rock cools and solidifies, this alignment is frozen into place, creating a permanent paleomagnetic record that includes magnetic inclination related to global latitude, and declination related to magnetic north.<\/p>\n<figure id=\"attachment_2509\" aria-describedby=\"caption-attachment-2509\" style=\"width: 240px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/02.1-magnetic_stripes.gif\"><img class=\"size-full wp-image-78\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/02.1-magnetic_stripes.gif\" alt=\"Animated gif depicting a mid-ocean ridge with two oceanic plates moving away from the center of the ridge. As the movement progresses, symettrical magnetic stripes appear on each side of the ridge.\" width=\"240\" height=\"180\"><\/a><figcaption id=\"caption-attachment-2509\" class=\"wp-caption-text\">The iron in the solidifying rock preserves the current magnetic polarity as new oceanic plates form at mid ocean ridges<\/figcaption><\/figure>\n<p>Scientists had noticed for some time the alignment of magnetic north in many rocks was nowhere close to the earth\u2019s current magnetic north. Some explained this away are part of the normal movement of earth\u2019s magnetic north pole. Eventually, scientists realized adding the idea of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> movement explained the data better than pole movement alone.<\/p>\n<h4><\/h4>\n<h4><\/h4>\n<h4><span style=\"font-weight: 400;\">Wadati-Benioff Zones<\/span><\/h4>\n<figure id=\"attachment_2510\" aria-describedby=\"caption-attachment-2510\" style=\"width: 297px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/benioff_zone.gif\"><img class=\"size-full wp-image-79\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/benioff_zone.gif\" alt=\"The earthquakes descend at an angle into the Earth.\" width=\"297\" height=\"243\"><\/a><figcaption id=\"caption-attachment-2510\" class=\"wp-caption-text\">The Wadati-Benioff zone, showing earthquakes following the subducting slab down.<\/figcaption><\/figure>\n<p>Around the same time <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridges<\/a> were being investigated, other scientists linked the creation of ocean trenches and island arcs to seismic activity and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> movement. Several independent research groups recognized earthquake epicenters traced the shapes of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> sinking into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a>. These deep earthquake zones congregated in planes that started near the surface around ocean trenches and angled beneath the continents and island arcs. Today these earthquake zones called Wadati-Benioff zones.<\/p>\n<figure id=\"attachment_2511\" aria-describedby=\"caption-attachment-2511\" style=\"width: 244px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/John_Tuzo_Wilson_in_1992-2.jpg\"><img class=\"size-medium wp-image-39\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/John_Tuzo_Wilson_in_1992-2-244x300.jpg\" alt=\"He is an older man in this 1992 image.\" width=\"244\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2511\" class=\"wp-caption-text\">J. Tuzo Wilson<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>Based on the mounting evidence, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">plate tectonics<\/a> continued to take shape. J. Tuzo Wilson was the first scientist to put the entire picture together by proposing that the opening and closing of the ocean basins. Before long, scientists proposed other models showing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> moving with respect to each other, with clear boundaries between them. Others started piecing together complicated histories of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> movement. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a> revolution had taken hold.<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<div id=\"h5p-8\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-8\" class=\"h5p-iframe\" data-content-id=\"8\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Continental Drift vs. Plate Tectonics\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3738\" aria-describedby=\"caption-attachment-3738\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Continental-Drive-Activity-QR-Code.png\"><img class=\"size-thumbnail wp-image-80\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Continental-Drive-Activity-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3738\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this interactive activity via this QR Code.<\/figcaption><\/figure>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-9\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-9\" class=\"h5p-iframe\" data-content-id=\"9\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"2.1 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3737\" aria-describedby=\"caption-attachment-3737\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/2.1-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-81\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.1-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3737\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 2.1 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-weight: 400;\">2.2 Layers of the Earth<\/span><\/h2>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2512\" aria-describedby=\"caption-attachment-2512\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Earth-cutaway-schematic-english.svg_-1.png\"><img class=\"size-medium wp-image-51\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Earth-cutaway-schematic-english.svg_-1-300x211.png\" alt=\"The crust and lithosphere are on the outside of the Earth and are thin. Below the crust is the mantle and core. Below the lithosphere is the asthenosphere.\" width=\"300\" height=\"211\"><\/a><figcaption id=\"caption-attachment-2512\" class=\"wp-caption-text\">The layers of the Earth. Physical layers include lithosphere and asthenosphere; chemical layers are crust, mantle, and core.<\/figcaption><\/figure>\n<p>In order to understand the details of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">plate tectonics<\/a>, it is essential to first understand the layers of the earth. Firsthand information about what is below the surface is very limited; most of what we know is pieced together from hypothetical models, and analyzing seismic wave data and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1254\">meteorite<\/a> materials. In general, the Earth can be divided into layers based on chemical composition and physical characteristics.<\/p>\n<h3><b>2.2.1 Chemical Layers<\/b><\/h3>\n<p>Certainly the earth is composed of a countless combination of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>. Regardless of what <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> are involved two major factors\u2014<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> and pressure\u2014are responsible for creating three distinct chemical layers.<\/p>\n<h4><span style=\"font-weight: 400;\">Crust<\/span><\/h4>\n<p>The outermost chemical layer and the one we currently reside on, is the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a>. There are two types of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">Continental crust<\/a> has a relatively low density and composition similar to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1014\">granite<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">Oceanic crust<\/a> has a relatively high density, especially when cold and old, and composition similar to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1013\">basalt<\/a>. The surface levels of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a> are relatively <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1661\">brittle<\/a>. The deeper parts of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a> are subjected to higher temperatures and pressure, which makes them more <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1660\">ductile<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1660\">Ductile<\/a> materials are like soft plastics or putty, they move under force. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1661\">Brittle<\/a> materials are like solid glass or pottery, they break under force, especially when it is applied quickly. Earthquakes, generally occur in the upper <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a> and are caused by the rapid movement of relatively <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1661\">brittle<\/a> materials.<\/p>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2513\" aria-describedby=\"caption-attachment-2513\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/MohoDepth-1.png\"><img class=\"size-medium wp-image-50\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MohoDepth-1-300x167.png\" alt=\"Places with mountain building have a deeper moho.\" width=\"300\" height=\"167\"><\/a><figcaption id=\"caption-attachment-2513\" class=\"wp-caption-text\">The global map of the depth of the moho.<\/figcaption><\/figure>\n<p>The base of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a> is characterized by a large increase in seismic velocity, which measures how fast earthquake waves travel through solid matter. Called the Mohorovi\u010di\u0107 Discontinuity, or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1662\">Moho<\/a> for short, this zone was discovered by Andrija Mohorovi\u010di\u0107 (pronounced mo-ho-ro-vee-cheech; <a href=\"https:\/\/www.merriam-webster.com\/dictionary\/Mohorovicic%20discontinuity\">audio pronunciation<\/a>) in 1909 after studying earthquake wave paths in his <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_976\">native<\/a> Croatia. The change in wave direction and speed is caused by dramatic chemical differences of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a>. Underneath the oceans, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1662\">Moho<\/a> is found roughly 5 km below the ocean floor. Under the continents, it is located about 30-40 km below the surface. Near certain large mountain-building events known as orogenies, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1662\">Moho<\/a> depth is doubled.<\/p>\n<h4><span style=\"font-weight: 400;\">Mantle<\/span><\/h4>\n<figure id=\"attachment_2514\" aria-describedby=\"caption-attachment-2514\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Iddingsite.jpg\"><img class=\"size-medium wp-image-82\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Iddingsite-300x225.jpg\" alt=\"The xenolith sits on top of a basalt rock. It has three sides like a pyramid; one of the sides is more altered to iddingsite.\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-2514\" class=\"wp-caption-text\">This mantle xenolith containing olivine (green) is chemically weathering by hydrolysis and oxidation into the pseudo-mineral iddingsite, which is a complex of water, clay, and iron oxides. The more altered side of the rock has been exposed to the environment longer.<\/figcaption><\/figure>\n<p>The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> sits below the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a> and above the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1667\">core<\/a>. It is the largest chemical layer by volume, extending from the base of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a> to a depth of about 2900 km. Most of what we know about the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> comes from seismic wave analysis, though information is gathered by studying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1700\">ophiolites<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1665\">xenoliths<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1700\">Ophiolites<\/a> are pieces of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> that have risen through the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a> until they are exposed as part of the ocean floor. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1665\">Xenoliths<\/a> are carried within <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> and brought to the Earth\u2019s surface by volcanic eruptions. Most <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1665\">xenoliths<\/a> are made of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1666\">peridotite<\/a>, an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1009\">ultramafic<\/a> class of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous rock<\/a> (see <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/4-igneous-processes-and-volcanoes#4-2BowensReaction\" target=\"_blank\" rel=\"noopener\">chapter 4.2<\/a> for explanation). Because of this, scientists hypothesize most of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> is made of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1666\">peridotite<\/a>.<\/p>\n<h4><span style=\"font-weight: 400;\">Core<\/span><\/h4>\n<figure id=\"attachment_2515\" aria-describedby=\"caption-attachment-2515\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/02.2_TolucaMeteorite.jpg\"><img class=\"size-medium wp-image-83\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/02.2_TolucaMeteorite-300x225.jpg\" alt=\"The meteorite is polished showing the Widmanst\u00e4tten Pattern.\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-2515\" class=\"wp-caption-text\">A polished fragment of the iron-rich Toluca Meteorite, with octahedral Widmanst\u00e4tten Pattern.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1667\">core<\/a> of the Earth, which has both liquid and solid layers, and consists mostly of iron, nickel, and possibly some oxygen. Scientists looking at seismic data first discovered this innermost chemical layer in 1906. Through a union of hypothetical modeling, astronomical insight, and hard seismic data, they concluded the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1667\">core<\/a> is mostly metallic iron. Scientists studying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1254\">meteorites<\/a>, which typically contain more iron than surface rocks, have proposed the earth was formed from meteoric material. They believe the liquid component of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1667\">core<\/a> was created as the iron and nickel sank into the center of the planet, where it was liquefied by intense pressure.<\/p>\n<h3><b>2.2.2 Physical Layers<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">The Earth can also be broken down into five distinct physical layers based on how each layer responds to stress. While there is some overlap in the chemical and physical designations of layers, specifically the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1667\">core<\/a>-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> boundary, there are significant differences between the two systems.<\/span><\/p>\n<h4><span style=\"font-weight: 400;\">Lithosphere<\/span><\/h4>\n<figure id=\"attachment_2516\" aria-describedby=\"caption-attachment-2516\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Plates_tect2_en.svg_-2.png\"><img class=\"size-medium wp-image-49\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plates_tect2_en.svg_-2-300x205.png\" alt=\"There are about 10 major plates\" width=\"300\" height=\"205\"><\/a><figcaption id=\"caption-attachment-2516\" class=\"wp-caption-text\">Map of the major plates and their motions along boundaries.<\/figcaption><\/figure>\n<p><em>Lithos<\/em> is Greek for stone, and the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> is the outermost physical layer of the Earth. It is grouped into two types: <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">Oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> is thin and relatively rigid. It ranges in thickness from nearly zero in new <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> found around <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridges<\/a>, to an average of 140 km in most other locations. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">Continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> is generally thicker and considerably more plastic, especially at the deeper levels. Its thickness ranges from 40 to 280 km. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> is not continuous. It is broken into segments called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a>. A <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1670\">plate boundary<\/a> is where two <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> meet and move relative to each other. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">Plate<\/a> boundaries are where we see <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">plate tectonics<\/a> in action\u2014mountain building, triggering earthquakes, and generating <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> activity.<\/p>\n<h4><span style=\"font-weight: 400;\">Asthenosphere<\/span><\/h4>\n<figure id=\"attachment_2517\" aria-describedby=\"caption-attachment-2517\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Earths_Inner_Layers_denoting_the_LAB.png\"><img class=\"size-medium wp-image-84\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Earths_Inner_Layers_denoting_the_LAB-300x207.png\" alt=\"It is thin at a mid-ocean ridge, thick under collisions\" width=\"300\" height=\"207\"><\/a><figcaption id=\"caption-attachment-2517\" class=\"wp-caption-text\">The lithosphere-asthenosphere boundary changes with certain tectonic situations.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1671\">asthenosphere<\/a> is the layer below the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a>. <em>Astheno-<\/em> means lacking strength, and the most distinctive property of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1671\">asthenosphere<\/a> is movement. Because it is mechanically weak, this layer moves and flows due to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1655\">convection<\/a> currents created by heat coming from the earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1667\">core<\/a> cause. Unlike the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> that consists of multiple <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a>, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1671\">asthenosphere<\/a> is relatively unbroken. Scientists have determined this by analyzing seismic waves that pass through the layer. The depth of at which the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1671\">asthenosphere<\/a> is found is <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a>-dependent. It tends to lie closer to the earth\u2019s surface around <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridges<\/a> and much deeper underneath mountains and the centers of lithospheric <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a>.<\/p>\n<h4><span style=\"font-weight: 400;\">Mesosphere<\/span><\/h4>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2518\" aria-describedby=\"caption-attachment-2518\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Perovskite.jpg\"><img class=\"size-medium wp-image-85\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Perovskite-300x288.jpg\" alt=\"The atoms are arranged.\" width=\"300\" height=\"288\"><\/a><figcaption id=\"caption-attachment-2518\" class=\"wp-caption-text\">General perovskite structure. Perovskite silicates (i.e.<br \/>Bridgmenite,<br \/>(Mg,Fe)SiO3) are thought to be the main component of the lower mantle, making it the most common mineral in or on Earth.<\/figcaption><\/figure>\n<p>The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1672\">mesosphere<\/a>, sometimes known as the lower <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a>, is more rigid and immobile than the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1671\">asthenosphere<\/a>. Located at a depth of approximately 410 and 660 km below the earth\u2019s surface, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1672\">mesosphere<\/a> is subjected to very high pressures and temperatures. These extreme conditions create a transition zone in the upper <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1672\">mesosphere<\/a> where <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> continuously change into various forms, or pseudomorphs. Scientists identify this zone by changes in seismic velocity and sometimes physical barriers to movement. Below this transitional zone, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1672\">mesosphere<\/a> is relatively uniform until it reaches the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1667\">core<\/a>.<\/p>\n<h4><span style=\"font-weight: 400;\">Inner and Outer Core<\/span><\/h4>\n<figure id=\"attachment_2519\" aria-describedby=\"caption-attachment-2519\" style=\"width: 206px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Inge_Lehmann_1932.jpg\"><img class=\"size-medium wp-image-86\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Inge_Lehmann_1932-206x300.jpg\" alt=\"Is shows her as a young woman\" width=\"206\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2519\" class=\"wp-caption-text\">Lehmann in 1932<\/figcaption><\/figure>\n<p>The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1673\">outer core<\/a> is the only entirely liquid layer within the Earth. It starts at a depth of 2,890 km and extends to 5,150 km, making it about 2,300 km thick. In 1936, the Danish geophysicist Inge Lehmann analyzed seismic data and was the first to prove a solid <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1674\">inner core<\/a> existed within a liquid <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1673\">outer core<\/a> . The solid <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1674\">inner core<\/a> is about 1,220 km thick, and the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1673\">outer core<\/a> is about 2,300 km thick.<\/p>\n<p>It seems like a contradiction that the hottest part of the Earth is solid, as the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> making up the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1667\">core<\/a> should be liquified or vaporized at this <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a>. Immense pressure keeps the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1674\">inner core<\/a> in a solid phase. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1674\">inner core<\/a> grows slowly from the lower <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1673\">outer core<\/a> solidifying as heat escapes the interior of the Earth and is dispersed to the outer layers.<\/p>\n<figure id=\"attachment_2520\" aria-describedby=\"caption-attachment-2520\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/02.2_SpinningOuterCore.gif\"><img class=\"size-medium wp-image-87\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/02.2_SpinningOuterCore-300x289.gif\" alt=\"The Earth is cut out with the core being shown.\" width=\"300\" height=\"289\"><\/a><figcaption id=\"caption-attachment-2520\" class=\"wp-caption-text\">The outer core's spin causes our protective magnetic field.<\/figcaption><\/figure>\n<p>The earth\u2019s liquid <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1673\">outer core<\/a> is critically important in maintaining a breathable <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1745\">atmosphere<\/a> and other environmental conditions favorable for life. Scientists believe the earth\u2019s magnetic field is generated by the circulation of molten iron and nickel within the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1673\">outer core<\/a>. If the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1673\">outer core<\/a> were to stop circulating or become solid, the loss of the magnetic field would result in Earth getting stripped of life-supporting gases and water. This is what happened, and continues to happen, on Mars.<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<div id=\"h5p-10\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-10\" class=\"h5p-iframe\" data-content-id=\"10\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Layers of the Earth practice\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3736\" aria-describedby=\"caption-attachment-3736\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Layers-of-Earth-Practice-QR-Code.png\"><img class=\"size-thumbnail wp-image-88\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Layers-of-Earth-Practice-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3736\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this interactive activity via this QR Code.<\/figcaption><\/figure>\n<h3><b>2.2.3 Plate Tectonic Boundaries<\/b><\/h3>\n<figure id=\"attachment_2521\" aria-describedby=\"caption-attachment-2521\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Passive_Contiental_Margin.jpg\"><img class=\"size-medium wp-image-89\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Passive_Contiental_Margin-300x143.jpg\" alt=\"The plate thins from continent to ocean\" width=\"300\" height=\"143\"><\/a><figcaption id=\"caption-attachment-2521\" class=\"wp-caption-text\">Passive margin<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>At passive margins the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> don\u2019t move\u2014the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> transitions into oceanic lithosphere and forms <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> made of both types. A <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> may be made of both <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> connected by a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1676\">passive margin<\/a>. North and South America\u2019s eastern coastlines are examples of passive margins. Active margins are places where the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> lithospheric <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> meet and move relative to each other, such as the western coasts of North and South America. This movement is caused by frictional drag created between the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> and differences in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> densities. The majority of mountain-building events, earthquake activity and active <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> on the Earth\u2019s surface can be attributed to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> movement at active margins.<\/p>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2522\" aria-describedby=\"caption-attachment-2522\" style=\"width: 775px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Tectonic_plate_boundaries.png\"><img class=\"size-full wp-image-90\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tectonic_plate_boundaries.png\" alt=\"It shows all the types\" width=\"775\" height=\"429\"><\/a><figcaption id=\"caption-attachment-2522\" class=\"wp-caption-text\">Schematic of plate boundary types.<\/figcaption><\/figure>\n<p>In a simplified model, there are three categories of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> boundaries. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1678\">Convergent<\/a> boundaries are places where <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> move toward each other. At <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1677\">divergent<\/a> boundaries, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> move apart. At <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1679\">transform<\/a> boundaries, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> slide past each other.<\/p>\n<p>&nbsp;<\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-11\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-11\" class=\"h5p-iframe\" data-content-id=\"11\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"2.2 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3735\" aria-describedby=\"caption-attachment-3735\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/2.2-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-91\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.2-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3735\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 2.2 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-size: 28px;\">2.3 Convergent Boundaries<\/span><\/h2>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2523\" aria-describedby=\"caption-attachment-2523\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/CratonGeolProv.jpg\"><img class=\"size-medium wp-image-92\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/CratonGeolProv-300x159.jpg\" alt=\"The legend shows shields, platforms, orogens, basins, large igneous provinces, and extended crust.\" width=\"300\" height=\"159\"><\/a><figcaption id=\"caption-attachment-2523\" class=\"wp-caption-text\">Geologic provinces with the Shield (orange) and Platform (pink) comprising the Craton, the stable interior of continents.<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1678\">Convergent<\/a> boundaries, also called destructive boundaries, are places where two or more <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> move toward each other. . <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1678\">Convergent<\/a> boundary movement is divided into two types, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1698\">collision<\/a>, depending on the density of the involved <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">Continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> is of lower density and thus more buoyant than the underlying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1671\">asthenosphere<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">Oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> is more dense than <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a>, and, when old and cold, may even be more dense than <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1671\">asthenosphere<\/a>.<\/p>\n<p>When <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> of different densities converge, the higher density <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> is pushed beneath the more buoyant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> in a process called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a>. When <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> converge without <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> occurring, this process is called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1698\">collision<\/a>.<\/p>\n<h3><b>2.3.1. Subduction<\/b><\/h3>\n<div style=\"width: 720px;\" class=\"wp-video\"><video class=\"wp-video-shortcode\" id=\"video-330-1\" width=\"720\" height=\"540\" preload=\"metadata\" controls=\"controls\"><source type=\"video\/mp4\" src=\"http:\/\/opengeology.org\/textbook\/wp-content\/uploads\/2016\/07\/Subduction.mp4?_=1\" \/><a href=\"http:\/\/opengeology.org\/textbook\/wp-content\/uploads\/2016\/07\/Subduction.mp4\">http:\/\/opengeology.org\/textbook\/wp-content\/uploads\/2016\/07\/Subduction.mp4<\/a><\/video><\/div>\n<p><em><a href=\"http:\/\/emvc.geol.ucsb.edu\/2_infopgs\/IP1GTect\/cSubduction.html\">Video<\/a> showing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\"><em>continental<\/em><\/a>-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\"><em>oceanic <\/em><\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\"><em>subduction<\/em><\/a>, causing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\"><em>volcanism<\/em><\/a>. By Tanya Atwater and John Iwerks.<\/em><\/p>\n<figure id=\"attachment_3734\" aria-describedby=\"caption-attachment-3734\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Subduction-Animation-QR-Code.png\"><img class=\"size-thumbnail wp-image-93\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Subduction-Animation-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3734\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this video via this QR Code.<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">Subduction<\/a> occurs when a dense <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> meets a more buoyant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a>, like a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> or warmer\/younger <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a>, and descends into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a>. The worldwide average rate of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> is 25 miles per million years, about a half-inch per year. As an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> descends, it pulls the ocean floor down into a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1681\">trench<\/a>. These trenches can be more than twice as deep as the average depth of the adjacent ocean <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_508\">basin<\/a>, which is usually three to four km. The Mariana <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1681\">Trench<\/a>, for example, approaches a staggering 11 km.<\/p>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2524\" aria-describedby=\"caption-attachment-2524\" style=\"width: 800px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Subduction-en.svg_.png\"><img class=\"size-full wp-image-94\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Subduction-en.svg_.png\" alt=\"Many features are labeled on the diagram, but the main idea is the ocean plate descending below the continental\" width=\"800\" height=\"391\"><\/a><figcaption id=\"caption-attachment-2524\" class=\"wp-caption-text\">Diagram of ocean-continent subduction.<\/figcaption><\/figure>\n<figure id=\"attachment_2525\" aria-describedby=\"caption-attachment-2525\" style=\"width: 212px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/drawing.png\"><img class=\"size-medium wp-image-95\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/drawing-212x300.png\" alt=\"This drawing depicts a microcontinent riding with a subducting plate, and not being subductable, becoming accreted to the melange.\" width=\"212\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2525\" class=\"wp-caption-text\">Microcontinents can become part of the accretionary prism of a subduction zone.<\/figcaption><\/figure>\n<p>Within the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1681\">trench<\/a>, ocean floor <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediments<\/a> are scraped together and compressed between the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subducting<\/a> and overriding <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a>. This feature is called the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1682\">accretionary wedge<\/a>, m\u00e9lange, or accretionary prism. Fragments of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> material, including microcontinents, riding atop the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subducting<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> may become sutured to the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1682\">accretionary wedge <\/a> and accumulate into a large area of land called a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1764\">terrane<\/a>. Vast portions of California are comprised of accreted terranes.<\/p>\n<figure id=\"attachment_2526\" aria-describedby=\"caption-attachment-2526\" style=\"width: 179px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/usgs_terranes.gif\"><img class=\"size-medium wp-image-96\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/usgs_terranes-179x300.gif\" alt=\"Map showing large areas of the western North American continent that are accreted.\" width=\"179\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2526\" class=\"wp-caption-text\">Accreted terranes of western North America. Everything that is not the \"Ancient continental interior (craton)\" has been smeared onto the side of the continent by accretion from subduction.<\/figcaption><\/figure>\n<p>When the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subducting<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a>, or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1683\">slab<\/a>, sinks into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a>, the immense heat and pressure pushes volatile materials like water and carbon dioxide into an area below the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> and above the descending <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> called the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1685\">mantle wedge<\/a>. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1684\">volatiles<\/a> are released mostly by hydrated <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> that revert to non-hydrated <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> in these higher <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> and pressure conditions. When mixed with asthenospheric material above the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a>, the volatile lower the melting point of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1685\">mantle wedge<\/a>, and through a process called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1686\">flux melting<\/a> it becomes liquid <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>. The molten <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> is more buoyant than the lithospheric <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> above it and migrates to the Earth\u2019s surface where it emerges as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a>. The resulting <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> frequently appear as curved mountain chains, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> arcs, due to the curvature of the earth. Both <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> can contain <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> arcs.<\/p>\n<figure id=\"attachment_2527\" aria-describedby=\"caption-attachment-2527\" style=\"width: 236px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/1755_Lisbon_Earthquake_Location.png\"><img class=\"size-medium wp-image-97\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/1755_Lisbon_Earthquake_Location-236x300.png\" alt=\"It is large and offshore.\" width=\"236\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2527\" class=\"wp-caption-text\">Location of the large (Mw 8.5-9.0) 1755 Lisbon Earthquake.<\/figcaption><\/figure>\n<p>How <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> is initiated is still a matter of scientific debate. It is generally accepted that <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> zones start as passive margins, where <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a>\u00a0and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> come together, and then gravity initiates <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> and converts the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1676\">passive margin<\/a> into an active one. One <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a> is gravity pulls the denser <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> down or the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> can start to flow ductility at a low angle. Scientists seeking to answer this question have collected evidence that suggests a new <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> zone is forming off the coast\u00a0of Portugal. Some scientists have proposed large earthquakes like the 1755 Lisbon earthquake may even have something to do with this process of creating a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> zone, although the evidence is not definitive. Another <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a> proposes <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> happens at <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1679\">transform<\/a> boundaries involving <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> of different densities.<\/p>\n<p>Some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> boundaries look like they should be active, but show no evidence of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a>. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> lithospheric <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> on either side of the Atlantic Ocean for example, are denser than the underlying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1671\">asthenosphere<\/a> and are not <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subducting<\/a> beneath the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a>. One <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a> is the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bond<\/a> holding the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> together is stronger than the downwards force created by the difference in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> densities.<\/p>\n<figure id=\"attachment_2528\" aria-describedby=\"caption-attachment-2528\" style=\"width: 234px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/SundaMegathrustSeismicity.png\"><img class=\"size-medium wp-image-98\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/SundaMegathrustSeismicity-234x300.png\" alt=\"The earthquakes follow the slab down.\" width=\"234\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2528\" class=\"wp-caption-text\">Earthquakes along the Sunda megathrust subduction zone, along the island of Sumatra, showing the 2006 Mw 9.1-9.3 Indian Ocean Earthquake as a star.<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">Subduction<\/a> zones are known for having the largest earthquakes and tsunamis; they are the only places with fault surfaces large enough to create magnitude-9 earthquakes. These <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a>-zone earthquakes not only are very large, but also are very deep. When a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subducting<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1683\">slab<\/a> becomes stuck and cannot descend, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_985\">massive<\/a> amount of energy builds up between the stuck <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a>. If this energy is not gradually dispersed, it may force the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> to suddenly release along several hundred kilometers of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> zone. Because <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a>-zone faults are located on the ocean floor, this <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_985\">massive<\/a> amount of movement can generate giant tsunamis such as those that followed the 2004 Indian Ocean Earthquake and 2011 T\u014dhoku Earthquake in Japan.<\/p>\n<figure id=\"attachment_2529\" aria-describedby=\"caption-attachment-2529\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Forearc.gif\"><img class=\"size-medium wp-image-99\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Forearc-300x258.gif\" alt=\"It shows backarc, forearc, and arc.\" width=\"300\" height=\"258\"><\/a><figcaption id=\"caption-attachment-2529\" class=\"wp-caption-text\">Various parts of a subduction zone. This subduction zone is ocean-ocean subduction, though the same features can apply to continent-ocean subduction.<\/figcaption><\/figure>\n<p>All <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> zones have a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1692\">forearc basin<\/a>, a feature of the overriding <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> found between the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1695\">volcanic arc<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1681\">trench<\/a>. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1692\">forearc basin<\/a> experiences a lot of faulting\u00a0and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_495\">deformation<\/a> activity, particularly within the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1682\">accretionary wedge<\/a>.<\/p>\n<p>In some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> zones, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_492\">tensional<\/a> forces\u00a0working on the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> create a backarc <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_508\">basin<\/a> on the interior side of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1695\">volcanic arc<\/a>. Some scientists have proposed a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> mechanism called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1683\">slab<\/a> rollback creates <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_492\">extension<\/a> faults in the overriding <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a>. In this model, the descending <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1683\">slab<\/a> does not slide directly under the overriding <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> but instead rolls back, pulling the overlying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> seaward. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> behind the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1695\">volcanic arc<\/a> gets stretched like pizza dough until the surface cracks and collapses to form a backarc <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_508\">basin<\/a>. If the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_492\">extension<\/a> activity is extensive and deep enough, a backarc <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_508\">basin<\/a> can develop into a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rifting<\/a> zone. These <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1677\">divergent<\/a> boundaries may be less symmetrical than their <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridge<\/a> counterparts.<\/p>\n<p>In places where numerous young buoyant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> are converging and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subducting<\/a> at a relatively high velocity, they may force the overlying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> to buckle and crack. This is called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1688\">back-arc<\/a> faulting. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_492\">Extensional<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1688\">back-arc<\/a> faults pull rocks and chunks of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> apart. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_493\">Compressional<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1688\">back-arc<\/a> faults, also known as thrust faults, push them together.<\/p>\n<p>The dual spines of the Andes Mountain range include a example of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_493\">compressional<\/a> thrust faulting. The western spine is part of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1695\">volcanic arc<\/a>. Thrust faults have deformed the non-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> eastern spine, \u00a0pushing rocks and pieces of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> on top of each other.<\/p>\n<p>There are two styles of thrust fault <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_495\">deformation<\/a>: <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1689\">thin-skinned<\/a> faults that occur in superficial rocks lying on top of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1690\">thick-skinned<\/a> faults that reach deeper into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a>. The Sevier <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1663\">Orogeny<\/a> in the western U.S. is a notable <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1689\">thin-skinned<\/a> type of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_495\">deformation<\/a> created during the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_487\">Cretaceous<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1244\">Period<\/a>. The Laramide <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1663\">Orogeny<\/a>, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1690\">thick-skinned<\/a> type of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_495\">deformation<\/a>, occurred near the end of and slightly after the Sevier <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1663\">Orogeny<\/a> \u00a0in the same region.<\/p>\n<figure id=\"attachment_2530\" aria-describedby=\"caption-attachment-2530\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Shallow_subduction_Laramide_orogeny.png\"><img class=\"size-medium wp-image-100\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Shallow_subduction_Laramide_orogeny-300x142.png\" alt=\"The subducting plate goes right under the overriding plate\" width=\"300\" height=\"142\"><\/a><figcaption id=\"caption-attachment-2530\" class=\"wp-caption-text\">Shallow subduction during the Laramide Orogeny.<\/figcaption><\/figure>\n<p>Flat-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1683\">slab<\/a>, or shallow, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> caused the Laramide <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1663\">Orogeny<\/a>. When the descending <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1683\">slab<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subducts<\/a> at a low angle, there is more contact between the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1683\">slab<\/a> and the overlying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> than in a typical <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> zone. The shallowly-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subducting<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1683\">slab<\/a> pushes against the overriding <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> and creates an area of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_495\">deformation<\/a> on the overriding <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> many kilometers away from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> zone.<\/p>\n<h4><span style=\"font-weight: 400;\">Oceanic-Continental subduction<\/span><\/h4>\n<figure id=\"attachment_2531\" aria-describedby=\"caption-attachment-2531\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/OceanContSub.gif\"><img class=\"size-medium wp-image-101\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/OceanContSub-300x177.gif\" alt=\"The thinner ocean plate is going under the thicker continental plate.\" width=\"300\" height=\"177\"><\/a><figcaption id=\"caption-attachment-2531\" class=\"wp-caption-text\">Subduction of an oceanic plate beneath a continental plate, forming a trench and volcanic arc.<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1694\">Oceanic-continental subduction<\/a> occurs when an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> dives below a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a>. This <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1678\">convergent<\/a> boundary has a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1681\">trench<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1685\">mantle wedge<\/a> and frequently, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1695\">volcanic arc<\/a>. Well-known examples of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1695\">volcanic arcs<\/a> are the Cascade Mountains in the Pacific Northwest and western Andes Mountains in South America.<\/p>\n<h4><span style=\"font-weight: 400;\">Oceanic-Oceanic Subduction<\/span><\/h4>\n<figure id=\"attachment_2532\" aria-describedby=\"caption-attachment-2532\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Fig21oceanocean.gif\"><img class=\"size-medium wp-image-102\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Fig21oceanocean-300x173.gif\" alt=\"The ocean plate subducts beneath a different ocean plate.\" width=\"300\" height=\"173\"><\/a><figcaption id=\"caption-attachment-2532\" class=\"wp-caption-text\">Subduction of an oceanic plate beneath another oceanic plate, forming a trench and an island arc.<\/figcaption><\/figure>\n<p>The boundaries of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1696\">oceanic-oceanic subduction<\/a> zones show very different activity from those involving <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a>-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a>. Since both <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> are made of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a>, it is usually the older <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> that <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subducts<\/a> because it is colder and denser. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> on the overlying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> may remain hidden underwater.. If the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> rise high enough the reach the ocean surface, the chain of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> forms an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1697\">island arc<\/a>. Examples of these island arcs include the Aleutian Islands in the northern Pacific Ocean, Lesser Antilles in the Caribbean Sea, and numerous island chains scattered throughout the western Pacific Ocean.<\/p>\n<h3><b>2.3.2. Collisions<\/b><\/h3>\n<figure id=\"attachment_2533\" aria-describedby=\"caption-attachment-2533\" style=\"width: 301px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/contcontCollision.gif\"><img class=\"size-full wp-image-103\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/contcontCollision.gif\" alt=\"The two continental plates stay up.\" width=\"301\" height=\"181\"><\/a><figcaption id=\"caption-attachment-2533\" class=\"wp-caption-text\">Two continental plates colliding.<\/figcaption><\/figure>\n<p>When <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> converge, during the closing of an ocean <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_508\">basin<\/a> for example, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> is not possible between the equally buoyant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a>. Instead of one <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> descending beneath another, the two masses of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> slam together in a process known as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1698\">collision<\/a>. Without <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a>, there is no <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> formation and no <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1698\">Collision<\/a> zones are characterized by tall, non-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> mountains; a broad zone of frequent, large earthquakes; and very little <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a>.<\/p>\n<p>When <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic crust<\/a> connected by a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1676\">passive margin<\/a> to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental crust<\/a> completely <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subducts<\/a> beneath a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continent<\/a>, an ocean <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_508\">basin<\/a> closes, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1698\">collision<\/a> begins. \u00a0Eventually, as ocean basins close, continents join together to form a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_985\">massive<\/a> accumulation of continents called a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1701\">supercontinent<\/a>, a process that has taken place in ~500 million year old cycles over earth\u2019s history.<\/p>\n<figure id=\"attachment_2534\" aria-describedby=\"caption-attachment-2534\" style=\"width: 267px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Pangaea_continents.png\"><img class=\"size-medium wp-image-104\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pangaea_continents-267x300.png\" alt=\"Pangaea has a crescent shape.\" width=\"267\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2534\" class=\"wp-caption-text\">A reconstruction of Pangaea, showing approximate positions of modern continents.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>The process of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1698\">collision<\/a> created Pangea, the supercontinent envisioned by Wegener as the key component of his <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> drift <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a>. Geologists now have evidence that <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> have been continuously converging into <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1701\">supercontinents<\/a> and splitting into smaller <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_508\">basin<\/a>-separated continents throughout Earth\u2019s existence, calling this process the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1701\">supercontinent<\/a> cycle, a process that takes place in approximately 500 million years. For example, they estimate Pangea began separating 200 million years ago. Pangea was preceded by an earlier <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1701\">supercontinents<\/a>, one of which being <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1263\">Rodinia<\/a>, which existed 1.1 billion years ago and started breaking apart 800 million to 600 million years ago.<\/p>\n<figure id=\"attachment_2535\" aria-describedby=\"caption-attachment-2535\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/ZagrosFTB.png\"><img class=\"size-medium wp-image-105\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ZagrosFTB-300x231.png\" alt=\"The mountains are loading the crust down, leading to a depressed basin, which is the Persian Gulf\" width=\"300\" height=\"231\"><\/a><figcaption id=\"caption-attachment-2535\" class=\"wp-caption-text\">The tectonics of the Zagros Mountains. Note the Persian Gulf foreland basin.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>A foreland <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_508\">basin<\/a> is a feature that develops near mountain belts, as the combined mass of the mountains forms a depression in the lithospheric <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a>. While foreland basins may occur at <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> zones, they are most commonly found at <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1698\">collision<\/a> boundaries. The Persian Gulf is possibly the best modern example, created entirely by the weight of the nearby Zagros Mountains.<\/p>\n<figure id=\"attachment_2536\" aria-describedby=\"caption-attachment-2536\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/02.3_ItalyPillowBasalt.jpg\"><img class=\"size-medium wp-image-106\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/02.3_ItalyPillowBasalt-300x225.jpg\" alt=\"The rock is cray with many circles inside\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-2536\" class=\"wp-caption-text\">Pillow lavas, which only form under water, from an ophiolite in the Apennine Mountains of central Italy.<\/figcaption><\/figure>\n<p>If <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> are fused on the same <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a>, it can partially subduct but its buoyancy prevents it from fully descending. In very rare cases, part of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> may become trapped beneath a descending <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> in a process called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1699\">obduction<\/a>. When a portion of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental crust<\/a> is driven down into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> zone, due to its buoyancy it returns to the surface relatively quickly.<\/p>\n<p>As pieces of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> break loose and migrate upward through the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1699\">obduction<\/a> zone, they bring along bits of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> and ocean floor and amend them on top of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a>. Rocks composed of this <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> and ocean-floor material are called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1700\">ophiolites<\/a> and they provide valuable information about the composition of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a>.<\/p>\n<p>The area of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1698\">collision<\/a>-zone <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_495\">deformation<\/a> and seismic activity usually covers a broader area because <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> is plastic and malleable. Unlike <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a>-zone earthquakes, which tend to be located along a narrow swath near the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1678\">convergent<\/a> boundary, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1698\">collision<\/a>-zone earthquakes may occur hundreds of kilometers from the boundary between the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a>.<\/p>\n<p>The Eurasian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continent<\/a> has many examples of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1698\">collision<\/a>-zone deformations covering vast areas. The Pyrenees mountains begin in the Iberian Peninsula and cross into France. Also, there are the Alps stretching from Italy to central Europe; the Zagros mountains from Arabia to Iran; and Himalaya mountains from the Indian subcontinent to central Asia.<\/p>\n<div style=\"width: 720px;\" class=\"wp-video\"><video class=\"wp-video-shortcode\" id=\"video-330-2\" width=\"720\" height=\"478\" preload=\"metadata\" controls=\"controls\"><source type=\"video\/mp4\" src=\"http:\/\/opengeology.org\/textbook\/wp-content\/uploads\/2016\/07\/IndiaAsiaCollision.mp4?_=2\" \/><a href=\"http:\/\/opengeology.org\/textbook\/wp-content\/uploads\/2016\/07\/IndiaAsiaCollision.mp4\">http:\/\/opengeology.org\/textbook\/wp-content\/uploads\/2016\/07\/IndiaAsiaCollision.mp4<\/a><\/video><\/div>\n<p><em>Animation of India crashing into Asia, by Tanya Atwater.<\/em><\/p>\n<figure id=\"attachment_3733\" aria-describedby=\"caption-attachment-3733\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/India-Asia-Collision-Animation-QR-Code.png\"><img class=\"size-thumbnail wp-image-107\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/India-Asia-Collision-Animation-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3733\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this animation via this QR Code.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-12\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-12\" class=\"h5p-iframe\" data-content-id=\"12\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"2.3 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3732\" aria-describedby=\"caption-attachment-3732\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/2.3-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-108\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.3-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3732\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 2.3 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-weight: 400;\">2.4 Divergent Boundaries<\/span><\/h2>\n<p>At <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1677\">divergent<\/a> boundaries, sometimes called constructive boundaries, lithospheric <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> move away from each other. There are two types of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1677\">divergent<\/a> boundaries, categorized by where they occur: <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rift<\/a> zones and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridges<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">Continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rift<\/a> zones occur in weak spots in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> lithospheric <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a>. A <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridge<\/a> usually originates in a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> as a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rift<\/a> zone that expands to the point of splitting the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> apart, with seawater filling in the gap. The separate pieces continue to drift apart and become individual continents. This process is known as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rift<\/a>-to-drift.<\/p>\n<h3><b>2.4.1. Continental Rifting<\/b><\/h3>\n<figure id=\"attachment_2537\" aria-describedby=\"caption-attachment-2537\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Horst-Graben.svg_.png\"><img class=\"size-medium wp-image-109\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Horst-Graben.svg_-300x154.png\" alt=\"While the area extends, individual grabens drop down relative to the horsts.\" width=\"300\" height=\"154\"><\/a><figcaption id=\"caption-attachment-2537\" class=\"wp-caption-text\">Faulting that occurs in divergent boundaries.<\/figcaption><\/figure>\n<p>In places where the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> are very thick, they reflect so much heat back into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> it develops strong <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1655\">convection<\/a> currents that push super-heated <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> material up against the overlying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a>, softening it. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_492\">Tensional<\/a> forces created by this convective upwelling begin to pull the weakened <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> apart. As it stretches, it becomes thinner and develops deep cracks called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_492\">extension<\/a> or normal faults. Eventually plate sections located between large faults drop into deep depressions known as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rift<\/a> valleys, which often contain keystone-shaped blocks of down-dropped <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a> known as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1704\">grabens<\/a>. The shoulders of these <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1704\">grabens<\/a> are called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1703\">horsts<\/a>. If only one side of a section drops, it is called a half-graben. Depending on the conditions, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rifts<\/a> can grow into very large lakes and even oceans.<\/p>\n<figure id=\"attachment_2538\" aria-describedby=\"caption-attachment-2538\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/TopographicAfar.png\"><img class=\"size-medium wp-image-110\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/TopographicAfar-300x300.png\" alt=\"The branches of the plate boundaries are 120 degrees apart.\" width=\"300\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2538\" class=\"wp-caption-text\">The Afar Triangle (center) has the Red Sea ridge (center to upper left), Gulf of Aden ridge (center to right), and East African Rift (center to lower left) form a triple junction that are about 120\u00b0 apart.<\/figcaption><\/figure>\n<p>While seemingly occurring at random, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rifting<\/a> is dictated by two factors. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">Rifting<\/a> does not occur in continents with older and more stable interiors, known as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1718\">cratons<\/a>. When <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rifting<\/a> does occur, the break-up pattern resembles the seams of a soccer ball, also called a truncated icosahedron. This is the most common surface-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_986\">fracture<\/a> pattern to develop on an evenly expanding sphere because it uses the least amount of energy.<\/p>\n<p>Using the soccer ball model, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rifting<\/a> tends to lengthen and expand along a particular seam while fizzling out in the other directions. These seams with little or no <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a> activity are called failed rift arms. A <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1705\">failed rift arm<\/a> is still a weak spot in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a>; even without the presence of active <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_492\">extension<\/a> faults, it may develop into a called an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1706\">aulacogen<\/a>. One example of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1705\">failed rift arm<\/a> is the Mississippi Valley Embayment, a depression through which the upper end of the Mississippi River flows. Occasionally connected <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rift<\/a> arms do develop concurrently, creating multiple boundaries of active <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rifting<\/a>. In places where the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rift<\/a> arms do not fail, for example the Afar Triangle, three <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1677\">divergent<\/a> boundaries can develop near each other forming a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1707\">triple junction<\/a>.<\/p>\n<figure id=\"attachment_2539\" aria-describedby=\"caption-attachment-2539\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Basin_range_province.jpg\"><img class=\"size-medium wp-image-111\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Basin_range_province-300x240.jpg\" alt=\"There is a series of mountains and valleys\" width=\"300\" height=\"240\"><\/a><figcaption id=\"caption-attachment-2539\" class=\"wp-caption-text\">NASA image of the Basin and Range horsts and grabens across central Nevada.<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">Rifts<\/a> come in two types: narrow and broad. Narrow <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rifts<\/a> are characterized by a high density of highly active <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1677\">divergent<\/a> boundaries. The East African <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">Rift<\/a> Zone, where the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1531\">horn<\/a> of Africa is pulling away from the mainland, is an excellent example of an active narrow <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rift<\/a>. Lake Baikal in Russia is another. Broad <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rifts<\/a> also have numerous fault zones, but they are distributed over wide areas of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_495\">deformation<\/a>. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1514\">Basin and Range<\/a> region located in the western United States is a type of broad <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rift<\/a>. The Wasatch Fault, which also created the Wasatch Mountain Range in the state of Utah, forms the eastern <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1677\">divergent<\/a> boundary of this broad <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rift<\/a>\u00a0 (<a href=\"https:\/\/youtu.be\/TvvWqAdNV84\">Animation 1<\/a> and <a href=\"https:\/\/youtu.be\/7DxcAMmNeZk\">Animation 2<\/a>).<\/p>\n<p>&nbsp;<\/p>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">Rifts<\/a> have earthquakes, although not of the magnitude and frequency of other boundaries. They may also exhibit <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a>. Unlike the flux-melted <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> found in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> zones, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rift<\/a>-zone <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> is created by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_223\">decompression melting<\/a>. As the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> are pulled apart, they create a region of low pressure that melts the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> and draws it upwards. When this molten <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> reaches the weakened and fault-riddled <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rift<\/a> zone, it migrates to surface by breaking through the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> or escaping via an open fault. Examples of young <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rift<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> dot the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1514\">Basin and Range<\/a> region in the United States. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">Rift<\/a>-zone activity is responsible for generating some unique <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a>, such as the Ol Doinyo Lengai in Tanzania. This <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a> erupts <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> consisting largely of carbonatite, a relatively cold, liquid <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>.<\/p>\n<div style=\"width: 720px;\" class=\"wp-video\"><video class=\"wp-video-shortcode\" id=\"video-330-3\" width=\"720\" height=\"474\" preload=\"metadata\" controls=\"controls\"><source type=\"video\/mp4\" src=\"http:\/\/opengeology.org\/textbook\/wp-content\/uploads\/2016\/07\/SoAtlantic_CutwithConvect.mp4?_=3\" \/><a href=\"http:\/\/opengeology.org\/textbook\/wp-content\/uploads\/2016\/07\/SoAtlantic_CutwithConvect.mp4\">http:\/\/opengeology.org\/textbook\/wp-content\/uploads\/2016\/07\/SoAtlantic_CutwithConvect.mp4<\/a><\/video><\/div>\n<p>South America and Africa <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rift<\/a>, forming the Atlantic. <a href=\"http:\/\/emvc.geol.ucsb.edu\/2_infopgs\/IP1GTect\/eSoAtlantic_CutGlobe.html\">Video<\/a> by Tanya Atwater.<\/p>\n<figure id=\"attachment_3731\" aria-describedby=\"caption-attachment-3731\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Rift-Atlantic-Animation-QR-Code.png\"><img class=\"size-thumbnail wp-image-112\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Rift-Atlantic-Animation-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3731\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this video via this QR Code.<\/figcaption><\/figure>\n<h3><b>2.4.2. Mid-ocean ridges<\/b><\/h3>\n<figure id=\"attachment_2541\" aria-describedby=\"caption-attachment-2541\" style=\"width: 212px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Ocean-birth.svg_.png\"><img class=\"size-medium wp-image-113\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ocean-birth.svg_-212x300.png\" alt=\"The ocean starts as a valley and then gets wider and wider.\" width=\"212\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2541\" class=\"wp-caption-text\">Progression from rift to mid-ocean ridge.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p><span style=\"font-weight: 400;\">As <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rifting<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> activity progress, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> becomes more <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> (see <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/4-igneous-processes-and-volcanoes\/\" target=\"_blank\" rel=\"noopener\">Chapter 4<\/a>) and thinner, with the eventual result transforming the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> under the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rifting<\/a> area into <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a>. This is the process that gives birth to a new ocean, much like the narrow Red Sea emerged with the movement of Arabia away from Africa. As the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> continues to diverge, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridge<\/a> is formed.<\/span><\/p>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">Mid-ocean ridges<\/a>, also known as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">spreading centers<\/a>, have several distinctive features. They are the only places on earth that create new <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_223\">Decompression melting<\/a> in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rift<\/a> zone changes <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1671\">asthenosphere<\/a> material into new <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a>, which oozes up through cracks in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a>. The amount of new <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> being created at <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridges<\/a> is highly significant. These undersea <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rift<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> produce more <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> than all other types of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> combined. Despite this, most mid-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> ridge <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> remains unmapped because the volcanoes are located deep on the ocean floor.<\/p>\n<p>In rare cases, such as a few locations in Iceland, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rift<\/a> zones display the type of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a>, spreading, and ridge formation found on the ocean floor.<\/p>\n<figure id=\"attachment_2542\" aria-describedby=\"caption-attachment-2542\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/age_oceanic_lith.jpg\"><img class=\"size-medium wp-image-114\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/age_oceanic_lith-300x191.jpg\" alt=\"The map shoes colors that represent different ages.\" width=\"300\" height=\"191\"><\/a><figcaption id=\"caption-attachment-2542\" class=\"wp-caption-text\">Age of oceanic lithosphere, in millions of years. Notice the differences in the Atlantic Ocean along the coasts of the continents.<\/figcaption><\/figure>\n<p>The ridge feature is created by the accumulation of hot <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> material, which is lighter than the dense underlying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1671\">asthenosphere<\/a>. This chunk of isostatically buoyant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> sits partially submerged and partially exposed on the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1671\">asthenosphere<\/a>, like an ice cube floating in a glass of water.<\/p>\n<p>As the ridge continues to spread, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> material is pulled away from the area of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> and becomes colder and denser. As it continues to spread and cool, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> settles into wide swathes of relatively featureless topography called abyssal plains with lower topography.<\/p>\n<p>This model of ridge formation suggests the sections of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a> furthest away from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridges<\/a> will be the oldest. Scientists have tested this idea by comparing the age of rocks located in various locations on the ocean floor. Rocks found near ridges are younger than those found far away from any ridges. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">Sediment<\/a> accumulation patterns also confirm the idea of sea-floor spreading. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">Sediment<\/a> layers tend to be thinner near <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridges<\/a>, indicating it has had less time to build up.<\/p>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2543\" aria-describedby=\"caption-attachment-2543\" style=\"width: 600px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/atwater_mag_reversal_mid_ocean_ridge.gif\"><img class=\"wp-image-115 size-full\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/atwater_mag_reversal_mid_ocean_ridge.gif\" alt=\"animation showing the mid ocean ridges. As new oceanic plate is made at the ridge, it cools and preserves the current magnetic field at the time of cooling. When the poles reverse, the magnetic polarity flip is preserved in the oceanic plate record.\" width=\"600\" height=\"400\"><\/a><figcaption id=\"caption-attachment-2543\" class=\"wp-caption-text\">Spreading along several mid-ocean ridges, showing magnetic striping symmetry. By Tanya Atwater.<\/figcaption><\/figure>\n<figure id=\"attachment_3743\" aria-describedby=\"caption-attachment-3743\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Atwater-Spreading-GIF.png\"><img class=\"size-thumbnail wp-image-116\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Atwater-Spreading-GIF-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3743\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this animation via this QR Code.<\/figcaption><\/figure>\n<p>As mentioned in the section on <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1657\">paleomagnetism<\/a> and the development of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a>, scientists noticed <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridges<\/a> contained unique magnetic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_765\">anomalies<\/a> that show up as symmetrical striping on both sides of the ridge. The Vine-Matthews-Morley <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a> proposes these alternating reversals are created by the earth\u2019s magnetic field being imprinted into <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a><\/p>\n<figure id=\"attachment_2544\" aria-describedby=\"caption-attachment-2544\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Oceanic.Stripe.Magnetic.Anomalies.Scheme.svg_.png\"><img class=\"size-medium wp-image-117\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Oceanic.Stripe.Magnetic.Anomalies.Scheme.svg_-300x212.png\" alt=\"The older stripes are farther from the ridge.\" width=\"300\" height=\"212\"><\/a><figcaption id=\"caption-attachment-2544\" class=\"wp-caption-text\">A time progression (with \"a\" being youngest and \"c\" being oldest) showing a spreading center getting wider while recording changes in the magnetic field of the Earth.<\/figcaption><\/figure>\n<p>after it emerges from the ridge. Very hot <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> has no magnetic field. As the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> get pulled apart, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> cools below the Curie point, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> below which a magnetic field gets locked into magnetic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. The alternating magnetic reversals in the rocks reflects the periodic swapping of earth\u2019s magnetic north and south poles. This paleomagnetic pattern provides a great historical record of ocean-floor movement, and is used to reconstruct past <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a> activity and determine rates of ridge spreading.<\/p>\n<p><em><a href=\"http:\/\/emvc.geol.ucsb.edu\/2_infopgs\/IP3RegTect\/bNoCentAtlantic.html\">Video<\/a> of the breakup of <em>Pangea<\/em> and <em>formation<\/em> of the northern Atlantic Ocean. By Tanya Atwater.<\/em><\/p>\n<figure id=\"attachment_3729\" aria-describedby=\"caption-attachment-3729\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Pangea-Animation-QR-Code.png\"><img class=\"size-thumbnail wp-image-118\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pangea-Animation-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3729\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this video via this QR Code.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2545\" aria-describedby=\"caption-attachment-2545\" style=\"width: 233px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/BlackSmoker.jpg\"><img class=\"wp-image-119 size-medium\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/BlackSmoker-233x300.jpg\" alt=\"There is a large build up of minerals around the vent\" width=\"233\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2545\" class=\"wp-caption-text\">Black smoker hydrothermal vent with a colony of giant (6'+) tube worms.<\/figcaption><\/figure>\n<p>Thanks to their distinctive geology, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridges<\/a> are home to some of the most unique ecosystems ever discovered. The ridges are often studded with hydrothermal vents, deep fissures that allow seawater to circulate through the upper portions of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> and interact with hot rock. The super-heated seawater rises back up to the surface of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a>, carrying dissolved gasses and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, and small particulates.\u00a0 The resulting emitted hydrothermal water looks like black underwater smoke.<\/p>\n<p>Scientists had known about these geothermal areas on the ocean floor for some time. However, it was not until 1977, when scientists piloting a deep submergence vehicle, the Alvin, discovered a thriving community of organisms clustered around these hydrothermal vents. These unique organisms, which include 10-foot-long tube worms taller than people, live in the complete darkness of the ocean floor  deprived of oxygen and sunlight. They use geothermal energy provided by the vents and a process called bacterial <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_231\">chemosynthesis<\/a> to feed on sulfur compounds. Before this discovery, scientists believed life on earth could not exist without photosynthesis, a process that requires sunlight. Some scientists suggest this type of environment could have been the origin of life on Earth, and perhaps even extraterrestrial life elsewhere in the galaxy, such as on Jupiter\u2019s moon Europa.<\/p>\n<p>&nbsp;<\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-13\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-13\" class=\"h5p-iframe\" data-content-id=\"13\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"2.4 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3728\" aria-describedby=\"caption-attachment-3728\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/2.4-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-120\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.4-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3728\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 2.4 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-weight: 400;\">2.5 Transform Boundaries<\/span><\/h2>\n<figure id=\"attachment_2546\" aria-describedby=\"caption-attachment-2546\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Strike_slip_fault.png\"><img class=\"size-medium wp-image-121\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Strike_slip_fault-300x137.png\" alt=\"Sinistral moves to the left, dextral moves to the right.\" width=\"300\" height=\"137\"><\/a><figcaption id=\"caption-attachment-2546\" class=\"wp-caption-text\">The two types of transform\/strike slip faults.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>A <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1679\">transform<\/a> boundary, sometimes called a strike-slip or conservative boundary, is where the lithospheric <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> slide past each other in the horizontal plane. This movement is described based on the perspective of an observer standing on one of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a>, looking across the boundary at the opposing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a>. Dextral, also known as right-lateral, movement describes the opposing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> moving to the right. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1710\">Sinistral<\/a>, also known as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1710\">left lateral<\/a>, movement describe the opposing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> moving to the left.<\/p>\n<p>Most <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1679\">transform<\/a> boundaries are found on the ocean floor, around <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridges<\/a>. These boundaries form aseismic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_986\">fracture<\/a> zones, filled with earthquake-free <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1679\">transform<\/a> faults, to accommodate different rates of spreading occurring at the ridge.<\/p>\n<figure id=\"attachment_2547\" aria-describedby=\"caption-attachment-2547\" style=\"width: 217px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Sanandreas.jpg\"><img class=\"size-medium wp-image-122\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Sanandreas-217x300.jpg\" alt=\"The fault runs through California.\" width=\"217\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2547\" class=\"wp-caption-text\">Map of the San Andreas fault, showing relative motion.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>Some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1679\">transform<\/a> boundaries produce significant seismic activity, primarily as earthquakes, with very little mountain-building or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a>. This type of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1679\">transform<\/a> boundary may contain a single fault or series of faults, which develop in places where <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a> stresses are transferred to the surface. As with other types of active boundaries, if the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> are unable to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_494\">shear<\/a> past each other the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a> forces will continue to build up. If the built up energy between the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> is suddenly released, the result is an earthquake.<\/p>\n<p>In the eyes of humanity, the most significant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1679\">transform<\/a> faults occur within <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a>, and have a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_494\">shearing<\/a> motion that frequently produces moderate-to-large magnitude earthquakes. Notable examples include the San Andreas Fault in California, Northern and Eastern Anatolian Faults\u00a0in Turkey, Altyn Tagh Fault in central Asia, and Alpine Fault in New Zealand.<\/p>\n<h3><b>2.5.1. Transpression and Transtension<\/b><\/h3>\n<figure id=\"attachment_2548\" aria-describedby=\"caption-attachment-2548\" style=\"width: 150px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Transpression.png\"><img class=\"wp-image-123 size-thumbnail\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Transpression-150x150.png\" alt=\"The fault is dextral, and has a leftward bend, causing uplift.\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-2548\" class=\"wp-caption-text\">A transpressional strike-slip fault, causing uplift called a restraining bend.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>Bends along <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1679\">transform<\/a> faults may create <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_493\">compressional<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_492\">extensional<\/a> forces that cause secondary faulting zones. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1712\">Transpression<\/a> occurs where there is a component of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_493\">compression<\/a> in addition to the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_494\">shearing<\/a> motion. These forces build up around the area of the bend, where the opposing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> are restricted from sliding past each other. As the forces continue to build up, they create mountains in the restraining bend around the fault. The Big Bend area, located in the southern part of the San Andreas Fault includes a large area of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1712\">transpression<\/a> where many mountains have been built, moved, and even rotated.<\/p>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2549\" aria-describedby=\"caption-attachment-2549\" style=\"width: 150px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Transtension.png\"><img class=\"wp-image-124 size-thumbnail\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Transtension-150x150.png\" alt=\"The fault is dextral, and has a rightward bend, causing a valley.\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-2549\" class=\"wp-caption-text\">A transtensional strike-slip fault, causing a restraining bend. In the center of the fault, a depression with extension would be found.<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1713\">Transtension<\/a> zones require a fault that includes a releasing bend, where the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> are being pulled apart by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_492\">extensional<\/a> forces. Depressions and sometimes <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> develop in the releasing bend, along the fault. The Dead Sea found between Israel and Jordan, and the Salton Sea of California are examples of basins formed by transtensional forces.<\/p>\n<h3><\/h3>\n<h3><b>2.5.2. Piercing Points<\/b><\/h3>\n<figure id=\"attachment_2550\" aria-describedby=\"caption-attachment-2550\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Wallace_Creek_offset_across_the_San_Andreas_Fault.png\"><img class=\"size-medium wp-image-125\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Wallace_Creek_offset_across_the_San_Andreas_Fault-300x205.png\" alt=\"The offset is to the left.\" width=\"300\" height=\"205\"><\/a><figcaption id=\"caption-attachment-2550\" class=\"wp-caption-text\">Wallace (dry) Creek on the Cariso Plain, California. Note as the creek flows from the northern mountainous part of the image, it takes a sharp right (as viewed from the flow of water), then a sharp left. This is caused by the San Andreas Fault cutting roughly perpendicular to the creek, and shifting the location of the creek over time. The fault can be seen about halfway down, trending left to right, as a change in the topography.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>When a geological feature is cut by a fault, it is called a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1714\">piercing point<\/a>. Piercing points are very useful for recreating past fault movement, especially along <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1679\">transform<\/a> boundaries. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1679\">Transform<\/a> faults are unique because their horizontal motion keeps a geological feature relatively intact, preserving the record of what happened. Other types of faults\u2014normal and reverse \u2014tend to be more destructive, obscuring or destroying these features. The best type of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1714\">piercing point<\/a> includes unique patterns that are used to match the parts of a geological feature separated by fault movement. Detailed studies of piercing points show the San Andreas Fault has experienced over 225 km of movement in the last 20 million years, and this movement occurred at three different fault traces.<\/p>\n<p><em>Video of the origin of the San Andreas <em>fault<\/em>. As the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\"><em>mid-ocean ridge<\/em><\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\"><em>subducts<\/em><\/a>, the relative motion between the remaining <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\"><em>plates<\/em><\/a> become <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1679\"><em>transform<\/em><\/a>, forming the <em>fault<\/em> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1742\"><em>system<\/em><\/a>. Note that because the motion of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\"><em>plates<\/em><\/a> is not exactly parallel to the <em>fault<\/em>, it causes <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1677\"><em>divergent<\/em><\/a> motion in the interior of North America. By Tanya Atwater.<\/em><\/p>\n<figure id=\"attachment_3727\" aria-describedby=\"caption-attachment-3727\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Plate-Tectonics-YouTube-QR-Code.png\"><img class=\"size-thumbnail wp-image-126\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plate-Tectonics-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3727\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this YouTube video via this QR Code.<\/figcaption><\/figure>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-14\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-14\" class=\"h5p-iframe\" data-content-id=\"14\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"2.5 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3726\" aria-describedby=\"caption-attachment-3726\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/2.5-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-127\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.5-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3726\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 2.5 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-weight: 400;\">2.6 The Wilson Cycle<\/span><\/h2>\n<figure id=\"attachment_2551\" aria-describedby=\"caption-attachment-2551\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Wilson-cycle_hg.svg_.png\"><img class=\"size-medium wp-image-128\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Wilson-cycle_hg.svg_-300x164.png\" alt=\"The diagram shows the last 1000 million years.\" width=\"300\" height=\"164\"><\/a><figcaption id=\"caption-attachment-2551\" class=\"wp-caption-text\">Diagram of the Wilson Cycle, showing rifting and collision phases.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1715\">Wilson Cycle<\/a> is named for J. Tuzo Wilson who first described it in 1966, and it outlines the ongoing origin and breakup of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1701\">supercontinents<\/a>, such as Pangea and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1263\">Rodinia<\/a>. Scientists have determined this cycle has been operating for at least three billion years and possibly earlier.<\/p>\n<p>There are a number of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypotheses<\/a> about how the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1715\">Wilson Cycle<\/a> works. One mechanism proposes that <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rifting<\/a> happens because <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> reflect the heat much better than <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a>. When continents congregate together, they reflect more of the Earth\u2019s heat back into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a>, generating more vigorous <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1655\">convection<\/a> currents that then start the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rifting<\/a> process. Some geologists believe <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> plumes are remnants of these <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1244\">periods<\/a> of increased <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1655\">convection<\/a> upwelling, and study them for clues about the origin of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rifting<\/a>.<\/p>\n<p>The mechanism behind how <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1701\">supercontinents<\/a> are created is still largely a mystery. There are three schools of thought about what continues to drive the continents further apart and eventually bring them together. The ridge-push <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a> suggests after the initial <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rifting<\/a> event, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> continue to be pushed apart by mid-ocean <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">spreading centers<\/a> and their underlying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1655\">convection<\/a> currents. Slab-pull proposes the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> are pulled apart by descending slabs in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> zones of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a>-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> margins. A third idea, gravitational sliding, attributes the movement to gravitational forces pulling the lithospheric <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> down from the elevated <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridges<\/a> and across the underlying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1671\">asthenosphere<\/a>. Current evidence seems to support <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1683\">slab<\/a> pull more than ridge push or gravitational sliding.<\/p>\n<h2><span style=\"font-weight: 400;\">2.7 Hotspots<\/span><\/h2>\n<figure id=\"attachment_2552\" aria-describedby=\"caption-attachment-2552\" style=\"width: 193px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Hotspotgeology-1.svg_.png\"><img class=\"size-medium wp-image-129\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hotspotgeology-1.svg_-193x300.png\" alt=\"The plate is moving to the left, the magma stays in the center am makes a chain of volcanoes.\" width=\"193\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2552\" class=\"wp-caption-text\">Diagram showing a non-moving source of magma (mantle plume) and a moving overriding plate.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1715\">Wilson Cycle<\/a> provides a broad overview of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> movement. To analyze <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> movement more precisely, scientists study <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspots<\/a>. First postulated by J. Tuzo Wilson in 1963, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a> is an area in the lithospheric <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> where molten <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> breaks through and creates a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> center, islands in the ocean and mountains on land. As the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> moves across the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a>, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a> center becomes <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_755\">extinct<\/a> because it is no longer over an active <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> source. Instead, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> emerges through another area in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> to create a new active <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a>. Over time, the combination of moving <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> and stationary <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a> creates a chain of islands or mountains. The classic definition of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspots<\/a> states they do not move, although recent evidence suggests that there may be exceptions.<\/p>\n<figure id=\"attachment_2553\" aria-describedby=\"caption-attachment-2553\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/HotspotsWorld.png\"><img class=\"size-medium wp-image-130\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/HotspotsWorld-300x175.png\" alt=\"Hotspots are scattered around the world.\" width=\"300\" height=\"175\"><\/a><figcaption id=\"caption-attachment-2553\" class=\"wp-caption-text\">Map of world hotspots. Larger circles indicate more active hotspots.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">Hotspots<\/a> are the only types of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> not associated with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rifting<\/a> zones at <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> boundaries; they seem totally disconnected from any <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">plate tectonics<\/a> processes, such as earthquakes. However, there are\u00a0 relationships between <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspots<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">plate tectonics<\/a>. There are several <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspots<\/a>, current and former, that are believed to have begun at the time of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rifting<\/a>. Also, scientists use the age of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> eruptions and shape of the chain to quantify the rate and direction of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> movement relative to the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a>.<\/p>\n<p>Scientists are divided over how <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> is generated in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspots<\/a>. Some suggest that <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspots<\/a> originate from super-heated material from as deep as the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1667\">core<\/a> that reaches the Earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a> as a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1717\">mantle plume<\/a>. Others argue the molten material that feeds <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspots<\/a> is sourced from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a>. Of course, it is difficult to collect data from these deep-Earth features due to the extremely high pressure and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a>.<\/p>\n<p>How <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspots<\/a> are initiated is another highly debated subject. The prevailing mechanism has <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspots<\/a> starting in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1677\">divergent<\/a> boundaries during <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1701\">supercontinent<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1702\">rifting<\/a>. Scientists have identified a number of current and past <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspots<\/a> believed to have begun this way. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">Subducting<\/a> slabs have also been named as causing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> plumes and hot-spot <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a>. Some geologists have suggested another geological process not involving <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">plate tectonics<\/a> may be involved, such as a large space objects crashing into Earth. Regardless of how they are formed, dozens are on the Earth. Some well-known examples include the Tahiti Islands, Afar Triangle, Easter Island, Iceland, Galapagos Islands, and Samoan Islands. The United States is home to two of the largest and best-studied <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspots<\/a>: Hawaii and Yellowstone.<\/p>\n<h3><b>2.7.1 Hawaiian hotspot<\/b><\/h3>\n<figure id=\"attachment_2554\" aria-describedby=\"caption-attachment-2554\" style=\"width: 296px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Hawaii-Emperor_engl.png\"><img class=\"size-medium wp-image-131\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hawaii-Emperor_engl-296x300.png\" alt=\"There are a series of island and seamounts in the Pacific Ocean, with a bend in the middle.\" width=\"296\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2554\" class=\"wp-caption-text\">The Hawaii-Emperor seamount and island chain.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>The active <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> in Hawaii represent one of the most active <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a> sites on earth. Scientific evidence indicates the Hawaiian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a> is at least 80 million years old. Geologists believe it is actually much older; however any rocks with proof of this have been <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subducted<\/a> under the ocean floor. The big island of Hawaii sits atop a large <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1717\">mantle plume<\/a> that marks the active <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a>. The Kilauea <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcano<\/a> is the main <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_234\">vent<\/a> for this <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a> and has been actively erupting since 1983.<\/p>\n<p>This enormous <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> island chain, much of which is underwater, stretches across the Pacific for almost 6,000 km. The seamount chain\u2019s most striking feature is a sharp 60-degree bend located at the midpoint, which marks a significant change in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> movement direction that occurred 50 million years ago. The change in direction has been more often linked to a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> reconfiguration, but also to other things like plume migration.<\/p>\n<figure id=\"attachment_2555\" aria-describedby=\"caption-attachment-2555\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Hawaii_hotspot_cross-sectional_diagram.jpg\"><img class=\"size-medium wp-image-132\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hawaii_hotspot_cross-sectional_diagram-300x159.jpg\" alt=\"The islands get older to the left.\" width=\"300\" height=\"159\"><\/a><figcaption id=\"caption-attachment-2555\" class=\"wp-caption-text\">Diagram of the Hawaiian hotspot and islands that it formed.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>In an attempt to map the Hawaiian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1717\">mantle plume<\/a> as far down as the lower <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a>, scientists have used tomography, a type of three-dimensional seismic imaging. This information\u2014along with other evidence gathered from rock ages, vegetation types, and island size\u2014indicate the oldest islands in the chain are located the furthest away from the active <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a>.<\/p>\n<h4><b>2.7.2 Yellowstone hotspot<\/b><\/h4>\n<figure id=\"attachment_2556\" aria-describedby=\"caption-attachment-2556\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/YellowstoneHotspot.jpg\"><img class=\"size-medium wp-image-133\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/YellowstoneHotspot-300x206.jpg\" alt=\"The hotspot started near the Idaho-Oregon-Nevada boarder, then moved toward its present location neat the Wyoming-Idaho-Montana boarder.\" width=\"300\" height=\"206\"><\/a><figcaption id=\"caption-attachment-2556\" class=\"wp-caption-text\">The track of the Yellowstone hotspot, which shows the age of different eruptions in millions of years ago.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>Like the Hawaiian version, the Yellowstone <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a> is formed by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> rising through the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a>. What makes it different is this <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a> is located under a thick, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a>. Hawaii sits on a thin <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a>\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a>, which is easily breached by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> coming to the surface. At Yellowstone, the thick <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> presents a much more difficult barrier for <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> to penetrate. When it does emerge, the eruptions are generally much more violent. Thankfully they are also less frequent.<\/p>\n<p>Over 15 million years of eruptions by this <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a> have carved a curved path across the western United States. It has been suggested the Yellowstone <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a> is connected to the much older Columbia River <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_244\">flood basalts<\/a> and even to 70 million-year-old <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanism<\/a> found in the Yukon region of Canada.<\/p>\n<figure id=\"attachment_2557\" aria-describedby=\"caption-attachment-2557\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Yellowstone_volcano_-_ash_beds.jpg\"><img class=\"size-medium wp-image-134\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Yellowstone_volcano_-_ash_beds-300x195.jpg\" alt=\"The eruptions trend eastward due to prevailing winds.\" width=\"300\" height=\"195\"><\/a><figcaption id=\"caption-attachment-2557\" class=\"wp-caption-text\">Several prominent ash beds found in North America, including three Yellowstone eruptions shaded pink (Mesa Falls, Huckleberry Ridge, and Lava Creek), the Bisho Tuff ash bed (brown dashed line), and the modern May 18th, 1980 ash fall (yellow).<\/figcaption><\/figure>\n<p>The most recent major eruption of this <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a> created the Yellowstone <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_235\">Caldera<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">Lava<\/a> Creek <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1005\">tuff<\/a> formation approximately 631,000 years ago. The eruption threw 1,000 cubic kilometers of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">ash<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1745\">atmosphere<\/a>, some of which was found as far away as Mississippi. Should the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspot<\/a> erupt again, scientists predict it will be another <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_985\">massive<\/a> event. This would be a calamity reaching far beyond the western United States. These super <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> eruptions fill the earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1745\">atmosphere<\/a> with so much gas and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">ash<\/a>, they block sunlight from reaching the earth. Not only would this drastically alter climates and environments around the globe, it could affect worldwide food production.<\/p>\n<p>&nbsp;<\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-15\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-15\" class=\"h5p-iframe\" data-content-id=\"15\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"2.6\/7 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3725\" aria-describedby=\"caption-attachment-3725\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/2.6-7-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-135\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.6-7-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3725\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for sections 2.6 and 2.7 via this QR Code.<\/figcaption><\/figure>\n<h2><\/h2>\n<h2>Summary<\/h2>\n<figure id=\"attachment_3724\" aria-describedby=\"caption-attachment-3724\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Plate-Tectonics-Basics-YouTube-QR-Code.png\"><img class=\"size-thumbnail wp-image-136\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plate-Tectonics-Basics-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3724\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this YouTube video via this QR Code.<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">Plate tectonics<\/a> is a unifying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a>; it explains nearly all of the major geologic processes on Earth. Since its early inception in the 1950s and 1960s, geologists have been guided by this revolutionary perception of the world. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a> of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">plate tectonics<\/a> states the surface layer of the Earth is broken into a network of solid, relatively <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1661\">brittle<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a>. Underneath the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> is a much hotter and more <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1660\">ductile<\/a> layer that contains zones of convective upwelling generated by the interior heat of Earth. These <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1655\">convection<\/a> currents move the surface <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> around\u2014bringing them together, pulling them apart, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_494\">shearing<\/a> them side-by-side. Earthquakes and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanoes<\/a> form at the boundaries where the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> interact, with the exception of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1716\">hotspots<\/a>, which are not caused by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> movement.<\/p>\n<p>&nbsp;<\/p>\n<h3>Take this quiz to check your comprehension of this Chapter.<\/h3>\n<div id=\"h5p-16\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-16\" class=\"h5p-iframe\" data-content-id=\"16\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Chapter 2 Review\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3723\" aria-describedby=\"caption-attachment-3723\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Ch.2-Review-QR-Code.png\"><img class=\"size-thumbnail wp-image-137\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ch.2-Review-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3723\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the review quiz for Chapter 2 via this QR Code.<\/figcaption><\/figure>\n<h2>References<\/h2>\n<div class=\"csl-bib-body\">\n<ol>\n<li class=\"csl-entry\">Aitta, A., 2006, Iron melting curve with a tricritical point: J. 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Rev. Earth Planet. Sci., v. 35, p. 349\u2013374.<\/li>\n<li class=\"csl-entry\">Scheidegger, A.E., 1953, Examination of the physics of theories of orogenesis: Geol. Soc. Am. Bull., v. 64, no. 2, p. 127\u2013150., doi: <a href=\"https:\/\/doi.org\/10.1130\/0016-7606(1953)64[127:EOTPOT]2.0.CO;2\">10.1130\/0016-7606(1953)64[127:EOTPOT]2.0.CO;2<\/a>.<\/li>\n<li class=\"csl-entry\">Simpson, G.G., 1943, Mammals and the nature of continents: Am. J. Sci., v. 241, no. 1, p. 1\u201331.<\/li>\n<li class=\"csl-entry\">Starr, A.M., 2015, Ambient resonance of rock arches: Salt Lake City, Utah, University of Utah, 134 p.<\/li>\n<li class=\"csl-entry\">Stern, R.J., 1998, A <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a> primer for instructors of introductory geology courses and authors of introductory-geology textbooks: J. Geosci. Educ., v. 46, p. 221.<\/li>\n<li class=\"csl-entry\">Stern, R.J., 2004, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">Subduction<\/a> initiation: spontaneous and induced: Earth Planet. Sci. Lett., v. 226, no. 3\u20134, p. 275\u2013292.<\/li>\n<li class=\"csl-entry\">Stich, D., Mancilla, F. de L., Pondrelli, S., and Morales, J., 2007, Source analysis of the February 12th 2007, Mw 6.0 Horseshoe earthquake: Implications for the 1755 Lisbon earthquake: Geophys. Res. Lett., v. 34, no. 12, p. L12308.<\/li>\n<li class=\"csl-entry\">Tatsumi, Y., 2005, The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subduction<\/a>\u00a0factory: how it operates in the evolving Earth: GSA Today, v. 15, no. 7, p. 4.<\/li>\n<li class=\"csl-entry\">Todo, Y., Kitazato, H., Hashimoto, J., and Gooday, A.J., 2005, Simple foraminifera flourish at the ocean\u2019s deepest point: Science, v. 307, no. 5710, p. 689., doi: <a href=\"https:\/\/doi.org\/10.1126\/science.1105407\">10.1126\/science.1105407<\/a>.<\/li>\n<li class=\"csl-entry\">Tolstoy, I., and Ewing, M., 1949, North Atlantic hydrography and the Mid-Atlantic Ridge: Geol. Soc. Am. Bull., v. 60, no. 10, p. 1527\u20131540., doi: <a href=\"https:\/\/doi.org\/10.1130\/0016-7606(1949)60[1527:NAHATM]2.0.CO;2\">10.1130\/0016-7606(1949)60[1527:NAHATM]2.0.CO;2<\/a>.<\/li>\n<li class=\"csl-entry\">Vine, F.J., and Matthews, D.H., 1963, Magnetic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_765\">anomalies<\/a> over <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic<\/a> ridges: Nature, v. 199, no. 4897, p. 947\u2013949.<\/li>\n<li class=\"csl-entry\">W\u00e4chtersh\u00e4user, G., 1990, Evolution of the first metabolic cycles: Proc. Natl. Acad. Sci. U. S. A., v. 87, no. 1, p. 200\u2013204.<\/li>\n<li class=\"csl-entry\">Wadati, K., 1935, On the activity of deep-focus earthquakes in the Japan Islands and neighbourhoods: Geophys. Mag., v. 8, no. 3\u20134, p. 305\u2013325.<\/li>\n<li class=\"csl-entry\">Waszek, L., Irving, J., and Deuss, A., 2011, Reconciling the hemispherical structure of Earth\/\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1674\">inner core<\/a> with its super-rotation: Nat. Geosci., v. 4, no. 4, p. 264\u2013267., doi: <a href=\"https:\/\/doi.org\/10.1038\/ngeo1083\">10.1038\/ngeo1083<\/a>.<\/li>\n<li class=\"csl-entry\">Wegener, A., 1912, Die Entstehung der Kontinente: Geol. Rundsch., v. 3, no. 4, p. 276\u2013292., doi: <a href=\"https:\/\/doi.org\/10.1007\/BF02202896\">10.1007\/BF02202896<\/a>.<\/li>\n<li class=\"csl-entry\">Wegener, A., 1920, Die entstehung der kontinente und ozeane: \u0420\u0438\u043f\u043e\u043b \u041a\u043b\u0430\u0441\u0441\u0438\u043a.<\/li>\n<li class=\"csl-entry\">Wells, H.G., Huxley, J., and Wells, G.P., 1931, The Science of Life: Philosophy, v. 6, no. 24, p. 506\u2013507.<\/li>\n<li class=\"csl-entry\">White, I.C., and Moreira, C., 1908, Commiss\u00e3o de estudos das minas de Carv\u00e3o de Pedra do Brazil:<\/li>\n<li class=\"csl-entry\">de Wijs, G.A., Kresse, G., Vo\u010dadlo, L., Dobson, D., Alf\u00e8, D., Gillan, M.J., and Price, G.D., 1998, The viscosity of liquid iron at the physical conditions of the Earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1667\">core<\/a>: Nature, v. 392, no. 6678, p. 805\u2013807., doi: <a href=\"https:\/\/doi.org\/10.1038\/33905\">10.1038\/33905<\/a>.<\/li>\n<li class=\"csl-entry\">Wilson, J.T., 1966, Did the Atlantic close and then re-open? Nature.<\/li>\n<li class=\"csl-entry\">Wilson, M., 1993, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">Plate<\/a>-moving mechanisms: constraints and controversies: Journal of the Geological Society, v. 150, no. 5, p. 923\u2013926., doi: <a href=\"https:\/\/doi.org\/10.1144\/gsjgs.150.5.0923\">10.1144\/gsjgs.150.5.0923<\/a>.<\/li>\n<li class=\"csl-entry\">Wyllie, P.J., 1970, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1009\">Ultramafic<\/a> rocks and the upper <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a>, <i>in<\/i> Morgan, B.A., editor, Fiftieth anniversary symposia: Mineralogy and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_220\">petrology<\/a> of the Upper <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">Mantle<\/a>; <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">Sulfides<\/a>; Mineralogy and geochemistry of non-marine evaporites: Washington, DC, Mineralogical Society of America, p. 3\u201332.<\/li>\n<li class=\"csl-entry\">Zhou, Z., 2004, The origin and early evolution of birds: discoveries, disputes, and perspectives from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1228\">fossil<\/a> evidence: Naturwissenschaften, v. 91, no. 10, p. 455\u2013471.<\/li>\n<\/ol>\n<\/div>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_4444\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_4444\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1790\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1790\"><div tabindex=\"-1\"><figure id=\"attachment_1683\" aria-describedby=\"caption-attachment-1683\" style=\"width: 3648px\" class=\"wp-caption alignnone\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/DT1-2-scaled.jpg\" target=\"_blank\" rel=\"noopener\"><img class=\"wp-image-1683 size-full\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/09\/DT1-2-scaled-1.jpg\" alt=\"It is a steep rock jutting out of the countryside.\" width=\"3648\" height=\"2736\"><\/a><figcaption id=\"caption-attachment-1683\" class=\"wp-caption-text\">Devils Tower, Wyoming.<\/figcaption><\/figure>\n<h1><strong>1 Understanding Science<\/strong><\/h1>\n<p><b>STUDENT LEARNING OUTCOMES<\/b><\/p>\n<p><b>At the end of this chapter, students should be able to:<\/b><\/p>\n<ul>\n<li>Contrast <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1722\">objective<\/a>\u00a0versus <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1723\">subjective<\/a>\u00a0observations, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1724\">quantitative<\/a>\u00a0versus <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1725\">qualitative<\/a>\u00a0observations<\/li>\n<li>Identify a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1727\">pseudoscience<\/a>\u00a0based on its lack of falsifiability<\/li>\n<li>Contrast the methods used by Aristotle and Galileo to describe the natural environment<\/li>\n<li>Explain the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1728\">scientific method<\/a>\u00a0and apply it to a problem or question<\/li>\n<li>Describe the foundations of modern geology, such as the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1736\">principle of uniformitarianism<\/a><\/li>\n<li>Contrast <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1736\">uniformitarianism<\/a>\u00a0with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1737\">catastrophism<\/a><\/li>\n<li>Explain why studying geology is important<\/li>\n<li>Identify how Earth materials are transformed by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1749\">rock cycle<\/a>\u00a0processes<\/li>\n<li>Describe the steps involved in a reputable scientific study<\/li>\n<li>Explain rhetorical arguments used by science deniers<\/li>\n<\/ul>\n<h2><span style=\"font-weight: 400\">1.1 <\/span><b>What is Science?<\/b><\/h2>\n<figure id=\"attachment_1627\" aria-describedby=\"caption-attachment-1627\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/YS1-1.jpg\" target=\"_blank\" rel=\"noopener\"><img class=\"wp-image-21 size-medium\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/YS1-1-300x225.jpg\" alt=\"The waterfall is in a valley\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-1627\" class=\"wp-caption-text\">This is Grand Canyon of the Yellowstone in Yellowstone National Park. An objective statement about this would be: \"The picture is of a waterfall.\" A subjective statement would be: \"The picture is beautiful.\" or \"The waterfall is there because of erosion.\"<\/figcaption><\/figure>\n<p>Scientists seek to understand the fundamental principles that explain natural patterns and processes. Science is more than just a body of knowledge, science provides a means to evaluate and create new knowledge without bias. Scientists use <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1722\">objective<\/a> evidence over <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1723\">subjective<\/a> evidence, to reach sound and logical conclusions.<\/p>\n<p>An <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1722\">objective<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1729\">observation<\/a> is without personal bias and the same by all individuals. Humans are biased by nature, so they cannot be completely <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1722\">objective<\/a>; the goal is to be as unbiased as possible. A <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1723\">subjective<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1729\">observation<\/a> is based on a person\u2019s feelings and beliefs and is unique to that individual.<\/p>\n<p>Another way scientists avoid bias is by using <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1724\">quantitative<\/a> over <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1725\">qualitative<\/a> measurements whenever possible. A <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1724\">quantitative<\/a> measurement is expressed with a specific numerical value. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1725\">Qualitative<\/a> observations are general or relative descriptions. For example, describing a rock as red or heavy is a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1725\">qualitative<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1729\">observation<\/a>. Determining a rock\u2019s color by measuring wavelengths of reflected light or its density by measuring the proportions of minerals it contains is <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1724\">quantitative<\/a>. Numerical values are more precise than general descriptions, and they can be analyzed using statistical calculations. This is why <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1724\">quantitative<\/a> measurements are much more useful to scientists than <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1725\">qualitative<\/a> observations.<\/p>\n<figure id=\"attachment_2460\" aria-describedby=\"caption-attachment-2460\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/MSH_Alex-2-scaled.jpg\" target=\"_blank\" rel=\"noopener\"><img class=\"wp-image-2460 size-medium\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MSH_Alex-2-scaled-1.jpg\" alt=\"A person is looking into the canyon.\" width=\"300\" height=\"200\"><\/a><figcaption id=\"caption-attachment-2460\" class=\"wp-caption-text\">Canyons like this, carved in the deposit left by the May 18th, 1980 eruption of Mt. St. Helens is sometimes used by purveyors of pseudoscience as evidence for the Earth being very young. In reality, the unconsolidated and unlithified volcanic deposit is carved much more easily than other canyons like the Grand Canyon.<\/figcaption><\/figure>\n<p>Establishing truth in science is difficult because all scientific claims are <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1726\">falsifiable<\/a>, which means any initial <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a> may be tested and proven false. Only after exhaustively eliminating false results, competing ideas, and possible variations does a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a> become regarded as a reliable scientific <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a>. This meticulous scrutiny reveals weaknesses or flaws in a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a> and is the strength that supports all scientific ideas and procedures. In fact, proving current ideas are wrong has been the driving force\u00a0behind many scientific careers.<\/p>\n<p>Falsifiability separates science from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1727\">pseudoscience<\/a>. Scientists are wary of explanations of natural phenomena that discourage or avoid falsifiability. An explanation that cannot be tested or does not meet scientific standards is not considered science, but <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1727\">pseudoscience<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1727\">Pseudoscience<\/a> is a collection of ideas that may appear scientific but does not use the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1728\">scientific method<\/a>. Astrology is an example of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1727\">pseudoscience<\/a>. It is a belief system that attributes the movement of celestial bodies to influencing human behavior. Astrologers rely on celestial observations, but their conclusions are not based on experimental evidence and their statements are not <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1726\">falsifiable<\/a>. This is not to be confused with astronomy which is the scientific study of celestial bodies and the cosmos<span style=\"font-weight: 400\">.<\/span><\/p>\n<figure id=\"attachment_2461\" aria-describedby=\"caption-attachment-2461\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/DSC00761-2-scaled.jpg\"><img class=\"wp-image-2461 size-medium\" title=\"Source: By Matt Affolter\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/DSC00761-2-scaled-1.jpg\" alt=\"Many people are standing around and talking.\" width=\"300\" height=\"200\"><\/a><figcaption id=\"caption-attachment-2461\" class=\"wp-caption-text\">Geologists share information by publishing, attending conferences, and even going on field trips, such as this trip to western Utah by the Utah Geological Association in 2009.<\/figcaption><\/figure>\n<p>Science is also a social process. Scientists share their ideas with peers at conferences, seeking guidance and feedback. Research papers and data submitted for publication are rigorously reviewed by qualified peers, scientists who are experts in the same field. The scientific review process aims to weed out misinformation, invalid research results, and wild speculation. Thus, it is slow, cautious, and conservative. Scientists tend to wait until a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a> is supported by overwhelming amount of evidence from many independent researchers before accepting it as scientific <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a>.<\/p>\n<p>&nbsp;<\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-1\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-1\" class=\"h5p-iframe\" data-content-id=\"1\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"1.1 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3715\" aria-describedby=\"caption-attachment-3715\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/1.1-Did-I-Get-It.png\"><img class=\"wp-image-24 size-thumbnail\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/1.1-Did-I-Get-It-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3715\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 1.1 via this QR Code.<\/figcaption><\/figure>\n<h2><strong>1.2 The Scientific Method<\/strong><\/h2>\n<figure id=\"attachment_2462\" aria-describedby=\"caption-attachment-2462\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/The_Scientific_Method_as_an_Ongoing_Process.svg_-2.png\"><img class=\"wp-image-25 size-medium\" title=\"Source: By ArchonMagnus (Own work) [<a href=&quot;http:\/\/creativecommons.org\/licenses\/by-sa\/4.0&quot;><figcaption id=\"caption-attachment-2462\" class=\"wp-caption-text\">CC BY-SA 4.0<\/a>], <a href=&quot;https:\/\/commons.wikimedia.org\/wiki\/File%3AThe_Scientific_Method_as_an_Ongoing_Process.svg&quot;>via Wikimedia Commons<\/a>\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/The_Scientific_Method_as_an_Ongoing_Process.svg_-2-300x247.png\" alt=\"The diagram is cyclical.\" width=\"300\" height=\"247\"><\/a> Diagram of the cyclical nature of the scientific method.<\/figcaption><\/figure>\n<p><span style=\"text-align: initial;font-size: 1em\">Modern science is based on the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1728\">scientific method<\/a>, a procedure that follows these steps:<\/span><\/p>\n<ul>\n<li>Formulate a question or observe a problem<\/li>\n<li>Apply <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1722\">objective<\/a> experimentation and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1729\">observation<\/a><\/li>\n<li>Analyze collected data and Interpret results<\/li>\n<li>Devise an evidence-based <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a><\/li>\n<li>Submit findings to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1732\">peer review<\/a> and\/or publication<\/li>\n<\/ul>\n<p>This has a long history in human thought but was first fully formed by Ibn al-Haytham over 1,000 years ago. At the forefront of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1728\">scientific method<\/a> are conclusions based on <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1722\">objective<\/a> evidence, not opinion or hearsay<span style=\"font-weight: 400\">. <\/span><\/p>\n<h4><strong>Step One: Observation, Problem, or Research Question<\/strong><\/h4>\n<p>The procedure begins with identifying a problem or research question, such as a geological phenomenon that is not well explained in the scientific community\u2019s collective knowledge. This step usually involves reviewing the scientific literature to understand previous studies that may be related to the question.<\/p>\n<h4><strong>Step Two: Hypothesis<\/strong><\/h4>\n<figure id=\"attachment_2463\" aria-describedby=\"caption-attachment-2463\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Eadweard_Muybridge-Sallie_Gardner_1878-1.jpg\"><img class=\"wp-image-26 size-medium\" title=\"Source: By Eadweard Muybridge, public domain.\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Eadweard_Muybridge-Sallie_Gardner_1878-1-300x187.jpg\" alt=\"There are 12 images of the horse, at least one has the legs off the ground.\" width=\"300\" height=\"187\"><\/a><figcaption id=\"caption-attachment-2463\" class=\"wp-caption-text\">A famous hypothesis: Leland Stanford wanted to know if a horse lifted all 4 legs off the ground during a gallop, since the legs are too fast for the human eye to perceive it. These series of photographs by Eadweard Muybridge proved the horse, in fact, does have all four legs off the ground during the gallop.<\/figcaption><\/figure>\n<p>Once the problem or question is well defined, the scientist proposes a possible answer, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a>, before conducting an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1731\">experiment<\/a> or field work. This <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a> must be specific, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1726\">falsifiable<\/a>, and should be based on other scientific work. Geologists often develop multiple working <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypotheses<\/a> because they usually cannot impose strict experimental controls or have limited opportunities to visit a field location.<\/p>\n<h4><strong>Step Three: Experiment and Hypothesis Revision<\/strong><\/h4>\n<figure id=\"attachment_2464\" aria-describedby=\"caption-attachment-2464\" style=\"width: 199px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/University_of_Queensland_Pitch_drop_experiment-white_bg-1.jpg\"><img class=\"size-medium wp-image-27\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/University_of_Queensland_Pitch_drop_experiment-white_bg-1-199x300.jpg\" alt=\"The setup is like an hourglass, and the black pitch sits in it\" width=\"199\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2464\" class=\"wp-caption-text\">An experiment at the University of Queensland has been going since 1927. A petroleum product called pitch, which is highly viscous, drips out of a funnel about once per decade.<\/figcaption><\/figure>\n<p>The next step is developing an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1731\">experiment<\/a> that either supports or refutes the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a>. Many people mistakenly think experiments are only done in a lab; however, an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1731\">experiment<\/a> can consist of observing natural processes in the field. Regardless of what form an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1731\">experiment<\/a> takes, it always includes the systematic gathering of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1722\">objective<\/a> data. This data is interpreted to determine whether it contradicts or supports the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a>, which may be revised and tested again. When a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a> holds up under experimentation, it is ready to be shared with other experts in the field.<\/p>\n<h4><strong>Step Four: Peer Review, Publication, and Replication<\/strong><\/h4>\n<p>Scientists share the results of their research by publishing articles in scientific journals, such as <em>Science<\/em> and <em>Nature<\/em>. Reputable journals and publishing houses will not publish an experimental study until they have determined its methods are scientifically rigorous and the conclusions are supported by evidence. Before an article is published, it undergoes a rigorous <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1732\">peer review<\/a> by scientific experts who scrutinize the methods, results, and discussion. Once an article is published, other scientists may attempt to replicate the results. This replication is necessary to confirm the reliability of the study\u2019s reported results. A <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a> that seemed compelling in one study might be proven false in studies conducted by other scientists. New technology can be applied to published studies, which can aid in confirming or rejecting once-accepted ideas and\/or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypotheses<\/a>.<\/p>\n<h4><strong>Step Five: Theory Development<\/strong><\/h4>\n<figure id=\"attachment_2500\" aria-describedby=\"caption-attachment-2500\" style=\"width: 195px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Alfred_Wegener_ca.1924-30-2.jpg\"><img class=\"size-full wp-image-28\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alfred_Wegener_ca.1924-30-2.jpg\" alt=\"He is a male in a suit.\" width=\"195\" height=\"240\"><\/a><figcaption id=\"caption-attachment-2500\" class=\"wp-caption-text\">Wegener later in his life, ca. 1924-1930.<\/figcaption><\/figure>\n<p>In casual conversation, the word <em><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a><\/em> implies guesswork or speculation. In the language of science, an explanation or conclusion made in a <em><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a><\/em> carries much more weight because it is supported by experimental verification and widely accepted by the scientific community. After a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a> has been repeatedly tested for falsifiability through documented and independent studies, it eventually becomes accepted as a scientific <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a>.<\/p>\n<p>While a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a> provides a tentative explanation <em>before <\/em>an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1731\">experiment<\/a>, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a> is the best explanation <em>after <\/em>being confirmed by multiple independent experiments. Confirmation of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a> may take years, or even longer. For example, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> drift <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a> first proposed by Alfred Wegener in 1912 was initially dismissed. After decades of additional evidence collection by other scientists using more advanced technology, Wegener\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a> was accepted and revised as the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a> of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">plate tectonics<\/a>.<\/p>\n<p>The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a> of evolution by natural selection is another example. Originating from the work of Charles Darwin in the mid-19th century, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a> of evolution has withstood generations of scientific testing for falsifiability. While it has been updated and revised to accommodate knowledge gained by using modern technologies, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a> of evolution continues to be supported by the latest evidence.<\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-2\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-2\" class=\"h5p-iframe\" data-content-id=\"2\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"1.2 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3714\" aria-describedby=\"caption-attachment-3714\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/1.2-Did-I-Get-It.png\"><img class=\"wp-image-29 size-thumbnail\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/1.2-Did-I-Get-It-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3714\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 1.2 via this QR Code.<\/figcaption><\/figure>\n<h2>1.3 Early Scientific Thought<\/h2>\n<figure id=\"attachment_2466\" aria-describedby=\"caption-attachment-2466\" style=\"width: 229px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Sanzio_01_Plato_Aristotle-1.jpg\"><img class=\"wp-image-30 size-medium\" title=\"Source: &quot;School of Athens&quot; by Raphael Date1509 Medium fresco\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Sanzio_01_Plato_Aristotle-1-229x300.jpg\" alt=\"The image is a likeness\" width=\"229\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2466\" class=\"wp-caption-text\">Fresco by Raphael of Plato (left) and Aristotle (right).<\/figcaption><\/figure>\n<p>Western scientific thought began in the ancient city of Athens, Greece. Athens was governed as a democracy, which encouraged individuals to think independently, at a time when most civilizations were ruled by monarchies or military conquerors. Foremost among the early philosopher\/scientists to use empirical thinking was Aristotle, born in 384 BCE. Empiricism emphasizes the value of evidence gained from experimentation and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1729\">observation<\/a>. Aristotle studied under Plato and tutored Alexander the Great. Alexander would later conquer the Persian Empire, and in the process spread Greek culture as far east as India.<\/p>\n<p>Aristotle applied an empirical method of analysis called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1734\">deductive reasoning<\/a>, which applies known principles of thought to establish new ideas or predict new outcomes. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1734\">Deductive reasoning<\/a> starts with generalized principles and logically extends them to new ideas or specific conclusions. If the initial principle is valid, then it is highly likely the conclusion is also valid. An example of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1734\">deductive reasoning<\/a> is if A=B, and B=C, then A=C. Another example is if all birds have feathers, and a sparrow is a bird, then a sparrow must also have feathers. The problem with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1734\">deductive reasoning<\/a> is if the initial principle is flawed, the conclusion will inherit that flaw. Here is an example of a flawed initial principle leading to the wrong conclusion; if all animals that fly are birds, and bats also fly, then bats must also be birds.<\/p>\n<p>This type of empirical thinking contrasts with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1735\">inductive reasoning<\/a>, which begins from new observations and attempts to discern underlying generalized principles. A conclusion made through <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1735\">inductive reasoning<\/a> comes from analyzing measurable evidence, rather making a logical connection. For example, to determine whether bats are birds a scientist might list various characteristics observed in birds\u2013the presence of feathers, a toothless beak, hollow bones, lack of forelegs, and externally laid eggs. Next, the scientist would check whether bats share the same characteristics, and if they do not, draw the conclusion that bats are not birds.<\/p>\n<p>Both types of reasoning are important in science because they emphasize the two most important aspects of science: <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1729\">observation<\/a> and inference. Scientists test existing principles to see if they accurately infer or predict their observations. They also analyze new observations to determine if the inferred underlying principles still support them.<\/p>\n<figure id=\"attachment_2467\" aria-describedby=\"caption-attachment-2467\" style=\"width: 193px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Avicenna-1.jpg\"><img class=\"wp-image-31 size-medium\" title=\"Source: \u2018Subtilties of Truth\u2019, 1271\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Avicenna-1-193x300.jpg\" alt=\"The drawing is black and white of a man\" width=\"193\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2467\" class=\"wp-caption-text\">1271 drawing of Avicenna (Ibn Sina). He is among the first to link\u00a0mountains to earthquakes and erosion.<\/figcaption><\/figure>\n<p>Greek culture was spread by Alexander and then absorbed by the Romans, who help further extend Greek knowledge into Europe through their vast infrastructure of roads, bridges, and aqueducts. After the fall of the Roman Empire in 476 CE, scientific progress in Europe stalled. Scientific thinkers of medieval time had such high regard for Aristotle\u2019s wisdom and knowledge they faithfully followed his logical approach to understanding nature for centuries. By contrast, science in the Middle East flourished and grew between 800 and 1450 CE, along with culture and the arts.<\/p>\n<p>Near the end of the medieval <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1244\">period<\/a>, empirical experimentation became more common in Europe. During the Renaissance, which lasted from the 14<sup>th<\/sup> through 17<sup>th<\/sup> centuries, artistic and scientific thought experienced a great awakening. European scholars began to criticize the traditional Aristotelian approach and by the end of the Renaissance <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1244\">period<\/a>, empiricism was poised to become a key component of the scientific revolution that would arise in the 17<sup>th<\/sup> century.<\/p>\n<figure id=\"attachment_2468\" aria-describedby=\"caption-attachment-2468\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Bartolomeu_Velho_1568-1.jpg\"><img class=\"wp-image-32 size-medium\" title=\"Source: Cosmographia, Bartolomeu Velho, 1568\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Bartolomeu_Velho_1568-1-300x221.jpg\" alt=\"Earth is at the center.\" width=\"300\" height=\"221\"><\/a><figcaption id=\"caption-attachment-2468\" class=\"wp-caption-text\">Geocentric drawing by Bartolomeu Velho in 1568<\/figcaption><\/figure>\n<p>An early example of how Renaissance scientists began to apply a modern empirical approach is their study of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1253\">solar system<\/a>. In the second century, the Greek astronomer Claudius Ptolemy observed the Sun, Moon, and stars moving across the sky. Applying Aristotelian logic to his astronomical calculations, he deductively reasoned all celestial bodies orbited around the Earth, which was located at the center of the universe. Ptolemy was a highly regarded mathematician, and his mathematical calculations were widely accepted by the scientific community.\u00a0 The view of the cosmos with Earth at its center is called the geocentric model. This geocentric model persisted until the Renaissance <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1244\">period<\/a>, when some revolutionary thinkers challenged the centuries-old <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1730\">hypothesis<\/a>.<\/p>\n<p>By contrast, early Renaissance scholars such as astronomer Nicolaus Copernicus (1473-1543) proposed an alternative explanation for the perceived movement of the Sun, Moon, and stars. Sometime between 1507 and 1515, he provided credible mathematical proof for a radically new model of the cosmos, one in which the Earth and other planets orbited around a centrally located Sun. After the invention of the telescope in 1608, scientists used their enhanced astronomical observations to support this heliocentric, Sun-centered, model.<\/p>\n<figure id=\"attachment_2470\" aria-describedby=\"caption-attachment-2470\" style=\"width: 210px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Galileo_manuscript-1.png\"><img class=\"wp-image-33 size-medium\" title=\"Source: Letter by Galileo, 1609.\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Galileo_manuscript-1-210x300.png\" alt=\"This is a manuscript showing 4 moons of Jupiter.\" width=\"210\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2470\" class=\"wp-caption-text\">Galileo's first mention of moons of Jupiter.<\/figcaption><\/figure>\n<figure id=\"attachment_2469\" aria-describedby=\"caption-attachment-2469\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Copernican_heliocentrism_diagram-2-1.jpg\"><img class=\"wp-image-34 size-medium\" title=\"Source: Nicolaus Copernicus' &quot;De revolutionibus orbium coelestium&quot; 1543\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Copernican_heliocentrism_diagram-2-1-300x275.jpg\" alt=\"The sun is in the center\" width=\"300\" height=\"275\"><\/a><figcaption id=\"caption-attachment-2469\" class=\"wp-caption-text\">Copernicus' heliocentric model<\/figcaption><\/figure>\n<p>Two scientists, Johannes Kepler and Galileo Galilei, are credited with jump-starting the scientific revolution. They accomplished this by building on Copernicus work and challenging long-established ideas about nature and science.<\/p>\n<p>Johannes Kepler (1571-1630) was a German mathematician and astronomer who expanded on the heliocentric model\u2014improving Copernicus\u2019 original calculations and describing planetary motion as elliptical paths. Galileo Galilei (1564 \u2013 1642) was an Italian astronomer who used the newly developed telescope to observe the four largest moons of Jupiter. This was the first piece of direct evidence to contradict the geocentric model, since moons orbiting Jupiter could not also be orbiting Earth.<\/p>\n<p>Galileo strongly supported the heliocentric model and attacked the geocentric model, arguing for a more scientific approach to determine the credibility of an idea. Because of this he found himself at odds with prevailing scientific views and the Catholic Church. In 1633 he was found guilty of heresy and placed under house arrest, where he would remain until his death in 1642.<\/p>\n<p>Galileo is regarded as the first modern scientist because he conducted experiments that would prove or disprove <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1726\">falsifiable<\/a> ideas and based his conclusions on mathematical analysis of quantifiable evidence\u2014a radical departure from the deductive thinking of Greek philosophers such as Aristotle . His methods marked the beginning of a major shift in how scientists studied the natural world, with an increasing number of them relying on evidence and experimentation to form their hypotheses. It was during this revolutionary time that geologists such as James Hutton and Nicolas Steno also made great advances in their scientific fields of study.<\/p>\n<p>&nbsp;<\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-3\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-3\" class=\"h5p-iframe\" data-content-id=\"3\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"1.3 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3713\" aria-describedby=\"caption-attachment-3713\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/1.3-Did-I-Get-It.png\"><img class=\"wp-image-35 size-thumbnail\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/1.3-Did-I-Get-It-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3713\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 1.3 via this QR Code.<\/figcaption><\/figure>\n<h2>1.4 Foundations of Modern Geology<\/h2>\n<figure id=\"attachment_2471\" aria-describedby=\"caption-attachment-2471\" style=\"width: 199px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Stenoshark-1.jpg\"><img class=\"wp-image-36 size-medium\" title=\"Source: Nicolas Steno's Elementorum myologi\u00e6 specimen, seu musculi descriptio geometrica : cui accedunt Canis Carchari\u00e6 dissectum caput, et dissectus piscis ex Canum genere, 1667\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Stenoshark-1-199x300.jpg\" alt=\"It shows a shark mouth and several teeth\" width=\"199\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2471\" class=\"wp-caption-text\">Illustration by Steno showing a comparison between fossil and modern shark teeth.<\/figcaption><\/figure>\n<p>As part of the scientific revolution in Europe, modern geologic principles developed in the 17th and 18th centuries. One major contributor was Nicolaus Steno (1638-1686), a Danish priest who studied anatomy and geology. Steno was the first to propose the Earth\u2019s surface could change over time. He suggested sedimentary rocks, such as sandstone and shale, originally formed in horizontal layers with the oldest on the bottom and progressively younger layers on top.<\/p>\n<p>In the 18th century, Scottish naturalist James Hutton (1726\u20131797) studied rivers and coastlines and compared the sediments they left behind to exposed sedimentary rock strata. He hypothesized the ancient rocks must have been formed by processes like those producing the features in the oceans and streams. Hutton also proposed the Earth was much older than previously thought. Modern geologic processes operate slowly. Hutton realized if these processes formed rocks, then the Earth must be very old, possibly hundreds of millions of years old.<\/p>\n<p>Hutton\u2019s idea is called the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1736\">principle of uniformitarianism<\/a> and states that natural processes operate the same now as in the past, i.e. the laws of nature are uniform across space and time. Geologist often state \u201cthe present is the key to the past,\u201d meaning they can understand ancient rocks by studying modern geologic processes.<\/p>\n<figure id=\"attachment_2472\" aria-describedby=\"caption-attachment-2472\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Cuvier_elephant_jaw-1.jpg\"><img class=\"wp-image-37 size-medium\" title=\"Source: Cuvier, 1799\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Cuvier_elephant_jaw-1-300x230.jpg\" alt=\"It shows two views of each jaw.\" width=\"300\" height=\"230\"><\/a><figcaption id=\"caption-attachment-2472\" class=\"wp-caption-text\">Cuvier's comparison of modern elephant and mammoth jaw bones.<\/figcaption><\/figure>\n<p>Prior to the acceptance of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1736\">uniformitarianism<\/a>, scientists such as German geologist Abraham Gottlob Werner (1750-1817) and French anatomist Georges Cuvier (1769-1832) thought rocks and landforms were formed by great catastrophic events. Cuvier championed this view, known as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1737\">catastrophism<\/a>, and stated, \u201cThe thread of operation is broken; nature has changed course, and none of the agents she employs today would have been sufficient to produce her former works.\u201d He meant processes that operate today did not operate in the past. Known as the father of vertebrate paleontology, Cuvier made significant contributions to the study of ancient life and taught at Paris\u2019s Museum of Natural History. Based on his study of large vertebrate <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1228\">fossils<\/a>, he was the first to suggest species could go <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_755\">extinct<\/a>. However, he thought new species were introduced by special creation after catastrophic floods.<\/p>\n<figure id=\"attachment_2492\" aria-describedby=\"caption-attachment-2492\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"http:\/\/opengeology.org\/textbook\/wp-content\/uploads\/2016\/07\/Lyell_Principles_frontispiece.jpg\"><img class=\"wp-image-38 size-medium\" title=\"Source: Charles Lyell, Elements of Geology (second American edition, 1857)\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Lyell_Principles_frontispiece-1.jpg\" alt=\"It shows a rudimentary cross section\" width=\"300\" height=\"191\"><\/a><figcaption id=\"caption-attachment-2492\" class=\"wp-caption-text\">Inside cover\u00a0of Lyell's Elements of Geology<\/figcaption><\/figure>\n<p>Hutton\u2019s ideas about <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1736\">uniformitarianism<\/a> and Earth\u2019s age were not well received by the scientific community of his time. His ideas were falling into obscurity when Charles Lyell, a British lawyer and geologist (1797-1875), wrote the <em>Principles of Geology <\/em>in the early 1830s and later, <em><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">Elements<\/a>\u00a0of Geology<\/em>. Lyell\u2019s books promoted Hutton\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1736\">principle of uniformitarianism<\/a>, his studies of rocks and the processes that formed them, and the idea that Earth was possibly over 300 million years old. Lyell and his three-volume <em>Principles of Geology<\/em> had a lasting influence on the geologic community and public at large, who eventually accepted <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1736\">uniformitarianism<\/a> and millionfold age for the Earth. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1736\">principle of uniformitarianism<\/a> became so widely accepted, that geologists regarded catastrophic change as heresy. This made it harder for ideas like the sudden demise of the dinosaurs by asteroid impact to gain traction.<\/p>\n<p>A contemporary of Lyell, Charles Darwin (1809-1882) took <em>Principles of Geology<\/em> on his five-year trip on the HMS Beagle. Darwin used <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1736\">uniformitarianism<\/a> and deep geologic time to develop his initial ideas about evolution. Lyell was one of the first to publish a reference to Darwin\u2019s idea of evolution.<\/p>\n<p>The next big advancement, and perhaps the largest in the history of geology, is the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a> of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">plate tectonics<\/a> and continental drift. Dogmatic acceptance of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1736\">uniformitarianism<\/a> inhibited the progress of this idea, mainly because of the permanency placed on the continents and their positions. Ironically, slow and steady movement of plates would fit well into a uniformitarianism model. However, much time passed and a great deal of scientific resistance had to be overcome before the idea took hold. This happened for several reasons. Firstly, the movement was so slow it was overlooked. Secondly, the best evidence was hidden under the ocean. Finally, the accepted theories were anchored by a large amount of inertia. Instead of being bias free, scientists resisted and ridiculed the emerging idea of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">plate tectonics<\/a>. This example of dogmatic thinking is still to this day a tarnish on the geoscience community.<\/p>\n<figure id=\"attachment_2511\" aria-describedby=\"caption-attachment-2511\" style=\"width: 244px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/John_Tuzo_Wilson_in_1992-2.jpg\"><img class=\"size-medium wp-image-39\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/John_Tuzo_Wilson_in_1992-2-244x300.jpg\" alt=\"He is an older man in this 1992 image.\" width=\"244\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2511\" class=\"wp-caption-text\">J. Tuzo Wilson<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">Plate tectonics<\/a> is most commonly attributed to Alfred Wegener, the first scientist to compile a large data set supporting the idea of continents shifting places over time. He was mostly ignored and ridiculed for his ideas, but later workers like Marie Tharp, Bruce Heezen, Harry Hess, Laurence Morley, Frederick Vine, Drummond Matthews, Kiyoo Wadati, Hugo Benioff, Robert Coats, and J. Tuzo Wilson benefited from advances in sub-sea technologies. They discovered, described, and analyzed new features like the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridge<\/a>, alignment of earthquakes, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1709\">magnetic striping<\/a>. Gradually these scientists introduced a paradigm shift that revolutionized geology into the science we know today.<\/p>\n<p>&nbsp;<\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-4\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-4\" class=\"h5p-iframe\" data-content-id=\"4\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"1.4 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3712\" aria-describedby=\"caption-attachment-3712\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/1.4-Did-I-Get-It.png\"><img class=\"wp-image-40 size-thumbnail\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/1.4-Did-I-Get-It-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3712\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 1.4 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-weight: 400\">1.5 The Study of Geology<br \/>\n<\/span><\/h2>\n<figure id=\"attachment_2475\" aria-describedby=\"caption-attachment-2475\" style=\"width: 225px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/DSC00832-1.jpg\"><img class=\"wp-image-41 size-medium\" title=\"By Mason Chuang\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/DSC00832-1-225x300.jpg\" alt=\"The students are on the red rock\" width=\"225\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2475\" class=\"wp-caption-text\">A class looks at rocks in Zion National Park.<\/figcaption><\/figure>\n<p>Geologists apply the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1728\">scientific method<\/a> to learn about Earth\u2019s materials and processes. Geology plays an important role in society; its principles are essential to locating, extracting, and managing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1738\">natural resources<\/a>; evaluating environmental impacts of using or extracting these resources; as well as understanding and mitigating the effects of natural hazards.<\/p>\n<p>Geology often applies information from physics and chemistry to the natural world, like understanding the physical forces in a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_246\">landslide<\/a> or the chemical interaction between water and rocks. The term comes from the Greek word <em>geo<\/em>, meaning Earth, and <em>logos<\/em>, meaning to think or reckon with.<\/p>\n<h3>1.5.1 Why Study Geology?<\/h3>\n<figure id=\"attachment_2476\" aria-describedby=\"caption-attachment-2476\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/16.1_Hoover_Dam_Colorado_River-1.jpg\"><img class=\"size-medium wp-image-42\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/16.1_Hoover_Dam_Colorado_River-1-300x200.jpg\" alt=\"The dam has a large lake behind it\" width=\"300\" height=\"200\"><\/a><figcaption id=\"caption-attachment-2476\" class=\"wp-caption-text\">Hoover Dam provides hydroelectric energy and stores water for southern Nevada.<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\">Geology plays a key role in how we use <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1738\">natural resources<\/a>\u2014any naturally occurring material that can be extracted from the Earth for economic gain. Our developed modern society, like all societies before it, is dependent on geologic resources. Geologists are involved in extracting fossil fuels, such as coal and petroleum; metals such as copper, aluminum, and iron; and water resources in streams and underground reservoirs inside <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_250\">soil<\/a> and rocks. They can help conserve our planet\u2019s finite supply of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">nonrenewable<\/a> resources, like petroleum, which are fixed in quantity and depleted by consumption. Geologists can also help manage <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1740\">renewable<\/a> resources that can be replaced or regenerated, such as solar or wind energy, and timber.<\/span><\/p>\n<figure id=\"attachment_2477\" aria-describedby=\"caption-attachment-2477\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/16.2_Castle_Gate_Power_Plant_Utah_2007-1.jpg\"><img class=\"size-medium wp-image-43\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/16.2_Castle_Gate_Power_Plant_Utah_2007-1-300x188.jpg\" alt=\"The power plant has smoke coming from it\" width=\"300\" height=\"188\"><\/a><figcaption id=\"caption-attachment-2477\" class=\"wp-caption-text\">Coal power plant in Helper, Utah.<\/figcaption><\/figure>\n<p>Resource extraction and usage impacts our environment, which can negatively affect human health. For example, burning fossil fuels\u00a0releases chemicals into the air that are unhealthy for humans, especially children. Mining activities can release toxic heavy metals, such as lead and mercury, into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_250\">soil<\/a> and waterways. Our choices will have an effect on Earth\u2019s environment for the foreseeable future. Understanding the remaining quantity, extractability, and renewability of geologic resources will help us better sustainably manage those resources.<\/p>\n<figure id=\"attachment_2478\" aria-describedby=\"caption-attachment-2478\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Liquefaction_at_Niigata-1.jpg\"><img class=\"size-medium wp-image-44\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Liquefaction_at_Niigata-1-300x178.jpg\" alt=\"Buildings toppled from liquefaction during a 7.5 magnitude earthquake in Japan.\" width=\"300\" height=\"178\"><\/a><figcaption id=\"caption-attachment-2478\" class=\"wp-caption-text\">Buildings toppled from liquefaction during a 7.5 magnitude earthquake in Japan.<\/figcaption><\/figure>\n<p>Geologists also study natural hazards created by geologic processes. Natural hazards are phenomena that are potentially dangerous to human life or property. No place on Earth is completely free of natural hazards, so one of the best ways people can protect themselves is by understanding geology. Geology can teach people about the natural hazards in an area and how to prepare for them. Geologic hazards include <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_246\">landslides<\/a>, earthquakes, tsunamis, floods, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> eruptions, and sea-level rise.<\/p>\n<figure id=\"attachment_2479\" aria-describedby=\"caption-attachment-2479\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Crater_lake_oregon-1.jpg\"><img class=\"wp-image-45 size-medium\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Crater_lake_oregon-1-300x200.jpg\" alt=\"The mountain has a large hole in the center that is filled with the lake.\" width=\"300\" height=\"200\"><\/a><figcaption id=\"caption-attachment-2479\" class=\"wp-caption-text\">Oregon's Crater Lake was formed about 7700 years ago after the eruption of Mount Mazama.<\/figcaption><\/figure>\n<p>Finally, geology is where other scientific disciplines intersect in the concept known as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1748\">Earth System Science<\/a>. In science, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1742\">system<\/a> is a group of interactive objects and processes. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1748\">Earth System Science<\/a> views the entire planet as a combination of systems that interact with each other via complex relationships. This geology textbook provides an introduction to science in general and will often reference other scientific disciplines.<\/p>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1748\">Earth System Science<\/a> includes five basic systems (or spheres), the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1743\">Geosphere<\/a> (the solid body of the Earth), the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1745\">Atmosphere<\/a> (the gas envelope surrounding the Earth), the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1744\">Hydrosphere<\/a> (water in all its forms at and near the surface of the Earth), the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1746\">Cryosphere<\/a> (frozen water part of Earth), and the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1747\">Biosphere<\/a> (life on Earth in all its forms and interactions, including humankind).<\/p>\n<p><span style=\"font-weight: 400\">Rather than viewing geology as an isolated <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1742\">system<\/a>, earth <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1742\">system<\/a> scientists study how geologic processes shape not only the world, but all the spheres it contains. They study how these multidisciplinary spheres relate, interact, and change in response to natural cycles and human-driven forces. They use <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>\u00a0from physics, chemistry, biology, meteorology, environmental science, zoology, hydrology, and many other sciences.<br \/>\n<\/span><\/p>\n<h3><b>1.5.2 Rock Cycle<\/b><\/h3>\n<figure id=\"attachment_2480\" aria-describedby=\"caption-attachment-2480\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Fig-6-1.jpg\"><img class=\"size-medium wp-image-46\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Fig-6-1-300x278.jpg\" alt=\"The rock cycle shows how different rock groups are interconnected. Metamorphic rocks can come from adding heat and\/or pressure to other metamorphic rock or sedimentary or igneous rocks\" width=\"300\" height=\"278\"><\/a><figcaption id=\"caption-attachment-2480\" class=\"wp-caption-text\">Rock cycle showing the five materials (such as igneous rocks and sediment) and the processes by which one changes into another (such as weathering). (Source: Peter Davis)<\/figcaption><\/figure>\n<p>The most fundamental view of Earth materials is the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1749\">rock cycle<\/a>, which describes the major materials that comprise the Earth, the processes that form them, and how they relate to each other. It usually begins with hot molten liquid rock called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">Magma<\/a> forms under the Earth\u2019s surface in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">Lava<\/a> is molten rock that erupts onto the Earth\u2019s surface. When <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a> cools, it solidifies by a process called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1752\">crystallization<\/a> in which minerals grow within the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a>. The rocks resulting rocks are igneous rocks. I<em>gnis<\/em> is Latin for fire.<\/p>\n<figure id=\"attachment_2481\" aria-describedby=\"caption-attachment-2481\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Raindrop_impressions_mcr1-1.jpg\"><img class=\"size-medium wp-image-47\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Raindrop_impressions_mcr1-1-300x200.jpg\" alt=\"This grey rock has round circles left by raindrops\" width=\"300\" height=\"200\"><\/a><figcaption id=\"caption-attachment-2481\" class=\"wp-caption-text\">Mississippian raindrop impressions over wave ripples from Nova Scotia.<\/figcaption><\/figure>\n<p>Igneous rocks, as well as other types of rocks, on Earth\u2019s surface are exposed to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1754\">weathering<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1755\">erosion<\/a>, which produces <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediments<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1754\">Weathering<\/a> is the physical and chemical breakdown of rocks into smaller fragments. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1755\">Erosion<\/a> is the removal of those fragments from their original location. The broken-down and transported fragments or grains are considered <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediments<\/a>, such as gravel, sand, silt, and clay. These <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediments<\/a> may be transported by streams and rivers, ocean currents, glaciers, and wind.<\/p>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">Sediments<\/a> come to rest in a process known as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1757\">deposition<\/a>. As the deposited <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediments<\/a> accumulate\u2014often under water, such as in a shallow marine environment\u2014the older <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediments<\/a> get buried by the new deposits. The deposits are compacted by the weight of the overlying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediments<\/a> and individual grains are cemented together by minerals in groundwater. These processes of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1758\">compaction<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1759\">cementation<\/a> are called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1760\">lithification<\/a>. Lithified <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediments<\/a> are considered a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1761\">sedimentary rock<\/a>, such as sandstone and shale. Other sedimentary rocks are made by direct chemical <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitation<\/a> of minerals rather than eroded <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediments<\/a>, and are known as chemical sedimentary rocks.<\/p>\n<figure id=\"attachment_2482\" aria-describedby=\"caption-attachment-2482\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/06.2-15-Mt-Blaca-Migmatite-1.jpg\"><img class=\"wp-image-48 size-medium\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/06.2-15-Mt-Blaca-Migmatite-1-300x225.jpg\" alt=\"Swirling bands of light and dark minerals.\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-2482\" class=\"wp-caption-text\">Migmatite, a rock which was partially molten. (Source: Peter Davis)<\/figcaption><\/figure>\n<p>Pre-existing rocks may be transformed into a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1762\">metamorphic rock<\/a>; <em>meta- <\/em>means change and <em>-morphos<\/em> means form or shape. When rocks are subjected to extreme increases in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> or pressure, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> crystals are enlarged or altered into entirely new minerals\u00a0with similar chemical make up. High temperatures and pressures occur in rocks buried deep within the Earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a> or that come into contact with hot <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a>. If the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> and pressure conditions melt the rocks to create <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a>, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1749\">rock cycle<\/a> begins anew with the creation of new rocks.<\/p>\n<h3><b>1.5.3 Plate Tectonics and Layers of Earth<\/b><\/h3>\n<figure id=\"attachment_2516\" aria-describedby=\"caption-attachment-2516\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Plates_tect2_en.svg_-2.png\"><img class=\"size-medium wp-image-49\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plates_tect2_en.svg_-2-300x205.png\" alt=\"There are about 10 major plates\" width=\"300\" height=\"205\"><\/a><figcaption id=\"caption-attachment-2516\" class=\"wp-caption-text\">Map of the major plates and their motions along boundaries.<\/figcaption><\/figure>\n<p>The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a> of <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">plate tectonics<\/a><\/strong> is the fundamental unifying principle of geology and the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1749\">rock cycle<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">Plate tectonics<\/a> describes how Earth\u2019s layers move relative to each other, focusing on the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a> or lithospheric <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> of the outer layer. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">Tectonic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a>\u00a0float, collide, slide past each other, and split apart on an underlying mobile layer called the <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1671\">asthenosphere<\/a><\/strong>. Major landforms are created at the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> boundaries, and rocks within the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> move through the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1749\">rock cycle<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">Plate tectonics<\/a> is discussed in more detail in <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/2-plate-tectonics\/\" target=\"_blank\" rel=\"noopener\">Chapter 2<\/a>.<\/p>\n<figure id=\"attachment_2513\" aria-describedby=\"caption-attachment-2513\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/MohoDepth-1.png\"><img class=\"wp-image-50 size-medium\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MohoDepth-1-300x167.png\" alt=\"Places with mountain building have a deeper moho.\" width=\"300\" height=\"167\"><\/a><figcaption id=\"caption-attachment-2513\" class=\"wp-caption-text\">The global map of the depth of the moho.<\/figcaption><\/figure>\n<p>Earth\u2019s three main geological layers can be categorized by chemical composition or the chemical makeup: <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1667\">core<\/a>. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a> is the outermost layer and composed\u00a0of mostly silicon, oxygen, aluminum, iron, and magnesium. There are two types, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental crust<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic crust<\/a>. <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">Continental crust<\/a><\/strong> is about 50 km (30 mi) thick, composed of low-density igneous and sedimentary rocks, <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">Oceanic crust<\/a><\/strong> is approximately 10 km (6 mi) thick and made of high-density igneous <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1013\">basalt<\/a>-type rocks. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">Oceanic crust<\/a> makes up most of the ocean floor, covering about 70% of the planet. Tectonic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a>\u00a0are made of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a> and a portion the upper <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a>, forming a rigid physical layer called the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a>.<\/p>\n<figure id=\"attachment_2512\" aria-describedby=\"caption-attachment-2512\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Earth-cutaway-schematic-english.svg_-1.png\"><img class=\"size-medium wp-image-51\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Earth-cutaway-schematic-english.svg_-1-300x211.png\" alt=\"The crust and lithosphere are on the outside of the Earth and are thin. Below the crust is the mantle and core. Below the lithosphere is the asthenosphere.\" width=\"300\" height=\"211\"><\/a><figcaption id=\"caption-attachment-2512\" class=\"wp-caption-text\">The layers of the Earth. Physical layers include lithosphere and asthenosphere; chemical layers are crust, mantle, and core.<\/figcaption><\/figure>\n<p>The <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a><\/strong>, the largest chemical layer by volume, lies below the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a> and extends down to about 2,900 km (1,800 mi) below the Earth\u2019s surface. The mostly solid <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> is made of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1666\">peridotite<\/a>, a high-density composed of silica, iron, and magnesium. The upper part of mantel is very hot and flexible, which allows the overlying tectonic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plates<\/a> to float and move about on it. Under the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> is the Earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1667\">core<\/a>, which is 3,500 km (2,200 mi) thick and made of iron and nickel. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1667\">core<\/a> consists of two parts, a liquid <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1673\">outer core<\/a><\/strong> and solid <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1674\">inner core<\/a><\/strong>. Rotations within the solid and liquid metallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1667\">core<\/a> generate Earth\u2019s magnetic field (see figure).<\/p>\n<h3><b>1.5.4 Geologic Time and Deep Time<\/b><\/h3>\n<blockquote>\n<figure id=\"attachment_2486\" aria-describedby=\"caption-attachment-2486\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/GeologicClock.png\"><img class=\"size-medium wp-image-52\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/GeologicClock-300x288.png\" alt=\"The circle starts at 4.6 billion years ago, then loops around to zero.\" width=\"300\" height=\"288\"><\/a><figcaption id=\"caption-attachment-2486\" class=\"wp-caption-text\">Geologic time on Earth, represented circularly, to show the individual time divisions and important events. Ga=billion years ago, Ma=million years ago.<\/figcaption><\/figure>\n<p>\u201cThe result, therefore, of our present enquiry is, that we find no vestige of a beginning; no prospect of an end.\u201d (James Hutton, 1788)<\/p><\/blockquote>\n<p>One of the early pioneers of geology, James Hutton, wrote this about the age of the Earth after many years of geological study. Although he wasn\u2019t exactly correct\u2014there is a beginning and will be an end to planet Earth\u2014Hutton was expressing the difficulty humans have in perceiving the vastness of geological time. Hutton did not assign an age to the Earth, although he was the first to suggest the planet was very old.<br \/>\nToday we know Earth is approximately 4.54 \u00b1 0.05 billion years old. This age was first calculated by Caltech professor Clair Patterson in 1956, who measured the half-lives of lead <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1779\">isotopes<\/a>\u00a0to radiometrically date a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1254\">meteorite<\/a> recovered in Arizona. Studying geologic time, also known as deep time, can help us overcome a perspective of Earth that is limited to our short lifetimes. Compared to the geologic scale, the human lifespan is very short, and we struggle to comprehend the depth of geologic time and slowness of geologic processes. For example, the study of earthquakes only goes back about 100 years; however, there is geologic evidence of large earthquakes occurring thousands of years ago. And scientific evidence indicates earthquakes will continue for many centuries into the future.<\/p>\n<figure id=\"attachment_2492\" aria-describedby=\"caption-attachment-2492\" style=\"width: 793px\" class=\"wp-caption aligncenter\"><a href=\"http:\/\/opengeology.org\/textbook\/wp-content\/uploads\/2016\/07\/17.18_Geologic_Time_Scale_with_years-1.jpg\"><img class=\"wp-image-53 size-large\" title=\"Source: Belinda Madsen, Salt Lake Community College\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/17.18_Geologic_Time_Scale_with_years-1-793x1024.jpg\" alt=\"The Geologic Time Scale with an age of each unit shown by a scale\" width=\"793\" height=\"1024\"><\/a><figcaption id=\"caption-attachment-2492\" class=\"wp-caption-text\">Geologic time scale showing time period names and ages. (Source: Belinda Madsen)<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1242\">Eons<\/a>\u00a0are the largest divisions of time, and from oldest to youngest are named <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1255\">Hadean<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1257\">Archean<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1261\">Proterozoic<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1269\">Phanerozoic<\/a>. The three oldest <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1242\">eons<\/a> are sometimes collectively referred to as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1270\">Precambrian<\/a> time.<\/p>\n<p>Life first appeared more than 3,800 million of years ago (Ma). From 3,500 Ma to 542 Ma, or 88% of geologic time, the predominant life forms were single-celled organisms such as bacteria. More complex organisms appeared only more recently, during the current <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1269\">Phanerozoic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1242\">Eon<\/a>, which includes the last 542 million years or 12% of geologic time.<\/p>\n<p>The name <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1269\">Phanerozoic<\/a> comes from <em>phaneros<\/em>, which means visible, and <em>zoic<\/em>, meaning life. This <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1242\">eon<\/a> marks the proliferation of multicellular animals with hard body parts, such as shells, which are preserved in the geological record as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1228\">fossils<\/a>. Land-dwelling animals have existed for 360 million years, or 8% of geologic time. The demise of the dinosaurs and subsequent rise of mammals occurred around 65 Ma, or 1.5% of geologic time. Our human ancestors belonging to the genus <em>Homo<\/em> have existed since approximately 2.2 Ma\u20140.05% of geological time or just 1\/2,000th the total age of Earth.<\/p>\n<p>The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1269\">Phanerozoic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1242\">Eon<\/a> is divided into three <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1243\">eras<\/a>: <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1271\">Paleozoic<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_479\">Mesozoic<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_488\">Cenozoic<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1271\">Paleozoic<\/a> means <em>ancient life<\/em>, and organisms of this era included invertebrate animals, fish, amphibians, and reptiles. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_479\">Mesozoic<\/a> (<em>middle life<\/em>) is popularly known as the Age of Reptiles and is characterized by the abundance of dinosaurs, many of which evolved into birds. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1275\">mass extinction<\/a> of the dinosaurs and other apex predator reptiles marked the end of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_479\">Mesozoic<\/a> and beginning of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_488\">Cenozoic<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_488\">Cenozoic<\/a> means <em>new life<\/em> and is also called the Age of Mammals, during which mammals evolved to become the predominant land-dwelling animals. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1228\">Fossils<\/a>\u00a0of early humans, or hominids, appear in the rock record only during the last few million years of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_488\">Cenozoic<\/a>. The geologic time scale, geologic time, and geologic history are discussed in more detail in\u00a0chapters <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/7-geologic-time\/\">7<\/a> and <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/8-earth-history\/\">8<\/a>.<\/p>\n<h3>1.5.5 \u00a0 The Geologist\u2019s Tools<\/h3>\n<figure id=\"attachment_2488\" aria-describedby=\"caption-attachment-2488\" style=\"width: 222px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Archaeopteryx_lithographica_Berlin_specimen.jpg\"><img class=\"size-medium wp-image-54\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Archaeopteryx_lithographica_Berlin_specimen-222x300.jpg\" alt=\"The fossil has bird and dinosaur features.\" width=\"222\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2488\" class=\"wp-caption-text\">Iconic Archaeopteryx lithographica fossil from Germany.<\/figcaption><\/figure>\n<p>In its simplest form, a geologist\u2019s tool may be a rock hammer used for sampling a fresh surface of a rock. A basic tool set for fieldwork might also include:<\/p>\n<ul>\n<li>Magnifying lens for looking at mineralogical details<\/li>\n<li>Compass for measuring the orientation of geologic features<\/li>\n<li>Map for documenting the local distribution of rocks and minerals<\/li>\n<li>Magnet for identifying magnetic minerals like magnetite<\/li>\n<li>Dilute <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a> of hydrochloric acid to identify <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a>-containing minerals like <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a> or limestone.<\/li>\n<\/ul>\n<p>In the laboratory, geologists use optical microscopes to closely examine rocks and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_250\">soil<\/a> for <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> composition and grain size. Laser and mass spectrometers precisely measure the chemical composition and geological age of minerals. Seismographs\u00a0record and locate earthquake activity, or when used in conjunction with ground penetrating radar, locate objects buried beneath the surface of the earth. Scientists apply computer simulations to turn their collected data into testable, theoretical models. Hydrogeologists drill wells to sample and analyze underground water quality and availability. Geochemists use scanning electron microscopes to analyze minerals at the atomic level, via x-rays. Other geologists use gas chromatography to analyze liquids and gases trapped in glacial ice or rocks.<\/p>\n<p>Technology provides new tools for scientific <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1729\">observation<\/a>, which leads to new evidence that helps scientists revise and even refute old ideas. Because the ultimate technology will never be discovered, the ultimate <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1729\">observation<\/a> will never be made. And this is the beauty of science\u2014it is ever-advancing and always discovering something new.<\/p>\n<p>&nbsp;<\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-5\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-5\" class=\"h5p-iframe\" data-content-id=\"5\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"1.5 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3711\" aria-describedby=\"caption-attachment-3711\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/1.5-Did-I-Get-It.png\"><img class=\"size-thumbnail wp-image-55\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/1.5-Did-I-Get-It-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3711\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 1.5 via this QR Code.<\/figcaption><\/figure>\n<h2><strong>1.6 Science Denial and Evaluating Sources<\/strong><\/h2>\n<p><iframe id='oembed-14' title=\"Science in America - Neil deGrasse Tyson\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/8MqTOEospfo?feature=oembed&rel=0\" frameborder=\"0\" allow=\"accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen><\/iframe><\/p>\n<figure id=\"attachment_3710\" aria-describedby=\"caption-attachment-3710\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Science-in-America-YouTube.png\"><img class=\"size-thumbnail wp-image-56\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Science-in-America-YouTube-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3710\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this YouTube video via this QR Code.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2489\" aria-describedby=\"caption-attachment-2489\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Anti-EvolutionLeague.jpg\"><img class=\"size-medium wp-image-57\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Anti-EvolutionLeague-300x223.jpg\" alt=\"There are several people around a sign\" width=\"300\" height=\"223\"><\/a><figcaption id=\"caption-attachment-2489\" class=\"wp-caption-text\">Anti-evolution league at the infamous Tennessee v. Scopes trial.<\/figcaption><\/figure>\n<p>Introductory science courses usually deal with accepted scientific <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a> and do not include opposing ideas, even though these alternate ideas may be credible. This makes it easier for students to understand the complex material. Advanced students will encounter more controversies as they continue to study their discipline.<\/p>\n<p><span style=\"font-weight: 400\">Some groups of people argue that some established scientific theories are wrong, not based on their scientific merit but rather on the ideology of the group. This section focuses on how to identify evidence based information and differentiate it from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1727\">pseudoscience<\/a>.<br \/>\n<\/span><\/p>\n<h3>1.6.1 Science Denial<\/h3>\n<figure id=\"attachment_2490\" aria-describedby=\"caption-attachment-2490\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/MarchForScience2017-scaled.jpg\"><img class=\"size-medium wp-image-2490\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MarchForScience2017-scaled-1.jpg\" alt=\"There are many people on the steps of the capitol.\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-2490\" class=\"wp-caption-text\">2017 March for Science in Salt Lake City. This and other similar marches were in response to funding cuts and anti-science rhetoric.<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1763\">Science denial<\/a> happens when people argue that established scientific theories are wrong, not based on scientific merit but rather on <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1723\">subjective<\/a> ideology\u2014such as for social, political, or economic reasons. Organizations and people use <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1763\">science denial<\/a> as a rhetorical argument against issues or ideas they oppose. Three examples of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1763\">science denial<\/a> versus science are: 1) teaching evolution in public schools, 2) linking tobacco smoke to cancer, and 3) linking human activity to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_757\">climate<\/a> change. Among these, denial of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_757\">climate<\/a> change is strongly connected with geology. A <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_757\">climate<\/a> denier specifically denies or doubts the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1722\">objective<\/a> conclusions of geologists and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_757\">climate<\/a> scientists.<\/p>\n<figure id=\"attachment_2491\" aria-describedby=\"caption-attachment-2491\" style=\"width: 263px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/1.4_pillars_Science-Denial_NCSE.png\"><img class=\"size-medium wp-image-59\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/1.4_pillars_Science-Denial_NCSE-263x300.png\" alt=\"Shows three pillars labeled &quot;Undermine the Science&quot;, &quot;Claim the Result is Evil&quot;, and &quot;Demand Equal Time&quot;.\" width=\"263\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2491\" class=\"wp-caption-text\">Three false rhetorical arguments of science denial (Source: National Center for Science Education)<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1763\">Science denial<\/a> generally uses three false arguments. The first argument tries to undermine the credibility of the scientific conclusion by claiming the research methods are flawed or the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a> is not universally accepted\u2014the science is unsettled. The notion that scientific ideas are not absolute creates doubt for non-scientists; however, a lack of universal truths should not be confused with scientific uncertainty. Because science is based on falsfiabiity, scientists avoid claiming universal truths and use language that conveys uncertainty. This allows scientific ideas to change and evolve as more evidence is uncovered.<\/p>\n<p>The second argument claims the researchers are not <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1722\">objective<\/a> and motivated by an ideology or economic agenda. This is an <em>ad hominem<\/em> argument in which a person\u2019s character is attacked instead of the merit of their argument. They claim results have been manipulated so researchers can justify asking for more funding. They claim that because the researchers are funded by a federal grant, they are using their results to lobby for expanded government regulation.<\/p>\n<p>The third argument is to demand a balanced view, equal time in media coverage and educational curricula, to engender the false illusion of two equally valid arguments. Science deniers frequently demand equal coverage of their proposals, even when there is little scientific evidence supporting their ideology. For example, science deniers might demand religious explanations be taught as an alternative to the well-established <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1733\">theory<\/a> of evolution <span style=\"font-weight: 400\"> [zotpressInText item=\"{X9U8B54N},{W934C3CR}\" format=\"%num%\" brackets=\"yes\"]<\/span>. Or that all possible causes of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_757\">climate<\/a> change be discussed as equally probable, regardless of the body of evidence. Conclusions derived using the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1728\">scientific method<\/a> should not be confused with those based on ideologies.<\/p>\n<p>Furthermore, conclusions about nature derived from ideologies have no place in science research and education. For example, it would be inappropriate to teach the flat earth model in a modern geology course because this idea has been disproved by the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1728\">scientific method<\/a>. Unfortunately, widespread scientific illiteracy allows these arguments to be used to suppress scientific knowledge and spread misinformation.<\/p>\n<p><span style=\"font-weight: 400\">The formation of new conclusions based on the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1728\">scientific method<\/a> is the only way to change scientific conclusions. We wouldn't teach Flat Earth geology along with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">plate tectonics<\/a> because Flat Earthers don't follow the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1728\">scientific method<\/a>. The fact that scientists avoid universal truths and change their ideas as more evidence is uncovered shouldn't be seen as meaning that the science is unsettled. Because of widespread scientific illiteracy, these arguments are used by those who wish to suppress\u00a0science and misinform the general public.<\/span><\/p>\n<figure id=\"attachment_2492\" aria-describedby=\"caption-attachment-2492\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Cancer_smoking_lung_cancer_correlation_from_NIH.svg_.png\"><img class=\"wp-image-60 size-medium\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Cancer_smoking_lung_cancer_correlation_from_NIH.svg_-300x293.png\" alt=\"The lines are similar when comparing smoking and cancer\" width=\"300\" height=\"293\"><\/a><figcaption id=\"caption-attachment-2492\" class=\"wp-caption-text\">The lag time between cancer after smoking, plus the ethics of running human trials, delayed the government in taking action against tobacco.<\/figcaption><\/figure>\n<p>In a classic case of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1763\">science denial<\/a>, beginning in the 1960s and for the next three decades, the tobacco industry and their scientists used rhetorical arguments to deny a connection between tobacco usage and cancer. Once it became clear scientific studies overwhelmingly found that using tobacco dramatically increased a person's likelihood of getting cancer, their next strategy was to create a sense of doubt about on the science. The tobacco industry suggested the results were not yet fully understood and more study was needed. They used this doubt to lobby for delaying legislative action that would warn consumers of the potential health hazards <span style=\"font-weight: 400\">[zotpressInText item=\"{X9U8B54N},{CBD5438R}\" format=\"%num%\" brackets=\"yes\"]<\/span>. This same tactic is currently being employed by those who deny the significance of human involvement in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_757\">climate<\/a> change.<\/p>\n<h3><strong>1.6.2 Evaluating Sources of Information<\/strong><\/h3>\n<figure id=\"attachment_2493\" aria-describedby=\"caption-attachment-2493\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/Cumulative_induced_seismicity.png\"><img class=\"size-medium wp-image-61\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Cumulative_induced_seismicity-300x228.png\" alt=\"There is a large spike in earthquakes\" width=\"300\" height=\"228\"><\/a><figcaption id=\"caption-attachment-2493\" class=\"wp-caption-text\">This graph shows earthquake data. To call this data induced, due to fracking, would be an interpretation.<\/figcaption><\/figure>\n<p>In the age of the internet, information is plentiful. Geologists, scientists, or anyone exploring scientific inquiry must discern valid sources of information from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1727\">pseudoscience<\/a> and misinformation. This evaluation is especially important in scientific research because scientific knowledge is respected for its reliability. Textbooks such as this one can aid this complex and crucial task. At its roots, quality information comes from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1728\">scientific method<\/a>, beginning with the empirical thinking of Aristotle. The application of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1728\">scientific method<\/a> helps produce unbiased results. A valid inference or interpretation is based on <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1722\">objective<\/a> evidence or data. Credible data and inferences are clearly labeled, separated, and differentiated. Anyone looking over the data can understand how the author\u2019s conclusion was derived or come to an alternative conclusion. Scientific procedures are clearly defined so the investigation can be replicated to confirm the original results or expanded further to produce new results. These measures make a scientific inquiry valid and its use as a source reputable. Of course, substandard work occasionally slips through and retractions are published from time to time. An infamous article linking the MMR vaccine to autism appeared in the highly reputable journal <em>Lancet<\/em> in 1998. Journalists discovered the author had multiple conflicts of interest and fabricated data, and the article was retracted in 2010.<\/p>\n<figure id=\"attachment_2494\" aria-describedby=\"caption-attachment-2494\" style=\"width: 100px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/09\/GSA_logo3R_web100.gif\"><img class=\"wp-image-62 size-full\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/GSA_logo3R_web100.gif\" alt=\"\" width=\"100\" height=\"111\"><\/a><figcaption id=\"caption-attachment-2494\" class=\"wp-caption-text\">Logo for The Geological Society of America, one of the leading geoscience organizations. They also publish GSA Bulletin, a reputable geology journal.<\/figcaption><\/figure>\n<p>In addition to methodology, data, and results, the authors of a study should be investigated. When looking into any research, the author(s) should be investigated. An author\u2019s credibility is based on multiple factors, such as having a degree in a relevant topic or being funded from an unbiased source.<\/p>\n<p>The same rigor should be applied to evaluating the publisher, ensuring the results reported come from an unbiased process. The publisher should be easy to discover. Good publishers will show the latest papers in the journal and make their contact information and identification clear.\u00a0 Reputable journals show their <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1732\">peer review<\/a> style.\u00a0 Some journal are predatory, where they use unexplained and unnecessary fees to submit and access journals. Reputable journals have recognizable editorial boards. Often, a reliable journal will associate with a trade, association, or recognized open source initiative.<\/p>\n<p>One of the hallmarks of scientific research is <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1732\">peer review<\/a>. \u00a0Research should be transparent to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1732\">peer review<\/a>. This allows the scientific community to reproduce experimental results, correct and retract errors, and validate theories. This allows reproduction of experimental results, corrections of errors, and proper justification of the research to experts.<\/p>\n<p>Citation is not only imperative to avoid plagiarism, but also allows readers to investigate an author\u2019s line of thought and conclusions. When reading scientific works, it is important to confirm the citations are from reputable scientific research. Most often, scientific citations are used to reference paraphrasing rather than quotes. The number of times a work is cited is said to measure of the influence an investigation has within the scientific community, although this technique is inherently biased.<\/p>\n<p>&nbsp;<\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-6\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-6\" class=\"h5p-iframe\" data-content-id=\"6\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"1.6 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3709\" aria-describedby=\"caption-attachment-3709\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/1.6-Did-I-Get-It.png\"><img class=\"size-thumbnail wp-image-63\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/1.6-Did-I-Get-It-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3709\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 1.6 via this QR Code.<\/figcaption><\/figure>\n<h2>Summary<\/h2>\n<p>Science is a process, with no beginning and no end. Science is never finished because a full truth can never be known. However, science and the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1728\">scientific method<\/a> are the best way to understand the universe we live in. Scientists draw conclusions based on <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1722\">objective<\/a> evidence; they consolidate these conclusions into unifying models. Geologists likewise understand studying the Earth is an ongoing process, beginning with James Hutton who declared the Earth has \u201c\u2026no vestige of a beginning, no prospect of an end.\u201d Geologists explore the 4.5 billion-year history of Earth, its resources, and its many hazards. From a larger viewpoint, geology can teach people how to develop credible conclusions, as well as identify and stop misinformation.<\/p>\n<p>&nbsp;<\/p>\n<h3>Take this quiz to check your comprehension of this chapter.<\/h3>\n<div id=\"h5p-7\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-7\" class=\"h5p-iframe\" data-content-id=\"7\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Chapter 1 Review\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3708\" aria-describedby=\"caption-attachment-3708\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Ch.1-Review.png\"><img class=\"size-thumbnail wp-image-64\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ch.1-Review-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3708\" class=\"wp-caption-text\">If you using the printed version of this OER, access the review quiz for Chapter 1 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-weight: 400\">References<\/span><\/h2>\n<div class=\"csl-bib-body\">\n<ol>\n<li class=\"csl-entry\">Adams, F.D., 1954, The birth and development of the geological sciences<\/li>\n<li class=\"csl-entry\">Alfe, D., Gillan, M.J., and Price, G.D., 2002, Composition and temperature of the Earth\u2019s core constrained by combining ab initio calculations and seismic data: Earth Planet. Sci. Lett., v. 195, no. 1, p. 91\u201398.<\/li>\n<li class=\"csl-entry\">Alkin, M.C., 2004, Evaluation Roots: Tracing theorists\u2019 views and influences: SAGE.<\/li>\n<li class=\"csl-entry\">Beckwith, C., 2013, How western Europe developed a full scientific method: Berfrois.<\/li>\n<li class=\"csl-entry\">Birch, F., 1952, Elasticity and constitution of the Earth\u2019s interior: J. Geophys. Res., v. 57, no. 2, p. 227\u2013286., doi: <a href=\"https:\/\/doi.org\/10.1029\/JZ057i002p00227\">10.1029\/JZ057i002p00227<\/a>.<\/li>\n<li class=\"csl-entry\">Bocking, S., 2004, Nature\u2019s experts: science, politics, and the environment: Rutgers University Press.<\/li>\n<li class=\"csl-entry\">Chamberlin, T.C., 1890, The method of multiple working hypotheses: Science, v. 15, no. 366, p. 92\u201396.<\/li>\n<li class=\"csl-entry\">Cohen, H.F., 2010, How modern science came into the world: Four civilizations, one 17th-century breakthrough: Amsterdam University Press.<\/li>\n<li class=\"csl-entry\">Darwin, C., 1846, Geological Observations on South America: Being the Third Part of the Geology of the Voyage of the Beagle, Under the Command of Capt. Fitzroy, R.N. During the Years 1832 to 1836: Smith, Elder and Company.<\/li>\n<li class=\"csl-entry\">Drake, S., 1990, Galileo: Pioneer Scientist: University of Toronto Press.<\/li>\n<li class=\"csl-entry\">Engdahl, E.R., Flynn, E.A., and Masse, R.P., 1974, Differential PkiKP travel times and the radius of the core: Geophysical J Royal Astro Soc, v. 40, p. 457\u2013463.<\/li>\n<li class=\"csl-entry\">Everitt, A., 2016, The Rise of Athens: The Story of the World\u2019s Greatest Civilization:<\/li>\n<li class=\"csl-entry\">Goldstein, B.R., 2002, Copernicus and the origin of his heliocentric system: Journal for the History of Astronomy, v. 33, p. 219\u2013235.<\/li>\n<li class=\"csl-entry\">Goldsworthy, A.K., 2011, The complete Roman army: Thames &amp; Hudson.<\/li>\n<li class=\"csl-entry\">Hans Wedepohl, K., 1995, The composition of the continental crust: Geochim. Cosmochim. 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GSA Today, v. 18, no. 2, p. 4.<\/li>\n<\/ol>\n<\/div>\n<p>&nbsp;<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1789\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1789\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1666\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1666\"><div tabindex=\"-1\"><p>Term for the extensional tectonic province that extends from California's Sierra Nevada Mountains in the west, to Utah's Wasatch Mountains to the east, to southern Oregon and Idaho to the north, to northern Mexico to the south. Known as a wide rift, as each graben 'basin,' bounded by horst 'ranges.' Each set of horsts with a graben has some individual extension, adding up to the overall rifting.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1010\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1010\"><div tabindex=\"-1\"><p>Components of magma which are dissolved until it reaches the surface, where they expand. Examples include water and carbon dioxide. Volatiles also cause flux melting in the mantle, causing volcanism.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1012\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1012\"><div tabindex=\"-1\"><p>The process in which volatiles enter the mantle wedge, and the volatiles lower the melting temperature, causing volcanism.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1015\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1015\"><div tabindex=\"-1\"><p>Faulting that is not deep into the crust, and typically only involves sedimentary cover, not basement rocks.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1013\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1013\"><div tabindex=\"-1\"><p>A chain of volcanic activity, typically in a curved pattern, rising from a subduction zone. The arc is on the overriding plate, typically a few hundred kilometers from the trench, but parallel to the trench.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1016\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1016\"><div tabindex=\"-1\"><p>Faulting that is deep into the crust, and typically involves crystalline basement rocks.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1257\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1257\"><div tabindex=\"-1\"><p>Limestone made of primarily fine-grained calcite mud. Microscopic fossils are commonly present.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1653\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1653\"><div tabindex=\"-1\"><p>Erosional rock face caused by sand abrasion.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1659\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1659\"><div tabindex=\"-1\"><p>Planar flow of water over land surfaces.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1708\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1708\"><div tabindex=\"-1\"><p>The measure of the amount of circular or elliptical nature of the Earth's orbit.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1963\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1963\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1756\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1756\"><div tabindex=\"-1\"><p>Carbonate rock that reacts with hot magmatic fluids, creating concentrated ore deposits, which include copper, iron, zinc, and gold.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1778\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1778\"><div tabindex=\"-1\"><p>[glossary]<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1755\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1755\"><div tabindex=\"-1\"><p>Oxidation that occurs in sulfide deposits which can concentrate valuable elements like copper.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_2158\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_2158\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1023\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1023\"><div tabindex=\"-1\"><p>Place where oceanic-oceanic subduction causes volcanoes to form on an overriding oceanic plate, making a chain of active volcanoes.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1021\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1021\"><div tabindex=\"-1\"><p>Place with a chain of mountain volcanism on a continent, from oceanic-continental subduction.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1022\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1022\"><div tabindex=\"-1\"><p>Where a dense ocean plate subducts beneath a less dense oceanic&nbsp;plate, causing an island arc to form.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1935\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1935\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_232\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_232\"><div tabindex=\"-1\"><p>QR Code generated with QRCode Monkey. All generated QR Codes are 100% free and can be used for whatever you want. This includes all commercial purposes.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_2419\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_2419\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1018\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1018\"><div tabindex=\"-1\"><p>Any depression formed between the arc and the trench, commonly between the arc and the accretionary wedge.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_976\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_976\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1733\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1733\"><div tabindex=\"-1\"><p>Large surface mine with opening carved into the ground.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1019\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1019\"><div tabindex=\"-1\"><p>Depression formed behind an arc, where extension has caused a basin, typically with seafloor spreading.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1017\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1017\"><div tabindex=\"-1\"><p>Area in front of the arc, between the arc and the trench. Often marked by an accretionary wedge or a forearc basin.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1020\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1020\"><div tabindex=\"-1\"><p>Where an ocean plate subducts beneath a continental plate, causing a volcanic arc to form.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_2038\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_2038\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1680\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1680\"><div tabindex=\"-1\"><p>Smooth surface carved in harder rocks by glacial action.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_219\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_219\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1767\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1767\"><div tabindex=\"-1\"><p>Sedimentary rocks made of mineral grains weathered as mechanical detritus of previous rocks, e.g. sand, gravel, etc.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1730\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1730\"><div tabindex=\"-1\"><p>Potentially extractible and valuable material, but unproven.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1244\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1244\"><div tabindex=\"-1\"><p>A rock made of primarily silt.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_220\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_220\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_2044\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_2044\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_222\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_222\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1667\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1667\"><div tabindex=\"-1\"><p>The process that turns non-desert land into desert.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_223\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_223\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1686\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1686\"><div tabindex=\"-1\"><p>An eroded&nbsp;ar\u00eate that forms a triangular shape.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1716\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1716\"><div tabindex=\"-1\"><p>A system which adds into itself.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1655\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1655\"><div tabindex=\"-1\"><p>A depression in dune sediment formed because of a lack of anchoring vegetation.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1671\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1671\"><div tabindex=\"-1\"><p>Thick glaciers that cover continents during ice ages.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1668\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1668\"><div tabindex=\"-1\"><p>A body of ice that moves downhill under its own mass.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1683\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1683\"><div tabindex=\"-1\"><p>Steep spire carved by several glaciers.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1781\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1781\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1787\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1787\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1717\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1717\"><div tabindex=\"-1\"><p>Soil and rock which is below freezing for long periods of time.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_2024\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_2024\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1992\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1992\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_2011\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_2011\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_226\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_226\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1259\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1259\"><div tabindex=\"-1\"><p>A limestone made of&nbsp;coccolithophore shells, a type of single-celled algae.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_225\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_225\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1665\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1665\"><div tabindex=\"-1\"><p>Dunes that form from many different wind directions.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_229\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_229\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1702\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1702\"><div tabindex=\"-1\"><p>Lake that forms next to a glacier because of crustal loading.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_230\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_230\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1677\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1677\"><div tabindex=\"-1\"><p>The line between the zone of accumulation and the&nbsp;zone of ablation.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1670\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1670\"><div tabindex=\"-1\"><p>An alpine glacier that fills a mountain valley.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1999\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1999\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_2000\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_2000\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_231\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_231\"><div tabindex=\"-1\"><p>QR Code generated with QRCode Monkey. All generated QR Codes are 100% free and can be used for whatever you want. This includes all commercial purposes.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_973\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_973\"><div tabindex=\"-1\"><figure id=\"attachment_4617\" aria-describedby=\"caption-attachment-4617\" style=\"width: 768px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Latrobe_gold_nugget_Natural_History_Museum.jpg\"><img class=\"wp-image-929 size-full\" title=\"&quot;I,\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/02\/Latrobe_gold_nugget_Natural_History_Museum.jpg\" alt=\"The nugget has cube shapes.\" width=\"768\" height=\"1024\"><\/a><figcaption id=\"caption-attachment-4617\" class=\"wp-caption-text\">The Latrobe Gold Nugget, as seen on display in the London Natural History Museum, is 717 grams and displays the rare cubic form of native gold. Most gold, even larger nuggets, grow in confined spaces where the euhedral nature of the mineral is not seen.<\/figcaption><\/figure>\n<h1>16 Energy and Mineral Resources<\/h1>\n<p><b>KEY CONCEPTS<\/b><\/p>\n<ul>\n<li>Describe how a\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1740\">renewable<\/a>\u00a0resource is different from a\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">nonrenewable<\/a>\u00a0resource.<\/li>\n<li>Compare the pros and cons of extracting and using fossil fuels and conventional and unconventional petroleum sources.<\/li>\n<li>Describe how metallic\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are formed\u00a0and extracted.<\/li>\n<li>Understand how society uses\u00a0nonmetallic\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>\u00a0resources.<\/li>\n<\/ul>\n<figure id=\"attachment_4618\" aria-describedby=\"caption-attachment-4618\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/16.0_Stone-Tool.jpg\"><img class=\"wp-image-930 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/16.0_Stone-Tool-300x225.jpg\" alt=\"The rock has a smooth side and a sharp side.\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-4618\" class=\"wp-caption-text\">A Mode 1 Oldowan tool used for chopping<\/figcaption><\/figure>\n<p>This text has previously discussed geology\u2019s pioneers, such as scientists James Hutton and Charles Lyell, but the first real \u201cgeologists\u201d were the hominids who picked up stones and began the stone age. Maybe stones were first used as curiosity pieces, maybe as weapons, but ultimately, they were used as tools. This was the Paleolithic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1244\">Period<\/a>, the beginning of geologic study, and it dates back 2.6 million years to east Africa.<\/p>\n<p>In modern times, geologic knowledge is important for locating economically valuable materials for society\u2019s use. In fact, all things we use come from only three sources: they are farmed, hunted or fished, or mined. At the turn of the twentieth century, speculation was rampant that food supplies would not keep pace with world demand, suggesting the need to develop artificial fertilizers. Sources of fertilizer ingredients are: nitrogen is processed from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1745\">atmosphere<\/a>, using the Haber process for the manufacture of ammonia from atmospheric nitrogen and hydrogen; potassium comes from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1744\">hydrosphere<\/a>, such as lakes or ocean evaporation; and phosphorus is mined from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a>, such as minerals like apatite from phosphorite rock, which is found in Florida, North Carolina, Idaho, Utah, and around the world. \u00a0Thus, without mining and processing of natural materials, modern civilization would not exist. Indeed, geologists are essential in this process.<\/p>\n<h2><strong>16.1 Mining<\/strong><\/h2>\n<figure id=\"attachment_4619\" aria-describedby=\"caption-attachment-4619\" style=\"width: 1024px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Simplified_world_mining_map_1.png\"><img class=\"wp-image-931 size-large\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Simplified_world_mining_map_1-1024x383.png\" alt=\"The map shows many different materials that are mined across the world.\" width=\"1024\" height=\"383\"><\/a><figcaption id=\"caption-attachment-4619\" class=\"wp-caption-text\">Map of world mining areas.<\/figcaption><\/figure>\n<p><strong>Mining<\/strong>\u00a0is defined as extracting valuable materials from the Earth for society\u2019s use. Usually, these include solid materials such as gold, iron,\u00a0coal, diamond, sand, and gravel, but materials can also include fluid resources such as\u00a0oil\u00a0and\u00a0natural gas. Modern\u00a0mining\u00a0has a long relationship with modern society. The oldest mine dates back 40,000 years to the Lion Cavern in Swaziland where there is evidence of\u00a0concentrated\u00a0digging\u00a0 into the Earth for hematite, an important iron ore used as red dye. Resources extracted by\u00a0mining\u00a0are generally considered to be\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">nonrenewable<\/a>.<\/p>\n<h3><b>16.1.1. Renewable vs. nonrenewable resources<\/b><\/h3>\n<p>Resources generally come in two major categories:\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1740\">renewable<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">nonrenewable<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1740\">Renewable<\/a> resources can be reused over and over or their availability replicated over a short human life span; <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">nonrenewable<\/a> resources cannot.<\/p>\n<figure id=\"attachment_4621\" aria-describedby=\"caption-attachment-4621\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/16.1_Hoover_Dam_Colorado_River.jpg\"><img class=\"wp-image-932 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/16.1_Hoover_Dam_Colorado_River-300x200.jpg\" alt=\"The dam has a large lake behind it\" width=\"300\" height=\"200\"><\/a><figcaption id=\"caption-attachment-4621\" class=\"wp-caption-text\">Hoover Dam provides hydroelectric energy and stores water for southern Nevada.<\/figcaption><\/figure>\n<p><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1740\">Renewable<\/a><\/strong><strong>\u00a0resources<\/strong> are materials present in our environment that can be exploited and replenished. Some common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1740\">renewable<\/a> energy sources are linked with green energy sources because they are associated with relatively small or easily remediated environmental impact. For example, solar energy comes from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1250\">fusion<\/a> within the Sun, which radiates electromagnetic energy. This energy reaches the Earth constantly and consistently and should continue to do so for about five billion more years. Wind energy, also related to solar energy, is maybe the oldest <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1740\">renewable<\/a> energy and is used to sail ships and power windmills. Both solar and wind-generated energy are variable on Earth\u2019s surface. These limitations are offset because we can use energy storing devices, such as batteries or electricity exchanges between producing sites. The Earth\u2019s heat, known as geothermal energy, can be viable anywhere that geologists drill deeply enough. In practice, geothermal energy is more useful where heat flow is great, such as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> zones or regions with a thinner <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a>. Hydroelectric dams provide energy by allowing water to fall through the dam under gravity, which activates turbines that produce the energy. Ocean tides are also a reliable energy source. All of these <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1740\">renewable<\/a> resources provide energy that powers society. Other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1740\">renewable<\/a> resources are plant and animal matter, which are used for food, clothing, and other necessities, but are being researched as possible energy sources.<\/p>\n<figure id=\"attachment_4622\" aria-describedby=\"caption-attachment-4622\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Rough_diamond.jpg\"><img class=\"wp-image-933 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Rough_diamond-300x226.jpg\" alt=\"The diamond is clear and pyramidal.\" width=\"300\" height=\"226\"><\/a><figcaption id=\"caption-attachment-4622\" class=\"wp-caption-text\">Natural, octahedral shape of diamond.<\/figcaption><\/figure>\n<p><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">Nonrenewable<\/a><\/strong><strong>\u00a0resources<\/strong> cannot be replenished at a sustainable rate. They are finite within human time frames. Many <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">nonrenewable<\/a> resources come from planetary, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a>, or long-term biologic processes and include materials such as gold, lead, copper, diamonds, marble, sand, natural gas, oil, and coal. Most <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">nonrenewable<\/a> resources include specific concentrated <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> listed on the periodic table; some are compounds of those <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>. For example, if society needs iron (Fe) sources, then an exploration geologist will search for iron-rich deposits that can be economically extracted. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">Nonrenewable<\/a> resources may be abandoned when other materials become cheaper or serve a better purpose. For example, coal is abundantly available in England and other nations, but because oil and natural gas are available at a lower cost and lower environmental impact, coal use has decreased. Economic competition among <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">nonrenewable<\/a> resources is shifting use away from coal in many developed countries.<\/p>\n<h3><b>16.1.2. Ore<\/b><\/h3>\n<figure id=\"attachment_4623\" aria-describedby=\"caption-attachment-4623\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/MichiganBIF.jpg\"><img class=\"wp-image-934 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MichiganBIF-300x206.jpg\" alt=\"The rock shows red and brown layering.\" width=\"300\" height=\"206\"><\/a><figcaption id=\"caption-attachment-4623\" class=\"wp-caption-text\">Banded-iron formations are an important ore of iron (Fe).<\/figcaption><\/figure>\n<p>Earth\u2019s materials include the\u00a0periodic table <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>. However, it is rare that\u00a0these <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> are concentrated\u00a0to the point where it is profitable to extract and process the material into usable products. Any place where a valuable material is\u00a0concentrated\u00a0is a geologic and geochemical\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_765\">anomaly<\/a>. A body of material from which one or more valuable substances can be\u00a0mined\u00a0at a profit, is called an\u00a0<strong>ore<\/strong>\u00a0deposit. Typically, the term\u00a0ore\u00a0is used for only metal-bearing\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, but it can be applied to valuable <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">nonrenewable<\/a>\u00a0resource concentrations such as fossil fuels, building stones, and other nonmetal deposits, even\u00a0groundwater. If a metal-bearing resource is not profitable to mine, it is referred to as a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> deposit. The term <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1738\">natural resource<\/a><\/strong> is more common than\u00a0the term ore\u00a0for non-metal-bearing materials.<\/p>\n<figure id=\"attachment_4624\" aria-describedby=\"caption-attachment-4624\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/16-Reserve-vs-Resource.jpg\"><img class=\"wp-image-935 size-medium\" style=\"font-weight: bold;background-color: transparent;text-align: inherit\" title=\"Source: Chris Johnson\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/16-Reserve-vs-Resource-300x233.jpg\" alt=\"Diagram shows the small box of &quot;reserves&quot; within a larger box of &quot;resources&quot;. There is also an &quot;inferred resources&quot; box that is slightly larger than &quot;proven reserves&quot; box and an &quot;undiscovered resources&quot; box slightly larger than the resources box.\" width=\"300\" height=\"233\"><\/a><figcaption id=\"caption-attachment-4624\" class=\"wp-caption-text\">Diagram illustrating the relative abundance of proven reserves, inferred reserves, resources, and undiscovered resources. (Source: Chris Johnson)<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\">It is implicit that the technology to mine is available, economic conditions are suitable, and political, social and environmental considerations are satisfied in order to classify a\u00a0 <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1738\">natural resource<\/a> deposit as ore. \u00a0Depending on the substance, it can be concentrated in a narrow vein or distributed over a large area as a low-concentration ore. Some materials are mined directly from bodies of water (e.g. sylvite for potassium; water through desalination) and the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1745\">atmosphere<\/a> (e.g. nitrogen for fertilizers). \u00a0These differences lead to various methods of mining, and differences in terminology depending on the certainty. <strong>Ore m<\/strong><\/span><b>ineral resource<\/b><span style=\"font-weight: 400\"> is used for an indication of ore that is potentially extractable, and the term <strong>ore\u00a0<\/strong><\/span><b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> reserve<\/b><span style=\"font-weight: 400\"> is used for a well defined (proven), profitable amount of extractable ore.<\/span><\/p>\n<figure id=\"attachment_4625\" aria-describedby=\"caption-attachment-4625\" style=\"width: 1024px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/McKelveyDiagram.jpg\"><img class=\"wp-image-936 size-large\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/McKelveyDiagram-1024x596.jpg\" alt=\"The chart shows reserves vs. resources\" width=\"1024\" height=\"596\"><\/a><figcaption id=\"caption-attachment-4625\" class=\"wp-caption-text\">McKelvey diagram showing different definitions for different degrees of concentration and understanding of mineral deposits.<\/figcaption><\/figure>\n<h3><b>16.1.3. Mining Techniques<\/b><\/h3>\n<p>The mining style is determined by technology, social license, and economics. It is in the best interest of the company extracting the resources to do so in a cost-effective way. Fluid resources, such as\u00a0oil\u00a0and gas, are extracted by drilling wells and pumping. Over the years, drilling has evolved into a complex discipline in which directional drilling can produce multiple bifurcations and curves originating from a single drill collar at the surface. Using geophysical tools like\u00a0seismic\u00a0imaging, geologists can pinpoint resources and extract efficiently.<\/p>\n<p>Solid resources are extracted by two\u00a0principal methods of which there are many variants.\u00a0<strong>Surface mining<\/strong>\u00a0is used to remove material from the outermost part\u00a0of the Earth.\u00a0<strong>Open pit<\/strong>\u00a0<strong>mining<\/strong>\u00a0is used to target shallow, broadly disseminated resources.<\/p>\n<figure id=\"attachment_4626\" aria-describedby=\"caption-attachment-4626\" style=\"width: 352px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Bingham_Canyon_mine_2016.jpg\"><img class=\"wp-image-4626\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Bingham_Canyon_mine_2016-1.jpg\" alt=\"The image is a large hole in a mountainside.\" width=\"352\" height=\"212\"><\/a><figcaption id=\"caption-attachment-4626\" class=\"wp-caption-text\">Bingham Canyon Mine, Utah. This open pit mine is the largest man-made removal of rock in the world.<\/figcaption><\/figure>\n<p>Open pit mining requires careful study of the ore body through surface mapping and drilling exploratory cores. The pit is progressively deepened through additional mining cuts to extract the ore. Typically, the pit\u2019s walls are as steep as can be safely managed. Once the pit is deepened, widening the top is very expensive. A steep wall is thus an engineering balance between efficient and profitable mining (from the company's point of view) and mass wasting (angle of repose from a safety p0int of view) so that there is less waste to remove. The waste is called non-valuable rock or overburden and moving it is costly. Occasionally, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_246\">landslides<\/a> do occur, such as the very large <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_246\">landslide<\/a> in the Kennecott Bingham Canyon mine, Utah, in 2013. These events are costly and dangerous. The job of engineering geologists is to carefully monitor the mine; when company management heeds their warnings, there is ample time and action to avoid or prepare for any slide.<\/p>\n<figure id=\"attachment_4627\" aria-describedby=\"caption-attachment-4627\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Coal_mine_Wyoming.jpg\"><img class=\"size-medium wp-image-938\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Coal_mine_Wyoming-300x200.jpg\" alt=\"A large machine is removing coal.\" width=\"300\" height=\"200\"><\/a><figcaption id=\"caption-attachment-4627\" class=\"wp-caption-text\">A surface coal mine in Wyoming.<\/figcaption><\/figure>\n<p><strong>Strip mining<\/strong>\u00a0and\u00a0<strong>mountaintop mining<\/strong>\u00a0are\u00a0surface mining\u00a0techniques that are used to mine resources that cover large areas, especially layered resources, such as coal. In this method, an entire mountaintop or rock layer is removed to access the\u00a0ore\u00a0below. Surface mining\u2019s\u00a0environmental impacts are usually much greater due to the large surface footprint that\u2019s disturbed.<\/p>\n<figure id=\"attachment_4628\" aria-describedby=\"caption-attachment-4628\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/UndergroundOilShaleEstonia.jpg\"><img class=\"size-medium wp-image-939\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/UndergroundOilShaleEstonia-300x193.jpg\" alt=\"A large truck is loading material underground.\" width=\"300\" height=\"193\"><\/a><figcaption id=\"caption-attachment-4628\" class=\"wp-caption-text\">Underground mining in Estonia of Oil Shale.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p><strong>Underground mining<\/strong>\u00a0is a method often used to mine higher-grade, more localized, or very\u00a0concentrated\u00a0resources. For one example, geologists mine some\u00a0underground ore\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>\u00a0by introducing chemical agents, which dissolve\u00a0the target\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>.\u00a0Then, they bring the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a> to the surface where\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitation<\/a> extracts the material. But more often, a\u00a0mining\u00a0shaft tunnel or a large network of these shafts and tunnels is dug to access the material. The decision to mine underground or from Earth\u2019s surface is dictated by\u00a0the ore\u00a0deposit\u2019s concentration, depth, geometry, land-use policies, economics, surrounding rock strength, and physical access to the\u00a0ore. For example, to use surface mining techniques for deeper deposits might require removing too much material, or the necessary method may be too dangerous or impractical, or removing the entire overburden may be too expensive, or the\u00a0mining\u00a0footprint would be too large. These factors may prevent geologists from surface mining\u00a0materials and cause a project to be\u00a0mined\u00a0underground. The mining method\u00a0and its feasibility depends on the commodity\u2019s price and the cost of the technology needed to remove it and deliver it to market.\u00a0Thus,\u00a0mines\u00a0and the towns that support them come and go as the commodity price varies.\u00a0And, conversely, technological advances and market demands may reopen\u00a0mines\u00a0and revive ghost towns.<\/p>\n<h3><b>16.1.4. Concentrating and Refining<\/b><\/h3>\n<figure id=\"attachment_4629\" aria-describedby=\"caption-attachment-4629\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/16.1_phosphate_smelting_furnace.jpg\"><img class=\"wp-image-940 size-medium\" title=\"&quot;Alfred\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/16.1_phosphate_smelting_furnace-300x233.jpg\" alt=\"A man is operating a large machine that looks like a blast furnace.\" width=\"300\" height=\"233\"><\/a><figcaption id=\"caption-attachment-4629\" class=\"wp-caption-text\">A phosphate smelting operation in Alabama, 1942.<\/figcaption><\/figure>\n<p>All\u00a0ore\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>\u00a0occur mixed with less desirable components called\u00a0<strong>gangue<\/strong>. The process of physically separating\u00a0gangue\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>\u00a0from\u00a0ore bearing\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>\u00a0is called\u00a0<strong>concentrating<\/strong>. Separating a desired\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a>\u00a0from a host\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>\u00a0by chemical means, including heating, is called\u00a0<strong>smelting<\/strong>. \u00a0Finally, taking a metal such as copper and removing other trace metals such as gold or silver is done through the <strong>refining<\/strong> process. Typically, <strong>refining<\/strong> is done one of three ways: 1. Materials can either be mechanically separated and processed based on the ore\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>\u2019s unique physical properties, such as recovering placer\u00a0gold based on its high density. 2. Materials can be heated to chemically separate desired components, such as refining\u00a0crude\u00a0oil\u00a0into\u00a0gasoline. 3. Materials can be smelted, in which controlled chemical reactions unbind metals from the\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>\u00a0they are contained in, such as when copper is taken out of chalcopyrite (CuFeS<sub>2<\/sub>).\u00a0Mining,\u00a0concentrating,\u00a0smelting,\u00a0and\u00a0refining\u00a0processes require enormous energy. Continual advances in metallurgy- and\u00a0mining-practice strive to develop ever more energy efficient and environmentally benign processes and practices.<\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-109\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-109\" class=\"h5p-iframe\" data-content-id=\"109\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"16.3 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_4901\" aria-describedby=\"caption-attachment-4901\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/03\/16.1-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-941\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/16.1-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4901\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 16.1 via this QR Code.<\/figcaption><\/figure>\n<h2><strong>16.2. Fossil Fuels<\/strong><\/h2>\n<figure id=\"attachment_4630\" aria-describedby=\"caption-attachment-4630\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/16.2_Castle_Gate_Power_Plant_Utah_2007.jpg\"><img class=\"wp-image-942 size-medium\" title=\"&quot;<a\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/16.2_Castle_Gate_Power_Plant_Utah_2007-300x188.jpg\" alt=\"The power plant has smoke coming from it\" width=\"300\" height=\"188\"><\/a><figcaption id=\"caption-attachment-4630\" class=\"wp-caption-text\">Coal power plant in Helper, Utah.<\/figcaption><\/figure>\n<p><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1228\">Fossils<\/a><\/strong><strong>\u00a0fuels<\/strong> are extractable sources of stored energy that were created by ancient ecosystems. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1738\">natural resources<\/a> that typically fall under this category are coal, oil, petroleum, and natural gas. These resources were originally formed via photosynthesis by living organisms such as plants, phytoplankton, algae, and cyanobacteria. This energy is actually <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1228\">fossil<\/a> solar energy, since the sun\u2019s ancient energy was converted by ancient organisms into tissues that preserved the chemical energy within the fossil fuel. Of course, as the energy is used, just like photosynthetic respiration that occurs today, carbon enters the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1745\">atmosphere<\/a> as CO<sub>2<\/sub>, causing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_757\">climate<\/a> consequences (see <a href=\"https:\/\/opengeology.org\/textbook\/15-global-climate-change\/\">Chapter 15<\/a>).\u00a0Today humanity uses fossil fuels\u00a0for most of the world\u2019s energy.<\/p>\n<figure id=\"attachment_4631\" aria-describedby=\"caption-attachment-4631\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Coral_Outcrop_Flynn_Reef.jpg\"><img class=\"wp-image-4631 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Coral_Outcrop_Flynn_Reef-2.jpg\" alt=\"The reef has many intricacies.\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-4631\" class=\"wp-caption-text\">Modern coral reefs and other highly-productive shallow marine environments are thought to be the sources of most petroleum resources.<\/figcaption><\/figure>\n<p>Converting solar energy by living organisms into hydrocarbon fossil fuels is a complex process. As organisms die, they decompose slowly, usually due to being buried rapidly, and the chemical energy stored within the organisms\u2019 tissues is buried within surrounding geologic materials. All fossil\u00a0fuels contain carbon that was produced in an ancient environment. In environments rich with organic matter such as swamps, coral reefs, and planktonic blooms, there is a higher potential for fossil fuels to accumulate. Indeed, there is some evidence that over geologic time, organic hydrocarbon fossil fuel material was highly produced globally. Lack of oxygen and moderate temperatures in the environment seem to help preserve these organic substances. Also, the heat and pressure applied to organic material after it is buried contribute to transforming it into higher quality materials, such as brown coal to anthracite and oil to gas. Heat and pressure can also cause mobile materials to migrate to conditions suitable for extraction.<\/p>\n<h3><b>16.2.1. Fossil Fuels<\/b><\/h3>\n<h4><span style=\"font-weight: 400\">OIL AND GAS<\/span><\/h4>\n<figure id=\"attachment_4632\" aria-describedby=\"caption-attachment-4632\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Oil_Reserves.png\"><img class=\"wp-image-944 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Oil_Reserves-300x136.png\" alt=\"Darker countries are higher in oil\" width=\"300\" height=\"136\"><\/a><figcaption id=\"caption-attachment-4632\" class=\"wp-caption-text\">World Oil Reserves in 2013. Scale in billions of barrels.<\/figcaption><\/figure>\n<p><strong>P<\/strong>etroleum is principally derived from organic-rich shallow\u00a0marine\u00a0sedimentary deposits where the remains of micro-organisms like plankton accumulated in fine grained <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediments<\/a>. Petroleum\u2019s liquid component is called\u00a0<strong>oil,<\/strong>\u00a0and its gas component is called\u00a0<strong>natural gas<\/strong>, which is mostly made up of methane (CH<sub>4<\/sub>). As rocks such as shale, mudstone, or limestone lithify, increasing pressure and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> cause the oil and gas to be squeezed out and migrate from the <strong>source rock<\/strong> to a different rock unit higher in the rock column. Similar to the discussion of good\u00a0aquifers\u00a0in\u00a0<a href=\"https:\/\/opengeology.org\/textbook\/11-water\/\">Chapter 11<\/a>, if that rock is a sandstone, limestone, or other porous and permeable rock, and involved in a suitable stratigraphic or structural trapping process, then that rock can act as an<strong>\u00a0<\/strong>oil\u00a0and gas<strong> reservoir<\/strong>.<\/p>\n<figure id=\"attachment_4633\" aria-describedby=\"caption-attachment-4633\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Structural_Trap_Anticlinal.svg_.png\"><img class=\"wp-image-945 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Structural_Trap_Anticlinal.svg_-300x194.png\" alt=\"The rock layers are folded, and the petroleum is pooling toward the top of the fold.\" width=\"300\" height=\"194\"><\/a><figcaption id=\"caption-attachment-4633\" class=\"wp-caption-text\">A structural or anticline trap. The red on the image represents pooling petroleum. The green layer would be a permeable rock, and the yellow would be a reservoir rock.<\/figcaption><\/figure>\n<p>A\u00a0<strong>trap<\/strong> is a combination of a subsurface geologic structure, a porous and permeable rock, and an impervious layer that helps block oil and gas from moving further, which concentrates it for humans to extract later. A trap develops due to many different geologic situations. Examples include an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_504\">anticline<\/a> or domal structure, an impermeable salt <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_507\">dome<\/a>, or a fault bounded stratigraphic block, which is porous rock next to nonporous rock. The different traps have one thing in common: they pool fluid fossil fuels into a configuration in which extracting it is more likely to be profitable. Oil or gas in strata outside of a trap renders it less viable to extract.<\/p>\n<figure id=\"attachment_4634\" aria-describedby=\"caption-attachment-4634\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/TransgressionRegression.png\"><img class=\"wp-image-946 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/TransgressionRegression-300x199.png\" alt=\"Onlap is sediments moving toward the land. Offlap is moving away.\" width=\"300\" height=\"199\"><\/a><figcaption id=\"caption-attachment-4634\" class=\"wp-caption-text\">The rising sea levels of transgressions create onlapping sediments, regressions create offlapping.<\/figcaption><\/figure>\n<p><strong>Sequence stratigraphy<\/strong> is a branch of geology that studies sedimentary facies both horizontally and vertically and is devoted to understanding how sea level changes create organic-rich shallow marine muds, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonates<\/a>, and sands in areas that are close to each other. For example, shoreline environments may have beaches, lagoons, reefs, nearshore and offshore deposits, all next to each other. Beach sand, lagoonal and nearshore muds, and coral reef layers accumulate into <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediments<\/a> that include sandstones\u2014good reservoir rocks\u2014 next to mudstones, next to limestones, both of which are potential source rocks. As sea level either rises or falls, the shoreline\u2019s location changes, and the sand, mud, and reef locations shift with it (see the figure). This places oil and gas producing rocks, such as mudstones and limestones next to oil and gas reservoirs, such as sandstones and some limestones. Understanding how the lithology and the facies\/stratigraphic relationships interplay is very important in finding new petroleum resources. Using sequence stratigraphy as a model allows geologists to predict favorable locations of the source rock and reservoir.<\/p>\n<h4><span style=\"font-weight: 400\">Tar Sands<\/span><\/h4>\n<figure id=\"attachment_4635\" aria-describedby=\"caption-attachment-4635\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Tar_Sandstone_California.jpg\"><img class=\"wp-image-947 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tar_Sandstone_California-300x286.jpg\" alt=\"The sandstone is black with tar.\" width=\"300\" height=\"286\"><\/a><figcaption id=\"caption-attachment-4635\" class=\"wp-caption-text\">Tar sandstone from the Miocene Monterrey Formation of California.<\/figcaption><\/figure>\n<p><strong>Conventional<\/strong>\u00a0oil\u00a0and gas, which is pumped from a\u00a0reservoir, is not the only way to obtain hydrocarbons. There are a few fuel sources known as <strong>unconventional<\/strong>\u00a0petroleum\u00a0sources. However, they are becoming more important as conventional sources become scarce.\u00a0<strong>Tar sands<\/strong>, or oil sands, are sandstones that contain petroleum products that are highly viscous, like tar, and thus cannot be drilled and pumped out of the ground readily like conventional oil. This unconventional fossil fuel is <strong>bitumen<\/strong>, which can be pumped as a fluid only at very low recovery rates and only when heated or mixed with solvents. So, using steam and solvent injections or directly mining tar sands to process later are ways to extract the tar from the sands. Alberta, Canada is known to have the largest tar sand reserves in the world. Note: as with ores, an energy resource becomes uneconomic if the total extraction and processing costs exceed the extracted material\u2019s sales revenue. Environmental costs may also contribute to a resource becoming uneconomic.<\/p>\n<h4><span style=\"font-weight: 400\">Oil Shale<\/span><\/h4>\n<figure id=\"attachment_4636\" aria-describedby=\"caption-attachment-4636\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Production_of_oil_shale.png\"><img class=\"wp-image-948 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Production_of_oil_shale-300x195.png\" alt=\"Oil shale has dramatically increased starting around 1945.\" width=\"300\" height=\"195\"><\/a><figcaption id=\"caption-attachment-4636\" class=\"wp-caption-text\">Global production of Oil Shale, 1880-2010.<\/figcaption><\/figure>\n<p><strong>Oil shale<\/strong>, or\u00a0tight oil, is a fine-grained\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1761\">sedimentary rock<\/a>\u00a0that has significant petroleum\u00a0or\u00a0natural gas quantities locked tightly in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediment<\/a>.\u00a0Shale\u00a0has high\u00a0porosity\u00a0but very low permeability and is a common fossil fuel source rock. To extract the\u00a0oil directly from the shale, the material has to be\u00a0mined\u00a0and heated, which, like with tar sands, is expensive and typically has a negative environmental impact.<\/p>\n<h4><span style=\"font-weight: 400\">Fracking<\/span><\/h4>\n<figure id=\"attachment_4637\" aria-describedby=\"caption-attachment-4637\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/HydroFrac2.svg_.png\"><img class=\"wp-image-949 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/HydroFrac2.svg_-300x175.png\" alt=\"The image shows fracking fluids cracking the rock, allowing methane to escape.\" width=\"300\" height=\"175\"><\/a><figcaption id=\"caption-attachment-4637\" class=\"wp-caption-text\">Schematic diagram of fracking.<\/figcaption><\/figure>\n<p>Another process used to extract the\u00a0oil\u00a0and gas from\u00a0shale\u00a0and other unconventional tight resources is called\u00a0<strong>hydraulic fracturing<\/strong>, better known as\u00a0<strong>fracking<\/strong>. In this method, high-pressure water, sand grains, and added chemicals are injected and pumped underground. Under high pressure, this creates and holds open\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_986\">fractures<\/a>\u00a0in the rocks, which help release the hard-to-access mostly\u00a0natural gas fluids. Fracking is more useful in tighter\u00a0sediments, especially\u00a0shale, which has a high\u00a0porosity\u00a0to store the hydrocarbons but low permeability to allow transmission of the hydrocarbons.\u00a0Fracking\u00a0has become controversial because its methods contaminate groundwater\u00a0and\u00a0induce seismic activity. This has created much controversy between public concerns, political concerns, and energy value.<\/p>\n<h3><b>16.2.2. Coal<\/b><\/h3>\n<figure id=\"attachment_4638\" aria-describedby=\"caption-attachment-4638\" style=\"width: 240px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Coal_Rank_USGS.png\"><img class=\"wp-image-950 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Coal_Rank_USGS-240x300.png\" alt=\"The chart shows many different coal rankings\" width=\"240\" height=\"300\"><\/a><figcaption id=\"caption-attachment-4638\" class=\"wp-caption-text\">USGS diagram of different coal rankings.<\/figcaption><\/figure>\n<p><strong>Coal<\/strong>\u00a0comes from fossilized swamps, though some older\u00a0coal\u00a0deposits that predate\u00a0terrestrial\u00a0plants are presumed to come from algal buildups. Coal is chiefly carbon, hydrogen, nitrogen, sulfur, and oxygen, with minor amounts of other\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>. As plant material is incorporated into\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediments<\/a>, heat and pressure cause several changes that concentrate the fixed carbon, which is the coal\u2019s combustible portion. So, the more heat and pressure that\u00a0coal\u00a0undergoes, the greater is its carbon concentration and fuel value and the more desirable is the\u00a0coal.<\/p>\n<p>This is the general sequence of a swamp progressing through the various stages of coal formation and becoming more concentrated in carbon: Swamp =&gt; Peat =&gt; Lignite =&gt; Sub-bituminous =&gt; Bituminous =&gt; Anthracite =&gt; Graphite. As swamp materials collect on the swamp floor and are buried under accumulating materials, they first turn to peat.<\/p>\n<figure id=\"attachment_4639\" aria-describedby=\"caption-attachment-4639\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Peat_49302157252.jpg\"><img class=\"size-medium wp-image-951\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Peat_49302157252-300x225.jpg\" alt=\"A lump of peat.\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-4639\" class=\"wp-caption-text\">Peat (also known as turf) consists of partially decayed organic matter. The Irish have long mined peat to be burned as fuel though this practice is now discouraged for environmental reasons.<\/figcaption><\/figure>\n<p>Peat itself is an economic fuel in some locations like the British Isles and Scandinavia. As <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1760\">lithification<\/a> occurs, peat turns to lignite. With increasing heat and pressure, lignite turns to sub-bituminous coal, bituminous coal, and then, in a process like metamorphism, anthracite. Anthracite is the highest metamorphic grade and most desirable coal since it provides the highest energy output. With even more heat and pressure driving out all the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1684\">volatiles<\/a> and leaving pure carbon, anthracite can become graphite.<\/p>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_4640\" aria-describedby=\"caption-attachment-4640\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Coal_anthracite.jpg\"><img class=\"wp-image-4640 size-medium\" title=\"&quot;USGS\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Coal_anthracite-1.jpg\" alt=\"It is very black and shiny.\" width=\"300\" height=\"281\"><\/a><figcaption id=\"caption-attachment-4640\" class=\"wp-caption-text\">Anthracite coal, the highest grade of coal.<\/figcaption><\/figure>\n<p>Humans have used coal for at least 6,000 years, mainly as a fuel source. Coal resources in Wales are often cited as a primary reason for Britain\u2019s rise, and later, for the United States\u2019 rise during the Industrial Revolution. According to the US Energy Information Administration, US coal production has decreased due to competing energy sources\u2019 cheaper prices and due to society recognizing its negative environmental impacts, including increased very fine-grained particulate matter as an air pollutant, greenhouse gases, acid rain, and heavy metal pollution. Seen from this perspective, the coal industry as a source of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1228\">fossil<\/a> energy is unlikely to revive.<\/p>\n<p>As the world transitions away from fossil fuels including coal, and manufacturing seeks strong, flexible, and lighter materials than steel including carbon fiber for many applications, current research is exploring coal as a source of this carbon.<\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-110\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-110\" class=\"h5p-iframe\" data-content-id=\"110\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Chapter 16 Review\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_4902\" aria-describedby=\"caption-attachment-4902\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/03\/16.2-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-953\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/16.2-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4902\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 16.2 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-weight: 400\">16.3 Mineral Resources<\/span><\/h2>\n<figure id=\"attachment_4641\" aria-describedby=\"caption-attachment-4641\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Mother_Lode_Gold_OreHarvard_mine_quartz-gold_vein.jpg\"><img class=\"wp-image-954 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mother_Lode_Gold_OreHarvard_mine_quartz-gold_vein-300x209.jpg\" alt=\"The yellow gold is inside white quartz.\" width=\"300\" height=\"209\"><\/a><figcaption id=\"caption-attachment-4641\" class=\"wp-caption-text\">Gold-bearing quartz vein from California.<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Mineral<\/a>\u00a0resources, while principally\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">nonrenewable<\/a>, are generally placed\u00a0in two main categories:\u00a0<strong>metallic<\/strong>, which contain metals, and\u00a0<strong>nonmetallic<\/strong>, which contain other useful materials. Most\u00a0mining\u00a0has been traditionally focused on\u00a0extracting metallic\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. Human society has advanced significantly because we\u2019ve developed the\u00a0knowledge and technologies to yield metal from the Earth. This knowledge has allowed humans to build the machines, buildings, and monetary systems that dominate our world today. Locating and recovering these metals has been a key facet of geologic study since its inception. Every\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a>\u00a0across the periodic table has specific applications in human civilization.\u00a0Metallic\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>\u00a0mining\u00a0is the source of many of these\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>.<\/p>\n<h3><b>16.3.1. Types of Metallic Mineral Deposits<\/b><\/h3>\n<p>The various ways in which <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>\u00a0and their associated\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>\u00a0concentrate to form\u00a0ore\u00a0deposits are too complex and numerous to fully review in this text. However, entire careers are built around them.\u00a0In the following section, we describe some of the more common deposit types along with their associated elemental concentrations and world class occurrences.<\/p>\n<h4><span style=\"font-weight: 400\">Magmatic Processes<\/span><\/h4>\n<figure id=\"attachment_4642\" aria-describedby=\"caption-attachment-4642\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/LayeredIntrusionChromitite_Bushveld_South_Africa.jpg\"><img class=\"wp-image-955 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/LayeredIntrusionChromitite_Bushveld_South_Africa-300x211.jpg\" alt=\"The rock has several layers, with the dark layers being the ones with value.\" width=\"300\" height=\"211\"><\/a><figcaption id=\"caption-attachment-4642\" class=\"wp-caption-text\">Layered intrusion of dark chromium-bearing minerals, Bushveld Complex, South Africa<\/figcaption><\/figure>\n<p>When a magmatic body crystallizes and differentiates (see Chapter 4), it can cause certain <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> to concentrate. <strong>Layered<\/strong>\u00a0<strong>intrusions<\/strong>, typically <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1009\">ultramafic<\/a> to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a>, can host deposits that contain copper, nickel, platinum, palladium, rhodium, and chromium. The Stillwater Complex in Montana is an example of economic quantities of layered <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> intrusion. Associated deposit types can contain chromium or titanium-vanadium. The largest magmatic deposits in the world are the chromite deposits in the Bushveld <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">Igneous<\/a> Complex in South Africa. These rocks have an areal extent larger than the state of Utah. The chromite occurs in layers, which resemble sedimentary layers, except these layers occur within a crystallizing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_232\">magma chamber<\/a>.<\/p>\n<figure id=\"attachment_4909\" aria-describedby=\"caption-attachment-4909\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/03\/Elbai\u0308te_et_mica_Bre\u0301sil_1.jpg\"><img class=\"size-medium wp-image-4909\" src=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/03\/Elbai\u0308te_et_mica_Bre\u0301sil_1-300x199.jpg#fixme\" alt=\"The rock is mostly green and purple\" width=\"300\" height=\"199\"><\/a><figcaption id=\"caption-attachment-4909\" class=\"wp-caption-text\">This pegmatite contains lithium-rich green elbaite (a tourmaline) and purple lepidolite (a mica).<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>Water and other\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1684\">volatiles<\/a>\u00a0that are not incorporated into\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>\u00a0crystals when a\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>\u00a0crystallizes can become\u00a0concentrated\u00a0around the crystallizing\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>\u2019s margins. Ions in these hot fluids are very mobile and can form exceptionally large crystals.\u00a0Once crystallized, these large crystal masses are then called\u00a0<strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_996\">pegmatites<\/a><\/strong>. They form from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> fluids that are expelled from the solidifying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> when nearly the entire <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> body has crystallized. In addition to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> that are predominant in the main <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> mass, such as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">mica<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_996\">pegmatite<\/a> bodies may also contain very large crystals of unusual <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> that contain rare <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> like beryllium, lithium, tantalum, niobium, and tin, as well as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_976\">native<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> like gold. Such <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_996\">pegmatites<\/a> are ores of these metals.<\/p>\n<figure id=\"attachment_4643\" aria-describedby=\"caption-attachment-4643\" style=\"width: 298px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/KimberlitePipe.jpg\"><img class=\"wp-image-956 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/KimberlitePipe-298x300.jpg\" alt=\"The pipe is deep and narrow.\" width=\"298\" height=\"300\"><\/a><figcaption id=\"caption-attachment-4643\" class=\"wp-caption-text\">Schematic diagram of a kimberlite pipe.<\/figcaption><\/figure>\n<p>An unusual magmatic process is a\u00a0<strong>kimberlite<\/strong> pipe, which is a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_233\">conduit<\/a> that transports <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1009\">ultramafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> from within the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> to the surface. Diamonds, which are formed at great temperatures and pressures of depth, are transported by a Kimberlite pipe to locations where they can be mined. The process that created these kimberlite <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1009\">ultramafic<\/a> rocks is no longer common on Earth. Most known deposits are from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1257\">Archean<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1242\">Eon<\/a>.<\/p>\n<h4><span style=\"font-weight: 400\">Hydrothermal Processes<\/span><\/h4>\n<figure id=\"attachment_4644\" aria-describedby=\"caption-attachment-4644\" style=\"width: 400px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Deep_sea_vent_chemistry_diagram.jpg\"><img class=\"wp-image-4644\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Deep_sea_vent_chemistry_diagram-1.jpg\" alt=\"The diagram shows water going into the ground and coming out, with many different reactions.\" width=\"400\" height=\"233\"><\/a><figcaption id=\"caption-attachment-4644\" class=\"wp-caption-text\">The complex chemistry around mid-ocean ridges.<\/figcaption><\/figure>\n<p>Fluids rising from crystallizing magmatic bodies or that are heated by the\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_222\">geothermal gradient<\/a>\u00a0cause many geochemical reactions that form various <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>\u00a0deposits. The most active\u00a0hydrothermal\u00a0process today produces\u00a0<strong>volcanogenic massive sulfide<\/strong><strong>\u00a0<\/strong>(VMS) deposits, which form from black smoker hydrothermal chimney activity near <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridges<\/a> all over the world. They commonly contain copper, zinc, lead, gold, and silver when found at the surface. Evidence from around 7000 BC in a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1244\">period<\/a> known as the Chalcolithic shows copper was among the earliest metals smelted by humans as means of obtaining higher temperatures were developed. The largest of these VMS deposits occur in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1270\">Precambrian<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1244\">period<\/a> rocks. The Jerome deposit in central Arizona is a good example.<\/p>\n<p>Another deposit type that draws on <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>-heated water is a\u00a0<strong>porphyry<\/strong> deposit. This is not to be confused with the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_994\">porphyritic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> texture, although the name is derived from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_994\">porphyritic<\/a> texture that is nearly always present in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks associated with a porphyry deposit. Several types of porphyry deposits exist, such as porphyry copper, porphyry molybdenum, and porphyry tin. These deposits contain low-grade disseminated ore <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> closely associated with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1007\">intermediate<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_991\">intrusive<\/a> rocks that are present over a very large area. Porphyry deposits are typically the largest mines on Earth. One of the largest, richest, and possibly best studied mine in the world is Utah\u2019s Kennecott Bingham Canyon Mine. It\u2019s an open pit mine, which, for over 100 years, has produced several <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> including copper, gold, molybdenum, and silver. Underground <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> replacement deposits produce lead, zinc, gold, silver, and copper. In the mine\u2019s past, the open pit predominately produced copper and gold from chalcopyrite and bornite. Gold only occurs in minor quantities in the copper-bearing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, but because the Kennecott Bingham Canyon Mine produces on such a large scale, it is one of the largest gold <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mines<\/a> in the US. In the future, this mine may produce more copper and molybdenum (molybdenite) from deeper underground mines.<\/p>\n<figure id=\"attachment_4645\" aria-describedby=\"caption-attachment-4645\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Morenci_Mine_2012.jpg\"><img class=\"wp-image-958 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Morenci_Mine_2012-300x200.jpg\" alt=\"The mine contains grey rocks, which are not enriched, and red rocks, which is where the enrichment occurs.\" width=\"300\" height=\"200\"><\/a><figcaption id=\"caption-attachment-4645\" class=\"wp-caption-text\">The Morenci porphyry is oxidized toward its top (as seen as red rocks in the wall of the mine), creating supergene enrichment.<\/figcaption><\/figure>\n<p>Most porphyry\u00a0copper deposits owe their high metal content, and hence, their economic value to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1754\">weathering<\/a>\u00a0processes called<strong> supergene enrichment<\/strong> which occurs when the\u00a0deposit is uplifted, eroded, and exposed to\u00a0<strong>oxidation<\/strong>. This process <b>occur<\/b>r<b>ed<\/b> millions of years after the initial <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> intrusion and hydrothermal expulsion ends. When the deposit\u2019s upper pyrite-rich portion is exposed to rain, the pyrite in the oxidizing zone creates an extremely acid condition that dissolves copper out of copper\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>,\u00a0such as chalcopyrite, and converts the chalcopyrite to iron\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxides<\/a>,\u00a0such as hematite or goethite. The copper <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are carried downward in\u00a0water until they arrive at the\u00a0groundwater\u00a0table and an environment where the primary copper\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are converted\u00a0into secondary higher-copper content\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. Chalcopyrite (35% Cu) is converted to bornite (63% Cu), and ultimately, chalcocite (80% Cu).\u00a0Without this enriched zone, which is two to five times higher in copper content than the main deposit, most\u00a0porphyry\u00a0copper deposits would not be economic to mine.<\/p>\n<figure id=\"attachment_4646\" aria-describedby=\"caption-attachment-4646\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/16.3_6_cm_grossular_calcite_augite_skarn.jpg\"><img class=\"wp-image-959 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/16.3_6_cm_grossular_calcite_augite_skarn-300x255.jpg\" alt=\"Calcite is blue, augite green, and garnet brown\/orange in this rock.\" width=\"300\" height=\"255\"><\/a><figcaption id=\"caption-attachment-4646\" class=\"wp-caption-text\">Garnet-augite skarn from Italy.<\/figcaption><\/figure>\n<p>If\u00a0limestone\u00a0or other calcareous sedimentary rocks are near the magmatic body, then another type of\u00a0ore\u00a0deposit called a\u00a0<strong>skarn<\/strong>\u00a0deposit forms. These\u00a0metamorphic\u00a0rocks form as\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>-derived, highly saline metalliferous fluids react with\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a>\u00a0rocks to create calcium-magnesium-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a>\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>\u00a0like\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">pyroxene<\/a>,\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1791\">amphibole<\/a>, and garnet, as well as high-grade\u00a0iron, copper, zinc\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>,\u00a0and gold. Intrusions that are genetically related to the intrusion that made the Kennecott Bingham Canyon deposit have also produced copper-gold skarns, which were\u00a0mined\u00a0by the early European settlers in Utah. When iron and\/or\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfide<\/a>\u00a0deposits undergo metamorphism, the\u00a0grain\u00a0size\u00a0commonly increases, which makes separating the\u00a0gangue\u00a0from the desired\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfide<\/a>\u00a0or\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxide<\/a>\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>\u00a0much easier.<\/p>\n<figure id=\"attachment_4647\" aria-describedby=\"caption-attachment-4647\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/GoldinPyrite.jpg\"><img class=\"wp-image-4647 size-medium\" title=\"&quot;<a\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/GoldinPyrite-1.jpg\" alt=\"The rock is red.\" width=\"300\" height=\"240\"><\/a><figcaption id=\"caption-attachment-4647\" class=\"wp-caption-text\">In this rock, a pyrite cube has dissolved (as seen with the negative \"corner\" impression in the rock), leaving behind small specks of gold.<\/figcaption><\/figure>\n<p><strong>Sediment-hosted disseminated gold<\/strong> deposits consist of low concentrations of microscopic gold as inclusions and disseminated atoms in pyrite crystals. These are formed via low-grade hydrothermal reactions, generally in the realm of diagenesis, that occur in certain rock types, namely muddy <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonates<\/a> and limey mudstones. This hydrothermal alteration is generally far removed from a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> source, but can be found in rocks situated with a high <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_222\">geothermal gradient<\/a>. The Mercur deposit in Utah\u2019s Oquirrh Mountains was this type\u2019s earliest locally mined deposit. There, almost a million ounces of gold was recovered between 1890 and 1917. In the 1960s, a metallurgical process using cyanide was developed for these low-grade ore types. These deposits are also called\u00a0<strong>Carlin-type<\/strong><strong>\u00a0<\/strong>deposits\u00a0because the disseminated deposit near Carlin, Nevada, is where the new technology was first applied and where the first definitive scientific studies were conducted. Gold was introduced into these deposits by\u00a0hydrothermal\u00a0fluids that reacted with silty calcareous rocks, removing\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a>, creating additional permeability, and adding silica and gold-bearing pyrite in the\u00a0pore\u00a0space between grains. The Betze-Post\u00a0mine\u00a0and the Gold Quarry\u00a0mine\u00a0on the Carlin Trend are two of the largest disseminated gold deposits in Nevada. Similar deposits, but not as large, have been found in China, Iran, and Macedonia.<\/p>\n<h4><span style=\"font-weight: 400\">Non-magmatic Geochemical Processes <\/span><\/h4>\n<figure id=\"attachment_4648\" aria-describedby=\"caption-attachment-4648\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/16.1_UraniumMineUtah.jpg\"><img class=\"wp-image-961 size-medium\" title=\"&quot;<a\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/16.1_UraniumMineUtah-300x225.jpg\" alt=\"A dark shaft runs into the mountain.\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-4648\" class=\"wp-caption-text\">Underground uranium mine near Moab, Utah.<\/figcaption><\/figure>\n<p>Geochemical processes that occur at or near the surface without <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>\u2019s\u00a0aid also concentrate metals, but to a lesser degree than\u00a0hydrothermal\u00a0processes. One of the main reactions is\u00a0<strong>redox<\/strong>, short for reduction\/oxidation chemistry, which has to do with the amount of available oxygen in a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1742\">system<\/a>. Places where oxygen is plentiful, as in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1745\">atmosphere<\/a> today, are considered oxidizing environments, while oxygen-poor places are considered reducing environments. Uranium deposits are an example of where redox concentrated the metal. Uranium is soluble in oxidizing groundwater environments and precipitates as uraninite when encountering reducing conditions. Many of the deposits across the Colorado Plateau, such as in \u00a0Moab, Utah, were formed by this method.<\/p>\n<p>Redox\u00a0reactions are also responsible for creating <strong>banded iron<\/strong><strong>\u00a0<\/strong><strong>formations<\/strong><strong>\u00a0<\/strong>(BIFs),<strong>\u00a0<\/strong>which are interbedded layers of iron\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxide<\/a>\u2014hematite and magnetite,\u00a0chert, and\u00a0shale\u00a0beds. These deposits formed early in the Earth\u2019s history as the\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1745\">atmosphere<\/a>\u00a0was becoming oxygenated. Cycles of oxygenating iron-rich waters initiated <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitation<\/a> of the\u00a0iron\u00a0beds. Because BIFs are generally\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1270\">Precambrian<\/a>\u00a0in age, happening at the event of atmospheric oxygenation, they are only found in some of the older exposed rocks in the United States, such as in Michigan\u2019s upper peninsula and northeast Minnesota.<\/p>\n<figure id=\"attachment_4649\" aria-describedby=\"caption-attachment-4649\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/MV-Type_and_clastic_sediment-hosted_lead-zinc_deposits.svg_.png\"><img class=\"wp-image-962 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MV-Type_and_clastic_sediment-hosted_lead-zinc_deposits.svg_-300x138.png\" alt=\"The are globally distributed.\" width=\"300\" height=\"138\"><\/a><figcaption id=\"caption-attachment-4649\" class=\"wp-caption-text\">Map of Mississippi-Valley type ore deposits.<\/figcaption><\/figure>\n<p>Deep, saline, connate fluids (trapped in pore spaces) within <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_510\">sedimentary basins<\/a>\u00a0may be highly metalliferous. When expelled outward and upward as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_508\">basin<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediments<\/a> compacted, these fluids formed lead and zinc deposits in limestone by replacing or filling open spaces, such as caves and faults, and in sandstone by filling pore spaces. The most famous are called\u00a0<strong>Mississippi Valley-type<\/strong><strong>\u00a0<\/strong>deposits. Also known as\u00a0carbonate-hosted replacement\u00a0deposits, they are large deposits of galena and sphalerite lead and zinc\u00a0ores that form from hot fluids ranging from 100\u00b0C to 200\u00b0C (212\u00b0F to 392\u00b0F). Although they are named for occurring along the Mississippi\u00a0River\u00a0Valley in the US, they are found worldwide.<\/p>\n<p><strong>Sediment-hosted copper<\/strong><strong>\u00a0<\/strong>deposits occurring in\u00a0sandstones,\u00a0shales, and marls are enormous, and their contained resources are comparable to\u00a0porphyry\u00a0copper deposits. These deposits were most likely formed diagenetically by\u00a0groundwater\u00a0fluids in highly permeable rocks. Well-known examples are the Kupferschiefer in Europe, which has an areal coverage of &gt;500,000 Km<sup>2<\/sup>, (310,685.596mi) and the Zambian Copper Belt in Africa.<\/p>\n<figure id=\"attachment_4650\" aria-describedby=\"caption-attachment-4650\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Bauxite_with_unweathered_rock_core._C_021.jpg\"><img class=\"wp-image-4650 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Bauxite_with_unweathered_rock_core._C_021-1.jpg\" alt=\"The outside of the rock is tan and weathered, the inside is grey.\" width=\"300\" height=\"195\"><\/a><figcaption id=\"caption-attachment-4650\" class=\"wp-caption-text\">A sample of bauxite. Note the unweathered igneous rock in the center.<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_250\">Soils<\/a>\u00a0and\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>\u00a0deposits that are exposed at the surface experience deep and intense\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1754\">weathering<\/a>, which\u00a0can form surficial deposits.\u00a0<strong>Bauxite<\/strong>, an aluminum ore, is preserved in karst topography and laterites, which are <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_250\">soils<\/a> formed in wet tropical environments. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_250\">Soils<\/a> containing aluminum concentrate <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, such as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a>, and ferromagnesian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> and metamorphic rocks, undergo chemical weathering processes that concentrate the metals. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1009\">Ultramafic<\/a> rocks that undergo <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1754\">weathering<\/a> form nickel-rich <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_250\">soils<\/a>, and when the magnetite and hematite in banded iron formations undergo <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1754\">weathering<\/a>, it forms goethite, a friable <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> that is easily mined for its iron content.<\/p>\n<h3><span style=\"font-weight: 400\">Surficial Physical Processes <\/span><\/h3>\n<figure id=\"attachment_4651\" aria-describedby=\"caption-attachment-4651\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/HeavyMineralsBeachSand.jpg\"><img class=\"wp-image-4651 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/HeavyMineralsBeachSand-1.jpg\" alt=\"The tan rock has dark streaks of minerals.\" width=\"300\" height=\"205\"><\/a><figcaption id=\"caption-attachment-4651\" class=\"wp-caption-text\">Lithified heavy mineral sand (dark layers) from a beach deposit in India.<\/figcaption><\/figure>\n<p>At the Earth\u2019s surface, mass wasting\u00a0and moving water can cause hydraulic\u00a0sorting, which forces high-density\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> to concentrate. When these\u00a0minerals\u00a0are\u00a0concentrated\u00a0in\u00a0streams,\u00a0rivers,\u00a0and beaches, they are called\u00a0<strong>placer<\/strong>\u00a0deposits, and occur in modern sands and ancient lithified rocks.\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_976\">Native<\/a>\u00a0gold,\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_976\">native<\/a>\u00a0platinum,\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1227\">zircon<\/a>, ilmenite, rutile, magnetite, diamonds, and other gemstones can be found in\u00a0placers. Humans have mimicked this natural process to recover gold manually by gold panning and by mechanized means such as dredging.<\/p>\n<h3><b>16.3.2. Environmental Impacts of Metallic Mineral Mining<\/b><\/h3>\n<figure id=\"attachment_4652\" aria-describedby=\"caption-attachment-4652\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Rio_tinto_river_CarolStoker_NASA_Ames_Research_Center.jpg\"><img class=\"wp-image-965 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Rio_tinto_river_CarolStoker_NASA_Ames_Research_Center-300x225.jpg\" alt=\"The water in the river is bright orange.\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-4652\" class=\"wp-caption-text\">Acid mine drainage in the Rio Tinto, Spain.<\/figcaption><\/figure>\n<p>Metallic\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>\u00a0mining\u2019s\u00a0primary impact comes from the\u00a0mining\u00a0itself, including disturbing the land surface, covering landscapes with tailings impoundments, and increasing\u00a0mass wasting\u00a0by accelerating\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1755\">erosion<\/a>. In addition, many metal deposits contain pyrite, an uneconomic\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfide<\/a>\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>, that when\u00a0placed on waste dumps, generates\u00a0<strong>acid rock drainage<\/strong>\u00a0(ARD)<strong>\u00a0<\/strong>during <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1754\">weathering<\/a>. In oxygenated water, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfides<\/a> such as pyrite react and undergo complex reactions to release metal ions and hydrogen ions, which lowers pH to highly acidic levels. Mining and processing of mined materials typically increase the surface area to volume ratio in the material, causing chemical reactions to occur even faster than would occur naturally. If not managed properly, these reactions lead to acidic streams and groundwater plumes that carry dissolved toxic metals. In mines where limestone is a waste rock or where <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> like <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a> or dolomite are present, their acid neutralizing potential helps reduce acid rock drainage. Although this is a natural process too, it is very important to isolate mine dumps and tailings from oxygenated water, both to prevent the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfides<\/a> from dissolving and subsequently percolating the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_974\">sulfate<\/a>-rich water into waterways. Industry has taken great strides to prevent contamination in recent decades, but earlier mining projects are still causing problems with local ecosystems.<\/p>\n<h3><strong>16.3.3. Nonmetallic Mineral\u00a0Deposits<\/strong><\/h3>\n<figure id=\"attachment_4653\" aria-describedby=\"caption-attachment-4653\" style=\"width: 225px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/CarraraMarblequarry.jpg\"><img class=\"wp-image-966 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/CarraraMarblequarry-225x300.jpg\" alt=\"The image shows a hillside with blocks of marble removed.\" width=\"225\" height=\"300\"><\/a><figcaption id=\"caption-attachment-4653\" class=\"wp-caption-text\">Carrara marble quarry in Italy, source to famous sculptures like Michelangelo's David.<\/figcaption><\/figure>\n<p>While receiving much less attention, nonmetallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> resources, also known as industrial <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, are just as vital to ancient and modern society as metallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. The most basic is building stone. Limestone, travertine, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1014\">granite<\/a>, slate, and marble are common building stones and have been quarried for centuries. Even today, building stones from slate roof tiles to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1014\">granite<\/a> countertops are very popular. Especially pure limestone is ground up, processed, and reformed as plaster, cement, and concrete. Some nonmetallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> resources are not <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> specific; nearly any rock or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> can be used. This is generally called aggregate, which is used in concrete, roads, and foundations. Gravel is one of the more common aggregates.<\/p>\n<h4><span style=\"font-weight: 400\">Evaporites<\/span><\/h4>\n<figure id=\"attachment_4654\" aria-describedby=\"caption-attachment-4654\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Bonneville_Salt_Flats_Utah.jpg\"><img class=\"wp-image-4654 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Bonneville_Salt_Flats_Utah-1.jpg\" alt=\"The ground is white and flat for a long distance.\" width=\"300\" height=\"200\"><\/a><figcaption id=\"caption-attachment-4654\" class=\"wp-caption-text\">Salt-covered plain known as the Bonneville Salt Flats, Utah.<\/figcaption><\/figure>\n<p><strong>Evaporite<\/strong><strong>\u00a0<\/strong>deposits\u00a0form in restricted basins where water evaporates faster than it recharges, such as the Great Salt Lake in Utah, or the Dead Sea, which borders Israel and Jordan. As the waters evaporate, soluble\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>\u00a0are\u00a0concentrated\u00a0and become supersaturated, at which point they\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitate<\/a>\u00a0from the now highly-saline waters. If these conditions persist for long stretches, thick rock salt, rock\u00a0gypsum,\u00a0and other\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>\u00a0deposits accumulate (see Chapter 5).<\/p>\n<figure id=\"attachment_4655\" aria-describedby=\"caption-attachment-4655\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Hanksite.jpg\"><img class=\"wp-image-968 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hanksite-300x200.jpg\" alt=\"The mineral is hexagonal and clear.\" width=\"300\" height=\"200\"><\/a><figcaption id=\"caption-attachment-4655\" class=\"wp-caption-text\">Hanksite, Na22K(SO4)9(CO3)2Cl, one of the few minerals that is considered a carbonate and a sulfate<\/figcaption><\/figure>\n<p>Evaporite <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, such as halite, are used in our food as common table salt. Salt was a vitally important food preservative and economic resource before refrigeration was developed. While still used in food, halite is now mainly mined as a chemical agent, water softener, or road de-icer. Gypsum is a common nonmetallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> used as a building material; it is the main component in dry wall. It is also used as a fertilizer. Other evaporites include sylvite\u2014potassium chloride, and bischofite\u2014magnesium chloride, both of which are used in agriculture, medicine, food processing, and other applications. Potash, a group of highly soluble potassium-bearing evaporite <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, is used as a fertilizer. In hyper-arid locations, even more rare and complex evaporites, like borax, trona, ulexite, and hanksite are mined. They can be found in places such as Searles Dry Lake and Death Valley, California, and in the Green River Formation\u2019s ancient evaporite deposits in Utah and Wyoming.<\/p>\n<h4><span style=\"font-weight: 400\">Phosphorus<\/span><\/h4>\n<figure id=\"attachment_4656\" aria-describedby=\"caption-attachment-4656\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Apatite-CaF-280343.jpg\"><img class=\"wp-image-4656 size-medium\" title=\"&quot;Rob\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Apatite-CaF-280343-1.jpg\" alt=\"The crystal is hexagonal and light green.\" width=\"300\" height=\"267\"><\/a><figcaption id=\"caption-attachment-4656\" class=\"wp-caption-text\">Apatite from Mexico.<\/figcaption><\/figure>\n<p>Phosphorus is an essential <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a> that occurs in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> apatite, which is found in trace amounts in common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks. Phosphorite rock, which is formed in sedimentary environments in the ocean, contains abundant apatite and is mined to make fertilizer. Without phosphorus, life as we know it is not possible. Phosphorous is an important component of bone and DNA. Bone <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">ash<\/a> and guano are natural sources of phosphorus.<\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<figure id=\"attachment_4903\" aria-describedby=\"caption-attachment-4903\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/03\/16.3-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-970\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/16.3-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4903\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 16.3 via this QR Code.<\/figcaption><\/figure>\n<h1>Summary<\/h1>\n<p>Energy and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> resources are vital to modern society, and it is the role of the geologist to locate these resources for human benefit. As environmental concerns have become more prominent, the value of the geologist has not decreased, as they are still vital in locating the deposits and identifying the least <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_991\">intrusive<\/a> methods of extraction.<\/p>\n<p>Energy resources are general grouped as being <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1740\">renewable<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">nonrenewable<\/a>. Geologists can aid in locating the best places to exploit <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1740\">renewable<\/a> resources (e.g. locating a dam), but are commonly tasked with finding <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">nonrenewable<\/a> fossil fuels. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Mineral<\/a> resources are also grouped in two categories: metallic and nonmetallic. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Minerals<\/a> have a wide variety of processes that concentrate them to economic levels, and are usually mined via surface or underground methods.<\/p>\n<h3>Take this quiz to check your comprehension of this Chapter.<\/h3>\n<figure id=\"attachment_4904\" aria-describedby=\"caption-attachment-4904\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/03\/Ch.16-Review-QR-Code.png\"><img class=\"size-thumbnail wp-image-971\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ch.16-Review-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4904\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the review quiz for Chapter 16 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-weight: 400\">References<\/span><\/h2>\n<ol>\n<li style=\"text-align: left\">Ague, Jay James, and George H. 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Simpson. 2003. \u201c2.6-Million-Year-Old Stone Tools and Associated Bones from OGS-6 and OGS-7, Gona, Afar, Ethiopia.\u201d <em>Journal of Human Evolution<\/em> 45 (2). Academic Press: 169\u201377.<\/li>\n<li style=\"text-align: left\">Tappan, Helen, and Alfred R. Loeblich. 1970. \u201cGeobiologic Implications of Fossil Phytoplankton Evolution and Time-Space Distribution.\u201d <em>Geological Society of America Special Papers<\/em> 127 (January). specialpapers.gsapubs.org: 247\u2013340.<\/li>\n<li style=\"text-align: left\">Taylor, E. L., T. N. Taylor, and M. Krings. 2009. <em>Paleobotany: The Biology and Evolution of Fossil Plants<\/em>. Elsevier Science.<\/li>\n<li style=\"text-align: left\">Tissot, B. 1979. \u201cEffects on Prolific Petroleum Source Rocks and Major Coal Deposits Caused by Sea-Level Changes.\u201d <em>Nature<\/em> 277. adsabs.harvard.edu: 463\u201365.<\/li>\n<li style=\"text-align: left\">Vail, P. R., R. M. Mitchum Jr, S. Thompson III, R. G. Todd, J. B. Sangree, J. M. Widmier, J. N. Bubb, and W. G. Hatelid. 1977. \u201cSeismic Stratigraphy and Global Sea Level Changes.\u201d <em>Seismic Stratigraphy-Applications to Hydrocarbon Exploration, Edited by Payton, CE, Tulsa, American Association of Petroleum Geologists Memoir<\/em> 26: 49\u2013212.<\/li>\n<li style=\"text-align: left\">Vogel, J. C. 1970. \u201cGroningen Radiocarbon Dates IX.\u201d <em>Radiocarbon<\/em> 12 (2). journals.uair.arizona.edu: 444\u201371.<\/li>\n<li style=\"text-align: left\">Willemse, J. 1969. \u201cThe Geology of the Bushveld Igneous Complex, the Largest Repository of Magmatic Ore Deposits in the World.\u201d <em>Economic Geology Monograph<\/em> 4: 1\u201322.<\/li>\n<li style=\"text-align: left\">Wrigley, E. A. 1990. <em>Continuity, Chance and Change: The Character of the Industrial Revolution in England. Ellen McArthur Lectures<\/em> ; 1987. Cambridge University Press.<\/li>\n<li style=\"text-align: left\">Youngquist, Walter. 1998. \u201cShale Oil--The Elusive Energy.\u201d <em>Hubbert Center Newsletter<\/em> 4.<\/li>\n<\/ol>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1678\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1678\"><div tabindex=\"-1\"><p>A process where ice from the ends of glaciers falls off into the ocean.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1695\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1695\"><div tabindex=\"-1\"><p>Large sediment (e.g. boulder) carried and then dropped by a glacier.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_508\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_508\"><div tabindex=\"-1\"><p>(Source: National Park Service modified after Garber et al. 1989)<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1514\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1514\"><div tabindex=\"-1\"><p>Any downhill movement of material, caused by gravity.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_244\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_244\"><div tabindex=\"-1\"><p>By Ji-ElleIt feels nice and warmIt feels like a ________ (Own work) [<a href=\"http:\/\/creativecommons.org\/licenses\/by-sa\/3.0\">CC BY-SA 3.0<\/a>], <a href=\"https:\/\/commons.wikimedia.org\/wiki\/File%3ALipari-Obsidienne_(5).jpg\">via Wikimedia Commons<\/a><\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_242\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_242\"><div tabindex=\"-1\"><p>I, <a href=\"\/wiki\/User:Digon3\" title=\"User:Digon3\">Jonathan Zander<\/a> [<a href=\"http:\/\/www.gnu.org\/copyleft\/fdl.html\">GFDL<\/a>, <a href=\"http:\/\/creativecommons.org\/licenses\/by-sa\/3.0\/\">CC-BY-SA-3.0<\/a> or <a href=\"http:\/\/creativecommons.org\/licenses\/by-sa\/2.5\">CC BY-SA 2.5<\/a>], <a href=\"https:\/\/commons.wikimedia.org\/wiki\/File%3AScoria_Macro_Digon3.jpg\">via Wikimedia Commons<\/a><\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_492\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_492\"><div tabindex=\"-1\"><p>Photo by Foto Chd (german wikipedia, https:\/\/de.wikipedia.org\/wiki\/Benutzer:Chd), used under the terms of the GNU Free Documentation License<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_235\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_235\"><div tabindex=\"-1\"><p>By Matt Affolter<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_755\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_755\"><div tabindex=\"-1\"><p>QR Code generated with QRCode Monkey. All generated QR Codes are 100% free and can be used for whatever you want. This includes all commercial purposes. <\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1977\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1977\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_240\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_240\"><div tabindex=\"-1\"><p>By Jstuby at en.wikipedia (Own workTransferred from en.wikipedia) [Public domain], <a href=\"https:\/\/commons.wikimedia.org\/wiki\/File%3AOlearyandesite.jpg\">via Wikimedia Commons<\/a><\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_233\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_233\"><div tabindex=\"-1\"><figure id=\"attachment_2752\" aria-describedby=\"caption-attachment-2752\" style=\"width: 1024px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Cristales_cueva_de_Naica.jpg\"><img class=\"wp-image-2752 size-large\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/09\/Cristales_cueva_de_Naica-1024x683-1.jpg\" alt=\"The crystals are huge!\" width=\"1024\" height=\"683\"><\/a><figcaption id=\"caption-attachment-2752\" class=\"wp-caption-text\">These selenite (gypsum) crystals, found in The Cave of the Crystals in Naica, Mexico, has some of the largest minerals ever found. The largest crystal found here is 39 feet (12 meters) and 55 tones.<\/figcaption><\/figure>\n<h1>3 Minerals<\/h1>\n<p><strong>KEY<\/strong><b> CONCEPTS<\/b><\/p>\n<p><b>At the end of this chapter, students should be able to:<\/b><\/p>\n<ul>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Define <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>.<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Describe the basic structure of the atom.<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Derive basic atomic information from the Periodic Table of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">Elements<\/a>.<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Describe chemical <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonding<\/a> related to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>.<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Describe the main ways <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> form.<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Describe the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silicon-oxygen tetrahedron<\/a> and how it forms common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>.<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">List common non-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxide<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfide<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_974\">sulfate<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> groups.<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Identify <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> using physical properties and identification tables. <\/span><\/li>\n<\/ul>\n<p>The term \u201c<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>\u201d as used in nutrition labels and pharmaceutical products is not the same as a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> in a geological sense. In geology, the classic definition of a <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a><\/strong> is: 1) naturally occurring, 2) inorganic, 3) solid at room <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a>, 4) regular crystal structure, and 5) defined chemical composition. Some natural substances technically should not be considered <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, but are included by exception. For example, water and mercury are liquid at room <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a>. Both are considered <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> because they were classified before the room-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> rule was accepted as part of the definition. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">Calcite<\/a> is quite often formed by organic processes, but is considered a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> because it is widely found and geologically important. Because of these discrepancies, the International Mineralogical Association in 1985 amended the definition to: \u201cA <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> is an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a> or chemical compound that is normally crystalline and that has been formed as a result of geological processes.\u201d This means that the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a> in the shell of a clam is not considered a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>. But once that clam shell undergoes burial, diagenesis, or other geological processes, then the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a> is considered a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>. Typically, substances like coal, pearl, opal, or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_999\">obsidian<\/a> that do not fit the definition of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> are called mineraloids.<\/p>\n<p>A <strong>rock<\/strong> is a substance that contains one or more <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> or mineraloids. As is discussed in later chapters, there are three types of rocks composed of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>: <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> (rocks crystallizing from molten material), sedimentary (rocks composed of products of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_251\">mechanical weathering<\/a> (sand, gravel, etc.) and chemical weathering (things <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitated<\/a> from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a>), and metamorphic (rocks produced by alteration of other rocks by heat and pressure.<\/p>\n<h2><span style=\"font-weight: 400\">3.1 Chemistry of Minerals<\/span><\/h2>\n<p>Rocks are composed of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> that have a specific chemical composition.\u00a0 To understand <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> chemistry, it is essential to examine the fundamental unit of all matter, the atom.<\/p>\n<h3><b>3.1.1 The Atom<\/b><\/h3>\n<figure id=\"attachment_2753\" aria-describedby=\"caption-attachment-2753\" style=\"width: 283px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.1-Electron_cloud_model_of_atom.jpg\"><img class=\"size-medium wp-image-2753\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/09\/03.1-Electron_cloud_model_of_atom-283x300-1.jpg\" alt=\"Image of atom with defined nucleus and electrons surrounding it in a cloud with concentrations of electrons in energy shells\" width=\"283\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2753\" class=\"wp-caption-text\">Electron cloud model of the atom<\/figcaption><\/figure>\n<p>Matter is made of atoms. Atoms consists of subatomic particles\u2014<strong>protons<\/strong>, <strong>neutrons<\/strong>, and <strong>electrons<\/strong>. A simple model of the atom has a central nucleus composed of protons, which have positive charges, and neutrons which have no charge. A cloud of negatively charged electrons surrounds the nucleus, the number of electrons equaling the number of protons thus balancing the positive charge of the protons for a neutral atom. Protons and neutrons each have a mass number of 1. The mass of an electron is less than\u00a01\/1000<sup>th<\/sup>\u00a0that of a proton or neutron, meaning most of the atom\u2019s mass is in the nucleus.<\/p>\n<h3><b>3.1.2 Periodic Table of the Elements<\/b><\/h3>\n<p>Matter is composed of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> which are atoms that have a specific number of protons in the nucleus. This number of protons is called the <strong>Atomic Number<\/strong> for the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a>. For example, an oxygen atom has 8 protons and an iron atom has 26 protons. An <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a> cannot be broken down chemically into a simpler form and retains unique chemical and physical properties. Each <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a> behaves in a unique manner in nature. This uniqueness led scientists to develop a periodic table of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>, a tabular arrangement of all known <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> listed in order of their atomic number.<\/p>\n<figure id=\"attachment_2754\" aria-describedby=\"caption-attachment-2754\" style=\"width: 1024px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Periodic_Table-02-scaled.jpg\"><img class=\"size-large wp-image-2754\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/09\/Periodic_Table-02-1024x795-1.jpg\" alt=\"The Periodic Table of the Elements showing all elements with their chemical symbols, atomic weight, and atomic number.\" width=\"1024\" height=\"795\"><\/a><figcaption id=\"caption-attachment-2754\" class=\"wp-caption-text\">The Periodic Table of the Elements<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p><span style=\"font-weight: 400\">The first arrangement of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> into a periodic table was done by Dmitri Mendeleev in 1869 using the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> known at the time<\/span><span style=\"font-weight: 400\">. In the periodic table, each <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a> has a chemical symbol, name, atomic number, and atomic mass. The chemical symbol is an abbreviation for the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a>, often derived from a Latin or Greek name for the substance<\/span><span style=\"font-weight: 400\">. The atomic number is the number of protons in the nucleus. The atomic mass is the number of protons and neutrons in the nucleus, each with a mass number of one. Since the mass of electrons is so much less than the protons and neutrons, the atomic mass is effectively the number of protons plus neutrons. <\/span><\/p>\n<figure id=\"attachment_2755\" aria-describedby=\"caption-attachment-2755\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/3.3a_Formation_of_Carbon14_from_Nitrogen14.jpg\"><img class=\"size-medium wp-image-2755\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/09\/3.3a_Formation_of_Carbon14_from_Nitrogen14-300x123-1.jpg\" alt=\"\" width=\"300\" height=\"123\"><\/a><figcaption id=\"caption-attachment-2755\" class=\"wp-caption-text\">Formation of Carbon 14 from Nitrogen 14<\/figcaption><\/figure>\n<p>The atomic mass of natural <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> represents an average mass of the atoms comprising that substance in nature and is usually not a whole number as seen on the periodic table, meaning that an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a> exists in nature with atoms having different numbers of neutrons. The differing number of neutrons affects the mass of an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a> in nature and the atomic mass number represents this average. This gives rise to the concept of\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1779\">isotope<\/a><strong>.\u00a0<\/strong><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1779\">Isotopes<\/a> <\/strong>are forms of an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a> with the same number of protons but different numbers of neutrons. There are usually several <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1779\">isotopes<\/a> for a particular <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a>. For example, 98.9% of carbon atoms have 6 protons and 6 neutrons. This <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1779\">isotope<\/a> of carbon is called carbon-12 (<sup>12<\/sup>C). A few carbon atoms, carbon-13 (<sup>13<\/sup>C), have 6 protons and 7 neutrons. A trace amount of carbon atoms, carbon-14 (<sup>14<\/sup>C), has 6 protons and 8 neutrons.<\/p>\n<figure id=\"attachment_2756\" aria-describedby=\"caption-attachment-2756\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/elemental-composition-crust.jpg\"><img class=\"size-medium wp-image-2756\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/09\/elemental-composition-crust-300x277-1.jpg\" alt=\"Oxygen and silicon make up 3\/4ths of the chart.\" width=\"300\" height=\"277\"><\/a><figcaption id=\"caption-attachment-2756\" class=\"wp-caption-text\">Element abundance pie chart for Earth's crust by Callan Bentley.<\/figcaption><\/figure>\n<p>Among the 118 known <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>, the heaviest are fleeting human creations known only in high energy particle accelerators, and they decay rapidly. The heaviest naturally occurring <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a> is uranium, atomic number 92. The eight most abundant elements in Earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental crust<\/a> are shown in Table 1<span style=\"font-weight: 400\">. These <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> are found in the most common rock forming <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>.<\/span><\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<table style=\"height: 135px\">\n<tbody>\n<tr style=\"height: 15px\">\n<td style=\"height: 15px;width: 202.188px\"><b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">Element<\/a><\/b><\/td>\n<td style=\"height: 15px;width: 134.797px\"><b>Symbol<\/b><\/td>\n<td style=\"height: 15px;width: 237.703px\"><b>Abundance %<\/b><\/td>\n<\/tr>\n<tr style=\"height: 15px\">\n<td style=\"height: 15px;width: 202.188px\"><span style=\"font-weight: 400\">Oxygen<\/span><\/td>\n<td style=\"height: 15px;width: 134.797px\"><span style=\"font-weight: 400\">O<\/span><\/td>\n<td style=\"height: 15px;width: 237.703px\"><span style=\"font-weight: 400\">47%<\/span><\/td>\n<\/tr>\n<tr style=\"height: 15px\">\n<td style=\"height: 15px;width: 202.188px\"><span style=\"font-weight: 400\">Silicon<\/span><\/td>\n<td style=\"height: 15px;width: 134.797px\"><span style=\"font-weight: 400\">Si<\/span><\/td>\n<td style=\"height: 15px;width: 237.703px\"><span style=\"font-weight: 400\">28%<\/span><\/td>\n<\/tr>\n<tr style=\"height: 15px\">\n<td style=\"height: 15px;width: 202.188px\"><span style=\"font-weight: 400\">Aluminum<\/span><\/td>\n<td style=\"height: 15px;width: 134.797px\"><span style=\"font-weight: 400\">Al<\/span><\/td>\n<td style=\"height: 15px;width: 237.703px\"><span style=\"font-weight: 400\">8%<\/span><\/td>\n<\/tr>\n<tr style=\"height: 15px\">\n<td style=\"height: 15px;width: 202.188px\"><span style=\"font-weight: 400\">Iron<\/span><\/td>\n<td style=\"height: 15px;width: 134.797px\"><span style=\"font-weight: 400\">Fe<\/span><\/td>\n<td style=\"height: 15px;width: 237.703px\"><span style=\"font-weight: 400\">5%<\/span><\/td>\n<\/tr>\n<tr style=\"height: 15px\">\n<td style=\"height: 15px;width: 202.188px\"><span style=\"font-weight: 400\">Calcium<\/span><\/td>\n<td style=\"height: 15px;width: 134.797px\"><span style=\"font-weight: 400\">Ca<\/span><\/td>\n<td style=\"height: 15px;width: 237.703px\"><span style=\"font-weight: 400\">4%<\/span><\/td>\n<\/tr>\n<tr style=\"height: 15px\">\n<td style=\"height: 15px;width: 202.188px\"><span style=\"font-weight: 400\">Sodium<\/span><\/td>\n<td style=\"height: 15px;width: 134.797px\"><span style=\"font-weight: 400\">Na<\/span><\/td>\n<td style=\"height: 15px;width: 237.703px\"><span style=\"font-weight: 400\">3%<\/span><\/td>\n<\/tr>\n<tr style=\"height: 15px\">\n<td style=\"height: 15px;width: 202.188px\"><span style=\"font-weight: 400\">Potassium<\/span><\/td>\n<td style=\"height: 15px;width: 134.797px\">K<\/td>\n<td style=\"height: 15px;width: 237.703px\"><span style=\"font-weight: 400\">3%<\/span><\/td>\n<\/tr>\n<tr style=\"height: 15px\">\n<td style=\"height: 15px;width: 202.188px\"><span style=\"font-weight: 400\">Magnesium<\/span><\/td>\n<td style=\"height: 15px;width: 134.797px\">Mg<\/td>\n<td style=\"height: 15px;width: 237.703px\"><span style=\"font-weight: 400\">2%<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><em style=\"font-size: 16px;font-weight: 400\">Table 1. Eight Most Abundant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">Elements<\/a> in the Earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">Continental Crust<\/a> % by weight (source:\u00a0<a href=\"https:\/\/pubs.usgs.gov\/circ\/1953\/0285\/report.pdf\">USGS<\/a>). All other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> are less than 1%.<\/em><\/p>\n<h3><b>3.1.3 Chemical Bonding<\/b><\/h3>\n<figure id=\"attachment_2757\" aria-describedby=\"caption-attachment-2757\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/H2O_2D_labelled.svg_.png\"><img class=\"wp-image-145 size-medium\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/09\/H2O_2D_labelled.svg_-300x131.png\" alt=\"The hydrogen atoms are on one side, about 105\u00b0 apart.\" width=\"300\" height=\"131\"><\/a><figcaption id=\"caption-attachment-2757\" class=\"wp-caption-text\">A model of a water molecule, showing the bonds between the hydrogen and oxygen.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p><span style=\"font-weight: 400\">Most substances on Earth are compounds containing multiple <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>. Chemical <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonding<\/a> describes how these atoms attach with each other to form compounds, such as sodium and chlorine combining to form NaCl, common table salt. Compounds that are held together by\u00a0<\/span>chemical <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> are called molecules. Water is a compound of hydrogen and oxygen in which two hydrogen atoms are covalently <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> with one oxygen making the water molecule. The oxygen we breathe is formed when one oxygen atom covalently <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> with another oxygen atom to make the molecule O<sub>2<\/sub>. The subscript 2 in the chemical formula indicates the molecule contains two atoms of oxygen.<\/p>\n<p>Most <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are also compounds of more than one <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a>. The common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a> has the chemical formula CaCO<sub>3<\/sub> indicating the molecule consists of one calcium, one carbon, and three oxygen atoms.\u00a0In <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a>, one carbon and three oxygen atoms are held together by covalent <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> to form a <strong>molecular ion<\/strong>, called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a>, which has a negative charge. Calcium as an <strong>ion<\/strong> has a positive charge of plus two. The two oppositely charged ions attract each other and combine to form the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a>, CaCO3. The name of the chemical compound is calcium <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a>, where calcium is Ca and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> refers to the molecular ion CO<sub>3<\/sub><sup>-2<\/sup>.<\/p>\n<p>The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">olivine<\/a> has the chemical formula (Mg,Fe)<sub>2<\/sub>SiO<sub>4<\/sub>, in which one silicon and four oxygen atoms are <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> with two atoms of either magnesium or iron.\u00a0The comma between iron (Fe) and magnesium (Mg) indicates the two <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> can occupy the same location in the crystal structure and substitute for one another.<\/p>\n<h4><i><span style=\"font-weight: 400\">3.1.3.1 Valence and Charge<\/span><\/i><\/h4>\n<p><span style=\"font-weight: 400\">The electrons around the atom\u2019s nucleus are located in shells representing different energy levels. The outermost shell is called the <strong>valence shell<\/strong>. Electrons in the valence shell are involved in chemical <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonding<\/a>. In 1913, Niels Bohr proposed a simple model of the atom that states atoms are more stable when their outermost shell is full<\/span><span style=\"font-weight: 400\">. Atoms of most <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> thus tend to gain or lose electrons so the outermost or valence shell is full. In Bohr\u2019s model, the innermost shell can have a maximum of two electrons and the second and third shells can have a maximum of eight electrons. <\/span>When the innermost shell is the valence shell, as in the case of hydrogen and helium, it obeys the octet rule when it is full with two electrons. For <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> in higher rows, the octet rule of eight electrons in the valence shell applies.<\/p>\n<figure id=\"attachment_2758\" aria-describedby=\"caption-attachment-2758\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.4_Carbon_dioxide_3D_ball.png\"><img class=\"wp-image-2758 size-medium\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.4_Carbon_dioxide_3D_ball-300x213-1.png\" alt=\"Carbon dioxide molecule with a carbon ion in the center and two oxygen ions on either side, each sharing two electrons with the carbon.\" width=\"300\" height=\"213\"><\/a><figcaption id=\"caption-attachment-2758\" class=\"wp-caption-text\">The carbon dioxide molecule. Since Oxygen is -2 and Carbon is +4, the two oxygens bond to the carbon to form a neutral molecule.<\/figcaption><\/figure>\n<p>The rows in the periodic table present the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> in order of atomic number and the columns organize <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> with similar characteristics, such as the same number of electrons in their valence shells. Columns are often labeled from left to right with Roman numerals I to VIII, and Arabic numerals 1 through 18. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> in columns I and II have 1 and 2 electrons in their respective valence shells and the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> in columns VI and VII have 6 and 7 electrons in their respective valence shells.<\/p>\n<p><span style=\"font-weight: 400\">In row 3 and column I, sodium (Na) has 11 protons in the nucleus and 11 electrons in three shells\u20142 electrons in the inner shell, 8 electrons in the second shell, and 1 electron in the valence shell. To maintain a full outer shell of 8 electrons per the octet rule, sodium readily gives up that 1 electron so there are 10 total electrons. With 11 positively charged protons in the nucleus and 10 negatively charged electrons in two shells, sodium when forming chemical <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> is an ion with an overall net charge of +1<\/span><span style=\"font-weight: 400\">.<\/span><\/p>\n<p><span style=\"font-weight: 400\">All <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> in column I have a single electron in their valence shell and a valence of 1.\u00a0<\/span>These other column I <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> also readily give up this single valence electron and thus become ions with a +1 charge. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">Elements<\/a> in column II readily give up 2 electrons and end up as ions with a charge of +2. Note that elements in columns I and II which readily give up their valence electrons, often form bonds with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> in columns VI and VII which readily take up these electrons. \u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">Elements<\/a> in columns 3 through 15 are usually involved in covalent <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonding<\/a>. The last column 18 (VIII) contains the <strong>noble gases<\/strong>. These <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> are chemically inert because the valence shell is already full with 8 electrons, so they do not gain or lose electrons. An example is the noble gas helium which has 2 valence electrons in the first shell. Its valence shell is therefore full. All <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> in column VIII possess full valence shells and do not form <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> with other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>.<\/p>\n<p><span style=\"font-weight: 400\">As seen above, an atom with a net positive or negative charge as a result of gaining or losing electrons is called an <strong>ion<\/strong>. In general the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> on the left side of the table lose electrons and become positive ions, called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1780\">cations<\/a> because they are attracted to the cathode in an electrical device. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> on the right side tend to gain electrons. These are called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1782\">anions<\/a> because they are attracted to the anode in an electrical device. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> in the center of the periodic table, columns 3 through 15, do not consistently follow the octet rule. These are called transition <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>. A common example is iron, which has a +2 or +3 charge depending on the oxidation state of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a>. Oxidized Fe<sup>+3<\/sup> carries a +3 charge and reduced Fe<sup>+2<\/sup> is +2. These two different oxidation states of iron often impart dramatic colors to rocks containing their <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>\u2014the oxidized form producing red colors and the reduced form producing green.<\/span><\/p>\n<h4><i><span style=\"font-weight: 400\">3.1.3.2\u00a0<\/span><\/i><i><span style=\"font-weight: 400\">Ionic Bonding<\/span><\/i><\/h4>\n<figure id=\"attachment_2759\" aria-describedby=\"caption-attachment-2759\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03-Sodium-chloride-3D-ionic.png\"><img class=\"size-medium wp-image-2759\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03-Sodium-chloride-3D-ionic-300x284-1.png\" alt=\"Image of crystal model of halite with ions of sodium and chlorine arranged in a cubic structure.\" width=\"300\" height=\"284\"><\/a><figcaption id=\"caption-attachment-2759\" class=\"wp-caption-text\">Cubic arrangement of Na and Cl in Halite<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p><span style=\"font-weight: 400\">Ionic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a>, also called electron-transfer <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a>, are formed by the electrostatic attraction between atoms having opposite charges. Atoms of two opposite charges attract each other electrostatically and form an <strong>ionic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bond<\/a><\/strong> in which the positive ion transfers its electron (or electrons) to the negative ion which takes them up. Through this transfer both atoms thus achieve a full valence shell.\u00a0<\/span>For example one atom of sodium (Na<sup>+1<\/sup>) and one atom of chlorine (Cl<sup>-1<\/sup>) form an ionic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bond<\/a> to make the compound sodium chloride (NaCl). This is also known as the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> halite or common table salt. Another example is calcium (Ca<sup>+2<\/sup>) and chlorine (Cl<sup>-1<\/sup>) combining to make the compound calcium chloride (CaCl<sub>2<\/sub>). The subscript 2 indicates two atoms of chlorine are ionically <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> to one atom of calcium.<\/p>\n<h4><i><span style=\"font-weight: 400\">3.1.3.3\u00a0<\/span><\/i><i><span style=\"font-weight: 400\">Covalent <\/span><\/i><i><span style=\"font-weight: 400\">Bonding<\/span><\/i><\/h4>\n<figure id=\"attachment_2760\" aria-describedby=\"caption-attachment-2760\" style=\"width: 249px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Covalent.svg_.png\"><img class=\"size-medium wp-image-2760\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Covalent.svg_-249x300-1.png\" alt=\"Each atom is sharing electrons.\" width=\"249\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2760\" class=\"wp-caption-text\">Methane molecule<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>Ionic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> are usually formed between a <strong>metal<\/strong> and a <strong>nonmetal<\/strong>. Another type, called a covalent or electron-sharing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bond<\/a>, commonly occurs between nonmetals. Covalent <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> share electrons between ions to complete their valence shells. For example, oxygen (atomic number 8) has 8 electrons\u20142 in the inner shell and 6 in the valence shell. Gases like oxygen often form diatomic molecules by sharing valence electrons. In the case of oxygen, two atoms attach to each other and share 2 electrons to fill their valence shells to become the common oxygen molecule we breathe (O<sub>2<\/sub>). Methane (CH<sub>4<\/sub>) is another covalently <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> gas. The carbon atom needs 4 electrons and each hydrogen needs 1. Each hydrogen shares its electron with the carbon to form a molecule as shown in the figure.<\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-17\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-17\" class=\"h5p-iframe\" data-content-id=\"17\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"3.1 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3754\" aria-describedby=\"caption-attachment-3754\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/3.1-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-149\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/3.1-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3754\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 3.1 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-size: 28px\">3.2 Formation of Minerals<\/span><\/h2>\n<p><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Minerals<\/a> form when atoms <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bond<\/a> together in a crystalline arrangement. Three main ways this occurs in nature are: 1) <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitation<\/a> directly from an aqueous (water) <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a> with a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> change, 2) <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1752\">crystallization<\/a> from a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> with a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> change, and 3) biological <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitation<\/a> by the action of organisms. <\/span><\/p>\n<h3><b> 3.2.1 Precipitation from aqueous solution<\/b><\/h3>\n<figure id=\"attachment_2761\" aria-describedby=\"caption-attachment-2761\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.5_Hard_Water_Calcification.jpg\"><img class=\"size-medium wp-image-2761\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.5_Hard_Water_Calcification-300x200-1.jpg\" alt=\"Encrusted calcium carbonate (lime) deposits on faucent\" width=\"300\" height=\"200\"><\/a><figcaption id=\"caption-attachment-2761\" class=\"wp-caption-text\">Calcium carbonate deposits from hard water<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">Solutions<\/a> consist of ions or molecules, known as solutes, dissolved in a medium or solvent. In nature this solvent is usually water. Many <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> can be dissolved in water, such as halite or table salt, which has the composition sodium chloride, NaCl. The Na<sup>+1<\/sup> and Cl<sup>-1<\/sup> ions separate and disperse into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a>.<\/p>\n<p><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">Precipitation<\/a><\/strong> is the reverse process, in which ions in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a> come together to form solid <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">Precipitation<\/a> is dependent on the concentration of ions in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a> and other factors such as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> and pressure. The point at which a solvent cannot hold any more solute is called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1784\">saturation<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">Precipitation<\/a> can occur when the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a> falls, when the solute evaporates, or with changing chemical conditions in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a>. An example of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitation<\/a> in our homes is when water evaporates and leaves behind a rind of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> on faucets, shower heads, and drinking glasses.<\/p>\n<p>In nature, changes in environmental conditions may cause the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> dissolved in water to form <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> and grow into crystals or cement grains of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediment<\/a> together. In Utah, deposits of tufa formed from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>-rich springs that emerged into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_747\">ice age<\/a> Lake Bonneville. Now exposed in dry valleys, this porous tufa was a natural insulation used by pioneers to build their homes with a natural protection against summer heat and winter cold. The travertine terraces at Mammoth Hot Springs in Yellowstone Park are another example formed by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitation<\/a> at the edges of the shallow spring-fed ponds.<\/p>\n<figure id=\"attachment_2762\" aria-describedby=\"caption-attachment-2762\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.6_1200px-Bonneville_Salt_Flats.jpg\"><img class=\"size-medium wp-image-2762\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.6_1200px-Bonneville_Salt_Flats-300x197-1.jpg\" alt=\"The Bonneville Salt Flats of Utah\" width=\"300\" height=\"197\"><\/a><figcaption id=\"caption-attachment-2762\" class=\"wp-caption-text\">The Bonneville Salt Flats of Utah<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\">Another example of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitation<\/a> occurs in the Great Salt Lake, Utah, where the concentration of sodium chloride and other salts is nearly eight times greater than in the world\u2019s oceans <\/span><span style=\"font-weight: 400\">[zotpressInText item=\"{DU5CMSHJ}\" format=\"%num%\" brackets=\"yes\"]<\/span><span style=\"font-weight: 400\">.\u00a0<\/span>Streams carry salt ions into the lake from the surrounding mountains. With no other outlet, the water in the lake evaporates and the concentration of salt increases until <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1784\">saturation<\/a> is reached and the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitate<\/a> out as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediments<\/a>. Similar salt deposits include halite and other precipitates, and occur in other lakes like Mono Lake in California and the Dead Sea.<\/p>\n<h3><b>3.2.2 Crystallization from Magma<\/b><\/h3>\n<figure id=\"attachment_2763\" aria-describedby=\"caption-attachment-2763\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.5a_Pahoehoe_toe.jpg\"><img class=\"size-medium wp-image-2763\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.5a_Pahoehoe_toe-300x188-1.jpg\" alt=\"A lava flow\" width=\"300\" height=\"188\"><\/a><figcaption id=\"caption-attachment-2763\" class=\"wp-caption-text\">Lava, magma at the earth\u2019s surface<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>Heat is energy that causes atoms in substances to vibrate. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">Temperature<\/a> is a measure of the intensity of the vibration. If the vibrations are violent enough, chemical <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> are broken and the crystals melt releasing the ions into the melt. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">Magma<\/a> is molten rock with freely moving ions. When <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> is emplaced at depth or extruded onto the surface (then called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a>), it starts to cool and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> crystals can form.<\/p>\n<h3><b>3.2.3 Precipitation by Organisms<\/b><\/h3>\n<figure id=\"attachment_2764\" aria-describedby=\"caption-attachment-2764\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.8_Ammonite_Asteroceras.jpg\"><img class=\"size-full wp-image-2764\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.8_Ammonite_Asteroceras.jpg\" alt=\"Shell of an ammonite, an extinct cephalopod, with a spiral shell in a plane.\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-2764\" class=\"wp-caption-text\">Ammonite shell made of calcium carbonate<\/figcaption><\/figure>\n<p><span style=\"font-size: 1em\">Many organisms build bones, shells, and body coverings by extracting ions from water and precipitating <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> biologically. The most common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitated<\/a> by organisms is <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a>, or calcium <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> (CaCO3). <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">Calcite<\/a> is often <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitated<\/a> by organisms as a polymorph called aragonite. <\/span><strong style=\"font-size: 1em\">Polymorphs<\/strong><span style=\"font-size: 1em\"> are crystals with the same chemical formula but different crystal structures. Marine invertebrates such as corals and clams <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitate<\/a> aragonite or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a> for their shells and structures. Upon death, their hard parts accumulate on the ocean floor as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediments<\/a>, and eventually may become the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1761\">sedimentary rock<\/a> limestone. Though limestone can form inorganically, the vast majority is formed by this biological process. Another example is marine organisms called radiolaria, which are zooplankton that <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitate<\/a> silica for their microscopic external shells. When the organisms die, the shells accumulate on the ocean floor and can form the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1761\">sedimentary rock<\/a> chert. An example of biologic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitation<\/a> from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1274\">vertebrate<\/a> world is bone, which is composed mostly of a type of apatite, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_975\">phosphate<\/a> group. The apatite found in bones contains calcium and water in its structure and is called hydroxycarbonate apatite, Ca<\/span><sub>5<\/sub><span style=\"font-size: 1em\">(PO<\/span><sub>4<\/sub><span style=\"font-size: 1em\">)<\/span><sub>3<\/sub><span style=\"font-size: 1em\">(OH).\u00a0 As mentioned above, such substances are not technically <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> until the organism dies and these hard parts become <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1228\">fossils<\/a>.<\/span><\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-18\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-18\" class=\"h5p-iframe\" data-content-id=\"18\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"3.2 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3753\" aria-describedby=\"caption-attachment-3753\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/3.2-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-154\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/3.2-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3753\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 3.2 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-weight: 400\">3.3 Silicate Minerals<\/span><\/h2>\n<figure id=\"attachment_2765\" aria-describedby=\"caption-attachment-2765\" style=\"width: 256px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Tetrahedron.gif\"><img class=\"size-full wp-image-2765\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tetrahedron.gif\" alt=\"It is a pyramid shape with a triangular base\" width=\"256\" height=\"256\"><\/a><figcaption id=\"caption-attachment-2765\" class=\"wp-caption-text\">Rotating animation of a tetrahedra<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Minerals<\/a> are categorized based on their composition and structure. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">Silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are built around a molecular ion called the <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silicon-oxygen tetrahedron<\/a><\/strong>. A tetrahedron has a pyramid-like shape with four sides and four corners.\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">Silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> form the largest group of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> on Earth, comprising the vast majority of the Earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a>. Of the nearly four thousand known <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> on Earth, most are rare. There are only a few that make up most of the rocks likely to be encountered by surface dwelling creatures like us. These are generally called the <strong>rock-forming <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a><\/strong>.<\/p>\n<figure id=\"attachment_2766\" aria-describedby=\"caption-attachment-2766\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.10_Tetrahedron.jpg\"><img class=\"size-medium wp-image-2766\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.10_Tetrahedron-300x300-1.jpg\" alt=\"Model of silicon-oxygen tetrahedron of ping pong balls with a tiny silicon ion in the space in the middle of the four large balls\" width=\"300\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2766\" class=\"wp-caption-text\">Ping pong ball model of tetrahedron: balls are oxygen, lead sinker in center is silicon<\/figcaption><\/figure>\n<p>The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silicon-oxygen tetrahedron<\/a> (SiO<sub>4<\/sub>) consists of a single silicon atom at the center and four oxygen atoms located at the four corners of the tetrahedron. Each oxygen ion has a -2 charge and the silicon ion has a +4 charge. The silicon ion shares one of its four valence electrons with each of the four oxygen ions in a covalent <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bond<\/a> to create a symmetrical geometric four-sided pyramid figure. Only half of the oxygen\u2019s valence electrons are shared, giving the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silicon-oxygen tetrahedron<\/a> an ionic charge of -4. This <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silicon-oxygen tetrahedron<\/a> forms bonds with many other combinations of ions to form the large group of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>.<\/p>\n<figure id=\"attachment_2767\" aria-describedby=\"caption-attachment-2767\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.11_Tetrahedron_open.jpg\"><img class=\"size-medium wp-image-2767\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.11_Tetrahedron_open-300x255-1.jpg\" alt=\"Top ball removed showing the tiny silicon ion in the center\" width=\"300\" height=\"255\"><\/a><figcaption id=\"caption-attachment-2767\" class=\"wp-caption-text\">The silicon ion in the center of the tetrahedron<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\">The silicon ion is much smaller than the oxygen ions (see the figures) and fits into a small space in the center of the four large oxygen ions, seen if the top ball is removed (as shown in the figure to the right). <\/span><span style=\"font-weight: 400\">Because only one of the valence electrons of the corner oxygens is shared, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silicon-oxygen tetrahedron<\/a> has chemically active corners available to form <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> with other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silica tetrahedra<\/a> or other positively charged ions such as Al<\/span><sub><span style=\"font-weight: 400\">+3<\/span><\/sub><span style=\"font-weight: 400\">, Fe<\/span><sub><span style=\"font-weight: 400\">+2,+3<\/span><\/sub><span style=\"font-weight: 400\">, Mg<\/span><sub><span style=\"font-weight: 400\">+2<\/span><\/sub><span style=\"font-weight: 400\">, K<\/span><sub><span style=\"font-weight: 400\">+1<\/span><\/sub><span style=\"font-weight: 400\">, Na<\/span><sub><span style=\"font-weight: 400\">+1<\/span><\/sub><span style=\"font-weight: 400\">, and Ca<\/span><sub><span style=\"font-weight: 400\">+2<\/span><\/sub><span style=\"font-weight: 400\">. Depending on many factors, such as the original <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> chemistry, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silica-oxygen tetrahedra<\/a> can combine with other tetrahedra in several different configurations. For example, tetrahedra can be isolated, attached in chains, sheets, or three dimensional structures. These combinations and others create the chemical structure in which positively charged ions can be inserted for unique chemical compositions forming <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> groups. \u00a0\u00a0<\/span><\/p>\n<h3><b>3.3.1 The dark ferromagnesian silicates<\/b><\/h3>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2768\" aria-describedby=\"caption-attachment-2768\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.12_Peridot_in_basalt.jpg\"><img class=\"size-medium wp-image-2768\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.12_Peridot_in_basalt-300x225-1.jpg\" alt=\"Many small crystall of the green mineral olivine in a mass of basalt\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-2768\" class=\"wp-caption-text\">Olivine crystals in basalt<\/figcaption><\/figure>\n<p><span style=\"font-size: 14pt\"><b>The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">Olivine<\/a> Family<\/b><\/span><\/p>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">Olivine<\/a> is the primary <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> component in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> rock such as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1666\">peridotite<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1013\">basalt<\/a>. It is characteristically green when not weathered. The chemical formula is (Fe,Mg)<sub>2<\/sub>SiO<sub>4<\/sub>. As previously described, the comma between iron (Fe) and magnesium (Mg) indicates these two <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> occur in a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1786\">solid solution<\/a>.\u00a0<span style=\"font-weight: 400\">Not to be confused with a liquid <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a>, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1786\">solid solution<\/a> occurs when two or more <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> have similar properties and can freely substitute for each other in the same location in the crystal structure.<\/span><\/p>\n<figure id=\"attachment_2769\" aria-describedby=\"caption-attachment-2769\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.13_Atomic_structure_of_olivine_1.png\"><img class=\"size-full wp-image-2769\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.13_Atomic_structure_of_olivine_1.png\" alt=\"Tetrahedral structure of olivine showing the independent tetrahedra connected together by anions of iron and\/or magnesium.\" width=\"300\" height=\"258\"><\/a><figcaption id=\"caption-attachment-2769\" class=\"wp-caption-text\">Tetrahedral structure of olivine<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">Olivine<\/a> is referred to as a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> family because of the ability of iron and magnesium to substitute for each other. Iron and magnesium in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">olivine<\/a> family indicates a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1786\">solid solution<\/a> forming a compositional series within the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> group which can form crystals of all iron as one end member and all mixtures of iron and magnesium in between to all magnesium at the other end member. Different <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> names are applied to compositions between these end members.\u00a0 In the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">olivine<\/a> series of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, the iron and magnesium ions in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1786\">solid solution<\/a> are about the same size and charge, so either atom can fit into the same location in the growing crystals. Within the cooling <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> crystals continue to grow until they solidify into <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous rock<\/a>. The relative amounts of iron and magnesium in the parent <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> determine which <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> in the series form. Other rarer <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> with similar properties to iron or magnesium, like manganese (Mn), can substitute into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">olivine<\/a> crystalline structure in small amounts. Such ionic substitutions in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> crystals give rise to the great variety of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> and are often responsible for differences in color and other properties within a group or family of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">Olivine<\/a> has a pure iron end-member (called fayalite) and a pure magnesium end-member (called forsterite). Chemically, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">olivine<\/a> is mostly silica, iron, and magnesium and therefore is grouped among the dark-colored <\/span>ferromagnesian<span style=\"font-weight: 400\"> (iron=ferro, magnesium=magnesian) or <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a><\/strong> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, a contraction of their chemical symbols Ma and Fe. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">Mafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are also referred to as dark-colored ferromagnesian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. <em>Ferro<\/em> means iron and <em>magnesian<\/em> refers to magnesium. Ferromagnesian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicates<\/a> tend to be more dense than non-ferromagnesian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicates<\/a>. This difference in density ends up being important in controlling the behavior of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks that are built from these <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>: whether a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subducts<\/a> or not is largely governed by the density of its rocks, which are in turn controlled by the density of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> that comprise them.<\/span><\/p>\n<p>The crystal structure of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">olivine<\/a> is built from independent <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silica tetrahedra<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Minerals <\/a>with independent tetrahedral structures are called neosilicates (or orthosilicates). In addition to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">olivine<\/a>, other common neosilicate <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> include garnet, topaz, kyanite, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1227\">zircon<\/a>.<\/p>\n<p>Two other similar arrangements of tetrahedra are close in structure to the neosilicates and grade toward the next group of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, the pyroxenes. In a variation on independent tetrahedra called sorosilicates, there are <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> that share one oxygen between two tetrahedra, and include <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> like pistachio-green epidote, a gemstone. Another variation are the cyclosilicates, which as the name suggests, consist of tetrahedral rings, and include gemstones such as beryl, emerald, aquamarine, and tourmaline<\/p>\n<h3><b>3.3.2 Pyroxene Family<\/b><\/h3>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2770\" aria-describedby=\"caption-attachment-2770\" style=\"width: 300px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.14_Diopside-172005.jpg\"><img class=\"wp-image-2770 size-medium\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.14_Diopside-172005-300x231-1.jpg\" alt=\"Dark green crystals of diopside, a member of the pyroxene family\" width=\"300\" height=\"231\"><\/a><figcaption id=\"caption-attachment-2770\" class=\"wp-caption-text\">Crystals of diopside, a member of the pyroxene family<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2771\" aria-describedby=\"caption-attachment-2771\" style=\"width: 70px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.15_Pyroxen-chain.png\"><img class=\"wp-image-2771\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.15_Pyroxen-chain.png\" alt=\"Single chain of tetrahedra in pyroxene, alternating with adjacent corner oxygens bonded. The outer corners are active to bond with other anions.\" width=\"70\" height=\"517\"><\/a><figcaption id=\"caption-attachment-2771\" class=\"wp-caption-text\">Single chain tetrahedral structure in pyroxene<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">Pyroxene<\/a> is another family of dark ferromagnesian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, typically black or dark green in color. Members of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">pyroxene<\/a> family have a complex chemical composition that includes iron, magnesium, aluminum, and other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> to polymerized <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silica tetrahedra<\/a>. <strong>Polymers<\/strong> are chains, sheets, or three-dimensional structures, and are formed by multiple tetrahedra covalently <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> via their corner oxygen atoms. Pyroxenes are commonly found in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks such as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1666\">peridotite<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1013\">basalt<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1016\">gabbro<\/a>, as well as metamorphic rocks like eclogite and blue schist.<\/p>\n<p>Pyroxenes are built from long, single chains of polymerized <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silica tetrahedra<\/a> in which tetrahedra share two corner oxygens. The silica chains are <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> together into the crystal structures by metal cations. A common member of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">pyroxene<\/a> family is augite, itself containing several <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1786\">solid solution<\/a> series with a complex chemical formula (Ca,Na)(Mg,Fe,Al,Ti)(Si,Al)<sub>2<\/sub>O<sub>6<\/sub> that gives rise to a number of individual <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> names.<\/p>\n<p>This single-chain crystalline structure <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> with many <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>, which can also freely substitute for each other. The generalized chemical composition for <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">pyroxene<\/a> is XZ(Al,Si)<sub>2<\/sub>O<sub>6<\/sub>. X represents the ions Na, Ca, Mg, or Fe, and Z represents Mg, Fe, or Al. These ions have similar ionic sizes, which allows many possible substitutions among them. Although the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1780\">cations<\/a> may freely substitute for each other in the crystal, they carry different ionic charges that must be balanced out in the final crystalline structure. For example Na has a charge of +1, but Ca has charge of +2. If a Na<sup>+<\/sup> ion substitutes for a Ca<sup>+2<\/sup> ion, it creates an unequal charge that must be balanced by other ionic substitutions elsewhere in the crystal. Note that ionic size is more important than ionic charge for substitutions to occur in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1786\">solid solution<\/a> series in crystals.<\/p>\n<h3><\/h3>\n<h3><b>3.3.3 Amphibole Family<\/b><\/h3>\n<figure id=\"attachment_2773\" aria-describedby=\"caption-attachment-2773\" style=\"width: 200px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.15_Orthoclase_Hornblende.jpg\"><img class=\"wp-image-2773\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.15_Orthoclase_Hornblende-300x300-1.jpg\" alt=\"A crystal of orthoclase (potassium feldspar) wth elongated dark crystals of hornblende\" width=\"200\" height=\"200\"><\/a><figcaption id=\"caption-attachment-2773\" class=\"wp-caption-text\">Elongated crystals of hornblende in orthoclase<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2772\" aria-describedby=\"caption-attachment-2772\" style=\"width: 200px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.16_Amphibole.jpg\"><img class=\"wp-image-2772\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.16_Amphibole-300x236-1.jpg\" alt=\"Black crystals of hornblende\" width=\"200\" height=\"157\"><\/a><figcaption id=\"caption-attachment-2772\" class=\"wp-caption-text\">Hornblende crystals<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1791\">Amphibole<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are built from polymerized double silica chains and they are also referred to as inosilicates. Imagine two <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">pyroxene<\/a> chains that connect together by sharing a third oxygen on each tetrahedra.\u00a0 Amphiboles are usually found in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> and metamorphic rocks and typically have a long-bladed <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_980\">crystal habit<\/a><\/strong>. The most common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1791\">amphibole<\/a>, hornblende, is usually black; however, they come in a variety of colors depending on their chemical composition. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1762\">metamorphic rock<\/a>, amphibolite, is primarily composed of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1791\">amphibole<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>.<\/p>\n<figure id=\"attachment_2774\" aria-describedby=\"caption-attachment-2774\" style=\"width: 79px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.17_Tremolite-chain.png\"><img class=\"size-medium wp-image-2774\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.17_Tremolite-chain-79x300-1.png\" alt=\"Double chain structure of amphibole; two single chains laying together with the inner corners of each tetrahedron bonded and the outer cornera active to bond with anions\" width=\"79\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2774\" class=\"wp-caption-text\">Double chain structure<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>Amphiboles are composed of iron, magnesium, aluminum, and other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1780\">cations<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silica tetrahedra<\/a>. These dark ferromagnesian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are commonly found in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1016\">gabbro<\/a>, baslt, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1015\">diorite<\/a>, and often form the black specks in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1014\">granite<\/a>. Their chemical formula is very complex and generally written as (RSi<sub>4<\/sub>O<sub>11<\/sub>)<sub>2<\/sub>, where R represents many different <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1780\">cations<\/a>. For example, it can also be written more exactly as AX<sub>2<\/sub>Z<sub>5<\/sub>((Si,Al,Ti)<sub>8<\/sub>O<sub>22<\/sub>)(OH,F,Cl,O)<sub>2<\/sub>. In this formula A may be Ca, Na, K, Pb, or blank; X equals Li, Na, Mg, Fe, Mn, or Ca; and Z is Li, Na, Mg, Fe, Mn, Zn, Co, Ni, Al, \u00a0Cr, Mn, V, Ti, or Zr. The substitutions create a wide variety of colors such as green, black, colorless, white, yellow, blue, or brown. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1791\">Amphibole<\/a> crystals can also include hydroxide ions (OH<sup>-<\/sup>)<sup>,<\/sup> which occurs from an interaction between the growing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> and water dissolved in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>.<\/p>\n<h3><\/h3>\n<h3><\/h3>\n<h3><strong>3.3.4 Sheet Silicates<\/strong><\/h3>\n<figure id=\"attachment_2775\" aria-describedby=\"caption-attachment-2775\" style=\"width: 200px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.19_Biotite_aggregate_-_Ochtendung_Eifel_Germany.jpg\"><img class=\"wp-image-2775\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.19_Biotite_aggregate_-_Ochtendung_Eifel_Germany-300x225-1.jpg\" alt=\"Dark brown crystals of biotite mica showing sheet-like habit\" width=\"200\" height=\"150\"><\/a><figcaption id=\"caption-attachment-2775\" class=\"wp-caption-text\">Sheet crystals of biotite mica<\/figcaption><\/figure>\n<figure id=\"attachment_3637\" aria-describedby=\"caption-attachment-3637\" style=\"width: 250px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/MicaSheetUSGOV.jpg\"><img class=\"wp-image-166\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MicaSheetUSGOV-300x226.jpg\" alt=\"Crystal of muscovite mica showing sheet structure of the mineral\" width=\"250\" height=\"188\"><\/a><figcaption id=\"caption-attachment-3637\" class=\"wp-caption-text\">Crystal of muscovite mica<\/figcaption><\/figure>\n<p>Sheet <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicates<\/a> are built from tetrahedra which share all three of their bottom corner oxygens thus forming sheets of tetrahedra with their top corners available for <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonding<\/a> with other atoms. Micas and clays are common types of sheet <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicates<\/a>, also known as phyllosilicates. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">Mica<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are usually found in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> and metamorphic rocks, while clay <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are more often found in sedimentary rocks. Two frequently found micas are dark-colored <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">biotite<\/a>, frequently found in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1014\">granite<\/a>, and light-colored <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">muscovite<\/a>, found in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1762\">metamorphic rock<\/a> called schist.<\/p>\n<figure id=\"attachment_2777\" aria-describedby=\"caption-attachment-2777\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.20_Silicate-sheet-3D-polyhedra.png\"><img class=\"size-medium wp-image-2777\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.20_Silicate-sheet-3D-polyhedra-300x197-1.png\" alt=\"Continuous sheets of tetradedra with all three base corners bonded to each other; the top corner active to bond with anions\" width=\"300\" height=\"197\"><\/a><figcaption id=\"caption-attachment-2777\" class=\"wp-caption-text\">Sheet structure of mica<\/figcaption><\/figure>\n<p>Chemically, sheet <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicates<\/a> usually contain silicon and oxygen in a 2:5 ratio (Si<sub>4<\/sub>O<sub>10<\/sub>). Micas contain mostly silica, aluminum, and potassium. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">Biotite<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">mica<\/a> has more iron and magnesium and is considered a ferromagnesian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">Muscovite<\/a> micas belong to the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">Felsic<\/a> is a contraction formed from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a>, the dominant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> rocks.<\/p>\n<figure id=\"attachment_2778\" aria-describedby=\"caption-attachment-2778\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.21_Crystal-structure-of-mica.jpg\"><img class=\"size-medium wp-image-2778\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.21_Crystal-structure-of-mica-300x300-1.jpg\" alt=\"Diagram of mica crystal structure with the sheets of tetrahedra inverted onto each other into sandwiches with the active corners bonded with anions and the sandwiches connected together with large potassium ions that form weak bonds easily separated so the crystal comes apart into sheets.\" width=\"300\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2778\" class=\"wp-caption-text\">Crystal structure of a mica<\/figcaption><\/figure>\n<figure id=\"attachment_2779\" aria-describedby=\"caption-attachment-2779\" style=\"width: 296px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Illmenite-mica-sandwich.jpg\"><img class=\"size-medium wp-image-2779\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Illmenite-mica-sandwich-296x300-1.jpg\" alt=\"Silica sheets layered in mica like bread and hjam in a stack of sandwiches\" width=\"296\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2779\" class=\"wp-caption-text\">Mica \"silica sandwich\" structure<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>The illustration of the crystalline structure of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">mica<\/a> shows the corner O atoms <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> with K, Al, Mg, Fe, and Si atoms, forming polymerized sheets of linked tetrahedra, with an octahedral layer of Fe, Mg, or Al, between them.\u00a0 The yellow potassium ions form Van der Waals <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> (attraction and repulsion between atoms, molecules, and surfaces) and hold the sheets together. Van der Waals <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> differ from\u00a0<a href=\"https:\/\/en.wikipedia.org\/wiki\/Covalent_bond\">covalent<\/a>\u00a0and\u00a0<a href=\"https:\/\/en.wikipedia.org\/wiki\/Ionic_bond\">ionic<\/a>\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a>, and exist here between the sandwiches, holding them together into a stack of sandwiches. The Van der Waals <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> are weak compared to the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> within the sheets, allowing the sandwiches to be separated along the potassium layers. This gives <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">mica<\/a> its characteristic property of easily cleaving into sheets.<\/p>\n<figure id=\"attachment_2780\" aria-describedby=\"caption-attachment-2780\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.22_Kaolinite-structure.jpg\"><img class=\"size-medium wp-image-2780\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.22_Kaolinite-structure-300x244-1.jpg\" alt=\"Crystal structure of kaolinite, a clay mineral with sheet structure like mica except that the\" width=\"300\" height=\"244\"><\/a><figcaption id=\"caption-attachment-2780\" class=\"wp-caption-text\">Structure of kaolinite<\/figcaption><\/figure>\n<p>Clays <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> occur in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediments<\/a> formed by the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1754\">weathering<\/a> of rocks and are another family of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> with a tetrahedral sheet structure. Clay <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> form a complex family, and are an important component of many sedimentary rocks. Other sheet <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicates<\/a> include serpentine and chlorite, found in metamorphic rocks.<\/p>\n<p>Clay <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are composed of hydrous aluminum <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicates<\/a>. One type of clay, kaolinite, has a structure like an open-faced sandwich, with the bread being a single layer of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silicon-oxygen tetrahedra<\/a> and a layer of aluminum as the spread in an octahedral configuration with the top oxygens of the sheets.<\/p>\n<h3><b>3.3.5 Framework Silicates<\/b><\/h3>\n<figure id=\"attachment_2829\" aria-describedby=\"caption-attachment-2829\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Quartz-crystals.jpg\"><img class=\"size-medium wp-image-2829\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Quartz-crystals-300x284-1.jpg\" alt=\"Freely grown quartz crystals showing crysatl faces\" width=\"300\" height=\"284\"><\/a><figcaption id=\"caption-attachment-2829\" class=\"wp-caption-text\">Freely growing quartz crystals showing crystal faces<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">Quartz<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> are the two most abundant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental crust<\/a>. In fact, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> itself is the single most abundant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> in the Earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a>. There are two types of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a>, one containing potassium and abundant in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> rocks of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental crust<\/a>, and the other with sodium and calcium abundant in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> rocks of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic crust<\/a>.\u00a0 Together with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a>, these <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are classified as framework <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicates<\/a>. They are built with a three-dimensional framework of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silica tetrahedra<\/a> in which all four corner oxygens are shared with adjacent tetrahedra. Within these frameworks in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> are holes and spaces into which other ions like aluminum, potassium, sodium, and calcium can fit giving rise to a variety of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> compositions and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> names.<\/p>\n<figure id=\"attachment_2781\" aria-describedby=\"caption-attachment-2781\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/min-crust-pie-chart.jpg\"><img class=\"size-medium wp-image-2781\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/min-crust-pie-chart-300x290-1.jpg\" alt=\"Feldspar is 51% of the chart.\" width=\"300\" height=\"290\"><\/a><figcaption id=\"caption-attachment-2781\" class=\"wp-caption-text\">Mineral abundance pie chart in Earth's crust by Callan Bentley.<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">Feldspars<\/a> are usually found in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks, such as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1014\">granite<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1010\">rhyolite<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1013\">basalt<\/a> as well as metamorphic rocks and detrital sedimentary rocks. Detrital sedimentary rocks are composed of mechanically weathered rock particles, like sand and gravel. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">Quartz<\/a> is especially abundant in detrital sedimentary rocks because it is very resistant to disintegration by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1754\">weathering<\/a>. While <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a> is the most abundant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> on the Earth's surface, due to its durability, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are the most abundant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> in the Earth's <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a>, comprising roughly 50% of the total <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> that make up the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a>.<\/p>\n<figure id=\"attachment_2782\" aria-describedby=\"caption-attachment-2782\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.24_kspar280x210-1.jpg\"><img class=\"size-medium wp-image-2782\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.24_kspar280x210-1-300x200-1.jpg\" alt=\"A group of crystals of pink potassium feldspar\" width=\"300\" height=\"200\"><\/a><figcaption id=\"caption-attachment-2782\" class=\"wp-caption-text\">Pink orthoclase crystals<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">Quartz<\/a> is composed of pure silica, SiO<sub>2<\/sub>, with the tetrahedra arranged in a three dimensional framework. Impurities consisting of atoms within this framework give rise to many varieties of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a> among which are gemstones like amethyst, rose <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a>, and citrine.\u00a0 <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">Feldspars<\/a> are mostly silica with aluminum, potassium, sodium, and calcium. Orthoclase <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> (KAlSi<sub>3<\/sub>O<sub>8<\/sub>), also called potassium <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">K-spar<\/a>, is made of silica, aluminum, and potassium. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">Quartz<\/a> and orthoclase <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> are <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">Felsic<\/a> is the compositional term applied to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> and rocks that contain an abundance of silica. Another <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> is <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">plagioclase<\/a> with the formula (Ca,Na)AlSi<sub>3<\/sub>O<sub>8<\/sub>, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1786\">solid solution<\/a> (Ca,Na) indicating a series of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, one end of the series with calcium CaAl<sub>2<\/sub>Si<sub>2<\/sub>O<sub>8<\/sub>, called anorthite, and the other end with sodium NaAlSi<sub>3<\/sub>O<sub>8<\/sub>, called albite.\u00a0Note how the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> accommodates the substitution of Ca<sup>++<\/sup> and Na<sup>+<\/sup>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Minerals<\/a> in this solid solution series have different <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> names.<\/p>\n<figure id=\"attachment_2783\" aria-describedby=\"caption-attachment-2783\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/23-feldspar-structure.gif\"><img class=\"size-medium wp-image-2783\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/23-feldspar-structure-300x271-1.gif\" alt=\"Framework structure of feldspar with all corners of tetrahedra shared with adjacent tetrahedra; there are holes in the structure in which large anions like potassium and sodium\/calcium fit\" width=\"300\" height=\"271\"><\/a><figcaption id=\"caption-attachment-2783\" class=\"wp-caption-text\">Crystal structure of feldspar<\/figcaption><\/figure>\n<p>Note that aluminum, which has a similar ionic size to silicon, can substitute for silicon inside the tetrahedra (see figure). Because potassium ions are so much larger than sodium and calcium ions, which are very similar in size, the inability of the crystal lattice to accommodate both potassium and sodium\/calcium gives rise to the two families of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a>, orthoclase and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">plagioclase<\/a> respectively.\u00a0Framework <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicates<\/a> are called tectosilicates and include the alkali metal-rich feldspathoids and zeolites.<\/p>\n<h3><\/h3>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-19\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-19\" class=\"h5p-iframe\" data-content-id=\"19\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"3.3 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3752\" aria-describedby=\"caption-attachment-3752\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/3.3-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-175\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/3.3-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3752\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 3.3 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-weight: 400\">3.4 Non-Silicate Minerals<\/span><\/h2>\n<figure id=\"attachment_2784\" aria-describedby=\"caption-attachment-2784\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Hanksite.jpg\"><img class=\"size-medium wp-image-2784\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hanksite-300x200-1.jpg\" alt=\"The mineral is hexagonal and clear.\" width=\"300\" height=\"200\"><\/a><figcaption id=\"caption-attachment-2784\" class=\"wp-caption-text\">Hanksite, Na22K(SO4)9(CO3)2Cl, one of the few minerals that is considered a carbonate and a sulfate<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>The crystal structure of non-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> (see table) does not contain <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silica-oxygen tetrahedra<\/a>. Many non-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are economically important and provide metallic resources such as copper, lead, and iron. They also include valuable non-metallic products such as salt, construction materials, and fertilizer.<\/p>\n<table>\n<tbody>\n<tr>\n<td><b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Mineral<\/a> \u00a0Group<\/b><\/td>\n<td><b>Examples<\/b><\/td>\n<td><b>Formula<\/b><\/td>\n<td><b>Uses<\/b><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_976\">Native<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a><\/span><\/td>\n<td><span style=\"font-weight: 400\">gold, silver, copper<\/span><\/td>\n<td><span style=\"font-weight: 400\">Au, Ag, Cu<\/span><\/td>\n<td><span style=\"font-weight: 400\">Jewelry, coins, industry<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">Carbonates<\/a><\/span><\/td>\n<td><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a>, dolomite <\/span><\/td>\n<td><span style=\"font-weight: 400\">CaCO<\/span><sub><span style=\"font-weight: 400\">3<\/span><\/sub><span style=\"font-weight: 400\">, CaMg(CO<\/span><sub><span style=\"font-weight: 400\">3<\/span><\/sub><span style=\"font-weight: 400\">)<\/span><sub><span style=\"font-weight: 400\">2<\/span><\/sub><\/td>\n<td><span style=\"font-weight: 400\">Lime, Portland cement<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">Oxides<\/a><\/span><\/td>\n<td><span style=\"font-weight: 400\">hematite, magnetite, bauxite<\/span><\/td>\n<td><span style=\"font-weight: 400\">Fe<\/span><sub><span style=\"font-weight: 400\">2<\/span><\/sub><span style=\"font-weight: 400\">O<\/span><sub><span style=\"font-weight: 400\">3<\/span><\/sub><span style=\"font-weight: 400\">, Fe<\/span><sub><span style=\"font-weight: 400\">3<\/span><\/sub><span style=\"font-weight: 400\">O<\/span><sub><span style=\"font-weight: 400\">4<\/span><\/sub><span style=\"font-weight: 400\">, a mixture of aluminum <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxides<\/a><\/span><\/td>\n<td><span style=\"font-weight: 400\">Ores of iron &amp; aluminum, pigments <\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_972\">Halides<\/a><\/span><\/td>\n<td><span style=\"font-weight: 400\">halite, sylvite<\/span><\/td>\n<td><span style=\"font-weight: 400\">NaCl, KCl<\/span><\/td>\n<td><span style=\"font-weight: 400\">Table salt, fertilizer<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">Sulfides<\/a><\/span><\/td>\n<td><span style=\"font-weight: 400\">galena, chalcopyrite, cinnabar<\/span><\/td>\n<td><span style=\"font-weight: 400\">PbS, CuFeS<\/span><sub><span style=\"font-weight: 400\">2<\/span><\/sub><span style=\"font-weight: 400\">, HgS<\/span><\/td>\n<td><span style=\"font-weight: 400\">Ores of lead, copper, mercury<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400\">Sulphates<\/span><\/td>\n<td><span style=\"font-weight: 400\">gypsum, epsom salts<\/span><\/td>\n<td><span style=\"font-weight: 400\">CaSo<\/span><sub><span style=\"font-weight: 400\">4<\/span><\/sub><span style=\"font-weight: 400\">\u00b72H<\/span><sub><span style=\"font-weight: 400\">2<\/span><\/sub><span style=\"font-weight: 400\">O, MgSO<\/span><sub><span style=\"font-weight: 400\">4<\/span><\/sub><span style=\"font-weight: 400\">\u00b77H<\/span><sub><span style=\"font-weight: 400\">2<\/span><\/sub><span style=\"font-weight: 400\">O<\/span><\/td>\n<td><span style=\"font-weight: 400\">Sheetrock, therapeutic soak<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_975\">Phosphates<\/a><\/span><\/td>\n<td><span style=\"font-weight: 400\">apatite<\/span><\/td>\n<td><span style=\"font-weight: 400\">Ca<\/span><sub><span style=\"font-weight: 400\">5<\/span><\/sub><span style=\"font-weight: 400\">(PO<\/span><sub><span style=\"font-weight: 400\">4<\/span><\/sub><span style=\"font-weight: 400\">)<\/span><sub><span style=\"font-weight: 400\">3<\/span><\/sub><span style=\"font-weight: 400\">(F,Cl,OH) <\/span><\/td>\n<td><span style=\"font-weight: 400\">Fertilizer, teeth, bones<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><em><span style=\"font-weight: 400\">Common non-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\"><em>silicate<\/em><\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\"><em>mineral<\/em><\/a> groups.<\/span><\/em><\/p>\n<h3><b>3.4.1 Carbonates<\/b><\/h3>\n<figure id=\"attachment_2785\" aria-describedby=\"caption-attachment-2785\" style=\"width: 245px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.26_Calcite-rhomb.jpg\"><img class=\"size-medium wp-image-2785\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.26_Calcite-rhomb-245x300-1.jpg\" alt=\"Calcite crystal in a shape called a rhomb like a cube squahed over toward one corner\" width=\"245\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2785\" class=\"wp-caption-text\">Calcite crystal in shape of rhomb. Note the double-refracted word \u201ccalcite\u201d in the center of the figure due to birefringence.<\/figcaption><\/figure>\n<figure id=\"attachment_2786\" aria-describedby=\"caption-attachment-2786\" style=\"width: 200px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.29_Limestone_etched_section_KopeFm_new.jpg\"><img class=\"wp-image-2786\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.29_Limestone_etched_section_KopeFm_new-281x300-1.jpg\" alt=\"Piece of limestone rock full of small fossils\" width=\"200\" height=\"214\"><\/a><figcaption id=\"caption-attachment-2786\" class=\"wp-caption-text\">Limestone with small fossils<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">Calcite<\/a>\u00a0(CaCO<sub>3<\/sub>) and dolomite (CaMg(CO<sub>3<\/sub>)<sub>2<\/sub>) are the two most frequently occurring <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, and usually occur in sedimentary rocks, such as limestone and dolostone rocks, respectively. Some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> rocks, such <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a> and dolomite, are formed via evaporation and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitation<\/a>. However, most <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a>-rich rocks, such as limestone, are created by the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1760\">lithification<\/a> of fossilized marine organisms. These organisms, including those we can see and many microscopic organisms, have shells or exoskeletons consisting of calcium <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> (CaCO<sub>3<\/sub>). When these organisms die, their remains accumulate on the floor of the water body in which they live and the soft body parts decompose and dissolve away. The calcium <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> hard parts become included in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediments<\/a>, eventually becoming the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1761\">sedimentary rock<\/a> called limestone. While limestone may contain large, easy to see <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1228\">fossils<\/a>, most limestones contain the remains of microscopic creatures and thus originate from biological processes.<\/p>\n<figure id=\"attachment_2787\" aria-describedby=\"caption-attachment-2787\" style=\"width: 282px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Bifringence.jpg\"><img class=\"size-medium wp-image-2787\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Bifringence-282x300-1.jpg\" alt=\"Calcite crystal polarize light into two waves that vibrate at right angles to each other and pass through the crystal in different paths.\" width=\"282\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2787\" class=\"wp-caption-text\">Bifringence in calcite crystals<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">Calcite<\/a> crystals show an interesting property called <strong>birefringence<\/strong>, meaning they polarize light into two wave components vibrating at right angles to each other. As the two light waves pass through the crystal, they travel at different velocities and are separated by refraction into two different travel paths. In other words, the crystal produces a double image of objects viewed through it. Because they polarize light, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a> crystals are used in special petrographic microscopes for studying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> and rocks.<\/p>\n<p>Many non-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are referred to as salts. The term <strong>salts<\/strong> used here refers to compounds made by replacing the hydrogen in natural acids. The most abundant natural acid is carbonic acid that forms by the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a> of carbon dioxide in water. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">Carbonate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are salts built around the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> ion (CO3<sup>-2<\/sup>) where calcium and\/or magnesium replace the hydrogen in carbonic acid (H<sub>2<\/sub>CO<sub>3<\/sub>). <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">Calcite<\/a> and a closely related polymorph aragonite are secreted by organisms to form shells and physical structures like corals. Many such creatures draw both calcium and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> from dissolved bicarbonate ions (HCO<sub>3<\/sub><sup>-<\/sup>) in ocean water. As seen in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> identification section below, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a> is easily dissolved in acid and thus effervesces in dilute hydrochloric acid (HCl). Small dropper bottles of dilute hydrochloric acid are often carried by geologists in the field as well as used in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> identification labs.<\/p>\n<p>Other salts include halite (NaCl) in which sodium replaces the hydrogen in hydrochloric acid and gypsum (Ca[SO<sub>4<\/sub>] \u2022 2 H<sub>2<\/sub>O) in which calcium replaces the hydrogen in sulfuric acid. Note that some water molecules are also included in the gypsum crystal. Salts are often formed by evaporation and are called evaporite <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>.<\/p>\n<figure id=\"attachment_2788\" aria-describedby=\"caption-attachment-2788\" style=\"width: 425px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.30_Crystal_structure_of_Calcite.png\"><img class=\"wp-image-2788\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.30_Crystal_structure_of_Calcite.png\" alt=\"Crystal structure of calcite showing the carbonate units of carbon surrounded by three oxygen ions and bonded to calcium ions.\" width=\"425\" height=\"520\"><\/a><figcaption id=\"caption-attachment-2788\" class=\"wp-caption-text\">Crystal structure of calcite<\/figcaption><\/figure>\n<p>The figure shows the crystal structure of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a> (CaCO<sub>3<\/sub>). Like silicon, carbon has four valence electrons. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> unit consists of carbon atoms (tiny white dots) covalently <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> to three oxygen atoms (red), one oxygen sharing two valence electrons with the carbon and the other two sharing one valence electron each with the carbon, thus creating triangular units with a charge of -2. The negatively charged <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> unit forms an ionic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bond<\/a> with the Ca ion (blue), which as a charge of +2.<\/p>\n<h3><\/h3>\n<h3><\/h3>\n<h3><\/h3>\n<h3><\/h3>\n<h3><\/h3>\n<h3><b>3.4.2 Oxides, Halides, and Sulfides<\/b><\/h3>\n<figure id=\"attachment_2789\" aria-describedby=\"caption-attachment-2789\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.31_Iron_oxide_LimoniteUSGOV.jpg\"><img class=\"size-medium wp-image-2789\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.31_Iron_oxide_LimoniteUSGOV-300x256-1.jpg\" alt=\"Image of limonite, a hydrated oxide of iron\" width=\"300\" height=\"256\"><\/a><figcaption id=\"caption-attachment-2789\" class=\"wp-caption-text\">Limonite, a hydrated oxide of iron<\/figcaption><\/figure>\n<p>After <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonates<\/a>, the next most common non-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxides<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_972\">halides<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfides<\/a>.<\/p>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">Oxides<\/a> consist of metal ions covalently <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> with oxygen. The most familiar <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxide<\/a> is rust, which is a combination of iron <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxides<\/a> (Fe<sub>2<\/sub>O<sub>3<\/sub>) and hydrated <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxides<\/a>. Hydrated <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxides<\/a> form when iron is exposed to oxygen and water. Iron <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxides<\/a> are important for producing metallic iron. When iron <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxide<\/a> or ore is smelted, it produces carbon dioxide (CO<sub>2<\/sub>) and metallic iron.<\/p>\n<p>The red color in rocks is usually due to the presence of iron <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxides<\/a>. For example, the red sandstone cliffs in Zion National Park and throughout Southern Utah consist of white or colorless grains of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a> coated with iron <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxide<\/a> which serve as cementing agents holding the grains together.<\/p>\n<figure id=\"attachment_2790\" aria-describedby=\"caption-attachment-2790\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.32_Hematite_-_oolitic_with_shale_Iron_Oxide_Clinton_Oneida_County_New_York-e1512421695503.jpg\"><img class=\"wp-image-2790 size-medium\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.32_Hematite_-_oolitic_with_shale_Iron_Oxide_Clinton_Oneida_County_New_York-e1512421695503-300x269-1.jpg\" alt=\"A red form of hematite called oolitic showing a mass of small round nodules\" width=\"300\" height=\"269\"><\/a><figcaption id=\"caption-attachment-2790\" class=\"wp-caption-text\">Oolitic hematite<\/figcaption><\/figure>\n<p>Other iron <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxides<\/a> include limonite, magnetite, and hematite. Hematite occurs in many different crystal forms. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_985\">massive<\/a> form shows no external structure. Botryoidal hematite shows large concentric blobs. Specular hematite looks like a mass of shiny metallic crystals. Oolitic hematite looks like a mass of dull red fish eggs. These different forms of hematite are polymorphs and all have the same formula, Fe<sub>2<\/sub>O<sub>3<\/sub>.<\/p>\n<p>Other common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxide<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> include:<\/p>\n<ul>\n<li>ice (H<sub>2<\/sub>O), an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxide<\/a> of hydrogen<\/li>\n<li>bauxite (Al<sub>2<\/sub>H<sub>2<\/sub>O<sub>4<\/sub>), hydrated <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxides<\/a> of aluminum, an ore for producing metallic aluminum<\/li>\n<li>corundum (Al<sub>2<\/sub>O<sub>3<\/sub>), which includes ruby and sapphire gemstones.<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2791\" aria-describedby=\"caption-attachment-2791\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.34_Halite-249324-1.jpg\"><img class=\"size-medium wp-image-2791\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.34_Halite-249324-1-300x225-1.jpg\" alt=\"Crystals of halite showing cubic crystal habit\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-2791\" class=\"wp-caption-text\">Halite crystal showing cubic habit<\/figcaption><\/figure>\n<p>The <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_972\">halides<\/a><\/strong> consist of halogens in column VII, usually fluorine or chlorine, ionically <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> with sodium or other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1780\">cations<\/a>. These include halite or sodium chloride (NaCl), common table salt; sylvite or potassium chloride (KCl); and fluorite or calcium fluoride (CaF<sub>2<\/sub>).<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2792\" aria-describedby=\"caption-attachment-2792\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.36_2014-07-05_13_04_30_View_across_the_Bonneville_Salt_Falts_Utah_from_ground_level.jpg\"><img class=\"size-medium wp-image-2792\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.36_2014-07-05_13_04_30_View_across_the_Bonneville_Salt_Falts_Utah_from_ground_level-300x220-1.jpg\" alt=\"Photo of salt crust at the Bonneville Salt Flats in Utah with mountains in the background.\" width=\"300\" height=\"220\"><\/a><figcaption id=\"caption-attachment-2792\" class=\"wp-caption-text\">Salt crystals at the Bonneville Salt Flats<\/figcaption><\/figure>\n<figure id=\"attachment_2793\" aria-describedby=\"caption-attachment-2793\" style=\"width: 244px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.35_FluoriteUV-scaled.jpg\"><img class=\"size-medium wp-image-2793\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.35_FluoriteUV-244x300-1.jpg\" alt=\"Purplish crystals of fluorite. The second image shows the deep blue fluorescence of fluorite under ultraviolet light.\" width=\"244\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2793\" class=\"wp-caption-text\">Fluorite. B shows fluorescence of fluorite under UV light<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_972\">Halide<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> usually form from the evaporation of sea water or other isolated bodies of water. A well-known example of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_972\">halide<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> deposits created by evaporation is the Bonneville Salt Flats, located west of the Great Salt Lake in Utah (see figure).<\/p>\n<p>&nbsp;<\/p>\n<p>Many important metal ores are <b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfides<\/a>, <\/b><span style=\"font-weight: 400\">in which metals are <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> to sulfur.\u00a0<\/span><span style=\"font-weight: 400\">Significant examples include: \u00a0<\/span>galena<span style=\"font-weight: 400\"> (lead <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfide<\/a>), <\/span>sphalerite<span style=\"font-weight: 400\"> (zinc <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfide<\/a>),<\/span> pyrite<\/p>\n<figure id=\"attachment_2794\" aria-describedby=\"caption-attachment-2794\" style=\"width: 175px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.37_pyrite1.jpg\"><img class=\"wp-image-2794\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.37_pyrite1-283x300-1.jpg\" alt=\"Cubic crystals of iron pyrite, called &quot;fools gold&quot;\" width=\"175\" height=\"185\"><\/a><figcaption id=\"caption-attachment-2794\" class=\"wp-caption-text\">Cubic crystals of pyrite<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\">(<\/span><span style=\"font-weight: 400\">iron<\/span><span style=\"font-weight: 400\">\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfide<\/a>, sometimes called \u201cfool's gold\u201d), and <\/span>chalcopyrite <span style=\"font-weight: 400\">(iron-copper <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfide<\/a>).<\/span><span style=\"font-weight: 400\">\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">Sulfides<\/a> are well known for being important ore <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. For example, galena is the main source of lead, sphalerite is the main source of zinc, and chalcopyrite is the main copper ore <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> mined in porphyry deposits like the Bingham mine (see <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/16-energy-and-mineral-resources\/\">chapter 16<\/a>). The largest sources of nickel, antimony, molybdenum, arsenic, and mercury are also <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfides<\/a>.<\/span><\/p>\n<h3><b>3.4.3 Sulfates<\/b><\/h3>\n<figure id=\"attachment_2795\" aria-describedby=\"caption-attachment-2795\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.39_SeleniteGypsumUSGOV.jpg\"><img class=\"size-medium wp-image-2795\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.39_SeleniteGypsumUSGOV-300x284-1.jpg\" alt=\"A clear crystal of gypsum\" width=\"300\" height=\"284\"><\/a><figcaption id=\"caption-attachment-2795\" class=\"wp-caption-text\">Gypsum crystal<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_974\">Sulfate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> contain a metal ion, such as calcium, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> to a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_974\">sulfate<\/a> ion. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_974\">sulfate<\/a> ion is a combination of sulfur and oxygen (SO<sub>4<sup>-<\/sup><\/sub><sup>2<\/sup>). The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_974\">sulfate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> gypsum (CaSO<sub>4<\/sub>\u14272H<sub>2<\/sub>O) is used in construction materials such as plaster and drywall. Gypsum is often formed from evaporating water and usually contains water molecules in its crystalline structure. The \u14272H<sub>2<\/sub>O in the formula indicates the water molecules are whole H<sub>2<\/sub>O. This is different from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> like <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1791\">amphibole<\/a>, which contain a hydroxide ion (OH<sup>-<\/sup>) that is derived from water, but is missing a hydrogen ion (H<sup>+<\/sup>). The calcium <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_974\">sulfate<\/a> without water is a different <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> than gypsum called anhydrite (CaSO<sub>4<\/sub>).<\/p>\n<h3><b>3.4.4 Phosphates<\/b><\/h3>\n<figure id=\"attachment_2796\" aria-describedby=\"caption-attachment-2796\" style=\"width: 150px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.40_Apatite_Canada.jpg\"><img class=\"wp-image-2796\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.40_Apatite_Canada-236x300-1.jpg\" alt=\"A crystal of apatite\" width=\"150\" height=\"191\"><\/a><figcaption id=\"caption-attachment-2796\" class=\"wp-caption-text\">Apatite crystal<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_975\">Phosphate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> have a tetrahedral <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_975\">phosphate<\/a> unit (PO<sub>4<\/sub><sup>-3<\/sup>) combined with various <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1782\">anions<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1780\">cations<\/a>. In some cases arsenic or vanadium can substitute for phosphorus. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_975\">Phosphates<\/a> are an important ingredient of fertilizers as well as detergents, paint, and other products. The best known <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_975\">phosphate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> is apatite, Ca<sub>5<\/sub>(PO<sub>4<\/sub>)<sub>3<\/sub>(F,Cl,OH), variations of which are found in teeth and bones. The gemstone turquoise [CuAl<sub>6<\/sub>(PO<sub>4<\/sub>)<sub>4<\/sub>(OH)<sub>8<\/sub>\u00b74H2O ] is a copper-rich <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_975\">phosphate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> that, like gypsum, contains water molecules.<\/span><\/p>\n<h3><b>3.4.5 Native Element Minerals<\/b><\/h3>\n<figure id=\"attachment_2798\" aria-describedby=\"caption-attachment-2798\" style=\"width: 200px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.43_Sulfer_Fumarola_Vulcano.jpg\"><img class=\"wp-image-2798\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.43_Sulfer_Fumarola_Vulcano-300x225-1.jpg\" alt=\"Native sulfur deposited around the vent of a volcanic fumarole\" width=\"200\" height=\"150\"><\/a><figcaption id=\"caption-attachment-2798\" class=\"wp-caption-text\">Native sulfur deposited around a volcanic fumarole<\/figcaption><\/figure>\n<figure id=\"attachment_2797\" aria-describedby=\"caption-attachment-2797\" style=\"width: 200px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.41_Native_Copper-1.jpg\"><img class=\"wp-image-2797\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.41_Native_Copper-1-300x284-1.jpg\" alt=\"Metallic native copper\" width=\"200\" height=\"189\"><\/a><figcaption id=\"caption-attachment-2797\" class=\"wp-caption-text\">Native copper<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_976\">Native element minerals<\/a>, usually metals, occur in nature in a pure or nearly pure state. Gold is an example of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_976\">native<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>; it is not very reactive and rarely <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> with other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> so it is usually found in an isolated or pure state. The non-metallic and poorly-reactive <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> carbon is often found as a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_976\">native<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a>, such as graphite and diamonds. Mildly reactive metals like silver, copper, platinum, mercury, and sulfur sometimes occur as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_976\">native element minerals<\/a>. Reactive metals such as iron, lead, and aluminum almost always <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bond<\/a> to other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> and are rarely found in a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_976\">native<\/a> state.<\/p>\n<h3><\/h3>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-20\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-20\" class=\"h5p-iframe\" data-content-id=\"20\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"3.4 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3751\" aria-describedby=\"caption-attachment-3751\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/3.4-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-191\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/3.4-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3751\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 3.4 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-weight: 400\">3.5 Identifying Minerals<\/span><\/h2>\n<figure id=\"attachment_2799\" aria-describedby=\"caption-attachment-2799\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Curiosity_Mars_Rover_Finds_Mineral_Match.jpg\"><img class=\"size-medium wp-image-2799\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Curiosity_Mars_Rover_Finds_Mineral_Match-300x268-1.jpg\" alt=\"The red rocks have a small hole drilled\" width=\"300\" height=\"268\"><\/a><figcaption id=\"caption-attachment-2799\" class=\"wp-caption-text\">The rover Curiosity drilled a hole in this rock from Mars, and confirmed the mineral Hematite, as mapped from satellites.<\/figcaption><\/figure>\n<p>Geologists identify <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> by their physical properties. In the field, where geologists may have limited access to advanced technology and powerful machines, they can still identify <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> by testing several physical properties: <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_977\">luster<\/a> and color, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">streak<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_979\">hardness<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_980\">crystal habit<\/a>, cleavage and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_986\">fracture<\/a>, and some special properties. Only a few common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> make up the majority of Earth's rocks and are usually seen as small grains in rocks. Of the several properties used for identifying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, it is good to consider which will be most useful for identifying them in small grains surrounded by other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>.<\/p>\n<h3><b>3.5.1 Luster and Color<\/b><\/h3>\n<figure id=\"attachment_2800\" aria-describedby=\"caption-attachment-2800\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Molly_Hill_molybdenite.jpg\"><img class=\"size-medium wp-image-2800\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Molly_Hill_molybdenite-300x225-1.jpg\" alt=\"The crystal looks like metal.\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-2800\" class=\"wp-caption-text\">15 mm metallic hexagonal molybdenite crystal from Quebec.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>The first thing to notice about a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> is its surface appearance, specifically <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_977\">luster<\/a> and color. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_977\">Luster<\/a> describes how the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> looks. Metallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_977\">luster<\/a> looks like a shiny metal such as chrome, steel, silver, or gold. Submetallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_977\">luster<\/a> has a duller appearance. Pewter, for example, shows submetallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_977\">luster<\/a>.<\/p>\n<figure id=\"attachment_2801\" aria-describedby=\"caption-attachment-2801\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Pewter-plate.jpg\"><img class=\"size-medium wp-image-2801\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pewter-plate-300x280-1.jpg\" alt=\"Antique pewter plate showing a more dull submetallic luster\" width=\"300\" height=\"280\"><\/a><figcaption id=\"caption-attachment-2801\" class=\"wp-caption-text\">Submetallic luster shown on an antique pewter plate.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>Nonmetallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_977\">luster<\/a> doesn\u2019t look like a metal and may be described as vitreous (glassy), earthy, silky, pearly, and other surface qualities. Nonmetallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> may be shiny, although their vitreous shine is different from metallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_977\">luster<\/a>. See the table for descriptions and examples of nonmetallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_977\">luster<\/a>.<\/p>\n<table style=\"width: 680px;height: 859px\">\n<tbody>\n<tr style=\"height: 32.625px\">\n<th style=\"border-color: #000000;background-color: #1ae8de;text-align: center;vertical-align: middle\"><span style=\"text-decoration: underline\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_977\">Luster<\/a><\/span><\/th>\n<th style=\"border-color: #000000;background-color: #1ae8de;text-align: center;vertical-align: middle\"><span style=\"text-decoration: underline\">Image<\/span><\/th>\n<th style=\"border-color: #000000;background-color: #1ae8de;text-align: center;vertical-align: middle\"><span style=\"text-decoration: underline\">Description<\/span><\/th>\n<\/tr>\n<tr style=\"height: 28px\">\n<td style=\"width: 155px;height: 28px;text-align: center;vertical-align: middle\">Vitreous\/glassy<\/td>\n<td style=\"width: 148px;height: 28px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_3669\" aria-describedby=\"caption-attachment-3669\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.23_-Quartz_Bresil.jpg\"><img class=\"size-thumbnail wp-image-195\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.23_-Quartz_Bresil-150x150.jpg\" alt=\"A mass of quartz crystals showing typical six sided habit with points\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3669\" class=\"wp-caption-text\">Quartz crystals<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 333px;height: 28px;text-align: center;vertical-align: middle\">Surface is shiny like glass<\/td>\n<\/tr>\n<tr style=\"height: 28px\">\n<td style=\"width: 155px;height: 28px;text-align: center;vertical-align: middle\">Earthy\/dull<\/td>\n<td style=\"width: 148px;height: 28px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2802\" aria-describedby=\"caption-attachment-2802\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.47_earthy_luster_KaolinUSGOV-1.jpg\"><img class=\"size-thumbnail wp-image-2802\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.47_earthy_luster_KaolinUSGOV-1-150x150-1.jpg\" alt=\"Specimen of kaolin, a clay oineral, showing dull or earthy luster\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-2802\" class=\"wp-caption-text\">Kaolin specimen showing dull or earthy luster<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 333px;height: 28px;text-align: center;vertical-align: middle\">Dull, like dried mud or clay<\/td>\n<\/tr>\n<tr style=\"height: 28px\">\n<td style=\"width: 155px;height: 28px;text-align: center;vertical-align: middle\">Silky<\/td>\n<td style=\"width: 148px;height: 28px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2803\" aria-describedby=\"caption-attachment-2803\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.48_silky_luster_Selenite_Gips_Marienglas-1.jpg\"><img class=\"wp-image-2803\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.48_silky_luster_Selenite_Gips_Marienglas-1-300x230-1.jpg\" alt=\"Specimen showing silky luster\" width=\"150\" height=\"115\"><\/a><figcaption id=\"caption-attachment-2803\" class=\"wp-caption-text\">Specimen showing silky luster<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 333px;height: 28px;text-align: center;vertical-align: middle\">Soft shine like silk fabric<\/td>\n<\/tr>\n<tr style=\"height: 28px\">\n<td style=\"width: 155px;height: 28px;text-align: center;vertical-align: middle\">Pearly<\/td>\n<td style=\"width: 148px;height: 28px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2804\" aria-describedby=\"caption-attachment-2804\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.49_pearly_luster_Mineral_Mica_GDFL006.jpg\"><img class=\"wp-image-2804\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.49_pearly_luster_Mineral_Mica_GDFL006-300x218-1.jpg\" alt=\"Specimen showing pearly luster like the inside of a clam shell\" width=\"150\" height=\"109\"><\/a><figcaption id=\"caption-attachment-2804\" class=\"wp-caption-text\">Specimen showing pearly luster<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 333px;height: 28px;text-align: center;vertical-align: middle\">Like the inside of a clam shell or mother-of-pearl<\/td>\n<\/tr>\n<tr style=\"height: 28px\">\n<td style=\"width: 155px;height: 28px;text-align: center;vertical-align: middle\">Submetallic<\/td>\n<td style=\"width: 148px;height: 28px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2805\" aria-describedby=\"caption-attachment-2805\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.44_submetallic_Sphalerite4.jpg\"><img class=\"wp-image-2805\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.44_submetallic_Sphalerite4-300x277-1.jpg\" alt=\"Photo of mineral exhibiting submetallic luster\" width=\"150\" height=\"138\"><\/a><figcaption id=\"caption-attachment-2805\" class=\"wp-caption-text\">Submetallic luster on sphalerite<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 333px;height: 28px;text-align: center;vertical-align: middle\">Has the appearance of dull metal,\u00a0like pewter. These <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> would usually still be considered metallic. Submetallic appearance can occur in metallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> because of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1754\">weathering<\/a>.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<figure id=\"attachment_2806\" aria-describedby=\"caption-attachment-2806\" style=\"width: 245px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Azurite_in_siltstone_Malbunka_mine_NT.jpg\"><img class=\"size-medium wp-image-2806\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Azurite_in_siltstone_Malbunka_mine_NT-245x300-1.jpg\" alt=\"There are two dark blue disks on white siltstone.\" width=\"245\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2806\" class=\"wp-caption-text\">Azurite is ALWAYS a dark blue color, and has been used for centuries for blue pigment.<\/figcaption><\/figure>\n<p>Surface color may be helpful in identifying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, although it can be quite variable within the same <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> family. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Mineral<\/a> colors are affected by the main <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> as well as impurities in the crystals. These impurities may be rare <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>\u2014like manganese, titanium, chromium, or lithium\u2014even other molecules that are not normally part of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> formula. For example, the incorporation of water molecules gives <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a>, which is normally clear, a milky color.<\/p>\n<p>Some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> predominantly show a single color. Malachite and azurite are green and blue, respectively, because of their copper content. Other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> have a predictable range of colors due to elemental substitutions, usually via a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1786\">solid solution<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">Feldspars<\/a>, the most abundant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> in the earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a>, are complex, have <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1786\">solid solution<\/a> series, and present several colors including pink, white, green, gray and others. Other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> also come in several colors, influenced by trace amounts of several <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>. The same <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a> may show up as different colors, in different <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. With notable exceptions, color is usually not a definitive property of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. For identifying many <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. a more reliable indicator is <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">streak<\/a>, which is the color of the powdered <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>.<\/p>\n<h3><b>3.5.2 Streak<\/b><\/h3>\n<figure id=\"attachment_2807\" aria-describedby=\"caption-attachment-2807\" style=\"width: 450px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.50_Streak_plate_with_Pyrite_and_Rhodochrosite-1-scaled.jpg\"><img class=\"wp-image-2807\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.50_Streak_plate_with_Pyrite_and_Rhodochrosite-1-300x227-1.jpg\" alt=\"Pyrite showing a black streak on a white streak plate and rhodochrosite with a white streak on a black streak plate\" width=\"450\" height=\"341\"><\/a><figcaption id=\"caption-attachment-2807\" class=\"wp-caption-text\">Different minerals may have different streaks<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">Streak<\/a> examines the color of a powdered <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>, and can be seen when a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> sample is scratched or scraped on an unglazed porcelain <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">streak<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a>. A paper page in a field notebook may also be used for the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">streak<\/a> of some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Minerals<\/a> that are harder than the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">streak<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> will not show <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">streak<\/a>, but will scratch the porcelain. For these <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">streak<\/a> test can be obtained by powdering the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> with a hammer and smearing the powder across a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">streak<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> or notebook paper.<\/p>\n<p>While <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> surface colors and appearances may vary, their <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">streak<\/a> colors can be diagnostically useful. An example of this property is seen in the iron-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxide<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> hematite. Hematite occurs in a variety of forms, colors and lusters, from shiny metallic silver to earthy red-brown, and different physical appearances. A hematite <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">streak<\/a> is consistently reddish brown, no matter what the original specimen looks like. Iron <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfide<\/a> or pyrite, is a brassy metallic yellow. Commonly named fool\u2019s gold, pyrite has a characteristic black to greenish-black <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">streak<\/a>.<\/p>\n<h3><b>3.5.3 Hardness<\/b><\/h3>\n<figure id=\"attachment_2808\" aria-describedby=\"caption-attachment-2808\" style=\"width: 1024px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.51_Mohs_Scale2.jpg\"><img class=\"size-large wp-image-2808\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.51_Mohs_Scale2-1024x714-1.jpg\" alt=\"Chart of Mohs Hardness Scale with minerals arranged in hardness from 1 to 10, also showing common items that correlate with the scale.\" width=\"1024\" height=\"714\"><\/a><figcaption id=\"caption-attachment-2808\" class=\"wp-caption-text\">Mohs Hardness Scale<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_979\">Hardness<\/a> measures the ability of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> to scratch other substances. The Mohs <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_979\">Hardness<\/a> Scale gives a number showing the relative scratch-resistance of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> when compared to a standardized set of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> of increasing hardness. The Mohs scale was developed by German geologist Fredrick Mohs in the early 20th century, although the idea of identifying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_979\">hardness<\/a> goes back thousands of years. Mohs <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_979\">hardness<\/a> values are determined by the strength of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>\u2019s atomic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a>.<\/p>\n<p>The figure shows the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> associated with specific <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_979\">hardness<\/a> values, together with some common items readily available for use in field testing and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> identification. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_979\">hardness<\/a> values run from 1 to 10, with 10 being the hardest; however, the scale is not linear. Diamond defines a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_979\">hardness<\/a> of 10 and is actually about four times harder than corundum, which is 9. A steel pocketknife blade, which has a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_979\">hardness<\/a> value of 5.5, separates between hard and soft <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> on many <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> identification keys.<\/p>\n<h3><b>3.5.4 Crystal Habit<\/b><\/h3>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Minerals<\/a> can be identified by <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_980\">crystal habit<\/a><\/strong>, how their crystals grow and appear in rocks. Crystal shapes are determined by the arrangement of the atoms within the crystal structure. For example, a cubic arrangement of atoms gives rise to a cubic-shaped <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> crystal. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_980\">Crystal habit<\/a> refers to typically observed shapes and characteristics; however, they can be affected by other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> crystallizing in the same rock. When <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are constrained so they do not develop their typical <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_980\">crystal habit<\/a>, they are called <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_981\">anhedral<\/a><\/strong>. <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_982\">Subhedral<\/a><\/strong> crystals are partially formed shapes. For some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> characteristic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_980\">crystal habit<\/a> is to grow crystal faces even when surrounded by other crystals in rock. An example is garnet. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Minerals<\/a> grown freely where the crystals are unconstrained and can take characteristic shapes often form crystal faces. A <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_983\">euhedral<\/a><\/strong> crystal has a perfectly formed, unconstrained shape. Some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> crystallize in such tiny crystals, they do not show a specific <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_980\">crystal habit<\/a> to the naked eye. Other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, like pyrite, can have an array of different crystal habits, including cubic, dodecahedral, octahedral, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_985\">massive<\/a>. The table lists typical crystal habits of various <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>.<\/p>\n<table style=\"width: 687px;height: 3774px\">\n<tbody>\n<tr>\n<th style=\"border-color: #000000;background-color: #6be86f;text-align: center;vertical-align: middle\" scope=\"row\"><strong><span style=\"text-decoration: underline\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_980\">Habit<\/a><\/span><\/strong><\/th>\n<th style=\"border-color: #000000;background-color: #6be86f;text-align: center;vertical-align: middle\" scope=\"row\"><strong><span style=\"text-decoration: underline\">Image<\/span><\/strong><\/th>\n<th style=\"border-color: #000000;background-color: #6be86f;text-align: center;vertical-align: middle\" scope=\"row\"><strong><span style=\"text-decoration: underline\">Examples<\/span><\/strong><\/th>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Bladed<\/strong><\/p>\n<p>long and flat crystals<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2809\" aria-describedby=\"caption-attachment-2809\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Kyanite_crystals.jpg\"><img class=\"wp-image-2809\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Kyanite_crystals-300x225-1.jpg\" alt=\"The crystals are long and rectangular\" width=\"150\" height=\"113\"><\/a><figcaption id=\"caption-attachment-2809\" class=\"wp-caption-text\">Bladed kyanite<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\">kyanite,\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1791\">amphibole<\/a>, gypsum<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Botryoidal\/mammillary<\/strong><\/p>\n<p>blobby, circular crystals<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2810\" aria-describedby=\"caption-attachment-2810\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Malachite_Kolwezi_Katanga_Congo.jpg\"><img class=\"wp-image-2810\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Malachite_Kolwezi_Katanga_Congo-300x174-1.jpg\" alt=\"The mineral is bulbous\" width=\"150\" height=\"87\"><\/a><figcaption id=\"caption-attachment-2810\" class=\"wp-caption-text\">Malachite from the Congo<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\">hematite, malachite, smithsonite<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Coating\/laminae\/druse<\/strong><\/p>\n<p>crystals that are small and coat surfaces<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2811\" aria-describedby=\"caption-attachment-2811\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Ametyst-geode.jpg\"><img class=\"wp-image-2811\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ametyst-geode-300x200-1.jpg\" alt=\"The rock is hollowed and filled with purple minerals\" width=\"150\" height=\"100\"><\/a><figcaption id=\"caption-attachment-2811\" class=\"wp-caption-text\">Quartz (var. amethyst) geode<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a>, malachite, azurite<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Cubic<\/strong><\/p>\n<p>cube-shaped crystals<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2812\" aria-describedby=\"caption-attachment-2812\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.55_Cubic_Calcite-Galena-elm56c.jpg\"><img class=\"wp-image-2812\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.55_Cubic_Calcite-Galena-elm56c-260x300-1.jpg\" alt=\"Cubic crystals of galena, a sulfide of lead\" width=\"150\" height=\"173\"><\/a><figcaption id=\"caption-attachment-2812\" class=\"wp-caption-text\">Cubic crystals of galena<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\">pyrite, galena, halite<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Dodecahedral<\/strong><\/p>\n<p>12-sided polygon shapes<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2813\" aria-describedby=\"caption-attachment-2813\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.53_habit_dodecahedral_Pyrite_elbe-scaled.jpg\"><img class=\"wp-image-2813\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.53_habit_dodecahedral_Pyrite_elbe-300x195-1.jpg\" alt=\"Crystals of pyrite showing dodecahedral habit\" width=\"150\" height=\"97\"><\/a><figcaption id=\"caption-attachment-2813\" class=\"wp-caption-text\">Pyrite crystals with dodecahedral habit<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\">garnet, pyrite<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Dendritic<\/strong><\/p>\n<p>branching crystals<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2814\" aria-describedby=\"caption-attachment-2814\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Dendrites01.jpg\"><img class=\"wp-image-2814\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Dendrites01-300x203-1.jpg\" alt=\"The mineral look like a fern. They are black and branching.\" width=\"150\" height=\"101\"><\/a><figcaption id=\"caption-attachment-2814\" class=\"wp-caption-text\">Manganese dendrites, scale in mm.<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\">Mn-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxides<\/a>, copper, gold<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_984\">Equant<\/a><\/strong><\/p>\n<p>crystals that do not have a long direction<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2815\" aria-describedby=\"caption-attachment-2815\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Peridot2.jpg\"><img class=\"wp-image-209\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Peridot2-272x300.jpg\" alt=\"The crystal is light green.\" width=\"150\" height=\"165\"><\/a><figcaption id=\"caption-attachment-2815\" class=\"wp-caption-text\">Large olivine crystal<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">olivine<\/a>, garnet, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">pyroxene<\/a><\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Fibrous<\/strong><\/p>\n<p>thin, very long crystals<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2816\" aria-describedby=\"caption-attachment-2816\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Tremolite_Campolungo.jpg\"><img class=\"wp-image-2816\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tremolite_Campolungo-300x186-1.jpg\" alt=\"It is white and fiberous\" width=\"150\" height=\"93\"><\/a><figcaption id=\"caption-attachment-2816\" class=\"wp-caption-text\">Tremolite, a type of amphibole<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\">serpentine, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1791\">amphibole<\/a>, zeolite<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Layered, sheets<\/strong><\/p>\n<p>stacked, very thin, flat crystals<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2817\" aria-describedby=\"caption-attachment-2817\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.18_Muscovite-Albite-122887.jpg\"><img class=\"wp-image-2817\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.18_Muscovite-Albite-122887-300x254-1.jpg\" alt=\"Sheets of muscovite mica in crystal mass\" width=\"150\" height=\"127\"><\/a><figcaption id=\"caption-attachment-2817\" class=\"wp-caption-text\">Sheet crystals of muscovite<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">mica <\/a>(<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">biotite<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">muscovite<\/a>, etc.)<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Lenticular\/platy<\/strong><\/p>\n<p>crystals that are <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a>-like<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2818\" aria-describedby=\"caption-attachment-2818\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Calcite-Wulfenite-tcw15b.jpg\"><img class=\"wp-image-2818\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Calcite-Wulfenite-tcw15b-251x300-1.jpg\" alt=\"The orange wulfenite is bladed\" width=\"150\" height=\"179\"><\/a><figcaption id=\"caption-attachment-2818\" class=\"wp-caption-text\">Orange wulfenite on calcite<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\">selenite roses, wulfenite, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a><\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Hexagonal<\/strong><\/p>\n<p>crystals with six sides<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_3687\" aria-describedby=\"caption-attachment-3687\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Hanksite-1.jpg\"><img class=\"wp-image-213 size-thumbnail\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hanksite-1-150x150.jpg\" alt=\"The mineral is hexagonal and clear.\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3687\" class=\"wp-caption-text\">Hexagonal hanksite<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a>, hanksite, corundum<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_985\">Massive<\/a>\/granular<\/strong><\/p>\n<p>Crystals with no obvious shape, microscopic crystals<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2789\" aria-describedby=\"caption-attachment-2789\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.31_Iron_oxide_LimoniteUSGOV.jpg\"><img class=\"wp-image-2789\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.31_Iron_oxide_LimoniteUSGOV-300x256-1.jpg\" alt=\"Image of limonite, a hydrated oxide of iron\" width=\"150\" height=\"128\"><\/a><figcaption id=\"caption-attachment-2789\" class=\"wp-caption-text\">Limonite, a hydrated oxide of iron<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\">limonite, pyrite, azurite, bornite<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Octahedral<\/strong><\/p>\n<p>4-sided double pyramid crystals<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2819\" aria-describedby=\"caption-attachment-2819\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.62_octahedral_cleavage_Fluorite_crystals_rotated_90.jpg\"><img class=\"wp-image-2819\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.62_octahedral_cleavage_Fluorite_crystals_rotated_90-300x182-1.jpg\" alt=\"Perfedt octahedral cleavage in fluorite generates octagon-shaped cleavage flakes.\" width=\"150\" height=\"91\"><\/a><figcaption id=\"caption-attachment-2819\" class=\"wp-caption-text\">Octagonal cleavage in fluorite<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\">diamond, fluorite, magnetite, pyrite<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Prismatic\/columnar<\/strong><\/p>\n<p>very long, cylindrical crystals<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2820\" aria-describedby=\"caption-attachment-2820\" style=\"width: 142px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Tourmaline.jpg\"><img class=\"size-medium wp-image-2820\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tourmaline-142x300-1.jpg\" alt=\"The mineral is a long cylinder.\" width=\"142\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2820\" class=\"wp-caption-text\">Columnar tourmaline<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\">tourmaline, beryl, barite<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Radiating<\/strong><\/p>\n<p>crystals that grow from a point and fan out<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2821\" aria-describedby=\"caption-attachment-2821\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Pyrophyllite-236595.jpg\"><img class=\"wp-image-2821\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pyrophyllite-236595-217x300-1.jpg\" alt=\"The mineral is orange\" width=\"150\" height=\"207\"><\/a><figcaption id=\"caption-attachment-2821\" class=\"wp-caption-text\">Pyrophyllite<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\">pyrite \"suns\", pyrophyllite<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Rhombohedral<\/strong><\/p>\n<p>crystals shaped like slanted cubes<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2785\" aria-describedby=\"caption-attachment-2785\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.26_Calcite-rhomb.jpg\"><img class=\"wp-image-2785\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.26_Calcite-rhomb-245x300-1.jpg\" alt=\"Calcite crystal in a shape called a rhomb like a cube squahed over toward one corner\" width=\"150\" height=\"183\"><\/a><figcaption id=\"caption-attachment-2785\" class=\"wp-caption-text\">Calcite crystal in shape of rhomb.<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a>, dolomite<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Tabular\/blocky\/stubby<\/strong><\/p>\n<p>sharp-sided crystals with no long direction<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2770\" aria-describedby=\"caption-attachment-2770\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.14_Diopside-172005.jpg\"><img class=\"wp-image-2770\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.14_Diopside-172005-300x231-1.jpg\" alt=\"Dark green crystals of diopside, a member of the pyroxene family\" width=\"150\" height=\"116\"><\/a><figcaption id=\"caption-attachment-2770\" class=\"wp-caption-text\">Crystals of diopside, a member of the pyroxene family<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">pyroxene<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a><\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Tetrahedral<\/strong><\/p>\n<p>three-sided, pyramid-shaped crystals<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2822\" aria-describedby=\"caption-attachment-2822\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Tetrahedrite-Chalcopyrite-Sphalerite-251531.jpg\"><img class=\"wp-image-2822\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tetrahedrite-Chalcopyrite-Sphalerite-251531-300x218-1.jpg\" alt=\"The dark brown mineral is triangular\" width=\"150\" height=\"109\"><\/a><figcaption id=\"caption-attachment-2822\" class=\"wp-caption-text\">Tetrahedrite<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\">magnetite, spinel, tetrahedrite<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2824\" aria-describedby=\"caption-attachment-2824\" style=\"width: 150px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/GypsumStriations.jpg\"><img class=\"wp-image-2824\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/GypsumStriations-251x300-1.jpg\" alt=\"The mineral has many parallel lines on it\" width=\"150\" height=\"179\"><\/a><figcaption id=\"caption-attachment-2824\" class=\"wp-caption-text\">Gypsum with striations<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2823\" aria-describedby=\"caption-attachment-2823\" style=\"width: 150px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Staurolite-62645.jpg\"><img class=\"wp-image-2823\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Staurolite-62645-279x300-1.jpg\" alt=\"The brown minerals are replicated in different directions\" width=\"150\" height=\"161\"><\/a><figcaption id=\"caption-attachment-2823\" class=\"wp-caption-text\">Twinned staurolite<\/figcaption><\/figure>\n<p>Another <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_980\">crystal habit<\/a> that may be used to identify <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> is striations, which are dark and light parallel lines on a crystal face. Twinning is another, which occurs when the crystal structure replicates in mirror images along certain directions in the crystal.<\/p>\n<figure id=\"attachment_2825\" aria-describedby=\"caption-attachment-2825\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.65_Striations_in_plagioclase.jpg\"><img class=\"size-medium wp-image-2825\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.65_Striations_in_plagioclase-300x242-1.jpg\" alt=\"Striations or parallel dark lines on one cleavage surface on plagioclase feldspar\" width=\"300\" height=\"242\"><\/a><figcaption id=\"caption-attachment-2825\" class=\"wp-caption-text\">Striations on plagioclase<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>Striations and twinning are related properties in some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> including <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">plagioclase<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a>. Striations are optical lines on a cleavage surface. Because of twinning in the crystal, striations show up on one of the two cleavage faces of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">plagioclase<\/a> crystal.<\/p>\n<h3><b>3.5.5 Cleavage and Fracture<\/b><\/h3>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Minerals<\/a> often show characteristic patterns of breaking along specific cleavage planes or show characteristic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_986\">fracture<\/a> patterns. Cleavage planes are smooth, flat, parallel planes within the crystal. The cleavage planes may show as reflective surfaces on the crystal, as parallel cracks that penetrate into the crystal, or show on the edge or side of the crystal as a series of steps like rice terraces. Cleavage arises in crystals where the atomic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> between atomic layers are weaker along some directions than others, meaning they will break preferentially along these planes.\u00a0Because they develop on atomic surfaces in the crystal, cleavage planes are optically smooth and reflect light, although the actual break on the crystal may appear jagged or uneven. In such cleavages, the cleavage surface may appear like rice terraces on a mountainside that all reflect sunlight from a particular sun angle. Some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> have a strong cleavage, some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> only have weak cleavage or do not typically demonstrate cleavage.<\/p>\n<figure id=\"attachment_2826\" aria-describedby=\"caption-attachment-2826\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.57_conchoidal_Citrine-sample2.jpg\"><img class=\"size-medium wp-image-2826\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.57_conchoidal_Citrine-sample2-300x225-1.jpg\" alt=\"A specimen of a variety of quartz showing conchoidal fracture\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-2826\" class=\"wp-caption-text\">Citrine, a variety of quartz showing conchoidal fracture<\/figcaption><\/figure>\n<p>For example, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">olivine<\/a> rarely show cleavage and typically break into <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_987\">conchoidal<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_986\">fracture<\/a> patterns.<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2827\" aria-describedby=\"caption-attachment-2827\" style=\"width: 452px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/cryview_graphite_v1.gif\"><img class=\"wp-image-2827 size-full\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/cryview_graphite_v1.gif\" alt=\"Structure of graphite, showing single carbon layers with weak bonds holding them together\" width=\"452\" height=\"504\"><\/a><figcaption id=\"caption-attachment-2827\" class=\"wp-caption-text\">Graphite showing layers of carbon atoms separated by a gap with weak bonds holding the layers together.<\/figcaption><\/figure>\n<p>Graphite has its carbon atoms arranged into layers with relatively strong <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> within the layer and very weak <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> between the layers.\u00a0 Thus graphite cleaves readily between the layers and the layers slide easily over one another giving graphite its lubricating quality.<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Mineral<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_986\">fracture<\/a> surfaces may be rough and uneven or they may be show <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_987\">conchoidal<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_986\">fracture<\/a>. Uneven <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_986\">fracture<\/a> patterns are described as irregular, splintery, fibrous. A conchoidal fracture has a smooth, curved surface like a shallow bowl or conch shell, often with curved ridges. Natural <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> glass, called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_999\">obsidian<\/a>, breaks with this characteristic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_987\">conchoidal<\/a> pattern<\/p>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2828\" aria-describedby=\"caption-attachment-2828\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.64_galena_cleavage_Argentiferous_Galena-458851.jpg\"><img class=\"wp-image-2828 size-medium\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.64_galena_cleavage_Argentiferous_Galena-458851-300x261-1.jpg\" alt=\"Specimen of galena showing cubic cleavage\" width=\"300\" height=\"261\"><\/a><figcaption id=\"caption-attachment-2828\" class=\"wp-caption-text\">Cubic cleavage of galena; note how the cleavage surfaces show up as different but parallel layers in the crystal.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>To work with cleavage, it is important to remember that cleavage is a result of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> separating along planes of atoms in the crystal structure. On some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, <strong>cleavage planes<\/strong> may be confused with crystal faces. This will usually not be an issue for crystals of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> that grew together within rocks. The act of breaking the rock to expose a fresh face will most likely break the crystals along cleavage planes. Some cleavage planes are parallel with crystal faces but many are not.\u00a0Cleavage planes are smooth, flat, parallel planes within the crystal. The cleavage planes may show as parallel cracks that penetrate into the crystal (see <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1791\">amphibole<\/a> below), or show on the edge or side of the crystal as a series of steps like rice terraces. For some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> characteristic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_980\">crystal habit<\/a> is to grow crystal faces even when surrounded by other crystals in rock. An example is garnet. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Minerals<\/a> grown freely where the crystals are unconstrained and can take characteristic shapes often form crystal faces (see <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a> below).<\/p>\n<figure id=\"attachment_2829\" aria-describedby=\"caption-attachment-2829\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Quartz-crystals.jpg\"><img class=\"size-medium wp-image-2829\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Quartz-crystals-300x284-1.jpg\" alt=\"Freely grown quartz crystals showing crysatl faces\" width=\"300\" height=\"284\"><\/a><figcaption id=\"caption-attachment-2829\" class=\"wp-caption-text\">Freely growing quartz crystals showing crystal faces<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\">In some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, distinguishing cleavage planes from crystal faces may be challenging for the student. Understanding the nature of cleavage and referring to the number of cleavage planes and cleavage angles on identification keys should provide the student with enough information to distinguish cleavages from crystal faces. Cleavage planes may show as multiple parallel cracks or flat surfaces on the crystal. Cleavage planes may be expressed as a series of steps like terraced rice paddies. See the cleavage surfaces on galena above or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">plagioclase<\/a> below. Cleavage planes arise from the tendency of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> crystals to break along specific planes of weakness within the crystal favored by atomic arrangements. The number of cleavage planes, the quality of the cleavage surfaces, and the angles between them are diagnostic for many <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> and cleavage is one of the most useful properties for identifying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. Learning to recognize cleavage is an especially important and useful skill in studying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>.<\/span><\/p>\n<figure id=\"attachment_2830\" aria-describedby=\"caption-attachment-2830\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.61_Cleavage_steps_in_wollastonite.jpg\"><img class=\"size-medium wp-image-2830\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.61_Cleavage_steps_in_wollastonite-300x224-1.jpg\" alt=\"Image of wollastonite, a crystal showing step-like cleavage on one side. All steps are along the same direction of cleavage.\" width=\"300\" height=\"224\"><\/a><figcaption id=\"caption-attachment-2830\" class=\"wp-caption-text\">Steps of cleavage along the same cleavage direction<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2831\" aria-describedby=\"caption-attachment-2831\" style=\"width: 220px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.63_cleavage_in_Amphibole.jpg\"><img class=\"wp-image-2831\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.63_cleavage_in_Amphibole-295x300-1.jpg\" alt=\"Photomicrograph showing 120\/60 degree cleavage in amphibole\" width=\"220\" height=\"224\"><\/a><figcaption id=\"caption-attachment-2831\" class=\"wp-caption-text\">Photomicrograph showing 120\/60 degree cleavage within a grain of amphibole<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>As an identification property of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, cleavage is usually given in terms of the quality of the cleavage (perfect, imperfect, or none), the number of cleavage surfaces, and the angles between the surfaces.\u00a0The most common number of cleavage plane directions in the common rock-forming <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are: one perfect cleavage (as in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">mica<\/a>), two cleavage planes (as in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">pyroxene<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1791\">amphibole<\/a>), and three cleavage planes (as in halite, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a>, and galena). One perfect cleavage (as in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">mica<\/a>) develops on the top and bottom of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> specimen with many parallel cracks showing on the sides but no angle of intersection. Two cleavage planes intersect at an angle. Common cleavage angles are 60\u00b0, 75\u00b0, 90\u00b0, and 120\u00b0.\u00a0 <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1791\">Amphibole<\/a> has two cleavage planes at\u00a060\u00b0 and\u00a0120\u00b0. Galena and halite have three cleavage planes at 90\u00b0 (cubic cleavage). <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">Calcite<\/a> cleaves readily in three directions producing a cleavage figure called a rhomb that looks like a cube squashed over toward one corner giving rise to the approximately 75\u00b0 cleavage angles. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">Pyroxene<\/a> has an imperfect cleavage with two planes at 90\u00b0.<\/p>\n<p><strong>Cleavages on common rock-forming <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a><\/strong><\/p>\n<ul>\n<li><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">Quartz<\/a>\u2014none (<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_987\">conchoidal<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_986\">fracture<\/a>)<\/li>\n<li><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">Olivine<\/a>\u2014none (<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_987\">conchoidal<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_986\">fracture<\/a>)<\/li>\n<li><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">Mica<\/a>\u20141 perfect<\/li>\n<li><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">Feldspar<\/a>\u20142 perfect at 90\u00b0<\/li>\n<li><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">Pyroxene<\/a>\u20142 imperfect at 90\u00b0<\/li>\n<li><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1791\">Amphibole<\/a>\u20142 perfect at 60\u00b0\/120\u00b0<\/li>\n<li><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">Calcite<\/a>\u20143 perfect at approximately 75\u00b0<\/li>\n<li>Halite, galena, pyrite\u20143 perfect at 90\u00b0<\/li>\n<\/ul>\n<h3><b>3.5.6 Special Properties <\/b><\/h3>\n<figure id=\"attachment_2832\" aria-describedby=\"caption-attachment-2832\" style=\"width: 150px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Ulexit_Fernsehstein.jpg\"><img class=\"size-thumbnail wp-image-2832\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ulexit_Fernsehstein-150x150-1.jpg\" alt=\"The words on the page are projected upwards onto the mineral\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-2832\" class=\"wp-caption-text\">A demonstration of ulexite's image projection<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\">Special properties are unique and identifiable characteristics used to identify <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> or that allow some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> to be used for special purposes.\u00a0<\/span>Ulexite has a fiber-optic property that can project images through the crystal like a high-definition television screen (see figure). A simple identifying special property is taste, such as the salty flavor of halite or common table salt (NaCl). Sylvite is potassium chloride (KCl) and has a more bitter taste.<\/p>\n<figure id=\"attachment_2833\" aria-describedby=\"caption-attachment-2833\" style=\"width: 225px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Latrobe_gold_nugget_Natural_History_Museum.jpg\"><img class=\"size-medium wp-image-2833\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Latrobe_gold_nugget_Natural_History_Museum-225x300-1.jpg\" alt=\"The nugget is gold\" width=\"225\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2833\" class=\"wp-caption-text\">Native gold has one of the highest specific gravities.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>Another property geologists may use to identify <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> is a property related to density called <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_989\">specific gravity<\/a><\/strong>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_989\">Specific gravity<\/a> measures the weight of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> specimen relative to the weight of an equal volume of water. The value is expressed as a ratio between the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> and water weights. To measure <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_989\">specific gravity<\/a>, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> specimen is first weighed in grams then submerged in a graduated cylinder filled with pure water at room <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a>. The rise in water level is noted using the cylinder\u2019s graduated scale. Since the weight of water at room <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> is 1 gram per cubic centimeter, the ratio of the two weight numbers gives the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_989\">specific gravity<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_989\">Specific gravity<\/a> is easy to measure in the laboratory but is less useful for <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> identification in the field than other more easily observed properties, except in a few rare cases such as the very dense galena or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_976\">native<\/a> gold. The high density of these <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> gives rise to a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1725\">qualitative<\/a> property called \u201cheft.\u201d Experienced geologists can roughly assess <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_989\">specific gravity<\/a> by heft, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1723\">subjective<\/a> quality of how heavy the specimen feels in one\u2019s hand relative to its size.<\/p>\n<p>A simple test for identifying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a> and dolomite is to drop a bit of dilute hydrochloric acid (10-15% HCl) on the specimen. If the acid drop effervesces or fizzes on the surface of the rock, the specimen is <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a>. If it does not, the specimen is scratched to produce a small amount of powder and test with acid again. If the acid drop fizzes slowly on the powdered <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>, the specimen is dolomite. The difference between these two <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> can be seen in the video. Geologists who work with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> rocks carry a small dropper bottle of dilute HCl in their field kit. Vinegar, which contains acetic acid, can be used for this test and is used to distinguish non-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1228\">fossils<\/a> from limestone. While acidic, vinegar produces less of a fizzing reaction because acetic acid is a weaker acid.<\/p>\n<figure id=\"attachment_3750\" aria-describedby=\"caption-attachment-3750\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Calcite-and-Dolomite-YouTube-QR-Code.png\"><img class=\"size-thumbnail wp-image-228\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Calcite-and-Dolomite-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3750\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this YouTube video via this QR Code.<\/figcaption><\/figure>\n<figure id=\"attachment_2834\" aria-describedby=\"caption-attachment-2834\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Magnetite_Lodestone.jpg\"><img class=\"size-medium wp-image-2834\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Magnetite_Lodestone-300x200-1.jpg\" alt=\"The paperclip is sticking up into the air.\" width=\"300\" height=\"200\"><\/a><figcaption id=\"caption-attachment-2834\" class=\"wp-caption-text\">Paperclips attach to lodestone (magnetite).<\/figcaption><\/figure>\n<p>Some iron-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxide<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are magnetic and are attracted to magnets. A common name for a naturally magnetic iron <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxide<\/a> is <strong>lodestone<\/strong>. Others include magnetite (Fe3O<sub>4<\/sub>) and ilmenite (FeTiO<sub>3<\/sub>). Magnetite is strongly attracted to magnets and can be magnetized. Ilmenite and some types of hematite are weakly magnetic.<\/p>\n<figure id=\"attachment_2825\" aria-describedby=\"caption-attachment-2825\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.65_Striations_in_plagioclase.jpg\"><img class=\"wp-image-2825 size-medium\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.65_Striations_in_plagioclase-300x242-1.jpg\" alt=\"Striations or parallel dark lines on one cleavage surface on plagioclase feldspar\" width=\"300\" height=\"242\"><\/a><figcaption id=\"caption-attachment-2825\" class=\"wp-caption-text\">Iridescence on plagioclase; also showing striations on the cleavage surface<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p><span style=\"font-weight: 400\">Some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> and mineraloids scatter light via a phenomenon called <strong>iridescence<\/strong>. This property occurs in labradorite (a variety of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">plagioclase<\/a>) and opal. It is also seen in biologically created substances like pearls and seashells. Cut diamonds show iridescence and the jeweler\u2019s diamond cut is designed to maximize this property.<\/span><\/p>\n<figure id=\"attachment_2835\" aria-describedby=\"caption-attachment-2835\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.66_exsolution-_lamellae_perthitic_feldspar_Dan_Patch_SD.jpg\"><img class=\"size-medium wp-image-2835\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.66_exsolution-_lamellae_perthitic_feldspar_Dan_Patch_SD-300x217-1.jpg\" alt=\"Image showing exsolution lamellae in potassium feldspar. These are separations of sodium feldspar from potassium feldspar within the crystal, not striations.\" width=\"300\" height=\"217\"><\/a><figcaption id=\"caption-attachment-2835\" class=\"wp-caption-text\">Exsolution lamellae within potassium feldspar<\/figcaption><\/figure>\n<p><strong>Striations<\/strong> on <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> cleavage faces are an optical property that can be used to separate <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">plagioclase<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> from potassium <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> (<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">K-spar<\/a>). A process called twinning creates parallel zones in the crystal that are repeating mirror images. The actual cleavage angle in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">plagioclase<\/a> is slightly different than 90<sup>o<\/sup> and the alternating mirror images in these twinned zones produce a series of parallel lines on one of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">plagioclase<\/a>\u2019s two cleavage faces. Light reflects off these twinned lines at slightly different angles which then appear as light and dark lines called striations on the cleavage surface.\u00a0Potassium <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> does not exhibit twinning or striations but may show linear features called <strong>exsolution lamellae<\/strong>, also known as perthitic lineation or simply perthite. Because sodium and potassium do not fit into the same <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> crystal structure, the lines are created by small amounts of sodium <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> (albite) separating from the dominant potassium <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> (<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">K-spar<\/a>) within the crystal structure. The two different <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspars<\/a> crystallize out into roughly parallel zones within the crystal, which are seen as these linear markings.<\/p>\n<figure id=\"attachment_2793\" aria-describedby=\"caption-attachment-2793\" style=\"width: 244px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.35_FluoriteUV-scaled.jpg\"><img class=\"size-medium wp-image-2793\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.35_FluoriteUV-244x300-1.jpg\" alt=\"Purplish crystals of fluorite. The second image shows the deep blue fluorescence of fluorite under ultraviolet light.\" width=\"244\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2793\" class=\"wp-caption-text\">Fluorite. B shows fluorescence of fluorite under UV light<\/figcaption><\/figure>\n<p>One of the most interesting special <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> properties is <strong>fluorescence<\/strong>. Certain <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, or \u00a0trace <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> within them, give off visible light when exposed to ultraviolet radiation or black light. Many <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> exhibits have a fluorescence room equipped with black lights so this property can be observed. An even rarer optical property is phosphorescence. <strong>Phosphorescent<\/strong> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> absorb light and then slowly release it, much like a glow-in-the-dark sticker.<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<h3><\/h3>\n<h3><\/h3>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-21\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-21\" class=\"h5p-iframe\" data-content-id=\"21\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"3.5 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3749\" aria-describedby=\"caption-attachment-3749\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/3.5-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-231\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/3.5-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3749\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 3.5 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-size: 18pt\"><strong>Summary<\/strong><\/span><\/h2>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Minerals<\/a> are the building blocks of rocks and essential to understanding geology. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Mineral<\/a> properties are determined by their atomic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a>. Most <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> begin in a fluid, and either crystallize out of cooling <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitate<\/a> as ions and molecules out of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1784\">saturated<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a>. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicates<\/a> are largest group of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> on Earth, by number of varieties and relative quantity, making up a large portion of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a>. Based on the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silicon-oxygen tetrahedra<\/a>, the crystal structure of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicates<\/a> reflects the fact that silicon and oxygen are the top two of Earth\u2019s most abundant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>. Non-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are also economically important, and providing many types of construction and manufacturing materials. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Minerals<\/a> are identified by their unique physical properties, including <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_977\">luster<\/a>, color, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">streak<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_979\">hardness<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_980\">crystal habit<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_986\">fracture<\/a>, cleavage, and special properties.<\/p>\n<h3>Take this quiz to check your comprehension of this Chapter.<\/h3>\n<div id=\"h5p-22\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-22\" class=\"h5p-iframe\" data-content-id=\"22\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Chapter 3 Review\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3748\" aria-describedby=\"caption-attachment-3748\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Ch.3-Review-QR-Code.png\"><img class=\"size-thumbnail wp-image-232\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ch.3-Review-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3748\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the review quiz for Chapter 3 via this QR Code.<\/figcaption><\/figure>\n<h2><b>References<\/b><\/h2>\n<div class=\"csl-bib-body\">\n<ol>\n<li class=\"csl-entry\">Clarke, F.W.H.S.W., 1927, The Composition of the Earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">Crust<\/a>: Professional Paper, United States Geological Survey, Professional Paper.<\/li>\n<li class=\"csl-entry\">Gordon, L.M., and Joester, D., 2011, Nanoscale chemical tomography of buried organic-inorganic interfaces in the chiton tooth: Nature, v. 469, no. 7329, p. 194\u2013197.<\/li>\n<li class=\"csl-entry\">Hans Wedepohl, K., 1995, The composition of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental crust<\/a>: Geochim. Cosmochim. Acta, v. 59, no. 7, p. 1217\u20131232.<\/li>\n<li class=\"csl-entry\">Lambeck, K., 1986, Planetary evolution: banded iron formations: v. 320, no. 6063, p. 574\u2013574.<\/li>\n<li class=\"csl-entry\">metallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bond<\/a> | chemistry.<\/li>\n<li class=\"csl-entry\">Scerri, E.R., 2007, The Periodic Table: Its Story and Its Significance: Oxford University Press, USA.<\/li>\n<li class=\"csl-entry\">Thomson, J.J., 1897, XL. Cathode Rays: Philosophical Magazine Series 5, v. 44, no. 269, p. 293\u2013316.<\/li>\n<li class=\"csl-entry\">Trenn, T.J., Geiger, H., Marsden, E., and Rutherford, E., 1974, The Geiger-Marsden Scattering Results and Rutherford\u2019s Atom, July 1912 to July 1913: The Shifting Significance of Scientific Evidence: Isis, v. 65, no. 1, p. 74\u201382.<\/li>\n<\/ol>\n<\/div>\n<p><span style=\"font-weight: 400\">\u00a0<\/span><\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_234\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_234\"><div tabindex=\"-1\"><figure id=\"attachment_2752\" aria-describedby=\"caption-attachment-2752\" style=\"width: 1024px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Cristales_cueva_de_Naica.jpg\"><img class=\"wp-image-2752 size-large\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/09\/Cristales_cueva_de_Naica-1024x683-1.jpg\" alt=\"The crystals are huge!\" width=\"1024\" height=\"683\"><\/a><figcaption id=\"caption-attachment-2752\" class=\"wp-caption-text\">These selenite (gypsum) crystals, found in The Cave of the Crystals in Naica, Mexico, has some of the largest minerals ever found. The largest crystal found here is 39 feet (12 meters) and 55 tones.<\/figcaption><\/figure>\n<h1>3 Minerals<\/h1>\n<p><strong>KEY<\/strong><b> CONCEPTS<\/b><\/p>\n<p><b>At the end of this chapter, students should be able to:<\/b><\/p>\n<ul>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Define <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>.<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Describe the basic structure of the atom.<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Derive basic atomic information from the Periodic Table of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">Elements<\/a>.<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Describe chemical <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonding<\/a> related to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>.<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Describe the main ways <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> form.<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Describe the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silicon-oxygen tetrahedron<\/a> and how it forms common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>.<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">List common non-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxide<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfide<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_974\">sulfate<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> groups.<\/span><\/li>\n<li style=\"font-weight: 400\"><span style=\"font-weight: 400\">Identify <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> using physical properties and identification tables. <\/span><\/li>\n<\/ul>\n<p>The term \u201c<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>\u201d as used in nutrition labels and pharmaceutical products is not the same as a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> in a geological sense. In geology, the classic definition of a <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a><\/strong> is: 1) naturally occurring, 2) inorganic, 3) solid at room <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a>, 4) regular crystal structure, and 5) defined chemical composition. Some natural substances technically should not be considered <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, but are included by exception. For example, water and mercury are liquid at room <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a>. Both are considered <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> because they were classified before the room-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> rule was accepted as part of the definition. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">Calcite<\/a> is quite often formed by organic processes, but is considered a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> because it is widely found and geologically important. Because of these discrepancies, the International Mineralogical Association in 1985 amended the definition to: \u201cA <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> is an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a> or chemical compound that is normally crystalline and that has been formed as a result of geological processes.\u201d This means that the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a> in the shell of a clam is not considered a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>. But once that clam shell undergoes burial, diagenesis, or other geological processes, then the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a> is considered a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>. Typically, substances like coal, pearl, opal, or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_999\">obsidian<\/a> that do not fit the definition of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> are called mineraloids.<\/p>\n<p>A <strong>rock<\/strong> is a substance that contains one or more <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> or mineraloids. As is discussed in later chapters, there are three types of rocks composed of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>: <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> (rocks crystallizing from molten material), sedimentary (rocks composed of products of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_251\">mechanical weathering<\/a> (sand, gravel, etc.) and chemical weathering (things <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitated<\/a> from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a>), and metamorphic (rocks produced by alteration of other rocks by heat and pressure.<\/p>\n<h2><span style=\"font-weight: 400\">3.1 Chemistry of Minerals<\/span><\/h2>\n<p>Rocks are composed of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> that have a specific chemical composition.\u00a0 To understand <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> chemistry, it is essential to examine the fundamental unit of all matter, the atom.<\/p>\n<h3><b>3.1.1 The Atom<\/b><\/h3>\n<figure id=\"attachment_2753\" aria-describedby=\"caption-attachment-2753\" style=\"width: 283px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.1-Electron_cloud_model_of_atom.jpg\"><img class=\"size-medium wp-image-2753\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/09\/03.1-Electron_cloud_model_of_atom-283x300-1.jpg\" alt=\"Image of atom with defined nucleus and electrons surrounding it in a cloud with concentrations of electrons in energy shells\" width=\"283\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2753\" class=\"wp-caption-text\">Electron cloud model of the atom<\/figcaption><\/figure>\n<p>Matter is made of atoms. Atoms consists of subatomic particles\u2014<strong>protons<\/strong>, <strong>neutrons<\/strong>, and <strong>electrons<\/strong>. A simple model of the atom has a central nucleus composed of protons, which have positive charges, and neutrons which have no charge. A cloud of negatively charged electrons surrounds the nucleus, the number of electrons equaling the number of protons thus balancing the positive charge of the protons for a neutral atom. Protons and neutrons each have a mass number of 1. The mass of an electron is less than\u00a01\/1000<sup>th<\/sup>\u00a0that of a proton or neutron, meaning most of the atom\u2019s mass is in the nucleus.<\/p>\n<h3><b>3.1.2 Periodic Table of the Elements<\/b><\/h3>\n<p>Matter is composed of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> which are atoms that have a specific number of protons in the nucleus. This number of protons is called the <strong>Atomic Number<\/strong> for the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a>. For example, an oxygen atom has 8 protons and an iron atom has 26 protons. An <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a> cannot be broken down chemically into a simpler form and retains unique chemical and physical properties. Each <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a> behaves in a unique manner in nature. This uniqueness led scientists to develop a periodic table of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>, a tabular arrangement of all known <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> listed in order of their atomic number.<\/p>\n<figure id=\"attachment_2754\" aria-describedby=\"caption-attachment-2754\" style=\"width: 1024px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Periodic_Table-02-scaled.jpg\"><img class=\"size-large wp-image-2754\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/09\/Periodic_Table-02-1024x795-1.jpg\" alt=\"The Periodic Table of the Elements showing all elements with their chemical symbols, atomic weight, and atomic number.\" width=\"1024\" height=\"795\"><\/a><figcaption id=\"caption-attachment-2754\" class=\"wp-caption-text\">The Periodic Table of the Elements<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p><span style=\"font-weight: 400\">The first arrangement of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> into a periodic table was done by Dmitri Mendeleev in 1869 using the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> known at the time<\/span><span style=\"font-weight: 400\">. In the periodic table, each <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a> has a chemical symbol, name, atomic number, and atomic mass. The chemical symbol is an abbreviation for the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a>, often derived from a Latin or Greek name for the substance<\/span><span style=\"font-weight: 400\">. The atomic number is the number of protons in the nucleus. The atomic mass is the number of protons and neutrons in the nucleus, each with a mass number of one. Since the mass of electrons is so much less than the protons and neutrons, the atomic mass is effectively the number of protons plus neutrons. <\/span><\/p>\n<figure id=\"attachment_2755\" aria-describedby=\"caption-attachment-2755\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/3.3a_Formation_of_Carbon14_from_Nitrogen14.jpg\"><img class=\"size-medium wp-image-2755\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/09\/3.3a_Formation_of_Carbon14_from_Nitrogen14-300x123-1.jpg\" alt=\"\" width=\"300\" height=\"123\"><\/a><figcaption id=\"caption-attachment-2755\" class=\"wp-caption-text\">Formation of Carbon 14 from Nitrogen 14<\/figcaption><\/figure>\n<p>The atomic mass of natural <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> represents an average mass of the atoms comprising that substance in nature and is usually not a whole number as seen on the periodic table, meaning that an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a> exists in nature with atoms having different numbers of neutrons. The differing number of neutrons affects the mass of an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a> in nature and the atomic mass number represents this average. This gives rise to the concept of\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1779\">isotope<\/a><strong>.\u00a0<\/strong><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1779\">Isotopes<\/a> <\/strong>are forms of an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a> with the same number of protons but different numbers of neutrons. There are usually several <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1779\">isotopes<\/a> for a particular <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a>. For example, 98.9% of carbon atoms have 6 protons and 6 neutrons. This <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1779\">isotope<\/a> of carbon is called carbon-12 (<sup>12<\/sup>C). A few carbon atoms, carbon-13 (<sup>13<\/sup>C), have 6 protons and 7 neutrons. A trace amount of carbon atoms, carbon-14 (<sup>14<\/sup>C), has 6 protons and 8 neutrons.<\/p>\n<figure id=\"attachment_2756\" aria-describedby=\"caption-attachment-2756\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/elemental-composition-crust.jpg\"><img class=\"size-medium wp-image-2756\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/09\/elemental-composition-crust-300x277-1.jpg\" alt=\"Oxygen and silicon make up 3\/4ths of the chart.\" width=\"300\" height=\"277\"><\/a><figcaption id=\"caption-attachment-2756\" class=\"wp-caption-text\">Element abundance pie chart for Earth's crust by Callan Bentley.<\/figcaption><\/figure>\n<p>Among the 118 known <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>, the heaviest are fleeting human creations known only in high energy particle accelerators, and they decay rapidly. The heaviest naturally occurring <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a> is uranium, atomic number 92. The eight most abundant elements in Earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental crust<\/a> are shown in Table 1<span style=\"font-weight: 400\">. These <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> are found in the most common rock forming <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>.<\/span><\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<table style=\"height: 135px\">\n<tbody>\n<tr style=\"height: 15px\">\n<td style=\"height: 15px;width: 202.188px\"><b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">Element<\/a><\/b><\/td>\n<td style=\"height: 15px;width: 134.797px\"><b>Symbol<\/b><\/td>\n<td style=\"height: 15px;width: 237.703px\"><b>Abundance %<\/b><\/td>\n<\/tr>\n<tr style=\"height: 15px\">\n<td style=\"height: 15px;width: 202.188px\"><span style=\"font-weight: 400\">Oxygen<\/span><\/td>\n<td style=\"height: 15px;width: 134.797px\"><span style=\"font-weight: 400\">O<\/span><\/td>\n<td style=\"height: 15px;width: 237.703px\"><span style=\"font-weight: 400\">47%<\/span><\/td>\n<\/tr>\n<tr style=\"height: 15px\">\n<td style=\"height: 15px;width: 202.188px\"><span style=\"font-weight: 400\">Silicon<\/span><\/td>\n<td style=\"height: 15px;width: 134.797px\"><span style=\"font-weight: 400\">Si<\/span><\/td>\n<td style=\"height: 15px;width: 237.703px\"><span style=\"font-weight: 400\">28%<\/span><\/td>\n<\/tr>\n<tr style=\"height: 15px\">\n<td style=\"height: 15px;width: 202.188px\"><span style=\"font-weight: 400\">Aluminum<\/span><\/td>\n<td style=\"height: 15px;width: 134.797px\"><span style=\"font-weight: 400\">Al<\/span><\/td>\n<td style=\"height: 15px;width: 237.703px\"><span style=\"font-weight: 400\">8%<\/span><\/td>\n<\/tr>\n<tr style=\"height: 15px\">\n<td style=\"height: 15px;width: 202.188px\"><span style=\"font-weight: 400\">Iron<\/span><\/td>\n<td style=\"height: 15px;width: 134.797px\"><span style=\"font-weight: 400\">Fe<\/span><\/td>\n<td style=\"height: 15px;width: 237.703px\"><span style=\"font-weight: 400\">5%<\/span><\/td>\n<\/tr>\n<tr style=\"height: 15px\">\n<td style=\"height: 15px;width: 202.188px\"><span style=\"font-weight: 400\">Calcium<\/span><\/td>\n<td style=\"height: 15px;width: 134.797px\"><span style=\"font-weight: 400\">Ca<\/span><\/td>\n<td style=\"height: 15px;width: 237.703px\"><span style=\"font-weight: 400\">4%<\/span><\/td>\n<\/tr>\n<tr style=\"height: 15px\">\n<td style=\"height: 15px;width: 202.188px\"><span style=\"font-weight: 400\">Sodium<\/span><\/td>\n<td style=\"height: 15px;width: 134.797px\"><span style=\"font-weight: 400\">Na<\/span><\/td>\n<td style=\"height: 15px;width: 237.703px\"><span style=\"font-weight: 400\">3%<\/span><\/td>\n<\/tr>\n<tr style=\"height: 15px\">\n<td style=\"height: 15px;width: 202.188px\"><span style=\"font-weight: 400\">Potassium<\/span><\/td>\n<td style=\"height: 15px;width: 134.797px\">K<\/td>\n<td style=\"height: 15px;width: 237.703px\"><span style=\"font-weight: 400\">3%<\/span><\/td>\n<\/tr>\n<tr style=\"height: 15px\">\n<td style=\"height: 15px;width: 202.188px\"><span style=\"font-weight: 400\">Magnesium<\/span><\/td>\n<td style=\"height: 15px;width: 134.797px\">Mg<\/td>\n<td style=\"height: 15px;width: 237.703px\"><span style=\"font-weight: 400\">2%<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><em style=\"font-size: 16px;font-weight: 400\">Table 1. Eight Most Abundant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">Elements<\/a> in the Earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">Continental Crust<\/a> % by weight (source:\u00a0<a href=\"https:\/\/pubs.usgs.gov\/circ\/1953\/0285\/report.pdf\">USGS<\/a>). All other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> are less than 1%.<\/em><\/p>\n<h3><b>3.1.3 Chemical Bonding<\/b><\/h3>\n<figure id=\"attachment_2757\" aria-describedby=\"caption-attachment-2757\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/H2O_2D_labelled.svg_.png\"><img class=\"wp-image-145 size-medium\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/09\/H2O_2D_labelled.svg_-300x131.png\" alt=\"The hydrogen atoms are on one side, about 105\u00b0 apart.\" width=\"300\" height=\"131\"><\/a><figcaption id=\"caption-attachment-2757\" class=\"wp-caption-text\">A model of a water molecule, showing the bonds between the hydrogen and oxygen.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p><span style=\"font-weight: 400\">Most substances on Earth are compounds containing multiple <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>. Chemical <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonding<\/a> describes how these atoms attach with each other to form compounds, such as sodium and chlorine combining to form NaCl, common table salt. Compounds that are held together by\u00a0<\/span>chemical <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> are called molecules. Water is a compound of hydrogen and oxygen in which two hydrogen atoms are covalently <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> with one oxygen making the water molecule. The oxygen we breathe is formed when one oxygen atom covalently <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> with another oxygen atom to make the molecule O<sub>2<\/sub>. The subscript 2 in the chemical formula indicates the molecule contains two atoms of oxygen.<\/p>\n<p>Most <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are also compounds of more than one <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a>. The common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a> has the chemical formula CaCO<sub>3<\/sub> indicating the molecule consists of one calcium, one carbon, and three oxygen atoms.\u00a0In <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a>, one carbon and three oxygen atoms are held together by covalent <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> to form a <strong>molecular ion<\/strong>, called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a>, which has a negative charge. Calcium as an <strong>ion<\/strong> has a positive charge of plus two. The two oppositely charged ions attract each other and combine to form the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a>, CaCO3. The name of the chemical compound is calcium <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a>, where calcium is Ca and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> refers to the molecular ion CO<sub>3<\/sub><sup>-2<\/sup>.<\/p>\n<p>The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">olivine<\/a> has the chemical formula (Mg,Fe)<sub>2<\/sub>SiO<sub>4<\/sub>, in which one silicon and four oxygen atoms are <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> with two atoms of either magnesium or iron.\u00a0The comma between iron (Fe) and magnesium (Mg) indicates the two <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> can occupy the same location in the crystal structure and substitute for one another.<\/p>\n<h4><i><span style=\"font-weight: 400\">3.1.3.1 Valence and Charge<\/span><\/i><\/h4>\n<p><span style=\"font-weight: 400\">The electrons around the atom\u2019s nucleus are located in shells representing different energy levels. The outermost shell is called the <strong>valence shell<\/strong>. Electrons in the valence shell are involved in chemical <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonding<\/a>. In 1913, Niels Bohr proposed a simple model of the atom that states atoms are more stable when their outermost shell is full<\/span><span style=\"font-weight: 400\">. Atoms of most <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> thus tend to gain or lose electrons so the outermost or valence shell is full. In Bohr\u2019s model, the innermost shell can have a maximum of two electrons and the second and third shells can have a maximum of eight electrons. <\/span>When the innermost shell is the valence shell, as in the case of hydrogen and helium, it obeys the octet rule when it is full with two electrons. For <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> in higher rows, the octet rule of eight electrons in the valence shell applies.<\/p>\n<figure id=\"attachment_2758\" aria-describedby=\"caption-attachment-2758\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.4_Carbon_dioxide_3D_ball.png\"><img class=\"wp-image-2758 size-medium\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.4_Carbon_dioxide_3D_ball-300x213-1.png\" alt=\"Carbon dioxide molecule with a carbon ion in the center and two oxygen ions on either side, each sharing two electrons with the carbon.\" width=\"300\" height=\"213\"><\/a><figcaption id=\"caption-attachment-2758\" class=\"wp-caption-text\">The carbon dioxide molecule. Since Oxygen is -2 and Carbon is +4, the two oxygens bond to the carbon to form a neutral molecule.<\/figcaption><\/figure>\n<p>The rows in the periodic table present the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> in order of atomic number and the columns organize <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> with similar characteristics, such as the same number of electrons in their valence shells. Columns are often labeled from left to right with Roman numerals I to VIII, and Arabic numerals 1 through 18. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> in columns I and II have 1 and 2 electrons in their respective valence shells and the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> in columns VI and VII have 6 and 7 electrons in their respective valence shells.<\/p>\n<p><span style=\"font-weight: 400\">In row 3 and column I, sodium (Na) has 11 protons in the nucleus and 11 electrons in three shells\u20142 electrons in the inner shell, 8 electrons in the second shell, and 1 electron in the valence shell. To maintain a full outer shell of 8 electrons per the octet rule, sodium readily gives up that 1 electron so there are 10 total electrons. With 11 positively charged protons in the nucleus and 10 negatively charged electrons in two shells, sodium when forming chemical <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> is an ion with an overall net charge of +1<\/span><span style=\"font-weight: 400\">.<\/span><\/p>\n<p><span style=\"font-weight: 400\">All <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> in column I have a single electron in their valence shell and a valence of 1.\u00a0<\/span>These other column I <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> also readily give up this single valence electron and thus become ions with a +1 charge. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">Elements<\/a> in column II readily give up 2 electrons and end up as ions with a charge of +2. Note that elements in columns I and II which readily give up their valence electrons, often form bonds with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> in columns VI and VII which readily take up these electrons. \u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">Elements<\/a> in columns 3 through 15 are usually involved in covalent <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonding<\/a>. The last column 18 (VIII) contains the <strong>noble gases<\/strong>. These <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> are chemically inert because the valence shell is already full with 8 electrons, so they do not gain or lose electrons. An example is the noble gas helium which has 2 valence electrons in the first shell. Its valence shell is therefore full. All <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> in column VIII possess full valence shells and do not form <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> with other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>.<\/p>\n<p><span style=\"font-weight: 400\">As seen above, an atom with a net positive or negative charge as a result of gaining or losing electrons is called an <strong>ion<\/strong>. In general the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> on the left side of the table lose electrons and become positive ions, called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1780\">cations<\/a> because they are attracted to the cathode in an electrical device. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> on the right side tend to gain electrons. These are called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1782\">anions<\/a> because they are attracted to the anode in an electrical device. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> in the center of the periodic table, columns 3 through 15, do not consistently follow the octet rule. These are called transition <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>. A common example is iron, which has a +2 or +3 charge depending on the oxidation state of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a>. Oxidized Fe<sup>+3<\/sup> carries a +3 charge and reduced Fe<sup>+2<\/sup> is +2. These two different oxidation states of iron often impart dramatic colors to rocks containing their <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>\u2014the oxidized form producing red colors and the reduced form producing green.<\/span><\/p>\n<h4><i><span style=\"font-weight: 400\">3.1.3.2\u00a0<\/span><\/i><i><span style=\"font-weight: 400\">Ionic Bonding<\/span><\/i><\/h4>\n<figure id=\"attachment_2759\" aria-describedby=\"caption-attachment-2759\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03-Sodium-chloride-3D-ionic.png\"><img class=\"size-medium wp-image-2759\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03-Sodium-chloride-3D-ionic-300x284-1.png\" alt=\"Image of crystal model of halite with ions of sodium and chlorine arranged in a cubic structure.\" width=\"300\" height=\"284\"><\/a><figcaption id=\"caption-attachment-2759\" class=\"wp-caption-text\">Cubic arrangement of Na and Cl in Halite<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p><span style=\"font-weight: 400\">Ionic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a>, also called electron-transfer <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a>, are formed by the electrostatic attraction between atoms having opposite charges. Atoms of two opposite charges attract each other electrostatically and form an <strong>ionic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bond<\/a><\/strong> in which the positive ion transfers its electron (or electrons) to the negative ion which takes them up. Through this transfer both atoms thus achieve a full valence shell.\u00a0<\/span>For example one atom of sodium (Na<sup>+1<\/sup>) and one atom of chlorine (Cl<sup>-1<\/sup>) form an ionic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bond<\/a> to make the compound sodium chloride (NaCl). This is also known as the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> halite or common table salt. Another example is calcium (Ca<sup>+2<\/sup>) and chlorine (Cl<sup>-1<\/sup>) combining to make the compound calcium chloride (CaCl<sub>2<\/sub>). The subscript 2 indicates two atoms of chlorine are ionically <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> to one atom of calcium.<\/p>\n<h4><i><span style=\"font-weight: 400\">3.1.3.3\u00a0<\/span><\/i><i><span style=\"font-weight: 400\">Covalent <\/span><\/i><i><span style=\"font-weight: 400\">Bonding<\/span><\/i><\/h4>\n<figure id=\"attachment_2760\" aria-describedby=\"caption-attachment-2760\" style=\"width: 249px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Covalent.svg_.png\"><img class=\"size-medium wp-image-2760\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Covalent.svg_-249x300-1.png\" alt=\"Each atom is sharing electrons.\" width=\"249\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2760\" class=\"wp-caption-text\">Methane molecule<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>Ionic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> are usually formed between a <strong>metal<\/strong> and a <strong>nonmetal<\/strong>. Another type, called a covalent or electron-sharing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bond<\/a>, commonly occurs between nonmetals. Covalent <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> share electrons between ions to complete their valence shells. For example, oxygen (atomic number 8) has 8 electrons\u20142 in the inner shell and 6 in the valence shell. Gases like oxygen often form diatomic molecules by sharing valence electrons. In the case of oxygen, two atoms attach to each other and share 2 electrons to fill their valence shells to become the common oxygen molecule we breathe (O<sub>2<\/sub>). Methane (CH<sub>4<\/sub>) is another covalently <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> gas. The carbon atom needs 4 electrons and each hydrogen needs 1. Each hydrogen shares its electron with the carbon to form a molecule as shown in the figure.<\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-18\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-18\" class=\"h5p-iframe\" data-content-id=\"18\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"3.2 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3754\" aria-describedby=\"caption-attachment-3754\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/3.1-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-149\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/3.1-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3754\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 3.1 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-size: 28px\">3.2 Formation of Minerals<\/span><\/h2>\n<p><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Minerals<\/a> form when atoms <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bond<\/a> together in a crystalline arrangement. Three main ways this occurs in nature are: 1) <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitation<\/a> directly from an aqueous (water) <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a> with a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> change, 2) <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1752\">crystallization<\/a> from a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> with a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> change, and 3) biological <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitation<\/a> by the action of organisms. <\/span><\/p>\n<h3><b> 3.2.1 Precipitation from aqueous solution<\/b><\/h3>\n<figure id=\"attachment_2761\" aria-describedby=\"caption-attachment-2761\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.5_Hard_Water_Calcification.jpg\"><img class=\"size-medium wp-image-2761\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.5_Hard_Water_Calcification-300x200-1.jpg\" alt=\"Encrusted calcium carbonate (lime) deposits on faucent\" width=\"300\" height=\"200\"><\/a><figcaption id=\"caption-attachment-2761\" class=\"wp-caption-text\">Calcium carbonate deposits from hard water<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">Solutions<\/a> consist of ions or molecules, known as solutes, dissolved in a medium or solvent. In nature this solvent is usually water. Many <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> can be dissolved in water, such as halite or table salt, which has the composition sodium chloride, NaCl. The Na<sup>+1<\/sup> and Cl<sup>-1<\/sup> ions separate and disperse into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a>.<\/p>\n<p><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">Precipitation<\/a><\/strong> is the reverse process, in which ions in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a> come together to form solid <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">Precipitation<\/a> is dependent on the concentration of ions in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a> and other factors such as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> and pressure. The point at which a solvent cannot hold any more solute is called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1784\">saturation<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">Precipitation<\/a> can occur when the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a> falls, when the solute evaporates, or with changing chemical conditions in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a>. An example of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitation<\/a> in our homes is when water evaporates and leaves behind a rind of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> on faucets, shower heads, and drinking glasses.<\/p>\n<p>In nature, changes in environmental conditions may cause the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> dissolved in water to form <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> and grow into crystals or cement grains of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediment<\/a> together. In Utah, deposits of tufa formed from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>-rich springs that emerged into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_747\">ice age<\/a> Lake Bonneville. Now exposed in dry valleys, this porous tufa was a natural insulation used by pioneers to build their homes with a natural protection against summer heat and winter cold. The travertine terraces at Mammoth Hot Springs in Yellowstone Park are another example formed by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitation<\/a> at the edges of the shallow spring-fed ponds.<\/p>\n<figure id=\"attachment_2762\" aria-describedby=\"caption-attachment-2762\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.6_1200px-Bonneville_Salt_Flats.jpg\"><img class=\"size-medium wp-image-2762\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.6_1200px-Bonneville_Salt_Flats-300x197-1.jpg\" alt=\"The Bonneville Salt Flats of Utah\" width=\"300\" height=\"197\"><\/a><figcaption id=\"caption-attachment-2762\" class=\"wp-caption-text\">The Bonneville Salt Flats of Utah<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\">Another example of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitation<\/a> occurs in the Great Salt Lake, Utah, where the concentration of sodium chloride and other salts is nearly eight times greater than in the world\u2019s oceans <\/span><span style=\"font-weight: 400\">[zotpressInText item=\"{DU5CMSHJ}\" format=\"%num%\" brackets=\"yes\"]<\/span><span style=\"font-weight: 400\">.\u00a0<\/span>Streams carry salt ions into the lake from the surrounding mountains. With no other outlet, the water in the lake evaporates and the concentration of salt increases until <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1784\">saturation<\/a> is reached and the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitate<\/a> out as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediments<\/a>. Similar salt deposits include halite and other precipitates, and occur in other lakes like Mono Lake in California and the Dead Sea.<\/p>\n<h3><b>3.2.2 Crystallization from Magma<\/b><\/h3>\n<figure id=\"attachment_2763\" aria-describedby=\"caption-attachment-2763\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.5a_Pahoehoe_toe.jpg\"><img class=\"size-medium wp-image-2763\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.5a_Pahoehoe_toe-300x188-1.jpg\" alt=\"A lava flow\" width=\"300\" height=\"188\"><\/a><figcaption id=\"caption-attachment-2763\" class=\"wp-caption-text\">Lava, magma at the earth\u2019s surface<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>Heat is energy that causes atoms in substances to vibrate. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">Temperature<\/a> is a measure of the intensity of the vibration. If the vibrations are violent enough, chemical <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> are broken and the crystals melt releasing the ions into the melt. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">Magma<\/a> is molten rock with freely moving ions. When <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> is emplaced at depth or extruded onto the surface (then called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1751\">lava<\/a>), it starts to cool and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> crystals can form.<\/p>\n<h3><b>3.2.3 Precipitation by Organisms<\/b><\/h3>\n<figure id=\"attachment_2764\" aria-describedby=\"caption-attachment-2764\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.8_Ammonite_Asteroceras.jpg\"><img class=\"size-full wp-image-2764\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.8_Ammonite_Asteroceras.jpg\" alt=\"Shell of an ammonite, an extinct cephalopod, with a spiral shell in a plane.\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-2764\" class=\"wp-caption-text\">Ammonite shell made of calcium carbonate<\/figcaption><\/figure>\n<p><span style=\"font-size: 1em\">Many organisms build bones, shells, and body coverings by extracting ions from water and precipitating <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> biologically. The most common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitated<\/a> by organisms is <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a>, or calcium <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> (CaCO3). <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">Calcite<\/a> is often <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitated<\/a> by organisms as a polymorph called aragonite. <\/span><strong style=\"font-size: 1em\">Polymorphs<\/strong><span style=\"font-size: 1em\"> are crystals with the same chemical formula but different crystal structures. Marine invertebrates such as corals and clams <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitate<\/a> aragonite or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a> for their shells and structures. Upon death, their hard parts accumulate on the ocean floor as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediments<\/a>, and eventually may become the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1761\">sedimentary rock<\/a> limestone. Though limestone can form inorganically, the vast majority is formed by this biological process. Another example is marine organisms called radiolaria, which are zooplankton that <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitate<\/a> silica for their microscopic external shells. When the organisms die, the shells accumulate on the ocean floor and can form the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1761\">sedimentary rock<\/a> chert. An example of biologic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitation<\/a> from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1274\">vertebrate<\/a> world is bone, which is composed mostly of a type of apatite, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_975\">phosphate<\/a> group. The apatite found in bones contains calcium and water in its structure and is called hydroxycarbonate apatite, Ca<\/span><sub>5<\/sub><span style=\"font-size: 1em\">(PO<\/span><sub>4<\/sub><span style=\"font-size: 1em\">)<\/span><sub>3<\/sub><span style=\"font-size: 1em\">(OH).\u00a0 As mentioned above, such substances are not technically <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> until the organism dies and these hard parts become <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1228\">fossils<\/a>.<\/span><\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-19\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-19\" class=\"h5p-iframe\" data-content-id=\"19\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"3.3 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3753\" aria-describedby=\"caption-attachment-3753\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/3.2-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-154\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/3.2-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3753\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 3.2 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-weight: 400\">3.3 Silicate Minerals<\/span><\/h2>\n<figure id=\"attachment_2765\" aria-describedby=\"caption-attachment-2765\" style=\"width: 256px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Tetrahedron.gif\"><img class=\"size-full wp-image-2765\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tetrahedron.gif\" alt=\"It is a pyramid shape with a triangular base\" width=\"256\" height=\"256\"><\/a><figcaption id=\"caption-attachment-2765\" class=\"wp-caption-text\">Rotating animation of a tetrahedra<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Minerals<\/a> are categorized based on their composition and structure. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">Silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are built around a molecular ion called the <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silicon-oxygen tetrahedron<\/a><\/strong>. A tetrahedron has a pyramid-like shape with four sides and four corners.\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">Silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> form the largest group of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> on Earth, comprising the vast majority of the Earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a>. Of the nearly four thousand known <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> on Earth, most are rare. There are only a few that make up most of the rocks likely to be encountered by surface dwelling creatures like us. These are generally called the <strong>rock-forming <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a><\/strong>.<\/p>\n<figure id=\"attachment_2766\" aria-describedby=\"caption-attachment-2766\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.10_Tetrahedron.jpg\"><img class=\"size-medium wp-image-2766\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.10_Tetrahedron-300x300-1.jpg\" alt=\"Model of silicon-oxygen tetrahedron of ping pong balls with a tiny silicon ion in the space in the middle of the four large balls\" width=\"300\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2766\" class=\"wp-caption-text\">Ping pong ball model of tetrahedron: balls are oxygen, lead sinker in center is silicon<\/figcaption><\/figure>\n<p>The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silicon-oxygen tetrahedron<\/a> (SiO<sub>4<\/sub>) consists of a single silicon atom at the center and four oxygen atoms located at the four corners of the tetrahedron. Each oxygen ion has a -2 charge and the silicon ion has a +4 charge. The silicon ion shares one of its four valence electrons with each of the four oxygen ions in a covalent <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bond<\/a> to create a symmetrical geometric four-sided pyramid figure. Only half of the oxygen\u2019s valence electrons are shared, giving the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silicon-oxygen tetrahedron<\/a> an ionic charge of -4. This <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silicon-oxygen tetrahedron<\/a> forms bonds with many other combinations of ions to form the large group of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>.<\/p>\n<figure id=\"attachment_2767\" aria-describedby=\"caption-attachment-2767\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.11_Tetrahedron_open.jpg\"><img class=\"size-medium wp-image-2767\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.11_Tetrahedron_open-300x255-1.jpg\" alt=\"Top ball removed showing the tiny silicon ion in the center\" width=\"300\" height=\"255\"><\/a><figcaption id=\"caption-attachment-2767\" class=\"wp-caption-text\">The silicon ion in the center of the tetrahedron<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\">The silicon ion is much smaller than the oxygen ions (see the figures) and fits into a small space in the center of the four large oxygen ions, seen if the top ball is removed (as shown in the figure to the right). <\/span><span style=\"font-weight: 400\">Because only one of the valence electrons of the corner oxygens is shared, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silicon-oxygen tetrahedron<\/a> has chemically active corners available to form <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> with other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silica tetrahedra<\/a> or other positively charged ions such as Al<\/span><sub><span style=\"font-weight: 400\">+3<\/span><\/sub><span style=\"font-weight: 400\">, Fe<\/span><sub><span style=\"font-weight: 400\">+2,+3<\/span><\/sub><span style=\"font-weight: 400\">, Mg<\/span><sub><span style=\"font-weight: 400\">+2<\/span><\/sub><span style=\"font-weight: 400\">, K<\/span><sub><span style=\"font-weight: 400\">+1<\/span><\/sub><span style=\"font-weight: 400\">, Na<\/span><sub><span style=\"font-weight: 400\">+1<\/span><\/sub><span style=\"font-weight: 400\">, and Ca<\/span><sub><span style=\"font-weight: 400\">+2<\/span><\/sub><span style=\"font-weight: 400\">. Depending on many factors, such as the original <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> chemistry, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silica-oxygen tetrahedra<\/a> can combine with other tetrahedra in several different configurations. For example, tetrahedra can be isolated, attached in chains, sheets, or three dimensional structures. These combinations and others create the chemical structure in which positively charged ions can be inserted for unique chemical compositions forming <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> groups. \u00a0\u00a0<\/span><\/p>\n<h3><b>3.3.1 The dark ferromagnesian silicates<\/b><\/h3>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2768\" aria-describedby=\"caption-attachment-2768\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.12_Peridot_in_basalt.jpg\"><img class=\"size-medium wp-image-2768\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.12_Peridot_in_basalt-300x225-1.jpg\" alt=\"Many small crystall of the green mineral olivine in a mass of basalt\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-2768\" class=\"wp-caption-text\">Olivine crystals in basalt<\/figcaption><\/figure>\n<p><span style=\"font-size: 14pt\"><b>The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">Olivine<\/a> Family<\/b><\/span><\/p>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">Olivine<\/a> is the primary <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> component in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> rock such as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1666\">peridotite<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1013\">basalt<\/a>. It is characteristically green when not weathered. The chemical formula is (Fe,Mg)<sub>2<\/sub>SiO<sub>4<\/sub>. As previously described, the comma between iron (Fe) and magnesium (Mg) indicates these two <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> occur in a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1786\">solid solution<\/a>.\u00a0<span style=\"font-weight: 400\">Not to be confused with a liquid <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a>, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1786\">solid solution<\/a> occurs when two or more <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> have similar properties and can freely substitute for each other in the same location in the crystal structure.<\/span><\/p>\n<figure id=\"attachment_2769\" aria-describedby=\"caption-attachment-2769\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.13_Atomic_structure_of_olivine_1.png\"><img class=\"size-full wp-image-2769\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.13_Atomic_structure_of_olivine_1.png\" alt=\"Tetrahedral structure of olivine showing the independent tetrahedra connected together by anions of iron and\/or magnesium.\" width=\"300\" height=\"258\"><\/a><figcaption id=\"caption-attachment-2769\" class=\"wp-caption-text\">Tetrahedral structure of olivine<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">Olivine<\/a> is referred to as a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> family because of the ability of iron and magnesium to substitute for each other. Iron and magnesium in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">olivine<\/a> family indicates a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1786\">solid solution<\/a> forming a compositional series within the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> group which can form crystals of all iron as one end member and all mixtures of iron and magnesium in between to all magnesium at the other end member. Different <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> names are applied to compositions between these end members.\u00a0 In the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">olivine<\/a> series of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, the iron and magnesium ions in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1786\">solid solution<\/a> are about the same size and charge, so either atom can fit into the same location in the growing crystals. Within the cooling <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> crystals continue to grow until they solidify into <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous rock<\/a>. The relative amounts of iron and magnesium in the parent <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> determine which <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> in the series form. Other rarer <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> with similar properties to iron or magnesium, like manganese (Mn), can substitute into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">olivine<\/a> crystalline structure in small amounts. Such ionic substitutions in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> crystals give rise to the great variety of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> and are often responsible for differences in color and other properties within a group or family of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">Olivine<\/a> has a pure iron end-member (called fayalite) and a pure magnesium end-member (called forsterite). Chemically, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">olivine<\/a> is mostly silica, iron, and magnesium and therefore is grouped among the dark-colored <\/span>ferromagnesian<span style=\"font-weight: 400\"> (iron=ferro, magnesium=magnesian) or <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a><\/strong> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, a contraction of their chemical symbols Ma and Fe. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">Mafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are also referred to as dark-colored ferromagnesian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. <em>Ferro<\/em> means iron and <em>magnesian<\/em> refers to magnesium. Ferromagnesian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicates<\/a> tend to be more dense than non-ferromagnesian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicates<\/a>. This difference in density ends up being important in controlling the behavior of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks that are built from these <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>: whether a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1680\">subducts<\/a> or not is largely governed by the density of its rocks, which are in turn controlled by the density of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> that comprise them.<\/span><\/p>\n<p>The crystal structure of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">olivine<\/a> is built from independent <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silica tetrahedra<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Minerals <\/a>with independent tetrahedral structures are called neosilicates (or orthosilicates). In addition to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">olivine<\/a>, other common neosilicate <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> include garnet, topaz, kyanite, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1227\">zircon<\/a>.<\/p>\n<p>Two other similar arrangements of tetrahedra are close in structure to the neosilicates and grade toward the next group of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, the pyroxenes. In a variation on independent tetrahedra called sorosilicates, there are <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> that share one oxygen between two tetrahedra, and include <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> like pistachio-green epidote, a gemstone. Another variation are the cyclosilicates, which as the name suggests, consist of tetrahedral rings, and include gemstones such as beryl, emerald, aquamarine, and tourmaline<\/p>\n<h3><b>3.3.2 Pyroxene Family<\/b><\/h3>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2770\" aria-describedby=\"caption-attachment-2770\" style=\"width: 300px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.14_Diopside-172005.jpg\"><img class=\"wp-image-2770 size-medium\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.14_Diopside-172005-300x231-1.jpg\" alt=\"Dark green crystals of diopside, a member of the pyroxene family\" width=\"300\" height=\"231\"><\/a><figcaption id=\"caption-attachment-2770\" class=\"wp-caption-text\">Crystals of diopside, a member of the pyroxene family<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2771\" aria-describedby=\"caption-attachment-2771\" style=\"width: 70px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.15_Pyroxen-chain.png\"><img class=\"wp-image-2771\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.15_Pyroxen-chain.png\" alt=\"Single chain of tetrahedra in pyroxene, alternating with adjacent corner oxygens bonded. The outer corners are active to bond with other anions.\" width=\"70\" height=\"517\"><\/a><figcaption id=\"caption-attachment-2771\" class=\"wp-caption-text\">Single chain tetrahedral structure in pyroxene<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">Pyroxene<\/a> is another family of dark ferromagnesian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, typically black or dark green in color. Members of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">pyroxene<\/a> family have a complex chemical composition that includes iron, magnesium, aluminum, and other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> to polymerized <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silica tetrahedra<\/a>. <strong>Polymers<\/strong> are chains, sheets, or three-dimensional structures, and are formed by multiple tetrahedra covalently <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> via their corner oxygen atoms. Pyroxenes are commonly found in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks such as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1666\">peridotite<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1013\">basalt<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1016\">gabbro<\/a>, as well as metamorphic rocks like eclogite and blue schist.<\/p>\n<p>Pyroxenes are built from long, single chains of polymerized <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silica tetrahedra<\/a> in which tetrahedra share two corner oxygens. The silica chains are <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> together into the crystal structures by metal cations. A common member of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">pyroxene<\/a> family is augite, itself containing several <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1786\">solid solution<\/a> series with a complex chemical formula (Ca,Na)(Mg,Fe,Al,Ti)(Si,Al)<sub>2<\/sub>O<sub>6<\/sub> that gives rise to a number of individual <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> names.<\/p>\n<p>This single-chain crystalline structure <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> with many <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>, which can also freely substitute for each other. The generalized chemical composition for <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">pyroxene<\/a> is XZ(Al,Si)<sub>2<\/sub>O<sub>6<\/sub>. X represents the ions Na, Ca, Mg, or Fe, and Z represents Mg, Fe, or Al. These ions have similar ionic sizes, which allows many possible substitutions among them. Although the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1780\">cations<\/a> may freely substitute for each other in the crystal, they carry different ionic charges that must be balanced out in the final crystalline structure. For example Na has a charge of +1, but Ca has charge of +2. If a Na<sup>+<\/sup> ion substitutes for a Ca<sup>+2<\/sup> ion, it creates an unequal charge that must be balanced by other ionic substitutions elsewhere in the crystal. Note that ionic size is more important than ionic charge for substitutions to occur in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1786\">solid solution<\/a> series in crystals.<\/p>\n<h3><\/h3>\n<h3><b>3.3.3 Amphibole Family<\/b><\/h3>\n<figure id=\"attachment_2773\" aria-describedby=\"caption-attachment-2773\" style=\"width: 200px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.15_Orthoclase_Hornblende.jpg\"><img class=\"wp-image-2773\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.15_Orthoclase_Hornblende-300x300-1.jpg\" alt=\"A crystal of orthoclase (potassium feldspar) wth elongated dark crystals of hornblende\" width=\"200\" height=\"200\"><\/a><figcaption id=\"caption-attachment-2773\" class=\"wp-caption-text\">Elongated crystals of hornblende in orthoclase<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2772\" aria-describedby=\"caption-attachment-2772\" style=\"width: 200px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.16_Amphibole.jpg\"><img class=\"wp-image-2772\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.16_Amphibole-300x236-1.jpg\" alt=\"Black crystals of hornblende\" width=\"200\" height=\"157\"><\/a><figcaption id=\"caption-attachment-2772\" class=\"wp-caption-text\">Hornblende crystals<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1791\">Amphibole<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are built from polymerized double silica chains and they are also referred to as inosilicates. Imagine two <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">pyroxene<\/a> chains that connect together by sharing a third oxygen on each tetrahedra.\u00a0 Amphiboles are usually found in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> and metamorphic rocks and typically have a long-bladed <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_980\">crystal habit<\/a><\/strong>. The most common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1791\">amphibole<\/a>, hornblende, is usually black; however, they come in a variety of colors depending on their chemical composition. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1762\">metamorphic rock<\/a>, amphibolite, is primarily composed of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1791\">amphibole<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>.<\/p>\n<figure id=\"attachment_2774\" aria-describedby=\"caption-attachment-2774\" style=\"width: 79px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.17_Tremolite-chain.png\"><img class=\"size-medium wp-image-2774\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.17_Tremolite-chain-79x300-1.png\" alt=\"Double chain structure of amphibole; two single chains laying together with the inner corners of each tetrahedron bonded and the outer cornera active to bond with anions\" width=\"79\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2774\" class=\"wp-caption-text\">Double chain structure<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>Amphiboles are composed of iron, magnesium, aluminum, and other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1780\">cations<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silica tetrahedra<\/a>. These dark ferromagnesian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are commonly found in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1016\">gabbro<\/a>, baslt, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1015\">diorite<\/a>, and often form the black specks in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1014\">granite<\/a>. Their chemical formula is very complex and generally written as (RSi<sub>4<\/sub>O<sub>11<\/sub>)<sub>2<\/sub>, where R represents many different <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1780\">cations<\/a>. For example, it can also be written more exactly as AX<sub>2<\/sub>Z<sub>5<\/sub>((Si,Al,Ti)<sub>8<\/sub>O<sub>22<\/sub>)(OH,F,Cl,O)<sub>2<\/sub>. In this formula A may be Ca, Na, K, Pb, or blank; X equals Li, Na, Mg, Fe, Mn, or Ca; and Z is Li, Na, Mg, Fe, Mn, Zn, Co, Ni, Al, \u00a0Cr, Mn, V, Ti, or Zr. The substitutions create a wide variety of colors such as green, black, colorless, white, yellow, blue, or brown. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1791\">Amphibole<\/a> crystals can also include hydroxide ions (OH<sup>-<\/sup>)<sup>,<\/sup> which occurs from an interaction between the growing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> and water dissolved in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>.<\/p>\n<h3><\/h3>\n<h3><\/h3>\n<h3><strong>3.3.4 Sheet Silicates<\/strong><\/h3>\n<figure id=\"attachment_2775\" aria-describedby=\"caption-attachment-2775\" style=\"width: 200px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.19_Biotite_aggregate_-_Ochtendung_Eifel_Germany.jpg\"><img class=\"wp-image-2775\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.19_Biotite_aggregate_-_Ochtendung_Eifel_Germany-300x225-1.jpg\" alt=\"Dark brown crystals of biotite mica showing sheet-like habit\" width=\"200\" height=\"150\"><\/a><figcaption id=\"caption-attachment-2775\" class=\"wp-caption-text\">Sheet crystals of biotite mica<\/figcaption><\/figure>\n<figure id=\"attachment_3637\" aria-describedby=\"caption-attachment-3637\" style=\"width: 250px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/MicaSheetUSGOV.jpg\"><img class=\"wp-image-166\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MicaSheetUSGOV-300x226.jpg\" alt=\"Crystal of muscovite mica showing sheet structure of the mineral\" width=\"250\" height=\"188\"><\/a><figcaption id=\"caption-attachment-3637\" class=\"wp-caption-text\">Crystal of muscovite mica<\/figcaption><\/figure>\n<p>Sheet <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicates<\/a> are built from tetrahedra which share all three of their bottom corner oxygens thus forming sheets of tetrahedra with their top corners available for <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonding<\/a> with other atoms. Micas and clays are common types of sheet <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicates<\/a>, also known as phyllosilicates. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">Mica<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are usually found in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> and metamorphic rocks, while clay <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are more often found in sedimentary rocks. Two frequently found micas are dark-colored <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">biotite<\/a>, frequently found in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1014\">granite<\/a>, and light-colored <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">muscovite<\/a>, found in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1762\">metamorphic rock<\/a> called schist.<\/p>\n<figure id=\"attachment_2777\" aria-describedby=\"caption-attachment-2777\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.20_Silicate-sheet-3D-polyhedra.png\"><img class=\"size-medium wp-image-2777\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.20_Silicate-sheet-3D-polyhedra-300x197-1.png\" alt=\"Continuous sheets of tetradedra with all three base corners bonded to each other; the top corner active to bond with anions\" width=\"300\" height=\"197\"><\/a><figcaption id=\"caption-attachment-2777\" class=\"wp-caption-text\">Sheet structure of mica<\/figcaption><\/figure>\n<p>Chemically, sheet <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicates<\/a> usually contain silicon and oxygen in a 2:5 ratio (Si<sub>4<\/sub>O<sub>10<\/sub>). Micas contain mostly silica, aluminum, and potassium. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">Biotite<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">mica<\/a> has more iron and magnesium and is considered a ferromagnesian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">Muscovite<\/a> micas belong to the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">Felsic<\/a> is a contraction formed from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a>, the dominant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> rocks.<\/p>\n<figure id=\"attachment_2778\" aria-describedby=\"caption-attachment-2778\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.21_Crystal-structure-of-mica.jpg\"><img class=\"size-medium wp-image-2778\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.21_Crystal-structure-of-mica-300x300-1.jpg\" alt=\"Diagram of mica crystal structure with the sheets of tetrahedra inverted onto each other into sandwiches with the active corners bonded with anions and the sandwiches connected together with large potassium ions that form weak bonds easily separated so the crystal comes apart into sheets.\" width=\"300\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2778\" class=\"wp-caption-text\">Crystal structure of a mica<\/figcaption><\/figure>\n<figure id=\"attachment_2779\" aria-describedby=\"caption-attachment-2779\" style=\"width: 296px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Illmenite-mica-sandwich.jpg\"><img class=\"size-medium wp-image-2779\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Illmenite-mica-sandwich-296x300-1.jpg\" alt=\"Silica sheets layered in mica like bread and hjam in a stack of sandwiches\" width=\"296\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2779\" class=\"wp-caption-text\">Mica \"silica sandwich\" structure<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>The illustration of the crystalline structure of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">mica<\/a> shows the corner O atoms <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> with K, Al, Mg, Fe, and Si atoms, forming polymerized sheets of linked tetrahedra, with an octahedral layer of Fe, Mg, or Al, between them.\u00a0 The yellow potassium ions form Van der Waals <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> (attraction and repulsion between atoms, molecules, and surfaces) and hold the sheets together. Van der Waals <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> differ from\u00a0<a href=\"https:\/\/en.wikipedia.org\/wiki\/Covalent_bond\">covalent<\/a>\u00a0and\u00a0<a href=\"https:\/\/en.wikipedia.org\/wiki\/Ionic_bond\">ionic<\/a>\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a>, and exist here between the sandwiches, holding them together into a stack of sandwiches. The Van der Waals <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> are weak compared to the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> within the sheets, allowing the sandwiches to be separated along the potassium layers. This gives <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">mica<\/a> its characteristic property of easily cleaving into sheets.<\/p>\n<figure id=\"attachment_2780\" aria-describedby=\"caption-attachment-2780\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.22_Kaolinite-structure.jpg\"><img class=\"size-medium wp-image-2780\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.22_Kaolinite-structure-300x244-1.jpg\" alt=\"Crystal structure of kaolinite, a clay mineral with sheet structure like mica except that the\" width=\"300\" height=\"244\"><\/a><figcaption id=\"caption-attachment-2780\" class=\"wp-caption-text\">Structure of kaolinite<\/figcaption><\/figure>\n<p>Clays <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> occur in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediments<\/a> formed by the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1754\">weathering<\/a> of rocks and are another family of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> with a tetrahedral sheet structure. Clay <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> form a complex family, and are an important component of many sedimentary rocks. Other sheet <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicates<\/a> include serpentine and chlorite, found in metamorphic rocks.<\/p>\n<p>Clay <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are composed of hydrous aluminum <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicates<\/a>. One type of clay, kaolinite, has a structure like an open-faced sandwich, with the bread being a single layer of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silicon-oxygen tetrahedra<\/a> and a layer of aluminum as the spread in an octahedral configuration with the top oxygens of the sheets.<\/p>\n<h3><b>3.3.5 Framework Silicates<\/b><\/h3>\n<figure id=\"attachment_2829\" aria-describedby=\"caption-attachment-2829\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Quartz-crystals.jpg\"><img class=\"size-medium wp-image-2829\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Quartz-crystals-300x284-1.jpg\" alt=\"Freely grown quartz crystals showing crysatl faces\" width=\"300\" height=\"284\"><\/a><figcaption id=\"caption-attachment-2829\" class=\"wp-caption-text\">Freely growing quartz crystals showing crystal faces<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">Quartz<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> are the two most abundant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental crust<\/a>. In fact, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> itself is the single most abundant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> in the Earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a>. There are two types of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a>, one containing potassium and abundant in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> rocks of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental crust<\/a>, and the other with sodium and calcium abundant in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> rocks of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1659\">oceanic crust<\/a>.\u00a0 Together with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a>, these <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are classified as framework <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicates<\/a>. They are built with a three-dimensional framework of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silica tetrahedra<\/a> in which all four corner oxygens are shared with adjacent tetrahedra. Within these frameworks in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> are holes and spaces into which other ions like aluminum, potassium, sodium, and calcium can fit giving rise to a variety of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> compositions and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> names.<\/p>\n<figure id=\"attachment_2781\" aria-describedby=\"caption-attachment-2781\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/min-crust-pie-chart.jpg\"><img class=\"size-medium wp-image-2781\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/min-crust-pie-chart-300x290-1.jpg\" alt=\"Feldspar is 51% of the chart.\" width=\"300\" height=\"290\"><\/a><figcaption id=\"caption-attachment-2781\" class=\"wp-caption-text\">Mineral abundance pie chart in Earth's crust by Callan Bentley.<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">Feldspars<\/a> are usually found in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks, such as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1014\">granite<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1010\">rhyolite<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1013\">basalt<\/a> as well as metamorphic rocks and detrital sedimentary rocks. Detrital sedimentary rocks are composed of mechanically weathered rock particles, like sand and gravel. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">Quartz<\/a> is especially abundant in detrital sedimentary rocks because it is very resistant to disintegration by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1754\">weathering<\/a>. While <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a> is the most abundant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> on the Earth's surface, due to its durability, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are the most abundant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> in the Earth's <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a>, comprising roughly 50% of the total <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> that make up the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a>.<\/p>\n<figure id=\"attachment_2782\" aria-describedby=\"caption-attachment-2782\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.24_kspar280x210-1.jpg\"><img class=\"size-medium wp-image-2782\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.24_kspar280x210-1-300x200-1.jpg\" alt=\"A group of crystals of pink potassium feldspar\" width=\"300\" height=\"200\"><\/a><figcaption id=\"caption-attachment-2782\" class=\"wp-caption-text\">Pink orthoclase crystals<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">Quartz<\/a> is composed of pure silica, SiO<sub>2<\/sub>, with the tetrahedra arranged in a three dimensional framework. Impurities consisting of atoms within this framework give rise to many varieties of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a> among which are gemstones like amethyst, rose <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a>, and citrine.\u00a0 <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">Feldspars<\/a> are mostly silica with aluminum, potassium, sodium, and calcium. Orthoclase <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> (KAlSi<sub>3<\/sub>O<sub>8<\/sub>), also called potassium <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">K-spar<\/a>, is made of silica, aluminum, and potassium. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">Quartz<\/a> and orthoclase <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> are <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">Felsic<\/a> is the compositional term applied to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> and rocks that contain an abundance of silica. Another <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> is <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">plagioclase<\/a> with the formula (Ca,Na)AlSi<sub>3<\/sub>O<sub>8<\/sub>, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1786\">solid solution<\/a> (Ca,Na) indicating a series of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, one end of the series with calcium CaAl<sub>2<\/sub>Si<sub>2<\/sub>O<sub>8<\/sub>, called anorthite, and the other end with sodium NaAlSi<sub>3<\/sub>O<sub>8<\/sub>, called albite.\u00a0Note how the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> accommodates the substitution of Ca<sup>++<\/sup> and Na<sup>+<\/sup>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Minerals<\/a> in this solid solution series have different <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> names.<\/p>\n<figure id=\"attachment_2783\" aria-describedby=\"caption-attachment-2783\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/23-feldspar-structure.gif\"><img class=\"size-medium wp-image-2783\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/23-feldspar-structure-300x271-1.gif\" alt=\"Framework structure of feldspar with all corners of tetrahedra shared with adjacent tetrahedra; there are holes in the structure in which large anions like potassium and sodium\/calcium fit\" width=\"300\" height=\"271\"><\/a><figcaption id=\"caption-attachment-2783\" class=\"wp-caption-text\">Crystal structure of feldspar<\/figcaption><\/figure>\n<p>Note that aluminum, which has a similar ionic size to silicon, can substitute for silicon inside the tetrahedra (see figure). Because potassium ions are so much larger than sodium and calcium ions, which are very similar in size, the inability of the crystal lattice to accommodate both potassium and sodium\/calcium gives rise to the two families of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a>, orthoclase and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">plagioclase<\/a> respectively.\u00a0Framework <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicates<\/a> are called tectosilicates and include the alkali metal-rich feldspathoids and zeolites.<\/p>\n<h3><\/h3>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-20\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-20\" class=\"h5p-iframe\" data-content-id=\"20\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"3.4 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3752\" aria-describedby=\"caption-attachment-3752\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/3.3-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-175\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/3.3-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3752\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 3.3 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-weight: 400\">3.4 Non-Silicate Minerals<\/span><\/h2>\n<figure id=\"attachment_2784\" aria-describedby=\"caption-attachment-2784\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Hanksite.jpg\"><img class=\"size-medium wp-image-2784\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hanksite-300x200-1.jpg\" alt=\"The mineral is hexagonal and clear.\" width=\"300\" height=\"200\"><\/a><figcaption id=\"caption-attachment-2784\" class=\"wp-caption-text\">Hanksite, Na22K(SO4)9(CO3)2Cl, one of the few minerals that is considered a carbonate and a sulfate<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>The crystal structure of non-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> (see table) does not contain <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silica-oxygen tetrahedra<\/a>. Many non-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are economically important and provide metallic resources such as copper, lead, and iron. They also include valuable non-metallic products such as salt, construction materials, and fertilizer.<\/p>\n<table>\n<tbody>\n<tr>\n<td><b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Mineral<\/a> \u00a0Group<\/b><\/td>\n<td><b>Examples<\/b><\/td>\n<td><b>Formula<\/b><\/td>\n<td><b>Uses<\/b><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_976\">Native<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a><\/span><\/td>\n<td><span style=\"font-weight: 400\">gold, silver, copper<\/span><\/td>\n<td><span style=\"font-weight: 400\">Au, Ag, Cu<\/span><\/td>\n<td><span style=\"font-weight: 400\">Jewelry, coins, industry<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">Carbonates<\/a><\/span><\/td>\n<td><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a>, dolomite <\/span><\/td>\n<td><span style=\"font-weight: 400\">CaCO<\/span><sub><span style=\"font-weight: 400\">3<\/span><\/sub><span style=\"font-weight: 400\">, CaMg(CO<\/span><sub><span style=\"font-weight: 400\">3<\/span><\/sub><span style=\"font-weight: 400\">)<\/span><sub><span style=\"font-weight: 400\">2<\/span><\/sub><\/td>\n<td><span style=\"font-weight: 400\">Lime, Portland cement<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">Oxides<\/a><\/span><\/td>\n<td><span style=\"font-weight: 400\">hematite, magnetite, bauxite<\/span><\/td>\n<td><span style=\"font-weight: 400\">Fe<\/span><sub><span style=\"font-weight: 400\">2<\/span><\/sub><span style=\"font-weight: 400\">O<\/span><sub><span style=\"font-weight: 400\">3<\/span><\/sub><span style=\"font-weight: 400\">, Fe<\/span><sub><span style=\"font-weight: 400\">3<\/span><\/sub><span style=\"font-weight: 400\">O<\/span><sub><span style=\"font-weight: 400\">4<\/span><\/sub><span style=\"font-weight: 400\">, a mixture of aluminum <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxides<\/a><\/span><\/td>\n<td><span style=\"font-weight: 400\">Ores of iron &amp; aluminum, pigments <\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_972\">Halides<\/a><\/span><\/td>\n<td><span style=\"font-weight: 400\">halite, sylvite<\/span><\/td>\n<td><span style=\"font-weight: 400\">NaCl, KCl<\/span><\/td>\n<td><span style=\"font-weight: 400\">Table salt, fertilizer<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">Sulfides<\/a><\/span><\/td>\n<td><span style=\"font-weight: 400\">galena, chalcopyrite, cinnabar<\/span><\/td>\n<td><span style=\"font-weight: 400\">PbS, CuFeS<\/span><sub><span style=\"font-weight: 400\">2<\/span><\/sub><span style=\"font-weight: 400\">, HgS<\/span><\/td>\n<td><span style=\"font-weight: 400\">Ores of lead, copper, mercury<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400\">Sulphates<\/span><\/td>\n<td><span style=\"font-weight: 400\">gypsum, epsom salts<\/span><\/td>\n<td><span style=\"font-weight: 400\">CaSo<\/span><sub><span style=\"font-weight: 400\">4<\/span><\/sub><span style=\"font-weight: 400\">\u00b72H<\/span><sub><span style=\"font-weight: 400\">2<\/span><\/sub><span style=\"font-weight: 400\">O, MgSO<\/span><sub><span style=\"font-weight: 400\">4<\/span><\/sub><span style=\"font-weight: 400\">\u00b77H<\/span><sub><span style=\"font-weight: 400\">2<\/span><\/sub><span style=\"font-weight: 400\">O<\/span><\/td>\n<td><span style=\"font-weight: 400\">Sheetrock, therapeutic soak<\/span><\/td>\n<\/tr>\n<tr>\n<td><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_975\">Phosphates<\/a><\/span><\/td>\n<td><span style=\"font-weight: 400\">apatite<\/span><\/td>\n<td><span style=\"font-weight: 400\">Ca<\/span><sub><span style=\"font-weight: 400\">5<\/span><\/sub><span style=\"font-weight: 400\">(PO<\/span><sub><span style=\"font-weight: 400\">4<\/span><\/sub><span style=\"font-weight: 400\">)<\/span><sub><span style=\"font-weight: 400\">3<\/span><\/sub><span style=\"font-weight: 400\">(F,Cl,OH) <\/span><\/td>\n<td><span style=\"font-weight: 400\">Fertilizer, teeth, bones<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><em><span style=\"font-weight: 400\">Common non-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\"><em>silicate<\/em><\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\"><em>mineral<\/em><\/a> groups.<\/span><\/em><\/p>\n<h3><b>3.4.1 Carbonates<\/b><\/h3>\n<figure id=\"attachment_2785\" aria-describedby=\"caption-attachment-2785\" style=\"width: 245px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.26_Calcite-rhomb.jpg\"><img class=\"size-medium wp-image-2785\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.26_Calcite-rhomb-245x300-1.jpg\" alt=\"Calcite crystal in a shape called a rhomb like a cube squahed over toward one corner\" width=\"245\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2785\" class=\"wp-caption-text\">Calcite crystal in shape of rhomb. Note the double-refracted word \u201ccalcite\u201d in the center of the figure due to birefringence.<\/figcaption><\/figure>\n<figure id=\"attachment_2786\" aria-describedby=\"caption-attachment-2786\" style=\"width: 200px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.29_Limestone_etched_section_KopeFm_new.jpg\"><img class=\"wp-image-2786\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.29_Limestone_etched_section_KopeFm_new-281x300-1.jpg\" alt=\"Piece of limestone rock full of small fossils\" width=\"200\" height=\"214\"><\/a><figcaption id=\"caption-attachment-2786\" class=\"wp-caption-text\">Limestone with small fossils<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">Calcite<\/a>\u00a0(CaCO<sub>3<\/sub>) and dolomite (CaMg(CO<sub>3<\/sub>)<sub>2<\/sub>) are the two most frequently occurring <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, and usually occur in sedimentary rocks, such as limestone and dolostone rocks, respectively. Some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> rocks, such <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a> and dolomite, are formed via evaporation and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitation<\/a>. However, most <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a>-rich rocks, such as limestone, are created by the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1760\">lithification<\/a> of fossilized marine organisms. These organisms, including those we can see and many microscopic organisms, have shells or exoskeletons consisting of calcium <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> (CaCO<sub>3<\/sub>). When these organisms die, their remains accumulate on the floor of the water body in which they live and the soft body parts decompose and dissolve away. The calcium <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> hard parts become included in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediments<\/a>, eventually becoming the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1761\">sedimentary rock<\/a> called limestone. While limestone may contain large, easy to see <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1228\">fossils<\/a>, most limestones contain the remains of microscopic creatures and thus originate from biological processes.<\/p>\n<figure id=\"attachment_2787\" aria-describedby=\"caption-attachment-2787\" style=\"width: 282px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Bifringence.jpg\"><img class=\"size-medium wp-image-2787\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Bifringence-282x300-1.jpg\" alt=\"Calcite crystal polarize light into two waves that vibrate at right angles to each other and pass through the crystal in different paths.\" width=\"282\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2787\" class=\"wp-caption-text\">Bifringence in calcite crystals<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">Calcite<\/a> crystals show an interesting property called <strong>birefringence<\/strong>, meaning they polarize light into two wave components vibrating at right angles to each other. As the two light waves pass through the crystal, they travel at different velocities and are separated by refraction into two different travel paths. In other words, the crystal produces a double image of objects viewed through it. Because they polarize light, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a> crystals are used in special petrographic microscopes for studying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> and rocks.<\/p>\n<p>Many non-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are referred to as salts. The term <strong>salts<\/strong> used here refers to compounds made by replacing the hydrogen in natural acids. The most abundant natural acid is carbonic acid that forms by the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a> of carbon dioxide in water. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">Carbonate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are salts built around the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> ion (CO3<sup>-2<\/sup>) where calcium and\/or magnesium replace the hydrogen in carbonic acid (H<sub>2<\/sub>CO<sub>3<\/sub>). <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">Calcite<\/a> and a closely related polymorph aragonite are secreted by organisms to form shells and physical structures like corals. Many such creatures draw both calcium and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> from dissolved bicarbonate ions (HCO<sub>3<\/sub><sup>-<\/sup>) in ocean water. As seen in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> identification section below, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a> is easily dissolved in acid and thus effervesces in dilute hydrochloric acid (HCl). Small dropper bottles of dilute hydrochloric acid are often carried by geologists in the field as well as used in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> identification labs.<\/p>\n<p>Other salts include halite (NaCl) in which sodium replaces the hydrogen in hydrochloric acid and gypsum (Ca[SO<sub>4<\/sub>] \u2022 2 H<sub>2<\/sub>O) in which calcium replaces the hydrogen in sulfuric acid. Note that some water molecules are also included in the gypsum crystal. Salts are often formed by evaporation and are called evaporite <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>.<\/p>\n<figure id=\"attachment_2788\" aria-describedby=\"caption-attachment-2788\" style=\"width: 425px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.30_Crystal_structure_of_Calcite.png\"><img class=\"wp-image-2788\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.30_Crystal_structure_of_Calcite.png\" alt=\"Crystal structure of calcite showing the carbonate units of carbon surrounded by three oxygen ions and bonded to calcium ions.\" width=\"425\" height=\"520\"><\/a><figcaption id=\"caption-attachment-2788\" class=\"wp-caption-text\">Crystal structure of calcite<\/figcaption><\/figure>\n<p>The figure shows the crystal structure of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a> (CaCO<sub>3<\/sub>). Like silicon, carbon has four valence electrons. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> unit consists of carbon atoms (tiny white dots) covalently <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> to three oxygen atoms (red), one oxygen sharing two valence electrons with the carbon and the other two sharing one valence electron each with the carbon, thus creating triangular units with a charge of -2. The negatively charged <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> unit forms an ionic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bond<\/a> with the Ca ion (blue), which as a charge of +2.<\/p>\n<h3><\/h3>\n<h3><\/h3>\n<h3><\/h3>\n<h3><\/h3>\n<h3><\/h3>\n<h3><b>3.4.2 Oxides, Halides, and Sulfides<\/b><\/h3>\n<figure id=\"attachment_2789\" aria-describedby=\"caption-attachment-2789\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.31_Iron_oxide_LimoniteUSGOV.jpg\"><img class=\"size-medium wp-image-2789\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.31_Iron_oxide_LimoniteUSGOV-300x256-1.jpg\" alt=\"Image of limonite, a hydrated oxide of iron\" width=\"300\" height=\"256\"><\/a><figcaption id=\"caption-attachment-2789\" class=\"wp-caption-text\">Limonite, a hydrated oxide of iron<\/figcaption><\/figure>\n<p>After <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonates<\/a>, the next most common non-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxides<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_972\">halides<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfides<\/a>.<\/p>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">Oxides<\/a> consist of metal ions covalently <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> with oxygen. The most familiar <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxide<\/a> is rust, which is a combination of iron <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxides<\/a> (Fe<sub>2<\/sub>O<sub>3<\/sub>) and hydrated <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxides<\/a>. Hydrated <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxides<\/a> form when iron is exposed to oxygen and water. Iron <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxides<\/a> are important for producing metallic iron. When iron <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxide<\/a> or ore is smelted, it produces carbon dioxide (CO<sub>2<\/sub>) and metallic iron.<\/p>\n<p>The red color in rocks is usually due to the presence of iron <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxides<\/a>. For example, the red sandstone cliffs in Zion National Park and throughout Southern Utah consist of white or colorless grains of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a> coated with iron <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxide<\/a> which serve as cementing agents holding the grains together.<\/p>\n<figure id=\"attachment_2790\" aria-describedby=\"caption-attachment-2790\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.32_Hematite_-_oolitic_with_shale_Iron_Oxide_Clinton_Oneida_County_New_York-e1512421695503.jpg\"><img class=\"wp-image-2790 size-medium\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.32_Hematite_-_oolitic_with_shale_Iron_Oxide_Clinton_Oneida_County_New_York-e1512421695503-300x269-1.jpg\" alt=\"A red form of hematite called oolitic showing a mass of small round nodules\" width=\"300\" height=\"269\"><\/a><figcaption id=\"caption-attachment-2790\" class=\"wp-caption-text\">Oolitic hematite<\/figcaption><\/figure>\n<p>Other iron <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxides<\/a> include limonite, magnetite, and hematite. Hematite occurs in many different crystal forms. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_985\">massive<\/a> form shows no external structure. Botryoidal hematite shows large concentric blobs. Specular hematite looks like a mass of shiny metallic crystals. Oolitic hematite looks like a mass of dull red fish eggs. These different forms of hematite are polymorphs and all have the same formula, Fe<sub>2<\/sub>O<sub>3<\/sub>.<\/p>\n<p>Other common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxide<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> include:<\/p>\n<ul>\n<li>ice (H<sub>2<\/sub>O), an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxide<\/a> of hydrogen<\/li>\n<li>bauxite (Al<sub>2<\/sub>H<sub>2<\/sub>O<sub>4<\/sub>), hydrated <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxides<\/a> of aluminum, an ore for producing metallic aluminum<\/li>\n<li>corundum (Al<sub>2<\/sub>O<sub>3<\/sub>), which includes ruby and sapphire gemstones.<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2791\" aria-describedby=\"caption-attachment-2791\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.34_Halite-249324-1.jpg\"><img class=\"size-medium wp-image-2791\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.34_Halite-249324-1-300x225-1.jpg\" alt=\"Crystals of halite showing cubic crystal habit\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-2791\" class=\"wp-caption-text\">Halite crystal showing cubic habit<\/figcaption><\/figure>\n<p>The <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_972\">halides<\/a><\/strong> consist of halogens in column VII, usually fluorine or chlorine, ionically <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> with sodium or other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1780\">cations<\/a>. These include halite or sodium chloride (NaCl), common table salt; sylvite or potassium chloride (KCl); and fluorite or calcium fluoride (CaF<sub>2<\/sub>).<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2792\" aria-describedby=\"caption-attachment-2792\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.36_2014-07-05_13_04_30_View_across_the_Bonneville_Salt_Falts_Utah_from_ground_level.jpg\"><img class=\"size-medium wp-image-2792\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.36_2014-07-05_13_04_30_View_across_the_Bonneville_Salt_Falts_Utah_from_ground_level-300x220-1.jpg\" alt=\"Photo of salt crust at the Bonneville Salt Flats in Utah with mountains in the background.\" width=\"300\" height=\"220\"><\/a><figcaption id=\"caption-attachment-2792\" class=\"wp-caption-text\">Salt crystals at the Bonneville Salt Flats<\/figcaption><\/figure>\n<figure id=\"attachment_2793\" aria-describedby=\"caption-attachment-2793\" style=\"width: 244px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.35_FluoriteUV-scaled.jpg\"><img class=\"size-medium wp-image-2793\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.35_FluoriteUV-244x300-1.jpg\" alt=\"Purplish crystals of fluorite. The second image shows the deep blue fluorescence of fluorite under ultraviolet light.\" width=\"244\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2793\" class=\"wp-caption-text\">Fluorite. B shows fluorescence of fluorite under UV light<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_972\">Halide<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> usually form from the evaporation of sea water or other isolated bodies of water. A well-known example of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_972\">halide<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> deposits created by evaporation is the Bonneville Salt Flats, located west of the Great Salt Lake in Utah (see figure).<\/p>\n<p>&nbsp;<\/p>\n<p>Many important metal ores are <b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfides<\/a>, <\/b><span style=\"font-weight: 400\">in which metals are <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> to sulfur.\u00a0<\/span><span style=\"font-weight: 400\">Significant examples include: \u00a0<\/span>galena<span style=\"font-weight: 400\"> (lead <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfide<\/a>), <\/span>sphalerite<span style=\"font-weight: 400\"> (zinc <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfide<\/a>),<\/span> pyrite<\/p>\n<figure id=\"attachment_2794\" aria-describedby=\"caption-attachment-2794\" style=\"width: 175px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.37_pyrite1.jpg\"><img class=\"wp-image-2794\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.37_pyrite1-283x300-1.jpg\" alt=\"Cubic crystals of iron pyrite, called &quot;fools gold&quot;\" width=\"175\" height=\"185\"><\/a><figcaption id=\"caption-attachment-2794\" class=\"wp-caption-text\">Cubic crystals of pyrite<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\">(<\/span><span style=\"font-weight: 400\">iron<\/span><span style=\"font-weight: 400\">\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfide<\/a>, sometimes called \u201cfool's gold\u201d), and <\/span>chalcopyrite <span style=\"font-weight: 400\">(iron-copper <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfide<\/a>).<\/span><span style=\"font-weight: 400\">\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">Sulfides<\/a> are well known for being important ore <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. For example, galena is the main source of lead, sphalerite is the main source of zinc, and chalcopyrite is the main copper ore <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> mined in porphyry deposits like the Bingham mine (see <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/16-energy-and-mineral-resources\/\">chapter 16<\/a>). The largest sources of nickel, antimony, molybdenum, arsenic, and mercury are also <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfides<\/a>.<\/span><\/p>\n<h3><b>3.4.3 Sulfates<\/b><\/h3>\n<figure id=\"attachment_2795\" aria-describedby=\"caption-attachment-2795\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.39_SeleniteGypsumUSGOV.jpg\"><img class=\"size-medium wp-image-2795\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.39_SeleniteGypsumUSGOV-300x284-1.jpg\" alt=\"A clear crystal of gypsum\" width=\"300\" height=\"284\"><\/a><figcaption id=\"caption-attachment-2795\" class=\"wp-caption-text\">Gypsum crystal<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_974\">Sulfate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> contain a metal ion, such as calcium, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonded<\/a> to a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_974\">sulfate<\/a> ion. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_974\">sulfate<\/a> ion is a combination of sulfur and oxygen (SO<sub>4<sup>-<\/sup><\/sub><sup>2<\/sup>). The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_974\">sulfate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> gypsum (CaSO<sub>4<\/sub>\u14272H<sub>2<\/sub>O) is used in construction materials such as plaster and drywall. Gypsum is often formed from evaporating water and usually contains water molecules in its crystalline structure. The \u14272H<sub>2<\/sub>O in the formula indicates the water molecules are whole H<sub>2<\/sub>O. This is different from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> like <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1791\">amphibole<\/a>, which contain a hydroxide ion (OH<sup>-<\/sup>) that is derived from water, but is missing a hydrogen ion (H<sup>+<\/sup>). The calcium <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_974\">sulfate<\/a> without water is a different <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> than gypsum called anhydrite (CaSO<sub>4<\/sub>).<\/p>\n<h3><b>3.4.4 Phosphates<\/b><\/h3>\n<figure id=\"attachment_2796\" aria-describedby=\"caption-attachment-2796\" style=\"width: 150px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.40_Apatite_Canada.jpg\"><img class=\"wp-image-2796\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.40_Apatite_Canada-236x300-1.jpg\" alt=\"A crystal of apatite\" width=\"150\" height=\"191\"><\/a><figcaption id=\"caption-attachment-2796\" class=\"wp-caption-text\">Apatite crystal<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_975\">Phosphate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> have a tetrahedral <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_975\">phosphate<\/a> unit (PO<sub>4<\/sub><sup>-3<\/sup>) combined with various <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1782\">anions<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1780\">cations<\/a>. In some cases arsenic or vanadium can substitute for phosphorus. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_975\">Phosphates<\/a> are an important ingredient of fertilizers as well as detergents, paint, and other products. The best known <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_975\">phosphate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> is apatite, Ca<sub>5<\/sub>(PO<sub>4<\/sub>)<sub>3<\/sub>(F,Cl,OH), variations of which are found in teeth and bones. The gemstone turquoise [CuAl<sub>6<\/sub>(PO<sub>4<\/sub>)<sub>4<\/sub>(OH)<sub>8<\/sub>\u00b74H2O ] is a copper-rich <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_975\">phosphate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> that, like gypsum, contains water molecules.<\/span><\/p>\n<h3><b>3.4.5 Native Element Minerals<\/b><\/h3>\n<figure id=\"attachment_2798\" aria-describedby=\"caption-attachment-2798\" style=\"width: 200px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.43_Sulfer_Fumarola_Vulcano.jpg\"><img class=\"wp-image-2798\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.43_Sulfer_Fumarola_Vulcano-300x225-1.jpg\" alt=\"Native sulfur deposited around the vent of a volcanic fumarole\" width=\"200\" height=\"150\"><\/a><figcaption id=\"caption-attachment-2798\" class=\"wp-caption-text\">Native sulfur deposited around a volcanic fumarole<\/figcaption><\/figure>\n<figure id=\"attachment_2797\" aria-describedby=\"caption-attachment-2797\" style=\"width: 200px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.41_Native_Copper-1.jpg\"><img class=\"wp-image-2797\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.41_Native_Copper-1-300x284-1.jpg\" alt=\"Metallic native copper\" width=\"200\" height=\"189\"><\/a><figcaption id=\"caption-attachment-2797\" class=\"wp-caption-text\">Native copper<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_976\">Native element minerals<\/a>, usually metals, occur in nature in a pure or nearly pure state. Gold is an example of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_976\">native<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>; it is not very reactive and rarely <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> with other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> so it is usually found in an isolated or pure state. The non-metallic and poorly-reactive <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> carbon is often found as a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_976\">native<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a>, such as graphite and diamonds. Mildly reactive metals like silver, copper, platinum, mercury, and sulfur sometimes occur as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_976\">native element minerals<\/a>. Reactive metals such as iron, lead, and aluminum almost always <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bond<\/a> to other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> and are rarely found in a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_976\">native<\/a> state.<\/p>\n<h3><\/h3>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-21\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-21\" class=\"h5p-iframe\" data-content-id=\"21\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"3.5 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3751\" aria-describedby=\"caption-attachment-3751\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/3.4-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-191\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/3.4-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3751\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 3.4 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-weight: 400\">3.5 Identifying Minerals<\/span><\/h2>\n<figure id=\"attachment_2799\" aria-describedby=\"caption-attachment-2799\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Curiosity_Mars_Rover_Finds_Mineral_Match.jpg\"><img class=\"size-medium wp-image-2799\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Curiosity_Mars_Rover_Finds_Mineral_Match-300x268-1.jpg\" alt=\"The red rocks have a small hole drilled\" width=\"300\" height=\"268\"><\/a><figcaption id=\"caption-attachment-2799\" class=\"wp-caption-text\">The rover Curiosity drilled a hole in this rock from Mars, and confirmed the mineral Hematite, as mapped from satellites.<\/figcaption><\/figure>\n<p>Geologists identify <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> by their physical properties. In the field, where geologists may have limited access to advanced technology and powerful machines, they can still identify <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> by testing several physical properties: <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_977\">luster<\/a> and color, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">streak<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_979\">hardness<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_980\">crystal habit<\/a>, cleavage and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_986\">fracture<\/a>, and some special properties. Only a few common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> make up the majority of Earth's rocks and are usually seen as small grains in rocks. Of the several properties used for identifying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, it is good to consider which will be most useful for identifying them in small grains surrounded by other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>.<\/p>\n<h3><b>3.5.1 Luster and Color<\/b><\/h3>\n<figure id=\"attachment_2800\" aria-describedby=\"caption-attachment-2800\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Molly_Hill_molybdenite.jpg\"><img class=\"size-medium wp-image-2800\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Molly_Hill_molybdenite-300x225-1.jpg\" alt=\"The crystal looks like metal.\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-2800\" class=\"wp-caption-text\">15 mm metallic hexagonal molybdenite crystal from Quebec.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>The first thing to notice about a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> is its surface appearance, specifically <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_977\">luster<\/a> and color. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_977\">Luster<\/a> describes how the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> looks. Metallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_977\">luster<\/a> looks like a shiny metal such as chrome, steel, silver, or gold. Submetallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_977\">luster<\/a> has a duller appearance. Pewter, for example, shows submetallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_977\">luster<\/a>.<\/p>\n<figure id=\"attachment_2801\" aria-describedby=\"caption-attachment-2801\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Pewter-plate.jpg\"><img class=\"size-medium wp-image-2801\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pewter-plate-300x280-1.jpg\" alt=\"Antique pewter plate showing a more dull submetallic luster\" width=\"300\" height=\"280\"><\/a><figcaption id=\"caption-attachment-2801\" class=\"wp-caption-text\">Submetallic luster shown on an antique pewter plate.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>Nonmetallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_977\">luster<\/a> doesn\u2019t look like a metal and may be described as vitreous (glassy), earthy, silky, pearly, and other surface qualities. Nonmetallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> may be shiny, although their vitreous shine is different from metallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_977\">luster<\/a>. See the table for descriptions and examples of nonmetallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_977\">luster<\/a>.<\/p>\n<table style=\"width: 680px;height: 859px\">\n<tbody>\n<tr style=\"height: 32.625px\">\n<th style=\"border-color: #000000;background-color: #1ae8de;text-align: center;vertical-align: middle\"><span style=\"text-decoration: underline\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_977\">Luster<\/a><\/span><\/th>\n<th style=\"border-color: #000000;background-color: #1ae8de;text-align: center;vertical-align: middle\"><span style=\"text-decoration: underline\">Image<\/span><\/th>\n<th style=\"border-color: #000000;background-color: #1ae8de;text-align: center;vertical-align: middle\"><span style=\"text-decoration: underline\">Description<\/span><\/th>\n<\/tr>\n<tr style=\"height: 28px\">\n<td style=\"width: 155px;height: 28px;text-align: center;vertical-align: middle\">Vitreous\/glassy<\/td>\n<td style=\"width: 148px;height: 28px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_3669\" aria-describedby=\"caption-attachment-3669\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.23_-Quartz_Bresil.jpg\"><img class=\"size-thumbnail wp-image-195\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.23_-Quartz_Bresil-150x150.jpg\" alt=\"A mass of quartz crystals showing typical six sided habit with points\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3669\" class=\"wp-caption-text\">Quartz crystals<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 333px;height: 28px;text-align: center;vertical-align: middle\">Surface is shiny like glass<\/td>\n<\/tr>\n<tr style=\"height: 28px\">\n<td style=\"width: 155px;height: 28px;text-align: center;vertical-align: middle\">Earthy\/dull<\/td>\n<td style=\"width: 148px;height: 28px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2802\" aria-describedby=\"caption-attachment-2802\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.47_earthy_luster_KaolinUSGOV-1.jpg\"><img class=\"size-thumbnail wp-image-2802\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.47_earthy_luster_KaolinUSGOV-1-150x150-1.jpg\" alt=\"Specimen of kaolin, a clay oineral, showing dull or earthy luster\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-2802\" class=\"wp-caption-text\">Kaolin specimen showing dull or earthy luster<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 333px;height: 28px;text-align: center;vertical-align: middle\">Dull, like dried mud or clay<\/td>\n<\/tr>\n<tr style=\"height: 28px\">\n<td style=\"width: 155px;height: 28px;text-align: center;vertical-align: middle\">Silky<\/td>\n<td style=\"width: 148px;height: 28px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2803\" aria-describedby=\"caption-attachment-2803\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.48_silky_luster_Selenite_Gips_Marienglas-1.jpg\"><img class=\"wp-image-2803\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.48_silky_luster_Selenite_Gips_Marienglas-1-300x230-1.jpg\" alt=\"Specimen showing silky luster\" width=\"150\" height=\"115\"><\/a><figcaption id=\"caption-attachment-2803\" class=\"wp-caption-text\">Specimen showing silky luster<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 333px;height: 28px;text-align: center;vertical-align: middle\">Soft shine like silk fabric<\/td>\n<\/tr>\n<tr style=\"height: 28px\">\n<td style=\"width: 155px;height: 28px;text-align: center;vertical-align: middle\">Pearly<\/td>\n<td style=\"width: 148px;height: 28px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2804\" aria-describedby=\"caption-attachment-2804\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.49_pearly_luster_Mineral_Mica_GDFL006.jpg\"><img class=\"wp-image-2804\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.49_pearly_luster_Mineral_Mica_GDFL006-300x218-1.jpg\" alt=\"Specimen showing pearly luster like the inside of a clam shell\" width=\"150\" height=\"109\"><\/a><figcaption id=\"caption-attachment-2804\" class=\"wp-caption-text\">Specimen showing pearly luster<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 333px;height: 28px;text-align: center;vertical-align: middle\">Like the inside of a clam shell or mother-of-pearl<\/td>\n<\/tr>\n<tr style=\"height: 28px\">\n<td style=\"width: 155px;height: 28px;text-align: center;vertical-align: middle\">Submetallic<\/td>\n<td style=\"width: 148px;height: 28px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2805\" aria-describedby=\"caption-attachment-2805\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.44_submetallic_Sphalerite4.jpg\"><img class=\"wp-image-2805\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.44_submetallic_Sphalerite4-300x277-1.jpg\" alt=\"Photo of mineral exhibiting submetallic luster\" width=\"150\" height=\"138\"><\/a><figcaption id=\"caption-attachment-2805\" class=\"wp-caption-text\">Submetallic luster on sphalerite<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 333px;height: 28px;text-align: center;vertical-align: middle\">Has the appearance of dull metal,\u00a0like pewter. These <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> would usually still be considered metallic. Submetallic appearance can occur in metallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> because of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1754\">weathering<\/a>.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<figure id=\"attachment_2806\" aria-describedby=\"caption-attachment-2806\" style=\"width: 245px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Azurite_in_siltstone_Malbunka_mine_NT.jpg\"><img class=\"size-medium wp-image-2806\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Azurite_in_siltstone_Malbunka_mine_NT-245x300-1.jpg\" alt=\"There are two dark blue disks on white siltstone.\" width=\"245\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2806\" class=\"wp-caption-text\">Azurite is ALWAYS a dark blue color, and has been used for centuries for blue pigment.<\/figcaption><\/figure>\n<p>Surface color may be helpful in identifying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, although it can be quite variable within the same <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> family. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Mineral<\/a> colors are affected by the main <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> as well as impurities in the crystals. These impurities may be rare <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>\u2014like manganese, titanium, chromium, or lithium\u2014even other molecules that are not normally part of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> formula. For example, the incorporation of water molecules gives <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a>, which is normally clear, a milky color.<\/p>\n<p>Some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> predominantly show a single color. Malachite and azurite are green and blue, respectively, because of their copper content. Other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> have a predictable range of colors due to elemental substitutions, usually via a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1786\">solid solution<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">Feldspars<\/a>, the most abundant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> in the earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a>, are complex, have <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1786\">solid solution<\/a> series, and present several colors including pink, white, green, gray and others. Other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> also come in several colors, influenced by trace amounts of several <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>. The same <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a> may show up as different colors, in different <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. With notable exceptions, color is usually not a definitive property of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. For identifying many <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. a more reliable indicator is <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">streak<\/a>, which is the color of the powdered <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>.<\/p>\n<h3><b>3.5.2 Streak<\/b><\/h3>\n<figure id=\"attachment_2807\" aria-describedby=\"caption-attachment-2807\" style=\"width: 450px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.50_Streak_plate_with_Pyrite_and_Rhodochrosite-1-scaled.jpg\"><img class=\"wp-image-2807\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.50_Streak_plate_with_Pyrite_and_Rhodochrosite-1-300x227-1.jpg\" alt=\"Pyrite showing a black streak on a white streak plate and rhodochrosite with a white streak on a black streak plate\" width=\"450\" height=\"341\"><\/a><figcaption id=\"caption-attachment-2807\" class=\"wp-caption-text\">Different minerals may have different streaks<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">Streak<\/a> examines the color of a powdered <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>, and can be seen when a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> sample is scratched or scraped on an unglazed porcelain <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">streak<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a>. A paper page in a field notebook may also be used for the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">streak<\/a> of some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Minerals<\/a> that are harder than the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">streak<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> will not show <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">streak<\/a>, but will scratch the porcelain. For these <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">streak<\/a> test can be obtained by powdering the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> with a hammer and smearing the powder across a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">streak<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a> or notebook paper.<\/p>\n<p>While <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> surface colors and appearances may vary, their <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">streak<\/a> colors can be diagnostically useful. An example of this property is seen in the iron-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxide<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> hematite. Hematite occurs in a variety of forms, colors and lusters, from shiny metallic silver to earthy red-brown, and different physical appearances. A hematite <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">streak<\/a> is consistently reddish brown, no matter what the original specimen looks like. Iron <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfide<\/a> or pyrite, is a brassy metallic yellow. Commonly named fool\u2019s gold, pyrite has a characteristic black to greenish-black <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">streak<\/a>.<\/p>\n<h3><b>3.5.3 Hardness<\/b><\/h3>\n<figure id=\"attachment_2808\" aria-describedby=\"caption-attachment-2808\" style=\"width: 1024px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.51_Mohs_Scale2.jpg\"><img class=\"size-large wp-image-2808\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.51_Mohs_Scale2-1024x714-1.jpg\" alt=\"Chart of Mohs Hardness Scale with minerals arranged in hardness from 1 to 10, also showing common items that correlate with the scale.\" width=\"1024\" height=\"714\"><\/a><figcaption id=\"caption-attachment-2808\" class=\"wp-caption-text\">Mohs Hardness Scale<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_979\">Hardness<\/a> measures the ability of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> to scratch other substances. The Mohs <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_979\">Hardness<\/a> Scale gives a number showing the relative scratch-resistance of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> when compared to a standardized set of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> of increasing hardness. The Mohs scale was developed by German geologist Fredrick Mohs in the early 20th century, although the idea of identifying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_979\">hardness<\/a> goes back thousands of years. Mohs <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_979\">hardness<\/a> values are determined by the strength of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>\u2019s atomic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a>.<\/p>\n<p>The figure shows the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> associated with specific <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_979\">hardness<\/a> values, together with some common items readily available for use in field testing and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> identification. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_979\">hardness<\/a> values run from 1 to 10, with 10 being the hardest; however, the scale is not linear. Diamond defines a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_979\">hardness<\/a> of 10 and is actually about four times harder than corundum, which is 9. A steel pocketknife blade, which has a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_979\">hardness<\/a> value of 5.5, separates between hard and soft <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> on many <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> identification keys.<\/p>\n<h3><b>3.5.4 Crystal Habit<\/b><\/h3>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Minerals<\/a> can be identified by <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_980\">crystal habit<\/a><\/strong>, how their crystals grow and appear in rocks. Crystal shapes are determined by the arrangement of the atoms within the crystal structure. For example, a cubic arrangement of atoms gives rise to a cubic-shaped <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> crystal. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_980\">Crystal habit<\/a> refers to typically observed shapes and characteristics; however, they can be affected by other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> crystallizing in the same rock. When <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are constrained so they do not develop their typical <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_980\">crystal habit<\/a>, they are called <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_981\">anhedral<\/a><\/strong>. <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_982\">Subhedral<\/a><\/strong> crystals are partially formed shapes. For some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> characteristic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_980\">crystal habit<\/a> is to grow crystal faces even when surrounded by other crystals in rock. An example is garnet. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Minerals<\/a> grown freely where the crystals are unconstrained and can take characteristic shapes often form crystal faces. A <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_983\">euhedral<\/a><\/strong> crystal has a perfectly formed, unconstrained shape. Some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> crystallize in such tiny crystals, they do not show a specific <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_980\">crystal habit<\/a> to the naked eye. Other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, like pyrite, can have an array of different crystal habits, including cubic, dodecahedral, octahedral, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_985\">massive<\/a>. The table lists typical crystal habits of various <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>.<\/p>\n<table style=\"width: 687px;height: 3774px\">\n<tbody>\n<tr>\n<th style=\"border-color: #000000;background-color: #6be86f;text-align: center;vertical-align: middle\" scope=\"row\"><strong><span style=\"text-decoration: underline\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_980\">Habit<\/a><\/span><\/strong><\/th>\n<th style=\"border-color: #000000;background-color: #6be86f;text-align: center;vertical-align: middle\" scope=\"row\"><strong><span style=\"text-decoration: underline\">Image<\/span><\/strong><\/th>\n<th style=\"border-color: #000000;background-color: #6be86f;text-align: center;vertical-align: middle\" scope=\"row\"><strong><span style=\"text-decoration: underline\">Examples<\/span><\/strong><\/th>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Bladed<\/strong><\/p>\n<p>long and flat crystals<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2809\" aria-describedby=\"caption-attachment-2809\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Kyanite_crystals.jpg\"><img class=\"wp-image-2809\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Kyanite_crystals-300x225-1.jpg\" alt=\"The crystals are long and rectangular\" width=\"150\" height=\"113\"><\/a><figcaption id=\"caption-attachment-2809\" class=\"wp-caption-text\">Bladed kyanite<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\">kyanite,\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1791\">amphibole<\/a>, gypsum<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Botryoidal\/mammillary<\/strong><\/p>\n<p>blobby, circular crystals<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2810\" aria-describedby=\"caption-attachment-2810\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Malachite_Kolwezi_Katanga_Congo.jpg\"><img class=\"wp-image-2810\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Malachite_Kolwezi_Katanga_Congo-300x174-1.jpg\" alt=\"The mineral is bulbous\" width=\"150\" height=\"87\"><\/a><figcaption id=\"caption-attachment-2810\" class=\"wp-caption-text\">Malachite from the Congo<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\">hematite, malachite, smithsonite<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Coating\/laminae\/druse<\/strong><\/p>\n<p>crystals that are small and coat surfaces<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2811\" aria-describedby=\"caption-attachment-2811\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Ametyst-geode.jpg\"><img class=\"wp-image-2811\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ametyst-geode-300x200-1.jpg\" alt=\"The rock is hollowed and filled with purple minerals\" width=\"150\" height=\"100\"><\/a><figcaption id=\"caption-attachment-2811\" class=\"wp-caption-text\">Quartz (var. amethyst) geode<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a>, malachite, azurite<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Cubic<\/strong><\/p>\n<p>cube-shaped crystals<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2812\" aria-describedby=\"caption-attachment-2812\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.55_Cubic_Calcite-Galena-elm56c.jpg\"><img class=\"wp-image-2812\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.55_Cubic_Calcite-Galena-elm56c-260x300-1.jpg\" alt=\"Cubic crystals of galena, a sulfide of lead\" width=\"150\" height=\"173\"><\/a><figcaption id=\"caption-attachment-2812\" class=\"wp-caption-text\">Cubic crystals of galena<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\">pyrite, galena, halite<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Dodecahedral<\/strong><\/p>\n<p>12-sided polygon shapes<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2813\" aria-describedby=\"caption-attachment-2813\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.53_habit_dodecahedral_Pyrite_elbe-scaled.jpg\"><img class=\"wp-image-2813\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.53_habit_dodecahedral_Pyrite_elbe-300x195-1.jpg\" alt=\"Crystals of pyrite showing dodecahedral habit\" width=\"150\" height=\"97\"><\/a><figcaption id=\"caption-attachment-2813\" class=\"wp-caption-text\">Pyrite crystals with dodecahedral habit<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\">garnet, pyrite<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Dendritic<\/strong><\/p>\n<p>branching crystals<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2814\" aria-describedby=\"caption-attachment-2814\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Dendrites01.jpg\"><img class=\"wp-image-2814\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Dendrites01-300x203-1.jpg\" alt=\"The mineral look like a fern. They are black and branching.\" width=\"150\" height=\"101\"><\/a><figcaption id=\"caption-attachment-2814\" class=\"wp-caption-text\">Manganese dendrites, scale in mm.<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\">Mn-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxides<\/a>, copper, gold<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_984\">Equant<\/a><\/strong><\/p>\n<p>crystals that do not have a long direction<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2815\" aria-describedby=\"caption-attachment-2815\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Peridot2.jpg\"><img class=\"wp-image-209\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Peridot2-272x300.jpg\" alt=\"The crystal is light green.\" width=\"150\" height=\"165\"><\/a><figcaption id=\"caption-attachment-2815\" class=\"wp-caption-text\">Large olivine crystal<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">olivine<\/a>, garnet, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">pyroxene<\/a><\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Fibrous<\/strong><\/p>\n<p>thin, very long crystals<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2816\" aria-describedby=\"caption-attachment-2816\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Tremolite_Campolungo.jpg\"><img class=\"wp-image-2816\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tremolite_Campolungo-300x186-1.jpg\" alt=\"It is white and fiberous\" width=\"150\" height=\"93\"><\/a><figcaption id=\"caption-attachment-2816\" class=\"wp-caption-text\">Tremolite, a type of amphibole<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\">serpentine, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1791\">amphibole<\/a>, zeolite<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Layered, sheets<\/strong><\/p>\n<p>stacked, very thin, flat crystals<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2817\" aria-describedby=\"caption-attachment-2817\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.18_Muscovite-Albite-122887.jpg\"><img class=\"wp-image-2817\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.18_Muscovite-Albite-122887-300x254-1.jpg\" alt=\"Sheets of muscovite mica in crystal mass\" width=\"150\" height=\"127\"><\/a><figcaption id=\"caption-attachment-2817\" class=\"wp-caption-text\">Sheet crystals of muscovite<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">mica <\/a>(<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">biotite<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">muscovite<\/a>, etc.)<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Lenticular\/platy<\/strong><\/p>\n<p>crystals that are <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1669\">plate<\/a>-like<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2818\" aria-describedby=\"caption-attachment-2818\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Calcite-Wulfenite-tcw15b.jpg\"><img class=\"wp-image-2818\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Calcite-Wulfenite-tcw15b-251x300-1.jpg\" alt=\"The orange wulfenite is bladed\" width=\"150\" height=\"179\"><\/a><figcaption id=\"caption-attachment-2818\" class=\"wp-caption-text\">Orange wulfenite on calcite<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\">selenite roses, wulfenite, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a><\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Hexagonal<\/strong><\/p>\n<p>crystals with six sides<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_3687\" aria-describedby=\"caption-attachment-3687\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Hanksite-1.jpg\"><img class=\"wp-image-213 size-thumbnail\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hanksite-1-150x150.jpg\" alt=\"The mineral is hexagonal and clear.\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3687\" class=\"wp-caption-text\">Hexagonal hanksite<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a>, hanksite, corundum<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_985\">Massive<\/a>\/granular<\/strong><\/p>\n<p>Crystals with no obvious shape, microscopic crystals<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2789\" aria-describedby=\"caption-attachment-2789\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.31_Iron_oxide_LimoniteUSGOV.jpg\"><img class=\"wp-image-2789\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.31_Iron_oxide_LimoniteUSGOV-300x256-1.jpg\" alt=\"Image of limonite, a hydrated oxide of iron\" width=\"150\" height=\"128\"><\/a><figcaption id=\"caption-attachment-2789\" class=\"wp-caption-text\">Limonite, a hydrated oxide of iron<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\">limonite, pyrite, azurite, bornite<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Octahedral<\/strong><\/p>\n<p>4-sided double pyramid crystals<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2819\" aria-describedby=\"caption-attachment-2819\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.62_octahedral_cleavage_Fluorite_crystals_rotated_90.jpg\"><img class=\"wp-image-2819\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.62_octahedral_cleavage_Fluorite_crystals_rotated_90-300x182-1.jpg\" alt=\"Perfedt octahedral cleavage in fluorite generates octagon-shaped cleavage flakes.\" width=\"150\" height=\"91\"><\/a><figcaption id=\"caption-attachment-2819\" class=\"wp-caption-text\">Octagonal cleavage in fluorite<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\">diamond, fluorite, magnetite, pyrite<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Prismatic\/columnar<\/strong><\/p>\n<p>very long, cylindrical crystals<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2820\" aria-describedby=\"caption-attachment-2820\" style=\"width: 142px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Tourmaline.jpg\"><img class=\"size-medium wp-image-2820\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tourmaline-142x300-1.jpg\" alt=\"The mineral is a long cylinder.\" width=\"142\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2820\" class=\"wp-caption-text\">Columnar tourmaline<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\">tourmaline, beryl, barite<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Radiating<\/strong><\/p>\n<p>crystals that grow from a point and fan out<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2821\" aria-describedby=\"caption-attachment-2821\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Pyrophyllite-236595.jpg\"><img class=\"wp-image-2821\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pyrophyllite-236595-217x300-1.jpg\" alt=\"The mineral is orange\" width=\"150\" height=\"207\"><\/a><figcaption id=\"caption-attachment-2821\" class=\"wp-caption-text\">Pyrophyllite<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\">pyrite \"suns\", pyrophyllite<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Rhombohedral<\/strong><\/p>\n<p>crystals shaped like slanted cubes<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2785\" aria-describedby=\"caption-attachment-2785\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.26_Calcite-rhomb.jpg\"><img class=\"wp-image-2785\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.26_Calcite-rhomb-245x300-1.jpg\" alt=\"Calcite crystal in a shape called a rhomb like a cube squahed over toward one corner\" width=\"150\" height=\"183\"><\/a><figcaption id=\"caption-attachment-2785\" class=\"wp-caption-text\">Calcite crystal in shape of rhomb.<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a>, dolomite<\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Tabular\/blocky\/stubby<\/strong><\/p>\n<p>sharp-sided crystals with no long direction<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2770\" aria-describedby=\"caption-attachment-2770\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.14_Diopside-172005.jpg\"><img class=\"wp-image-2770\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.14_Diopside-172005-300x231-1.jpg\" alt=\"Dark green crystals of diopside, a member of the pyroxene family\" width=\"150\" height=\"116\"><\/a><figcaption id=\"caption-attachment-2770\" class=\"wp-caption-text\">Crystals of diopside, a member of the pyroxene family<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">pyroxene<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a><\/td>\n<\/tr>\n<tr>\n<td style=\"width: 196px;text-align: center;vertical-align: middle\"><strong>Tetrahedral<\/strong><\/p>\n<p>three-sided, pyramid-shaped crystals<\/td>\n<td style=\"width: 133px;text-align: center;vertical-align: middle\">\n<figure id=\"attachment_2822\" aria-describedby=\"caption-attachment-2822\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Tetrahedrite-Chalcopyrite-Sphalerite-251531.jpg\"><img class=\"wp-image-2822\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tetrahedrite-Chalcopyrite-Sphalerite-251531-300x218-1.jpg\" alt=\"The dark brown mineral is triangular\" width=\"150\" height=\"109\"><\/a><figcaption id=\"caption-attachment-2822\" class=\"wp-caption-text\">Tetrahedrite<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 312px;text-align: center;vertical-align: middle\">magnetite, spinel, tetrahedrite<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2824\" aria-describedby=\"caption-attachment-2824\" style=\"width: 150px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/GypsumStriations.jpg\"><img class=\"wp-image-2824\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/GypsumStriations-251x300-1.jpg\" alt=\"The mineral has many parallel lines on it\" width=\"150\" height=\"179\"><\/a><figcaption id=\"caption-attachment-2824\" class=\"wp-caption-text\">Gypsum with striations<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2823\" aria-describedby=\"caption-attachment-2823\" style=\"width: 150px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Staurolite-62645.jpg\"><img class=\"wp-image-2823\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Staurolite-62645-279x300-1.jpg\" alt=\"The brown minerals are replicated in different directions\" width=\"150\" height=\"161\"><\/a><figcaption id=\"caption-attachment-2823\" class=\"wp-caption-text\">Twinned staurolite<\/figcaption><\/figure>\n<p>Another <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_980\">crystal habit<\/a> that may be used to identify <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> is striations, which are dark and light parallel lines on a crystal face. Twinning is another, which occurs when the crystal structure replicates in mirror images along certain directions in the crystal.<\/p>\n<figure id=\"attachment_2825\" aria-describedby=\"caption-attachment-2825\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.65_Striations_in_plagioclase.jpg\"><img class=\"size-medium wp-image-2825\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.65_Striations_in_plagioclase-300x242-1.jpg\" alt=\"Striations or parallel dark lines on one cleavage surface on plagioclase feldspar\" width=\"300\" height=\"242\"><\/a><figcaption id=\"caption-attachment-2825\" class=\"wp-caption-text\">Striations on plagioclase<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>Striations and twinning are related properties in some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> including <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">plagioclase<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a>. Striations are optical lines on a cleavage surface. Because of twinning in the crystal, striations show up on one of the two cleavage faces of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">plagioclase<\/a> crystal.<\/p>\n<h3><b>3.5.5 Cleavage and Fracture<\/b><\/h3>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Minerals<\/a> often show characteristic patterns of breaking along specific cleavage planes or show characteristic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_986\">fracture<\/a> patterns. Cleavage planes are smooth, flat, parallel planes within the crystal. The cleavage planes may show as reflective surfaces on the crystal, as parallel cracks that penetrate into the crystal, or show on the edge or side of the crystal as a series of steps like rice terraces. Cleavage arises in crystals where the atomic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> between atomic layers are weaker along some directions than others, meaning they will break preferentially along these planes.\u00a0Because they develop on atomic surfaces in the crystal, cleavage planes are optically smooth and reflect light, although the actual break on the crystal may appear jagged or uneven. In such cleavages, the cleavage surface may appear like rice terraces on a mountainside that all reflect sunlight from a particular sun angle. Some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> have a strong cleavage, some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> only have weak cleavage or do not typically demonstrate cleavage.<\/p>\n<figure id=\"attachment_2826\" aria-describedby=\"caption-attachment-2826\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.57_conchoidal_Citrine-sample2.jpg\"><img class=\"size-medium wp-image-2826\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.57_conchoidal_Citrine-sample2-300x225-1.jpg\" alt=\"A specimen of a variety of quartz showing conchoidal fracture\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-2826\" class=\"wp-caption-text\">Citrine, a variety of quartz showing conchoidal fracture<\/figcaption><\/figure>\n<p>For example, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">olivine<\/a> rarely show cleavage and typically break into <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_987\">conchoidal<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_986\">fracture<\/a> patterns.<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2827\" aria-describedby=\"caption-attachment-2827\" style=\"width: 452px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/cryview_graphite_v1.gif\"><img class=\"wp-image-2827 size-full\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/cryview_graphite_v1.gif\" alt=\"Structure of graphite, showing single carbon layers with weak bonds holding them together\" width=\"452\" height=\"504\"><\/a><figcaption id=\"caption-attachment-2827\" class=\"wp-caption-text\">Graphite showing layers of carbon atoms separated by a gap with weak bonds holding the layers together.<\/figcaption><\/figure>\n<p>Graphite has its carbon atoms arranged into layers with relatively strong <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> within the layer and very weak <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> between the layers.\u00a0 Thus graphite cleaves readily between the layers and the layers slide easily over one another giving graphite its lubricating quality.<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Mineral<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_986\">fracture<\/a> surfaces may be rough and uneven or they may be show <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_987\">conchoidal<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_986\">fracture<\/a>. Uneven <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_986\">fracture<\/a> patterns are described as irregular, splintery, fibrous. A conchoidal fracture has a smooth, curved surface like a shallow bowl or conch shell, often with curved ridges. Natural <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> glass, called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_999\">obsidian<\/a>, breaks with this characteristic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_987\">conchoidal<\/a> pattern<\/p>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2828\" aria-describedby=\"caption-attachment-2828\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.64_galena_cleavage_Argentiferous_Galena-458851.jpg\"><img class=\"wp-image-2828 size-medium\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.64_galena_cleavage_Argentiferous_Galena-458851-300x261-1.jpg\" alt=\"Specimen of galena showing cubic cleavage\" width=\"300\" height=\"261\"><\/a><figcaption id=\"caption-attachment-2828\" class=\"wp-caption-text\">Cubic cleavage of galena; note how the cleavage surfaces show up as different but parallel layers in the crystal.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>To work with cleavage, it is important to remember that cleavage is a result of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a> separating along planes of atoms in the crystal structure. On some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, <strong>cleavage planes<\/strong> may be confused with crystal faces. This will usually not be an issue for crystals of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> that grew together within rocks. The act of breaking the rock to expose a fresh face will most likely break the crystals along cleavage planes. Some cleavage planes are parallel with crystal faces but many are not.\u00a0Cleavage planes are smooth, flat, parallel planes within the crystal. The cleavage planes may show as parallel cracks that penetrate into the crystal (see <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1791\">amphibole<\/a> below), or show on the edge or side of the crystal as a series of steps like rice terraces. For some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> characteristic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_980\">crystal habit<\/a> is to grow crystal faces even when surrounded by other crystals in rock. An example is garnet. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Minerals<\/a> grown freely where the crystals are unconstrained and can take characteristic shapes often form crystal faces (see <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a> below).<\/p>\n<figure id=\"attachment_2829\" aria-describedby=\"caption-attachment-2829\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Quartz-crystals.jpg\"><img class=\"size-medium wp-image-2829\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Quartz-crystals-300x284-1.jpg\" alt=\"Freely grown quartz crystals showing crysatl faces\" width=\"300\" height=\"284\"><\/a><figcaption id=\"caption-attachment-2829\" class=\"wp-caption-text\">Freely growing quartz crystals showing crystal faces<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\">In some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, distinguishing cleavage planes from crystal faces may be challenging for the student. Understanding the nature of cleavage and referring to the number of cleavage planes and cleavage angles on identification keys should provide the student with enough information to distinguish cleavages from crystal faces. Cleavage planes may show as multiple parallel cracks or flat surfaces on the crystal. Cleavage planes may be expressed as a series of steps like terraced rice paddies. See the cleavage surfaces on galena above or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">plagioclase<\/a> below. Cleavage planes arise from the tendency of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> crystals to break along specific planes of weakness within the crystal favored by atomic arrangements. The number of cleavage planes, the quality of the cleavage surfaces, and the angles between them are diagnostic for many <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> and cleavage is one of the most useful properties for identifying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. Learning to recognize cleavage is an especially important and useful skill in studying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>.<\/span><\/p>\n<figure id=\"attachment_2830\" aria-describedby=\"caption-attachment-2830\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.61_Cleavage_steps_in_wollastonite.jpg\"><img class=\"size-medium wp-image-2830\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.61_Cleavage_steps_in_wollastonite-300x224-1.jpg\" alt=\"Image of wollastonite, a crystal showing step-like cleavage on one side. All steps are along the same direction of cleavage.\" width=\"300\" height=\"224\"><\/a><figcaption id=\"caption-attachment-2830\" class=\"wp-caption-text\">Steps of cleavage along the same cleavage direction<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_2831\" aria-describedby=\"caption-attachment-2831\" style=\"width: 220px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.63_cleavage_in_Amphibole.jpg\"><img class=\"wp-image-2831\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.63_cleavage_in_Amphibole-295x300-1.jpg\" alt=\"Photomicrograph showing 120\/60 degree cleavage in amphibole\" width=\"220\" height=\"224\"><\/a><figcaption id=\"caption-attachment-2831\" class=\"wp-caption-text\">Photomicrograph showing 120\/60 degree cleavage within a grain of amphibole<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>As an identification property of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, cleavage is usually given in terms of the quality of the cleavage (perfect, imperfect, or none), the number of cleavage surfaces, and the angles between the surfaces.\u00a0The most common number of cleavage plane directions in the common rock-forming <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are: one perfect cleavage (as in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">mica<\/a>), two cleavage planes (as in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">pyroxene<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1791\">amphibole<\/a>), and three cleavage planes (as in halite, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a>, and galena). One perfect cleavage (as in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">mica<\/a>) develops on the top and bottom of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> specimen with many parallel cracks showing on the sides but no angle of intersection. Two cleavage planes intersect at an angle. Common cleavage angles are 60\u00b0, 75\u00b0, 90\u00b0, and 120\u00b0.\u00a0 <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1791\">Amphibole<\/a> has two cleavage planes at\u00a060\u00b0 and\u00a0120\u00b0. Galena and halite have three cleavage planes at 90\u00b0 (cubic cleavage). <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">Calcite<\/a> cleaves readily in three directions producing a cleavage figure called a rhomb that looks like a cube squashed over toward one corner giving rise to the approximately 75\u00b0 cleavage angles. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">Pyroxene<\/a> has an imperfect cleavage with two planes at 90\u00b0.<\/p>\n<p><strong>Cleavages on common rock-forming <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a><\/strong><\/p>\n<ul>\n<li><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">Quartz<\/a>\u2014none (<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_987\">conchoidal<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_986\">fracture<\/a>)<\/li>\n<li><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1789\">Olivine<\/a>\u2014none (<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_987\">conchoidal<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_986\">fracture<\/a>)<\/li>\n<li><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">Mica<\/a>\u20141 perfect<\/li>\n<li><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">Feldspar<\/a>\u20142 perfect at 90\u00b0<\/li>\n<li><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">Pyroxene<\/a>\u20142 imperfect at 90\u00b0<\/li>\n<li><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1791\">Amphibole<\/a>\u20142 perfect at 60\u00b0\/120\u00b0<\/li>\n<li><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">Calcite<\/a>\u20143 perfect at approximately 75\u00b0<\/li>\n<li>Halite, galena, pyrite\u20143 perfect at 90\u00b0<\/li>\n<\/ul>\n<h3><b>3.5.6 Special Properties <\/b><\/h3>\n<figure id=\"attachment_2832\" aria-describedby=\"caption-attachment-2832\" style=\"width: 150px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Ulexit_Fernsehstein.jpg\"><img class=\"size-thumbnail wp-image-2832\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ulexit_Fernsehstein-150x150-1.jpg\" alt=\"The words on the page are projected upwards onto the mineral\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-2832\" class=\"wp-caption-text\">A demonstration of ulexite's image projection<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\">Special properties are unique and identifiable characteristics used to identify <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> or that allow some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> to be used for special purposes.\u00a0<\/span>Ulexite has a fiber-optic property that can project images through the crystal like a high-definition television screen (see figure). A simple identifying special property is taste, such as the salty flavor of halite or common table salt (NaCl). Sylvite is potassium chloride (KCl) and has a more bitter taste.<\/p>\n<figure id=\"attachment_2833\" aria-describedby=\"caption-attachment-2833\" style=\"width: 225px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Latrobe_gold_nugget_Natural_History_Museum.jpg\"><img class=\"size-medium wp-image-2833\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Latrobe_gold_nugget_Natural_History_Museum-225x300-1.jpg\" alt=\"The nugget is gold\" width=\"225\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2833\" class=\"wp-caption-text\">Native gold has one of the highest specific gravities.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>Another property geologists may use to identify <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> is a property related to density called <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_989\">specific gravity<\/a><\/strong>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_989\">Specific gravity<\/a> measures the weight of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> specimen relative to the weight of an equal volume of water. The value is expressed as a ratio between the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> and water weights. To measure <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_989\">specific gravity<\/a>, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> specimen is first weighed in grams then submerged in a graduated cylinder filled with pure water at room <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a>. The rise in water level is noted using the cylinder\u2019s graduated scale. Since the weight of water at room <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> is 1 gram per cubic centimeter, the ratio of the two weight numbers gives the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_989\">specific gravity<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_989\">Specific gravity<\/a> is easy to measure in the laboratory but is less useful for <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> identification in the field than other more easily observed properties, except in a few rare cases such as the very dense galena or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_976\">native<\/a> gold. The high density of these <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> gives rise to a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1725\">qualitative<\/a> property called \u201cheft.\u201d Experienced geologists can roughly assess <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_989\">specific gravity<\/a> by heft, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1723\">subjective<\/a> quality of how heavy the specimen feels in one\u2019s hand relative to its size.<\/p>\n<p>A simple test for identifying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a> and dolomite is to drop a bit of dilute hydrochloric acid (10-15% HCl) on the specimen. If the acid drop effervesces or fizzes on the surface of the rock, the specimen is <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a>. If it does not, the specimen is scratched to produce a small amount of powder and test with acid again. If the acid drop fizzes slowly on the powdered <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>, the specimen is dolomite. The difference between these two <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> can be seen in the video. Geologists who work with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> rocks carry a small dropper bottle of dilute HCl in their field kit. Vinegar, which contains acetic acid, can be used for this test and is used to distinguish non-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1228\">fossils<\/a> from limestone. While acidic, vinegar produces less of a fizzing reaction because acetic acid is a weaker acid.<\/p>\n<figure id=\"attachment_3750\" aria-describedby=\"caption-attachment-3750\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Calcite-and-Dolomite-YouTube-QR-Code.png\"><img class=\"size-thumbnail wp-image-228\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Calcite-and-Dolomite-YouTube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3750\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this YouTube video via this QR Code.<\/figcaption><\/figure>\n<figure id=\"attachment_2834\" aria-describedby=\"caption-attachment-2834\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Magnetite_Lodestone.jpg\"><img class=\"size-medium wp-image-2834\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Magnetite_Lodestone-300x200-1.jpg\" alt=\"The paperclip is sticking up into the air.\" width=\"300\" height=\"200\"><\/a><figcaption id=\"caption-attachment-2834\" class=\"wp-caption-text\">Paperclips attach to lodestone (magnetite).<\/figcaption><\/figure>\n<p>Some iron-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxide<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are magnetic and are attracted to magnets. A common name for a naturally magnetic iron <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxide<\/a> is <strong>lodestone<\/strong>. Others include magnetite (Fe3O<sub>4<\/sub>) and ilmenite (FeTiO<sub>3<\/sub>). Magnetite is strongly attracted to magnets and can be magnetized. Ilmenite and some types of hematite are weakly magnetic.<\/p>\n<figure id=\"attachment_2825\" aria-describedby=\"caption-attachment-2825\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.65_Striations_in_plagioclase.jpg\"><img class=\"wp-image-2825 size-medium\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.65_Striations_in_plagioclase-300x242-1.jpg\" alt=\"Striations or parallel dark lines on one cleavage surface on plagioclase feldspar\" width=\"300\" height=\"242\"><\/a><figcaption id=\"caption-attachment-2825\" class=\"wp-caption-text\">Iridescence on plagioclase; also showing striations on the cleavage surface<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p><span style=\"font-weight: 400\">Some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> and mineraloids scatter light via a phenomenon called <strong>iridescence<\/strong>. This property occurs in labradorite (a variety of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">plagioclase<\/a>) and opal. It is also seen in biologically created substances like pearls and seashells. Cut diamonds show iridescence and the jeweler\u2019s diamond cut is designed to maximize this property.<\/span><\/p>\n<figure id=\"attachment_2835\" aria-describedby=\"caption-attachment-2835\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.66_exsolution-_lamellae_perthitic_feldspar_Dan_Patch_SD.jpg\"><img class=\"size-medium wp-image-2835\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.66_exsolution-_lamellae_perthitic_feldspar_Dan_Patch_SD-300x217-1.jpg\" alt=\"Image showing exsolution lamellae in potassium feldspar. These are separations of sodium feldspar from potassium feldspar within the crystal, not striations.\" width=\"300\" height=\"217\"><\/a><figcaption id=\"caption-attachment-2835\" class=\"wp-caption-text\">Exsolution lamellae within potassium feldspar<\/figcaption><\/figure>\n<p><strong>Striations<\/strong> on <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> cleavage faces are an optical property that can be used to separate <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">plagioclase<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> from potassium <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> (<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">K-spar<\/a>). A process called twinning creates parallel zones in the crystal that are repeating mirror images. The actual cleavage angle in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">plagioclase<\/a> is slightly different than 90<sup>o<\/sup> and the alternating mirror images in these twinned zones produce a series of parallel lines on one of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">plagioclase<\/a>\u2019s two cleavage faces. Light reflects off these twinned lines at slightly different angles which then appear as light and dark lines called striations on the cleavage surface.\u00a0Potassium <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> does not exhibit twinning or striations but may show linear features called <strong>exsolution lamellae<\/strong>, also known as perthitic lineation or simply perthite. Because sodium and potassium do not fit into the same <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> crystal structure, the lines are created by small amounts of sodium <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> (albite) separating from the dominant potassium <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a> (<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">K-spar<\/a>) within the crystal structure. The two different <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspars<\/a> crystallize out into roughly parallel zones within the crystal, which are seen as these linear markings.<\/p>\n<figure id=\"attachment_2793\" aria-describedby=\"caption-attachment-2793\" style=\"width: 244px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/03.35_FluoriteUV-scaled.jpg\"><img class=\"size-medium wp-image-2793\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/03.35_FluoriteUV-244x300-1.jpg\" alt=\"Purplish crystals of fluorite. The second image shows the deep blue fluorescence of fluorite under ultraviolet light.\" width=\"244\" height=\"300\"><\/a><figcaption id=\"caption-attachment-2793\" class=\"wp-caption-text\">Fluorite. B shows fluorescence of fluorite under UV light<\/figcaption><\/figure>\n<p>One of the most interesting special <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> properties is <strong>fluorescence<\/strong>. Certain <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, or \u00a0trace <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> within them, give off visible light when exposed to ultraviolet radiation or black light. Many <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> exhibits have a fluorescence room equipped with black lights so this property can be observed. An even rarer optical property is phosphorescence. <strong>Phosphorescent<\/strong> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> absorb light and then slowly release it, much like a glow-in-the-dark sticker.<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<h3><\/h3>\n<h3><\/h3>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-23\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-23\" class=\"h5p-iframe\" data-content-id=\"23\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"4.2 Schematic diagram of plutonic and volcanic structures and processes (Source: Woudloper).\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3749\" aria-describedby=\"caption-attachment-3749\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/3.5-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-231\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/3.5-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3749\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 3.5 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-size: 18pt\"><strong>Summary<\/strong><\/span><\/h2>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Minerals<\/a> are the building blocks of rocks and essential to understanding geology. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Mineral<\/a> properties are determined by their atomic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bonds<\/a>. Most <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> begin in a fluid, and either crystallize out of cooling <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitate<\/a> as ions and molecules out of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1784\">saturated<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a>. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicates<\/a> are largest group of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> on Earth, by number of varieties and relative quantity, making up a large portion of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a>. Based on the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1788\">silicon-oxygen tetrahedra<\/a>, the crystal structure of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicates<\/a> reflects the fact that silicon and oxygen are the top two of Earth\u2019s most abundant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>. Non-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are also economically important, and providing many types of construction and manufacturing materials. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Minerals<\/a> are identified by their unique physical properties, including <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_977\">luster<\/a>, color, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_978\">streak<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_979\">hardness<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_980\">crystal habit<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_986\">fracture<\/a>, cleavage, and special properties.<\/p>\n<h3>Take this quiz to check your comprehension of this Chapter.<\/h3>\n<div id=\"h5p-22\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-22\" class=\"h5p-iframe\" data-content-id=\"22\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Chapter 3 Review\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_3748\" aria-describedby=\"caption-attachment-3748\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Ch.3-Review-QR-Code.png\"><img class=\"size-thumbnail wp-image-232\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ch.3-Review-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-3748\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the review quiz for Chapter 3 via this QR Code.<\/figcaption><\/figure>\n<h2><b>References<\/b><\/h2>\n<div class=\"csl-bib-body\">\n<ol>\n<li class=\"csl-entry\">Clarke, F.W.H.S.W., 1927, The Composition of the Earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">Crust<\/a>: Professional Paper, United States Geological Survey, Professional Paper.<\/li>\n<li class=\"csl-entry\">Gordon, L.M., and Joester, D., 2011, Nanoscale chemical tomography of buried organic-inorganic interfaces in the chiton tooth: Nature, v. 469, no. 7329, p. 194\u2013197.<\/li>\n<li class=\"csl-entry\">Hans Wedepohl, K., 1995, The composition of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1653\">continental crust<\/a>: Geochim. Cosmochim. Acta, v. 59, no. 7, p. 1217\u20131232.<\/li>\n<li class=\"csl-entry\">Lambeck, K., 1986, Planetary evolution: banded iron formations: v. 320, no. 6063, p. 574\u2013574.<\/li>\n<li class=\"csl-entry\">metallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1781\">bond<\/a> | chemistry.<\/li>\n<li class=\"csl-entry\">Scerri, E.R., 2007, The Periodic Table: Its Story and Its Significance: Oxford University Press, USA.<\/li>\n<li class=\"csl-entry\">Thomson, J.J., 1897, XL. Cathode Rays: Philosophical Magazine Series 5, v. 44, no. 269, p. 293\u2013316.<\/li>\n<li class=\"csl-entry\">Trenn, T.J., Geiger, H., Marsden, E., and Rutherford, E., 1974, The Geiger-Marsden Scattering Results and Rutherford\u2019s Atom, July 1912 to July 1913: The Shifting Significance of Scientific Evidence: Isis, v. 65, no. 1, p. 74\u201382.<\/li>\n<\/ol>\n<\/div>\n<p><span style=\"font-weight: 400\">\u00a0<\/span><\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_236\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_236\"><div tabindex=\"-1\"><p>By Brocken Inaglory (Own work) [<a href=\"http:\/\/www.gnu.org\/copyleft\/fdl.html\">GFDL<\/a> or <a href=\"http:\/\/creativecommons.org\/licenses\/by-sa\/3.0\">CC BY-SA 3.0<\/a>], <a href=\"https:\/\/commons.wikimedia.org\/wiki\/File%3AP%C4%81hoehoe_and_Aa_flows_at_Hawaii.jpg\">via Wikimedia Commons<\/a><\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_237\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_237\"><div tabindex=\"-1\"><p>By Jon Sullivan ([1]) [Public domain], <a href=\"https:\/\/commons.wikimedia.org\/wiki\/File:Yosemite_20_bg_090404.jpg\">via Wikimedia Commons<\/a><\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1253\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1253\"><div tabindex=\"-1\"><p>A very fine grained version of silica deposited with or without microfossils.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_238\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_238\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_239\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_239\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_2212\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_2212\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_2165\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_2165\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_507\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_507\"><div tabindex=\"-1\"><p>By G. Thomas at English Wikipedia [Public domain], <a href=\"https:\/\/commons.wikimedia.org\/wiki\/File%3AStevensArchUT.jpg\">via Wikimedia Commons<\/a><\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_241\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_241\"><div tabindex=\"-1\"><p>By Jstuby at English Wikipedia [Public domain], <a href=\"https:\/\/commons.wikimedia.org\/wiki\/File%3AWe-pegmatite.jpg\">via Wikimedia Commons<\/a><\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1742\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1742\"><div tabindex=\"-1\"><p>A dark liquid fossil fuel derived from petroleum.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_747\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_747\"><div tabindex=\"-1\"><p>https:\/\/waterdata.usgs.gov\/nwis\/dv\/?ts_id=143976&amp;format=img_default&amp;site_no=404356111503901&amp;set_arithscale_y=on&amp;begin_date=19750718&amp;end_date=19890930<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_243\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_243\"><div tabindex=\"-1\"><p>By deltalimatrieste (Canon Ixus) [Public domain], <a href=\"https:\/\/commons.wikimedia.org\/wiki\/File%3APomice_di_veglia.jpg\">via Wikimedia Commons<\/a><\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_2420\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_2420\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1275\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1275\"><div tabindex=\"-1\"><p>A special type of cross bedding that forms when strong storms produce mounds and divots of cross-bedded sand in deeper water.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_2443\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_2443\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_969\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_969\"><div tabindex=\"-1\"><p>Rob Lavinsky, <a rel=\"nofollow\" class=\"external text\" href=\"http:\/\/www.irocks.com\/\">iRocks.com<\/a> \u2013 CC-BY-SA-3.0 [<a href=\"http:\/\/creativecommons.org\/licenses\/by-sa\/3.0\">CC BY-SA 3.0<\/a>], <a href=\"https:\/\/commons.wikimedia.org\/wiki\/File%3AApatite-(CaF)-280343.jpg\">via Wikimedia Commons<\/a><\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_246\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_246\"><div tabindex=\"-1\"><p>By Woudloper (Own work) [Public domain], <a href=\"https:\/\/commons.wikimedia.org\/wiki\/File%3AMineralogy_igneous_rocks_EN.svg\">via Wikimedia Commons<\/a><\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_245\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_245\"><div tabindex=\"-1\"><p>By Wilson44691 (Own work) [Public domain], <a href=\"https:\/\/commons.wikimedia.org\/wiki\/File%3AHoleInTheWallTuff.JPG\">via Wikimedia Commons<\/a><\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1231\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1231\"><div tabindex=\"-1\"><p>Changes in sedimentary rocks due to increased (but low when compared to metamorphism) temperatures and pressures. This can include deposition of new minerals (e.g. limestone converting to dolomite) or dissolution of existing minerals.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_2207\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_2207\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_2272\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_2272\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_2197\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_2197\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1995\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1995\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_972\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_972\"><div tabindex=\"-1\"><figure id=\"attachment_4617\" aria-describedby=\"caption-attachment-4617\" style=\"width: 768px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Latrobe_gold_nugget_Natural_History_Museum.jpg\"><img class=\"wp-image-929 size-full\" title=\"&quot;I,\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/02\/Latrobe_gold_nugget_Natural_History_Museum.jpg\" alt=\"The nugget has cube shapes.\" width=\"768\" height=\"1024\"><\/a><figcaption id=\"caption-attachment-4617\" class=\"wp-caption-text\">The Latrobe Gold Nugget, as seen on display in the London Natural History Museum, is 717 grams and displays the rare cubic form of native gold. Most gold, even larger nuggets, grow in confined spaces where the euhedral nature of the mineral is not seen.<\/figcaption><\/figure>\n<h1>16 Energy and Mineral Resources<\/h1>\n<p><b>KEY CONCEPTS<\/b><\/p>\n<ul>\n<li>Describe how a\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1740\">renewable<\/a>\u00a0resource is different from a\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">nonrenewable<\/a>\u00a0resource.<\/li>\n<li>Compare the pros and cons of extracting and using fossil fuels and conventional and unconventional petroleum sources.<\/li>\n<li>Describe how metallic\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are formed\u00a0and extracted.<\/li>\n<li>Understand how society uses\u00a0nonmetallic\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>\u00a0resources.<\/li>\n<\/ul>\n<figure id=\"attachment_4618\" aria-describedby=\"caption-attachment-4618\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/16.0_Stone-Tool.jpg\"><img class=\"wp-image-930 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/16.0_Stone-Tool-300x225.jpg\" alt=\"The rock has a smooth side and a sharp side.\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-4618\" class=\"wp-caption-text\">A Mode 1 Oldowan tool used for chopping<\/figcaption><\/figure>\n<p>This text has previously discussed geology\u2019s pioneers, such as scientists James Hutton and Charles Lyell, but the first real \u201cgeologists\u201d were the hominids who picked up stones and began the stone age. Maybe stones were first used as curiosity pieces, maybe as weapons, but ultimately, they were used as tools. This was the Paleolithic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1244\">Period<\/a>, the beginning of geologic study, and it dates back 2.6 million years to east Africa.<\/p>\n<p>In modern times, geologic knowledge is important for locating economically valuable materials for society\u2019s use. In fact, all things we use come from only three sources: they are farmed, hunted or fished, or mined. At the turn of the twentieth century, speculation was rampant that food supplies would not keep pace with world demand, suggesting the need to develop artificial fertilizers. Sources of fertilizer ingredients are: nitrogen is processed from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1745\">atmosphere<\/a>, using the Haber process for the manufacture of ammonia from atmospheric nitrogen and hydrogen; potassium comes from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1744\">hydrosphere<\/a>, such as lakes or ocean evaporation; and phosphorus is mined from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1668\">lithosphere<\/a>, such as minerals like apatite from phosphorite rock, which is found in Florida, North Carolina, Idaho, Utah, and around the world. \u00a0Thus, without mining and processing of natural materials, modern civilization would not exist. Indeed, geologists are essential in this process.<\/p>\n<h2><strong>16.1 Mining<\/strong><\/h2>\n<figure id=\"attachment_4619\" aria-describedby=\"caption-attachment-4619\" style=\"width: 1024px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Simplified_world_mining_map_1.png\"><img class=\"wp-image-931 size-large\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Simplified_world_mining_map_1-1024x383.png\" alt=\"The map shows many different materials that are mined across the world.\" width=\"1024\" height=\"383\"><\/a><figcaption id=\"caption-attachment-4619\" class=\"wp-caption-text\">Map of world mining areas.<\/figcaption><\/figure>\n<p><strong>Mining<\/strong>\u00a0is defined as extracting valuable materials from the Earth for society\u2019s use. Usually, these include solid materials such as gold, iron,\u00a0coal, diamond, sand, and gravel, but materials can also include fluid resources such as\u00a0oil\u00a0and\u00a0natural gas. Modern\u00a0mining\u00a0has a long relationship with modern society. The oldest mine dates back 40,000 years to the Lion Cavern in Swaziland where there is evidence of\u00a0concentrated\u00a0digging\u00a0 into the Earth for hematite, an important iron ore used as red dye. Resources extracted by\u00a0mining\u00a0are generally considered to be\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">nonrenewable<\/a>.<\/p>\n<h3><b>16.1.1. Renewable vs. nonrenewable resources<\/b><\/h3>\n<p>Resources generally come in two major categories:\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1740\">renewable<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">nonrenewable<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1740\">Renewable<\/a> resources can be reused over and over or their availability replicated over a short human life span; <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">nonrenewable<\/a> resources cannot.<\/p>\n<figure id=\"attachment_4621\" aria-describedby=\"caption-attachment-4621\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/16.1_Hoover_Dam_Colorado_River.jpg\"><img class=\"wp-image-932 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/16.1_Hoover_Dam_Colorado_River-300x200.jpg\" alt=\"The dam has a large lake behind it\" width=\"300\" height=\"200\"><\/a><figcaption id=\"caption-attachment-4621\" class=\"wp-caption-text\">Hoover Dam provides hydroelectric energy and stores water for southern Nevada.<\/figcaption><\/figure>\n<p><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1740\">Renewable<\/a><\/strong><strong>\u00a0resources<\/strong> are materials present in our environment that can be exploited and replenished. Some common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1740\">renewable<\/a> energy sources are linked with green energy sources because they are associated with relatively small or easily remediated environmental impact. For example, solar energy comes from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1250\">fusion<\/a> within the Sun, which radiates electromagnetic energy. This energy reaches the Earth constantly and consistently and should continue to do so for about five billion more years. Wind energy, also related to solar energy, is maybe the oldest <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1740\">renewable<\/a> energy and is used to sail ships and power windmills. Both solar and wind-generated energy are variable on Earth\u2019s surface. These limitations are offset because we can use energy storing devices, such as batteries or electricity exchanges between producing sites. The Earth\u2019s heat, known as geothermal energy, can be viable anywhere that geologists drill deeply enough. In practice, geothermal energy is more useful where heat flow is great, such as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> zones or regions with a thinner <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1658\">crust<\/a>. Hydroelectric dams provide energy by allowing water to fall through the dam under gravity, which activates turbines that produce the energy. Ocean tides are also a reliable energy source. All of these <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1740\">renewable<\/a> resources provide energy that powers society. Other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1740\">renewable<\/a> resources are plant and animal matter, which are used for food, clothing, and other necessities, but are being researched as possible energy sources.<\/p>\n<figure id=\"attachment_4622\" aria-describedby=\"caption-attachment-4622\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Rough_diamond.jpg\"><img class=\"wp-image-933 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Rough_diamond-300x226.jpg\" alt=\"The diamond is clear and pyramidal.\" width=\"300\" height=\"226\"><\/a><figcaption id=\"caption-attachment-4622\" class=\"wp-caption-text\">Natural, octahedral shape of diamond.<\/figcaption><\/figure>\n<p><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">Nonrenewable<\/a><\/strong><strong>\u00a0resources<\/strong> cannot be replenished at a sustainable rate. They are finite within human time frames. Many <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">nonrenewable<\/a> resources come from planetary, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1654\">tectonic<\/a>, or long-term biologic processes and include materials such as gold, lead, copper, diamonds, marble, sand, natural gas, oil, and coal. Most <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">nonrenewable<\/a> resources include specific concentrated <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> listed on the periodic table; some are compounds of those <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>. For example, if society needs iron (Fe) sources, then an exploration geologist will search for iron-rich deposits that can be economically extracted. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">Nonrenewable<\/a> resources may be abandoned when other materials become cheaper or serve a better purpose. For example, coal is abundantly available in England and other nations, but because oil and natural gas are available at a lower cost and lower environmental impact, coal use has decreased. Economic competition among <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">nonrenewable<\/a> resources is shifting use away from coal in many developed countries.<\/p>\n<h3><b>16.1.2. Ore<\/b><\/h3>\n<figure id=\"attachment_4623\" aria-describedby=\"caption-attachment-4623\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/MichiganBIF.jpg\"><img class=\"wp-image-934 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MichiganBIF-300x206.jpg\" alt=\"The rock shows red and brown layering.\" width=\"300\" height=\"206\"><\/a><figcaption id=\"caption-attachment-4623\" class=\"wp-caption-text\">Banded-iron formations are an important ore of iron (Fe).<\/figcaption><\/figure>\n<p>Earth\u2019s materials include the\u00a0periodic table <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>. However, it is rare that\u00a0these <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> are concentrated\u00a0to the point where it is profitable to extract and process the material into usable products. Any place where a valuable material is\u00a0concentrated\u00a0is a geologic and geochemical\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_765\">anomaly<\/a>. A body of material from which one or more valuable substances can be\u00a0mined\u00a0at a profit, is called an\u00a0<strong>ore<\/strong>\u00a0deposit. Typically, the term\u00a0ore\u00a0is used for only metal-bearing\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, but it can be applied to valuable <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">nonrenewable<\/a>\u00a0resource concentrations such as fossil fuels, building stones, and other nonmetal deposits, even\u00a0groundwater. If a metal-bearing resource is not profitable to mine, it is referred to as a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> deposit. The term <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1738\">natural resource<\/a><\/strong> is more common than\u00a0the term ore\u00a0for non-metal-bearing materials.<\/p>\n<figure id=\"attachment_4624\" aria-describedby=\"caption-attachment-4624\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/16-Reserve-vs-Resource.jpg\"><img class=\"wp-image-935 size-medium\" style=\"font-weight: bold;background-color: transparent;text-align: inherit\" title=\"Source: Chris Johnson\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/16-Reserve-vs-Resource-300x233.jpg\" alt=\"Diagram shows the small box of &quot;reserves&quot; within a larger box of &quot;resources&quot;. There is also an &quot;inferred resources&quot; box that is slightly larger than &quot;proven reserves&quot; box and an &quot;undiscovered resources&quot; box slightly larger than the resources box.\" width=\"300\" height=\"233\"><\/a><figcaption id=\"caption-attachment-4624\" class=\"wp-caption-text\">Diagram illustrating the relative abundance of proven reserves, inferred reserves, resources, and undiscovered resources. (Source: Chris Johnson)<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400\">It is implicit that the technology to mine is available, economic conditions are suitable, and political, social and environmental considerations are satisfied in order to classify a\u00a0 <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1738\">natural resource<\/a> deposit as ore. \u00a0Depending on the substance, it can be concentrated in a narrow vein or distributed over a large area as a low-concentration ore. Some materials are mined directly from bodies of water (e.g. sylvite for potassium; water through desalination) and the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1745\">atmosphere<\/a> (e.g. nitrogen for fertilizers). \u00a0These differences lead to various methods of mining, and differences in terminology depending on the certainty. <strong>Ore m<\/strong><\/span><b>ineral resource<\/b><span style=\"font-weight: 400\"> is used for an indication of ore that is potentially extractable, and the term <strong>ore\u00a0<\/strong><\/span><b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> reserve<\/b><span style=\"font-weight: 400\"> is used for a well defined (proven), profitable amount of extractable ore.<\/span><\/p>\n<figure id=\"attachment_4625\" aria-describedby=\"caption-attachment-4625\" style=\"width: 1024px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/McKelveyDiagram.jpg\"><img class=\"wp-image-936 size-large\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/McKelveyDiagram-1024x596.jpg\" alt=\"The chart shows reserves vs. resources\" width=\"1024\" height=\"596\"><\/a><figcaption id=\"caption-attachment-4625\" class=\"wp-caption-text\">McKelvey diagram showing different definitions for different degrees of concentration and understanding of mineral deposits.<\/figcaption><\/figure>\n<h3><b>16.1.3. Mining Techniques<\/b><\/h3>\n<p>The mining style is determined by technology, social license, and economics. It is in the best interest of the company extracting the resources to do so in a cost-effective way. Fluid resources, such as\u00a0oil\u00a0and gas, are extracted by drilling wells and pumping. Over the years, drilling has evolved into a complex discipline in which directional drilling can produce multiple bifurcations and curves originating from a single drill collar at the surface. Using geophysical tools like\u00a0seismic\u00a0imaging, geologists can pinpoint resources and extract efficiently.<\/p>\n<p>Solid resources are extracted by two\u00a0principal methods of which there are many variants.\u00a0<strong>Surface mining<\/strong>\u00a0is used to remove material from the outermost part\u00a0of the Earth.\u00a0<strong>Open pit<\/strong>\u00a0<strong>mining<\/strong>\u00a0is used to target shallow, broadly disseminated resources.<\/p>\n<figure id=\"attachment_4626\" aria-describedby=\"caption-attachment-4626\" style=\"width: 352px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Bingham_Canyon_mine_2016.jpg\"><img class=\"wp-image-4626\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Bingham_Canyon_mine_2016-1.jpg\" alt=\"The image is a large hole in a mountainside.\" width=\"352\" height=\"212\"><\/a><figcaption id=\"caption-attachment-4626\" class=\"wp-caption-text\">Bingham Canyon Mine, Utah. This open pit mine is the largest man-made removal of rock in the world.<\/figcaption><\/figure>\n<p>Open pit mining requires careful study of the ore body through surface mapping and drilling exploratory cores. The pit is progressively deepened through additional mining cuts to extract the ore. Typically, the pit\u2019s walls are as steep as can be safely managed. Once the pit is deepened, widening the top is very expensive. A steep wall is thus an engineering balance between efficient and profitable mining (from the company's point of view) and mass wasting (angle of repose from a safety p0int of view) so that there is less waste to remove. The waste is called non-valuable rock or overburden and moving it is costly. Occasionally, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_246\">landslides<\/a> do occur, such as the very large <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_246\">landslide<\/a> in the Kennecott Bingham Canyon mine, Utah, in 2013. These events are costly and dangerous. The job of engineering geologists is to carefully monitor the mine; when company management heeds their warnings, there is ample time and action to avoid or prepare for any slide.<\/p>\n<figure id=\"attachment_4627\" aria-describedby=\"caption-attachment-4627\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Coal_mine_Wyoming.jpg\"><img class=\"size-medium wp-image-938\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Coal_mine_Wyoming-300x200.jpg\" alt=\"A large machine is removing coal.\" width=\"300\" height=\"200\"><\/a><figcaption id=\"caption-attachment-4627\" class=\"wp-caption-text\">A surface coal mine in Wyoming.<\/figcaption><\/figure>\n<p><strong>Strip mining<\/strong>\u00a0and\u00a0<strong>mountaintop mining<\/strong>\u00a0are\u00a0surface mining\u00a0techniques that are used to mine resources that cover large areas, especially layered resources, such as coal. In this method, an entire mountaintop or rock layer is removed to access the\u00a0ore\u00a0below. Surface mining\u2019s\u00a0environmental impacts are usually much greater due to the large surface footprint that\u2019s disturbed.<\/p>\n<figure id=\"attachment_4628\" aria-describedby=\"caption-attachment-4628\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/UndergroundOilShaleEstonia.jpg\"><img class=\"size-medium wp-image-939\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/UndergroundOilShaleEstonia-300x193.jpg\" alt=\"A large truck is loading material underground.\" width=\"300\" height=\"193\"><\/a><figcaption id=\"caption-attachment-4628\" class=\"wp-caption-text\">Underground mining in Estonia of Oil Shale.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p><strong>Underground mining<\/strong>\u00a0is a method often used to mine higher-grade, more localized, or very\u00a0concentrated\u00a0resources. For one example, geologists mine some\u00a0underground ore\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>\u00a0by introducing chemical agents, which dissolve\u00a0the target\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>.\u00a0Then, they bring the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1783\">solution<\/a> to the surface where\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitation<\/a> extracts the material. But more often, a\u00a0mining\u00a0shaft tunnel or a large network of these shafts and tunnels is dug to access the material. The decision to mine underground or from Earth\u2019s surface is dictated by\u00a0the ore\u00a0deposit\u2019s concentration, depth, geometry, land-use policies, economics, surrounding rock strength, and physical access to the\u00a0ore. For example, to use surface mining techniques for deeper deposits might require removing too much material, or the necessary method may be too dangerous or impractical, or removing the entire overburden may be too expensive, or the\u00a0mining\u00a0footprint would be too large. These factors may prevent geologists from surface mining\u00a0materials and cause a project to be\u00a0mined\u00a0underground. The mining method\u00a0and its feasibility depends on the commodity\u2019s price and the cost of the technology needed to remove it and deliver it to market.\u00a0Thus,\u00a0mines\u00a0and the towns that support them come and go as the commodity price varies.\u00a0And, conversely, technological advances and market demands may reopen\u00a0mines\u00a0and revive ghost towns.<\/p>\n<h3><b>16.1.4. Concentrating and Refining<\/b><\/h3>\n<figure id=\"attachment_4629\" aria-describedby=\"caption-attachment-4629\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/16.1_phosphate_smelting_furnace.jpg\"><img class=\"wp-image-940 size-medium\" title=\"&quot;Alfred\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/16.1_phosphate_smelting_furnace-300x233.jpg\" alt=\"A man is operating a large machine that looks like a blast furnace.\" width=\"300\" height=\"233\"><\/a><figcaption id=\"caption-attachment-4629\" class=\"wp-caption-text\">A phosphate smelting operation in Alabama, 1942.<\/figcaption><\/figure>\n<p>All\u00a0ore\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>\u00a0occur mixed with less desirable components called\u00a0<strong>gangue<\/strong>. The process of physically separating\u00a0gangue\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>\u00a0from\u00a0ore bearing\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>\u00a0is called\u00a0<strong>concentrating<\/strong>. Separating a desired\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a>\u00a0from a host\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>\u00a0by chemical means, including heating, is called\u00a0<strong>smelting<\/strong>. \u00a0Finally, taking a metal such as copper and removing other trace metals such as gold or silver is done through the <strong>refining<\/strong> process. Typically, <strong>refining<\/strong> is done one of three ways: 1. Materials can either be mechanically separated and processed based on the ore\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>\u2019s unique physical properties, such as recovering placer\u00a0gold based on its high density. 2. Materials can be heated to chemically separate desired components, such as refining\u00a0crude\u00a0oil\u00a0into\u00a0gasoline. 3. Materials can be smelted, in which controlled chemical reactions unbind metals from the\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>\u00a0they are contained in, such as when copper is taken out of chalcopyrite (CuFeS<sub>2<\/sub>).\u00a0Mining,\u00a0concentrating,\u00a0smelting,\u00a0and\u00a0refining\u00a0processes require enormous energy. Continual advances in metallurgy- and\u00a0mining-practice strive to develop ever more energy efficient and environmentally benign processes and practices.<\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-107\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-107\" class=\"h5p-iframe\" data-content-id=\"107\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"16.1 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_4901\" aria-describedby=\"caption-attachment-4901\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/03\/16.1-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-941\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/16.1-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4901\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 16.1 via this QR Code.<\/figcaption><\/figure>\n<h2><strong>16.2. Fossil Fuels<\/strong><\/h2>\n<figure id=\"attachment_4630\" aria-describedby=\"caption-attachment-4630\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/16.2_Castle_Gate_Power_Plant_Utah_2007.jpg\"><img class=\"wp-image-942 size-medium\" title=\"&quot;<a\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/16.2_Castle_Gate_Power_Plant_Utah_2007-300x188.jpg\" alt=\"The power plant has smoke coming from it\" width=\"300\" height=\"188\"><\/a><figcaption id=\"caption-attachment-4630\" class=\"wp-caption-text\">Coal power plant in Helper, Utah.<\/figcaption><\/figure>\n<p><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1228\">Fossils<\/a><\/strong><strong>\u00a0fuels<\/strong> are extractable sources of stored energy that were created by ancient ecosystems. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1738\">natural resources<\/a> that typically fall under this category are coal, oil, petroleum, and natural gas. These resources were originally formed via photosynthesis by living organisms such as plants, phytoplankton, algae, and cyanobacteria. This energy is actually <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1228\">fossil<\/a> solar energy, since the sun\u2019s ancient energy was converted by ancient organisms into tissues that preserved the chemical energy within the fossil fuel. Of course, as the energy is used, just like photosynthetic respiration that occurs today, carbon enters the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1745\">atmosphere<\/a> as CO<sub>2<\/sub>, causing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_757\">climate<\/a> consequences (see <a href=\"https:\/\/opengeology.org\/textbook\/15-global-climate-change\/\">Chapter 15<\/a>).\u00a0Today humanity uses fossil fuels\u00a0for most of the world\u2019s energy.<\/p>\n<figure id=\"attachment_4631\" aria-describedby=\"caption-attachment-4631\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Coral_Outcrop_Flynn_Reef.jpg\"><img class=\"wp-image-4631 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Coral_Outcrop_Flynn_Reef-2.jpg\" alt=\"The reef has many intricacies.\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-4631\" class=\"wp-caption-text\">Modern coral reefs and other highly-productive shallow marine environments are thought to be the sources of most petroleum resources.<\/figcaption><\/figure>\n<p>Converting solar energy by living organisms into hydrocarbon fossil fuels is a complex process. As organisms die, they decompose slowly, usually due to being buried rapidly, and the chemical energy stored within the organisms\u2019 tissues is buried within surrounding geologic materials. All fossil\u00a0fuels contain carbon that was produced in an ancient environment. In environments rich with organic matter such as swamps, coral reefs, and planktonic blooms, there is a higher potential for fossil fuels to accumulate. Indeed, there is some evidence that over geologic time, organic hydrocarbon fossil fuel material was highly produced globally. Lack of oxygen and moderate temperatures in the environment seem to help preserve these organic substances. Also, the heat and pressure applied to organic material after it is buried contribute to transforming it into higher quality materials, such as brown coal to anthracite and oil to gas. Heat and pressure can also cause mobile materials to migrate to conditions suitable for extraction.<\/p>\n<h3><b>16.2.1. Fossil Fuels<\/b><\/h3>\n<h4><span style=\"font-weight: 400\">OIL AND GAS<\/span><\/h4>\n<figure id=\"attachment_4632\" aria-describedby=\"caption-attachment-4632\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Oil_Reserves.png\"><img class=\"wp-image-944 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Oil_Reserves-300x136.png\" alt=\"Darker countries are higher in oil\" width=\"300\" height=\"136\"><\/a><figcaption id=\"caption-attachment-4632\" class=\"wp-caption-text\">World Oil Reserves in 2013. Scale in billions of barrels.<\/figcaption><\/figure>\n<p><strong>P<\/strong>etroleum is principally derived from organic-rich shallow\u00a0marine\u00a0sedimentary deposits where the remains of micro-organisms like plankton accumulated in fine grained <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediments<\/a>. Petroleum\u2019s liquid component is called\u00a0<strong>oil,<\/strong>\u00a0and its gas component is called\u00a0<strong>natural gas<\/strong>, which is mostly made up of methane (CH<sub>4<\/sub>). As rocks such as shale, mudstone, or limestone lithify, increasing pressure and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1767\">temperature<\/a> cause the oil and gas to be squeezed out and migrate from the <strong>source rock<\/strong> to a different rock unit higher in the rock column. Similar to the discussion of good\u00a0aquifers\u00a0in\u00a0<a href=\"https:\/\/opengeology.org\/textbook\/11-water\/\">Chapter 11<\/a>, if that rock is a sandstone, limestone, or other porous and permeable rock, and involved in a suitable stratigraphic or structural trapping process, then that rock can act as an<strong>\u00a0<\/strong>oil\u00a0and gas<strong> reservoir<\/strong>.<\/p>\n<figure id=\"attachment_4633\" aria-describedby=\"caption-attachment-4633\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Structural_Trap_Anticlinal.svg_.png\"><img class=\"wp-image-945 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Structural_Trap_Anticlinal.svg_-300x194.png\" alt=\"The rock layers are folded, and the petroleum is pooling toward the top of the fold.\" width=\"300\" height=\"194\"><\/a><figcaption id=\"caption-attachment-4633\" class=\"wp-caption-text\">A structural or anticline trap. The red on the image represents pooling petroleum. The green layer would be a permeable rock, and the yellow would be a reservoir rock.<\/figcaption><\/figure>\n<p>A\u00a0<strong>trap<\/strong> is a combination of a subsurface geologic structure, a porous and permeable rock, and an impervious layer that helps block oil and gas from moving further, which concentrates it for humans to extract later. A trap develops due to many different geologic situations. Examples include an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_504\">anticline<\/a> or domal structure, an impermeable salt <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_507\">dome<\/a>, or a fault bounded stratigraphic block, which is porous rock next to nonporous rock. The different traps have one thing in common: they pool fluid fossil fuels into a configuration in which extracting it is more likely to be profitable. Oil or gas in strata outside of a trap renders it less viable to extract.<\/p>\n<figure id=\"attachment_4634\" aria-describedby=\"caption-attachment-4634\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/TransgressionRegression.png\"><img class=\"wp-image-946 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/TransgressionRegression-300x199.png\" alt=\"Onlap is sediments moving toward the land. Offlap is moving away.\" width=\"300\" height=\"199\"><\/a><figcaption id=\"caption-attachment-4634\" class=\"wp-caption-text\">The rising sea levels of transgressions create onlapping sediments, regressions create offlapping.<\/figcaption><\/figure>\n<p><strong>Sequence stratigraphy<\/strong> is a branch of geology that studies sedimentary facies both horizontally and vertically and is devoted to understanding how sea level changes create organic-rich shallow marine muds, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonates<\/a>, and sands in areas that are close to each other. For example, shoreline environments may have beaches, lagoons, reefs, nearshore and offshore deposits, all next to each other. Beach sand, lagoonal and nearshore muds, and coral reef layers accumulate into <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediments<\/a> that include sandstones\u2014good reservoir rocks\u2014 next to mudstones, next to limestones, both of which are potential source rocks. As sea level either rises or falls, the shoreline\u2019s location changes, and the sand, mud, and reef locations shift with it (see the figure). This places oil and gas producing rocks, such as mudstones and limestones next to oil and gas reservoirs, such as sandstones and some limestones. Understanding how the lithology and the facies\/stratigraphic relationships interplay is very important in finding new petroleum resources. Using sequence stratigraphy as a model allows geologists to predict favorable locations of the source rock and reservoir.<\/p>\n<h4><span style=\"font-weight: 400\">Tar Sands<\/span><\/h4>\n<figure id=\"attachment_4635\" aria-describedby=\"caption-attachment-4635\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Tar_Sandstone_California.jpg\"><img class=\"wp-image-947 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tar_Sandstone_California-300x286.jpg\" alt=\"The sandstone is black with tar.\" width=\"300\" height=\"286\"><\/a><figcaption id=\"caption-attachment-4635\" class=\"wp-caption-text\">Tar sandstone from the Miocene Monterrey Formation of California.<\/figcaption><\/figure>\n<p><strong>Conventional<\/strong>\u00a0oil\u00a0and gas, which is pumped from a\u00a0reservoir, is not the only way to obtain hydrocarbons. There are a few fuel sources known as <strong>unconventional<\/strong>\u00a0petroleum\u00a0sources. However, they are becoming more important as conventional sources become scarce.\u00a0<strong>Tar sands<\/strong>, or oil sands, are sandstones that contain petroleum products that are highly viscous, like tar, and thus cannot be drilled and pumped out of the ground readily like conventional oil. This unconventional fossil fuel is <strong>bitumen<\/strong>, which can be pumped as a fluid only at very low recovery rates and only when heated or mixed with solvents. So, using steam and solvent injections or directly mining tar sands to process later are ways to extract the tar from the sands. Alberta, Canada is known to have the largest tar sand reserves in the world. Note: as with ores, an energy resource becomes uneconomic if the total extraction and processing costs exceed the extracted material\u2019s sales revenue. Environmental costs may also contribute to a resource becoming uneconomic.<\/p>\n<h4><span style=\"font-weight: 400\">Oil Shale<\/span><\/h4>\n<figure id=\"attachment_4636\" aria-describedby=\"caption-attachment-4636\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Production_of_oil_shale.png\"><img class=\"wp-image-948 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Production_of_oil_shale-300x195.png\" alt=\"Oil shale has dramatically increased starting around 1945.\" width=\"300\" height=\"195\"><\/a><figcaption id=\"caption-attachment-4636\" class=\"wp-caption-text\">Global production of Oil Shale, 1880-2010.<\/figcaption><\/figure>\n<p><strong>Oil shale<\/strong>, or\u00a0tight oil, is a fine-grained\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1761\">sedimentary rock<\/a>\u00a0that has significant petroleum\u00a0or\u00a0natural gas quantities locked tightly in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediment<\/a>.\u00a0Shale\u00a0has high\u00a0porosity\u00a0but very low permeability and is a common fossil fuel source rock. To extract the\u00a0oil directly from the shale, the material has to be\u00a0mined\u00a0and heated, which, like with tar sands, is expensive and typically has a negative environmental impact.<\/p>\n<h4><span style=\"font-weight: 400\">Fracking<\/span><\/h4>\n<figure id=\"attachment_4637\" aria-describedby=\"caption-attachment-4637\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/HydroFrac2.svg_.png\"><img class=\"wp-image-949 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/HydroFrac2.svg_-300x175.png\" alt=\"The image shows fracking fluids cracking the rock, allowing methane to escape.\" width=\"300\" height=\"175\"><\/a><figcaption id=\"caption-attachment-4637\" class=\"wp-caption-text\">Schematic diagram of fracking.<\/figcaption><\/figure>\n<p>Another process used to extract the\u00a0oil\u00a0and gas from\u00a0shale\u00a0and other unconventional tight resources is called\u00a0<strong>hydraulic fracturing<\/strong>, better known as\u00a0<strong>fracking<\/strong>. In this method, high-pressure water, sand grains, and added chemicals are injected and pumped underground. Under high pressure, this creates and holds open\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_986\">fractures<\/a>\u00a0in the rocks, which help release the hard-to-access mostly\u00a0natural gas fluids. Fracking is more useful in tighter\u00a0sediments, especially\u00a0shale, which has a high\u00a0porosity\u00a0to store the hydrocarbons but low permeability to allow transmission of the hydrocarbons.\u00a0Fracking\u00a0has become controversial because its methods contaminate groundwater\u00a0and\u00a0induce seismic activity. This has created much controversy between public concerns, political concerns, and energy value.<\/p>\n<h3><b>16.2.2. Coal<\/b><\/h3>\n<figure id=\"attachment_4638\" aria-describedby=\"caption-attachment-4638\" style=\"width: 240px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Coal_Rank_USGS.png\"><img class=\"wp-image-950 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Coal_Rank_USGS-240x300.png\" alt=\"The chart shows many different coal rankings\" width=\"240\" height=\"300\"><\/a><figcaption id=\"caption-attachment-4638\" class=\"wp-caption-text\">USGS diagram of different coal rankings.<\/figcaption><\/figure>\n<p><strong>Coal<\/strong>\u00a0comes from fossilized swamps, though some older\u00a0coal\u00a0deposits that predate\u00a0terrestrial\u00a0plants are presumed to come from algal buildups. Coal is chiefly carbon, hydrogen, nitrogen, sulfur, and oxygen, with minor amounts of other\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>. As plant material is incorporated into\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediments<\/a>, heat and pressure cause several changes that concentrate the fixed carbon, which is the coal\u2019s combustible portion. So, the more heat and pressure that\u00a0coal\u00a0undergoes, the greater is its carbon concentration and fuel value and the more desirable is the\u00a0coal.<\/p>\n<p>This is the general sequence of a swamp progressing through the various stages of coal formation and becoming more concentrated in carbon: Swamp =&gt; Peat =&gt; Lignite =&gt; Sub-bituminous =&gt; Bituminous =&gt; Anthracite =&gt; Graphite. As swamp materials collect on the swamp floor and are buried under accumulating materials, they first turn to peat.<\/p>\n<figure id=\"attachment_4639\" aria-describedby=\"caption-attachment-4639\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Peat_49302157252.jpg\"><img class=\"size-medium wp-image-951\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Peat_49302157252-300x225.jpg\" alt=\"A lump of peat.\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-4639\" class=\"wp-caption-text\">Peat (also known as turf) consists of partially decayed organic matter. The Irish have long mined peat to be burned as fuel though this practice is now discouraged for environmental reasons.<\/figcaption><\/figure>\n<p>Peat itself is an economic fuel in some locations like the British Isles and Scandinavia. As <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1760\">lithification<\/a> occurs, peat turns to lignite. With increasing heat and pressure, lignite turns to sub-bituminous coal, bituminous coal, and then, in a process like metamorphism, anthracite. Anthracite is the highest metamorphic grade and most desirable coal since it provides the highest energy output. With even more heat and pressure driving out all the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1684\">volatiles<\/a> and leaving pure carbon, anthracite can become graphite.<\/p>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_4640\" aria-describedby=\"caption-attachment-4640\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Coal_anthracite.jpg\"><img class=\"wp-image-4640 size-medium\" title=\"&quot;USGS\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Coal_anthracite-1.jpg\" alt=\"It is very black and shiny.\" width=\"300\" height=\"281\"><\/a><figcaption id=\"caption-attachment-4640\" class=\"wp-caption-text\">Anthracite coal, the highest grade of coal.<\/figcaption><\/figure>\n<p>Humans have used coal for at least 6,000 years, mainly as a fuel source. Coal resources in Wales are often cited as a primary reason for Britain\u2019s rise, and later, for the United States\u2019 rise during the Industrial Revolution. According to the US Energy Information Administration, US coal production has decreased due to competing energy sources\u2019 cheaper prices and due to society recognizing its negative environmental impacts, including increased very fine-grained particulate matter as an air pollutant, greenhouse gases, acid rain, and heavy metal pollution. Seen from this perspective, the coal industry as a source of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1228\">fossil<\/a> energy is unlikely to revive.<\/p>\n<p>As the world transitions away from fossil fuels including coal, and manufacturing seeks strong, flexible, and lighter materials than steel including carbon fiber for many applications, current research is exploring coal as a source of this carbon.<\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-108\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-108\" class=\"h5p-iframe\" data-content-id=\"108\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"16.2 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_4902\" aria-describedby=\"caption-attachment-4902\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/03\/16.2-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-953\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/16.2-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4902\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 16.2 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-weight: 400\">16.3 Mineral Resources<\/span><\/h2>\n<figure id=\"attachment_4641\" aria-describedby=\"caption-attachment-4641\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Mother_Lode_Gold_OreHarvard_mine_quartz-gold_vein.jpg\"><img class=\"wp-image-954 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Mother_Lode_Gold_OreHarvard_mine_quartz-gold_vein-300x209.jpg\" alt=\"The yellow gold is inside white quartz.\" width=\"300\" height=\"209\"><\/a><figcaption id=\"caption-attachment-4641\" class=\"wp-caption-text\">Gold-bearing quartz vein from California.<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Mineral<\/a>\u00a0resources, while principally\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">nonrenewable<\/a>, are generally placed\u00a0in two main categories:\u00a0<strong>metallic<\/strong>, which contain metals, and\u00a0<strong>nonmetallic<\/strong>, which contain other useful materials. Most\u00a0mining\u00a0has been traditionally focused on\u00a0extracting metallic\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. Human society has advanced significantly because we\u2019ve developed the\u00a0knowledge and technologies to yield metal from the Earth. This knowledge has allowed humans to build the machines, buildings, and monetary systems that dominate our world today. Locating and recovering these metals has been a key facet of geologic study since its inception. Every\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a>\u00a0across the periodic table has specific applications in human civilization.\u00a0Metallic\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>\u00a0mining\u00a0is the source of many of these\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>.<\/p>\n<h3><b>16.3.1. Types of Metallic Mineral Deposits<\/b><\/h3>\n<p>The various ways in which <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>\u00a0and their associated\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a>\u00a0concentrate to form\u00a0ore\u00a0deposits are too complex and numerous to fully review in this text. However, entire careers are built around them.\u00a0In the following section, we describe some of the more common deposit types along with their associated elemental concentrations and world class occurrences.<\/p>\n<h4><span style=\"font-weight: 400\">Magmatic Processes<\/span><\/h4>\n<figure id=\"attachment_4642\" aria-describedby=\"caption-attachment-4642\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/LayeredIntrusionChromitite_Bushveld_South_Africa.jpg\"><img class=\"wp-image-955 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/LayeredIntrusionChromitite_Bushveld_South_Africa-300x211.jpg\" alt=\"The rock has several layers, with the dark layers being the ones with value.\" width=\"300\" height=\"211\"><\/a><figcaption id=\"caption-attachment-4642\" class=\"wp-caption-text\">Layered intrusion of dark chromium-bearing minerals, Bushveld Complex, South Africa<\/figcaption><\/figure>\n<p>When a magmatic body crystallizes and differentiates (see Chapter 4), it can cause certain <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> to concentrate. <strong>Layered<\/strong>\u00a0<strong>intrusions<\/strong>, typically <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1009\">ultramafic<\/a> to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a>, can host deposits that contain copper, nickel, platinum, palladium, rhodium, and chromium. The Stillwater Complex in Montana is an example of economic quantities of layered <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1008\">mafic<\/a> intrusion. Associated deposit types can contain chromium or titanium-vanadium. The largest magmatic deposits in the world are the chromite deposits in the Bushveld <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">Igneous<\/a> Complex in South Africa. These rocks have an areal extent larger than the state of Utah. The chromite occurs in layers, which resemble sedimentary layers, except these layers occur within a crystallizing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_232\">magma chamber<\/a>.<\/p>\n<figure id=\"attachment_4909\" aria-describedby=\"caption-attachment-4909\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/03\/Elbai\u0308te_et_mica_Bre\u0301sil_1.jpg\"><img class=\"size-medium wp-image-4909\" src=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/03\/Elbai\u0308te_et_mica_Bre\u0301sil_1-300x199.jpg#fixme\" alt=\"The rock is mostly green and purple\" width=\"300\" height=\"199\"><\/a><figcaption id=\"caption-attachment-4909\" class=\"wp-caption-text\">This pegmatite contains lithium-rich green elbaite (a tourmaline) and purple lepidolite (a mica).<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>Water and other\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1684\">volatiles<\/a>\u00a0that are not incorporated into\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>\u00a0crystals when a\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>\u00a0crystallizes can become\u00a0concentrated\u00a0around the crystallizing\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>\u2019s margins. Ions in these hot fluids are very mobile and can form exceptionally large crystals.\u00a0Once crystallized, these large crystal masses are then called\u00a0<strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_996\">pegmatites<\/a><\/strong>. They form from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> fluids that are expelled from the solidifying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> when nearly the entire <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> body has crystallized. In addition to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> that are predominant in the main <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> mass, such as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_967\">quartz<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_966\">mica<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_996\">pegmatite<\/a> bodies may also contain very large crystals of unusual <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> that contain rare <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> like beryllium, lithium, tantalum, niobium, and tin, as well as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_976\">native<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> like gold. Such <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_996\">pegmatites<\/a> are ores of these metals.<\/p>\n<figure id=\"attachment_4643\" aria-describedby=\"caption-attachment-4643\" style=\"width: 298px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/KimberlitePipe.jpg\"><img class=\"wp-image-956 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/KimberlitePipe-298x300.jpg\" alt=\"The pipe is deep and narrow.\" width=\"298\" height=\"300\"><\/a><figcaption id=\"caption-attachment-4643\" class=\"wp-caption-text\">Schematic diagram of a kimberlite pipe.<\/figcaption><\/figure>\n<p>An unusual magmatic process is a\u00a0<strong>kimberlite<\/strong> pipe, which is a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_228\">volcanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_233\">conduit<\/a> that transports <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1009\">ultramafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> from within the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1664\">mantle<\/a> to the surface. Diamonds, which are formed at great temperatures and pressures of depth, are transported by a Kimberlite pipe to locations where they can be mined. The process that created these kimberlite <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1009\">ultramafic<\/a> rocks is no longer common on Earth. Most known deposits are from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1257\">Archean<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1242\">Eon<\/a>.<\/p>\n<h4><span style=\"font-weight: 400\">Hydrothermal Processes<\/span><\/h4>\n<figure id=\"attachment_4644\" aria-describedby=\"caption-attachment-4644\" style=\"width: 400px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Deep_sea_vent_chemistry_diagram.jpg\"><img class=\"wp-image-4644\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Deep_sea_vent_chemistry_diagram-1.jpg\" alt=\"The diagram shows water going into the ground and coming out, with many different reactions.\" width=\"400\" height=\"233\"><\/a><figcaption id=\"caption-attachment-4644\" class=\"wp-caption-text\">The complex chemistry around mid-ocean ridges.<\/figcaption><\/figure>\n<p>Fluids rising from crystallizing magmatic bodies or that are heated by the\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_222\">geothermal gradient<\/a>\u00a0cause many geochemical reactions that form various <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>\u00a0deposits. The most active\u00a0hydrothermal\u00a0process today produces\u00a0<strong>volcanogenic massive sulfide<\/strong><strong>\u00a0<\/strong>(VMS) deposits, which form from black smoker hydrothermal chimney activity near <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1708\">mid-ocean ridges<\/a> all over the world. They commonly contain copper, zinc, lead, gold, and silver when found at the surface. Evidence from around 7000 BC in a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1244\">period<\/a> known as the Chalcolithic shows copper was among the earliest metals smelted by humans as means of obtaining higher temperatures were developed. The largest of these VMS deposits occur in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1270\">Precambrian<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1244\">period<\/a> rocks. The Jerome deposit in central Arizona is a good example.<\/p>\n<p>Another deposit type that draws on <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>-heated water is a\u00a0<strong>porphyry<\/strong> deposit. This is not to be confused with the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_994\">porphyritic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> texture, although the name is derived from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_994\">porphyritic<\/a> texture that is nearly always present in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks associated with a porphyry deposit. Several types of porphyry deposits exist, such as porphyry copper, porphyry molybdenum, and porphyry tin. These deposits contain low-grade disseminated ore <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> closely associated with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1007\">intermediate<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1006\">felsic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_991\">intrusive<\/a> rocks that are present over a very large area. Porphyry deposits are typically the largest mines on Earth. One of the largest, richest, and possibly best studied mine in the world is Utah\u2019s Kennecott Bingham Canyon Mine. It\u2019s an open pit mine, which, for over 100 years, has produced several <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">elements<\/a> including copper, gold, molybdenum, and silver. Underground <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> replacement deposits produce lead, zinc, gold, silver, and copper. In the mine\u2019s past, the open pit predominately produced copper and gold from chalcopyrite and bornite. Gold only occurs in minor quantities in the copper-bearing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, but because the Kennecott Bingham Canyon Mine produces on such a large scale, it is one of the largest gold <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mines<\/a> in the US. In the future, this mine may produce more copper and molybdenum (molybdenite) from deeper underground mines.<\/p>\n<figure id=\"attachment_4645\" aria-describedby=\"caption-attachment-4645\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Morenci_Mine_2012.jpg\"><img class=\"wp-image-958 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Morenci_Mine_2012-300x200.jpg\" alt=\"The mine contains grey rocks, which are not enriched, and red rocks, which is where the enrichment occurs.\" width=\"300\" height=\"200\"><\/a><figcaption id=\"caption-attachment-4645\" class=\"wp-caption-text\">The Morenci porphyry is oxidized toward its top (as seen as red rocks in the wall of the mine), creating supergene enrichment.<\/figcaption><\/figure>\n<p>Most porphyry\u00a0copper deposits owe their high metal content, and hence, their economic value to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1754\">weathering<\/a>\u00a0processes called<strong> supergene enrichment<\/strong> which occurs when the\u00a0deposit is uplifted, eroded, and exposed to\u00a0<strong>oxidation<\/strong>. This process <b>occur<\/b>r<b>ed<\/b> millions of years after the initial <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> intrusion and hydrothermal expulsion ends. When the deposit\u2019s upper pyrite-rich portion is exposed to rain, the pyrite in the oxidizing zone creates an extremely acid condition that dissolves copper out of copper\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>,\u00a0such as chalcopyrite, and converts the chalcopyrite to iron\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxides<\/a>,\u00a0such as hematite or goethite. The copper <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are carried downward in\u00a0water until they arrive at the\u00a0groundwater\u00a0table and an environment where the primary copper\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> are converted\u00a0into secondary higher-copper content\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. Chalcopyrite (35% Cu) is converted to bornite (63% Cu), and ultimately, chalcocite (80% Cu).\u00a0Without this enriched zone, which is two to five times higher in copper content than the main deposit, most\u00a0porphyry\u00a0copper deposits would not be economic to mine.<\/p>\n<figure id=\"attachment_4646\" aria-describedby=\"caption-attachment-4646\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/16.3_6_cm_grossular_calcite_augite_skarn.jpg\"><img class=\"wp-image-959 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/16.3_6_cm_grossular_calcite_augite_skarn-300x255.jpg\" alt=\"Calcite is blue, augite green, and garnet brown\/orange in this rock.\" width=\"300\" height=\"255\"><\/a><figcaption id=\"caption-attachment-4646\" class=\"wp-caption-text\">Garnet-augite skarn from Italy.<\/figcaption><\/figure>\n<p>If\u00a0limestone\u00a0or other calcareous sedimentary rocks are near the magmatic body, then another type of\u00a0ore\u00a0deposit called a\u00a0<strong>skarn<\/strong>\u00a0deposit forms. These\u00a0metamorphic\u00a0rocks form as\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>-derived, highly saline metalliferous fluids react with\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a>\u00a0rocks to create calcium-magnesium-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1787\">silicate<\/a>\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>\u00a0like\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1790\">pyroxene<\/a>,\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1791\">amphibole<\/a>, and garnet, as well as high-grade\u00a0iron, copper, zinc\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>,\u00a0and gold. Intrusions that are genetically related to the intrusion that made the Kennecott Bingham Canyon deposit have also produced copper-gold skarns, which were\u00a0mined\u00a0by the early European settlers in Utah. When iron and\/or\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfide<\/a>\u00a0deposits undergo metamorphism, the\u00a0grain\u00a0size\u00a0commonly increases, which makes separating the\u00a0gangue\u00a0from the desired\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfide<\/a>\u00a0or\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxide<\/a>\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>\u00a0much easier.<\/p>\n<figure id=\"attachment_4647\" aria-describedby=\"caption-attachment-4647\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/GoldinPyrite.jpg\"><img class=\"wp-image-4647 size-medium\" title=\"&quot;<a\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/GoldinPyrite-1.jpg\" alt=\"The rock is red.\" width=\"300\" height=\"240\"><\/a><figcaption id=\"caption-attachment-4647\" class=\"wp-caption-text\">In this rock, a pyrite cube has dissolved (as seen with the negative \"corner\" impression in the rock), leaving behind small specks of gold.<\/figcaption><\/figure>\n<p><strong>Sediment-hosted disseminated gold<\/strong> deposits consist of low concentrations of microscopic gold as inclusions and disseminated atoms in pyrite crystals. These are formed via low-grade hydrothermal reactions, generally in the realm of diagenesis, that occur in certain rock types, namely muddy <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonates<\/a> and limey mudstones. This hydrothermal alteration is generally far removed from a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a> source, but can be found in rocks situated with a high <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_222\">geothermal gradient<\/a>. The Mercur deposit in Utah\u2019s Oquirrh Mountains was this type\u2019s earliest locally mined deposit. There, almost a million ounces of gold was recovered between 1890 and 1917. In the 1960s, a metallurgical process using cyanide was developed for these low-grade ore types. These deposits are also called\u00a0<strong>Carlin-type<\/strong><strong>\u00a0<\/strong>deposits\u00a0because the disseminated deposit near Carlin, Nevada, is where the new technology was first applied and where the first definitive scientific studies were conducted. Gold was introduced into these deposits by\u00a0hydrothermal\u00a0fluids that reacted with silty calcareous rocks, removing\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a>, creating additional permeability, and adding silica and gold-bearing pyrite in the\u00a0pore\u00a0space between grains. The Betze-Post\u00a0mine\u00a0and the Gold Quarry\u00a0mine\u00a0on the Carlin Trend are two of the largest disseminated gold deposits in Nevada. Similar deposits, but not as large, have been found in China, Iran, and Macedonia.<\/p>\n<h4><span style=\"font-weight: 400\">Non-magmatic Geochemical Processes <\/span><\/h4>\n<figure id=\"attachment_4648\" aria-describedby=\"caption-attachment-4648\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/16.1_UraniumMineUtah.jpg\"><img class=\"wp-image-961 size-medium\" title=\"&quot;<a\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/16.1_UraniumMineUtah-300x225.jpg\" alt=\"A dark shaft runs into the mountain.\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-4648\" class=\"wp-caption-text\">Underground uranium mine near Moab, Utah.<\/figcaption><\/figure>\n<p>Geochemical processes that occur at or near the surface without <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1750\">magma<\/a>\u2019s\u00a0aid also concentrate metals, but to a lesser degree than\u00a0hydrothermal\u00a0processes. One of the main reactions is\u00a0<strong>redox<\/strong>, short for reduction\/oxidation chemistry, which has to do with the amount of available oxygen in a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1742\">system<\/a>. Places where oxygen is plentiful, as in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1745\">atmosphere<\/a> today, are considered oxidizing environments, while oxygen-poor places are considered reducing environments. Uranium deposits are an example of where redox concentrated the metal. Uranium is soluble in oxidizing groundwater environments and precipitates as uraninite when encountering reducing conditions. Many of the deposits across the Colorado Plateau, such as in \u00a0Moab, Utah, were formed by this method.<\/p>\n<p>Redox\u00a0reactions are also responsible for creating <strong>banded iron<\/strong><strong>\u00a0<\/strong><strong>formations<\/strong><strong>\u00a0<\/strong>(BIFs),<strong>\u00a0<\/strong>which are interbedded layers of iron\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_971\">oxide<\/a>\u2014hematite and magnetite,\u00a0chert, and\u00a0shale\u00a0beds. These deposits formed early in the Earth\u2019s history as the\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1745\">atmosphere<\/a>\u00a0was becoming oxygenated. Cycles of oxygenating iron-rich waters initiated <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitation<\/a> of the\u00a0iron\u00a0beds. Because BIFs are generally\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1270\">Precambrian<\/a>\u00a0in age, happening at the event of atmospheric oxygenation, they are only found in some of the older exposed rocks in the United States, such as in Michigan\u2019s upper peninsula and northeast Minnesota.<\/p>\n<figure id=\"attachment_4649\" aria-describedby=\"caption-attachment-4649\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/MV-Type_and_clastic_sediment-hosted_lead-zinc_deposits.svg_.png\"><img class=\"wp-image-962 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MV-Type_and_clastic_sediment-hosted_lead-zinc_deposits.svg_-300x138.png\" alt=\"The are globally distributed.\" width=\"300\" height=\"138\"><\/a><figcaption id=\"caption-attachment-4649\" class=\"wp-caption-text\">Map of Mississippi-Valley type ore deposits.<\/figcaption><\/figure>\n<p>Deep, saline, connate fluids (trapped in pore spaces) within <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_510\">sedimentary basins<\/a>\u00a0may be highly metalliferous. When expelled outward and upward as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_508\">basin<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1756\">sediments<\/a> compacted, these fluids formed lead and zinc deposits in limestone by replacing or filling open spaces, such as caves and faults, and in sandstone by filling pore spaces. The most famous are called\u00a0<strong>Mississippi Valley-type<\/strong><strong>\u00a0<\/strong>deposits. Also known as\u00a0carbonate-hosted replacement\u00a0deposits, they are large deposits of galena and sphalerite lead and zinc\u00a0ores that form from hot fluids ranging from 100\u00b0C to 200\u00b0C (212\u00b0F to 392\u00b0F). Although they are named for occurring along the Mississippi\u00a0River\u00a0Valley in the US, they are found worldwide.<\/p>\n<p><strong>Sediment-hosted copper<\/strong><strong>\u00a0<\/strong>deposits occurring in\u00a0sandstones,\u00a0shales, and marls are enormous, and their contained resources are comparable to\u00a0porphyry\u00a0copper deposits. These deposits were most likely formed diagenetically by\u00a0groundwater\u00a0fluids in highly permeable rocks. Well-known examples are the Kupferschiefer in Europe, which has an areal coverage of &gt;500,000 Km<sup>2<\/sup>, (310,685.596mi) and the Zambian Copper Belt in Africa.<\/p>\n<figure id=\"attachment_4650\" aria-describedby=\"caption-attachment-4650\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Bauxite_with_unweathered_rock_core._C_021.jpg\"><img class=\"wp-image-4650 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Bauxite_with_unweathered_rock_core._C_021-1.jpg\" alt=\"The outside of the rock is tan and weathered, the inside is grey.\" width=\"300\" height=\"195\"><\/a><figcaption id=\"caption-attachment-4650\" class=\"wp-caption-text\">A sample of bauxite. Note the unweathered igneous rock in the center.<\/figcaption><\/figure>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_250\">Soils<\/a>\u00a0and\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>\u00a0deposits that are exposed at the surface experience deep and intense\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1754\">weathering<\/a>, which\u00a0can form surficial deposits.\u00a0<strong>Bauxite<\/strong>, an aluminum ore, is preserved in karst topography and laterites, which are <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_250\">soils<\/a> formed in wet tropical environments. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_250\">Soils<\/a> containing aluminum concentrate <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, such as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_968\">feldspar<\/a>, and ferromagnesian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> and metamorphic rocks, undergo chemical weathering processes that concentrate the metals. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1009\">Ultramafic<\/a> rocks that undergo <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1754\">weathering<\/a> form nickel-rich <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_250\">soils<\/a>, and when the magnetite and hematite in banded iron formations undergo <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1754\">weathering<\/a>, it forms goethite, a friable <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> that is easily mined for its iron content.<\/p>\n<h3><span style=\"font-weight: 400\">Surficial Physical Processes <\/span><\/h3>\n<figure id=\"attachment_4651\" aria-describedby=\"caption-attachment-4651\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/HeavyMineralsBeachSand.jpg\"><img class=\"wp-image-4651 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/HeavyMineralsBeachSand-1.jpg\" alt=\"The tan rock has dark streaks of minerals.\" width=\"300\" height=\"205\"><\/a><figcaption id=\"caption-attachment-4651\" class=\"wp-caption-text\">Lithified heavy mineral sand (dark layers) from a beach deposit in India.<\/figcaption><\/figure>\n<p>At the Earth\u2019s surface, mass wasting\u00a0and moving water can cause hydraulic\u00a0sorting, which forces high-density\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> to concentrate. When these\u00a0minerals\u00a0are\u00a0concentrated\u00a0in\u00a0streams,\u00a0rivers,\u00a0and beaches, they are called\u00a0<strong>placer<\/strong>\u00a0deposits, and occur in modern sands and ancient lithified rocks.\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_976\">Native<\/a>\u00a0gold,\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_976\">native<\/a>\u00a0platinum,\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1227\">zircon<\/a>, ilmenite, rutile, magnetite, diamonds, and other gemstones can be found in\u00a0placers. Humans have mimicked this natural process to recover gold manually by gold panning and by mechanized means such as dredging.<\/p>\n<h3><b>16.3.2. Environmental Impacts of Metallic Mineral Mining<\/b><\/h3>\n<figure id=\"attachment_4652\" aria-describedby=\"caption-attachment-4652\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Rio_tinto_river_CarolStoker_NASA_Ames_Research_Center.jpg\"><img class=\"wp-image-965 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Rio_tinto_river_CarolStoker_NASA_Ames_Research_Center-300x225.jpg\" alt=\"The water in the river is bright orange.\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-4652\" class=\"wp-caption-text\">Acid mine drainage in the Rio Tinto, Spain.<\/figcaption><\/figure>\n<p>Metallic\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>\u00a0mining\u2019s\u00a0primary impact comes from the\u00a0mining\u00a0itself, including disturbing the land surface, covering landscapes with tailings impoundments, and increasing\u00a0mass wasting\u00a0by accelerating\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1755\">erosion<\/a>. In addition, many metal deposits contain pyrite, an uneconomic\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfide<\/a>\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>, that when\u00a0placed on waste dumps, generates\u00a0<strong>acid rock drainage<\/strong>\u00a0(ARD)<strong>\u00a0<\/strong>during <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1754\">weathering<\/a>. In oxygenated water, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfides<\/a> such as pyrite react and undergo complex reactions to release metal ions and hydrogen ions, which lowers pH to highly acidic levels. Mining and processing of mined materials typically increase the surface area to volume ratio in the material, causing chemical reactions to occur even faster than would occur naturally. If not managed properly, these reactions lead to acidic streams and groundwater plumes that carry dissolved toxic metals. In mines where limestone is a waste rock or where <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_969\">carbonate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a> like <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_970\">calcite<\/a> or dolomite are present, their acid neutralizing potential helps reduce acid rock drainage. Although this is a natural process too, it is very important to isolate mine dumps and tailings from oxygenated water, both to prevent the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_973\">sulfides<\/a> from dissolving and subsequently percolating the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_974\">sulfate<\/a>-rich water into waterways. Industry has taken great strides to prevent contamination in recent decades, but earlier mining projects are still causing problems with local ecosystems.<\/p>\n<h3><strong>16.3.3. Nonmetallic Mineral\u00a0Deposits<\/strong><\/h3>\n<figure id=\"attachment_4653\" aria-describedby=\"caption-attachment-4653\" style=\"width: 225px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/CarraraMarblequarry.jpg\"><img class=\"wp-image-966 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/CarraraMarblequarry-225x300.jpg\" alt=\"The image shows a hillside with blocks of marble removed.\" width=\"225\" height=\"300\"><\/a><figcaption id=\"caption-attachment-4653\" class=\"wp-caption-text\">Carrara marble quarry in Italy, source to famous sculptures like Michelangelo's David.<\/figcaption><\/figure>\n<p>While receiving much less attention, nonmetallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> resources, also known as industrial <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, are just as vital to ancient and modern society as metallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>. The most basic is building stone. Limestone, travertine, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1014\">granite<\/a>, slate, and marble are common building stones and have been quarried for centuries. Even today, building stones from slate roof tiles to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1014\">granite<\/a> countertops are very popular. Especially pure limestone is ground up, processed, and reformed as plaster, cement, and concrete. Some nonmetallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> resources are not <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> specific; nearly any rock or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> can be used. This is generally called aggregate, which is used in concrete, roads, and foundations. Gravel is one of the more common aggregates.<\/p>\n<h4><span style=\"font-weight: 400\">Evaporites<\/span><\/h4>\n<figure id=\"attachment_4654\" aria-describedby=\"caption-attachment-4654\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Bonneville_Salt_Flats_Utah.jpg\"><img class=\"wp-image-4654 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Bonneville_Salt_Flats_Utah-1.jpg\" alt=\"The ground is white and flat for a long distance.\" width=\"300\" height=\"200\"><\/a><figcaption id=\"caption-attachment-4654\" class=\"wp-caption-text\">Salt-covered plain known as the Bonneville Salt Flats, Utah.<\/figcaption><\/figure>\n<p><strong>Evaporite<\/strong><strong>\u00a0<\/strong>deposits\u00a0form in restricted basins where water evaporates faster than it recharges, such as the Great Salt Lake in Utah, or the Dead Sea, which borders Israel and Jordan. As the waters evaporate, soluble\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>\u00a0are\u00a0concentrated\u00a0and become supersaturated, at which point they\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1785\">precipitate<\/a>\u00a0from the now highly-saline waters. If these conditions persist for long stretches, thick rock salt, rock\u00a0gypsum,\u00a0and other\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a>\u00a0deposits accumulate (see Chapter 5).<\/p>\n<figure id=\"attachment_4655\" aria-describedby=\"caption-attachment-4655\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Hanksite.jpg\"><img class=\"wp-image-968 size-medium\" title=\"&quot;By\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hanksite-300x200.jpg\" alt=\"The mineral is hexagonal and clear.\" width=\"300\" height=\"200\"><\/a><figcaption id=\"caption-attachment-4655\" class=\"wp-caption-text\">Hanksite, Na22K(SO4)9(CO3)2Cl, one of the few minerals that is considered a carbonate and a sulfate<\/figcaption><\/figure>\n<p>Evaporite <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, such as halite, are used in our food as common table salt. Salt was a vitally important food preservative and economic resource before refrigeration was developed. While still used in food, halite is now mainly mined as a chemical agent, water softener, or road de-icer. Gypsum is a common nonmetallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> used as a building material; it is the main component in dry wall. It is also used as a fertilizer. Other evaporites include sylvite\u2014potassium chloride, and bischofite\u2014magnesium chloride, both of which are used in agriculture, medicine, food processing, and other applications. Potash, a group of highly soluble potassium-bearing evaporite <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">minerals<\/a>, is used as a fertilizer. In hyper-arid locations, even more rare and complex evaporites, like borax, trona, ulexite, and hanksite are mined. They can be found in places such as Searles Dry Lake and Death Valley, California, and in the Green River Formation\u2019s ancient evaporite deposits in Utah and Wyoming.<\/p>\n<h4><span style=\"font-weight: 400\">Phosphorus<\/span><\/h4>\n<figure id=\"attachment_4656\" aria-describedby=\"caption-attachment-4656\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Apatite-CaF-280343.jpg\"><img class=\"wp-image-4656 size-medium\" title=\"&quot;Rob\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Apatite-CaF-280343-1.jpg\" alt=\"The crystal is hexagonal and light green.\" width=\"300\" height=\"267\"><\/a><figcaption id=\"caption-attachment-4656\" class=\"wp-caption-text\">Apatite from Mexico.<\/figcaption><\/figure>\n<p>Phosphorus is an essential <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1778\">element<\/a> that occurs in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> apatite, which is found in trace amounts in common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1753\">igneous<\/a> rocks. Phosphorite rock, which is formed in sedimentary environments in the ocean, contains abundant apatite and is mined to make fertilizer. Without phosphorus, life as we know it is not possible. Phosphorous is an important component of bone and DNA. Bone <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1001\">ash<\/a> and guano are natural sources of phosphorus.<\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-109\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-109\" class=\"h5p-iframe\" data-content-id=\"109\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"16.3 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_4903\" aria-describedby=\"caption-attachment-4903\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/03\/16.3-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-970\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/16.3-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4903\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 16.3 via this QR Code.<\/figcaption><\/figure>\n<h1>Summary<\/h1>\n<p>Energy and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">mineral<\/a> resources are vital to modern society, and it is the role of the geologist to locate these resources for human benefit. As environmental concerns have become more prominent, the value of the geologist has not decreased, as they are still vital in locating the deposits and identifying the least <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_991\">intrusive<\/a> methods of extraction.<\/p>\n<p>Energy resources are general grouped as being <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1740\">renewable<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">nonrenewable<\/a>. Geologists can aid in locating the best places to exploit <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1740\">renewable<\/a> resources (e.g. locating a dam), but are commonly tasked with finding <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1739\">nonrenewable<\/a> fossil fuels. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Mineral<\/a> resources are also grouped in two categories: metallic and nonmetallic. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_330_1765\">Minerals<\/a> have a wide variety of processes that concentrate them to economic levels, and are usually mined via surface or underground methods.<\/p>\n<h3>Take this quiz to check your comprehension of this Chapter.<\/h3>\n<div id=\"h5p-110\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-110\" class=\"h5p-iframe\" data-content-id=\"110\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Chapter 16 Review\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_4904\" aria-describedby=\"caption-attachment-4904\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/03\/Ch.16-Review-QR-Code.png\"><img class=\"size-thumbnail wp-image-971\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ch.16-Review-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4904\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the review quiz for Chapter 16 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-weight: 400\">References<\/span><\/h2>\n<ol>\n<li style=\"text-align: left\">Ague, Jay James, and George H. Brimhall. 1989. \u201cGeochemical Modeling of Steady State Fluid Flow and Chemical Reaction during Supergene Enrichment of Porphyry Copper Deposits.\u201d <em>Economic Geology and the Bulletin of the Society of Economic Geologists<\/em> 84 (3). economicgeology.org: 506\u201328.<\/li>\n<li style=\"text-align: left\">Arndt, N. T. 1994. \u201cChapter 1 Archean Komatiites.\u201d In <em>Developments in Precambrian Geology<\/em>, edited by K.C. Condie, 11:11\u201344. Elsevier.<\/li>\n<li style=\"text-align: left\">B\u00e1rdossy, Gy\u00f6rgy, and Gerardus Jacobus Johannes Aleva. 1990. <em>Lateritic Bauxites<\/em>. Vol. 27. Elsevier Science Ltd.<\/li>\n<li style=\"text-align: left\">Barrie, C. T. 1999. \u201cVolcanic-Associated Massive Sulfide Deposits: Processes and Examples in Modern and Ancient Settings.\u201d Reviews in Economic Geology, v. 8. https:\/\/www.researchgate.net\/profile\/Michael_Perfit\/publication\/241276560_Geologic_petrologic_and_geochemical_relationships_between_magmatism_and_massive_sulfide_mineralization_along_the_eastern_Galapagos_Spreading_Center\/links\/02e7e51c8707bbfe9c000000.pdf.<\/li>\n<li style=\"text-align: left\">Barrie, L. A., and R. M. Hoff. 1984. \u201cThe Oxidation Rate and Residence Time of Sulphur Dioxide in the Arctic Atmosphere.\u201d <em>Atmospheric Environment<\/em> 18 (12). Elsevier: 2711\u201322.<\/li>\n<li style=\"text-align: left\">Bauquis, Pierre-Ren\u00e9. 1998. \u201cWhat Future for Extra Heavy Oil and Bitumen: The Orinoco Case.\u201d In <em>Paper Presented by TOTAL at the World Energy Congress<\/em>, 13:18.<\/li>\n<li style=\"text-align: left\">Belloc, H. 1913. <em>The Servile State<\/em>. T.N. Foulis.<\/li>\n<li style=\"text-align: left\">Blander, M., S. Sinha, A. Pelton, and G. Eriksson. 2011. \u201cCalculations of the Influence of Additives on Coal Combustion Deposits.\u201d <em>Argonne National Laboratory, Lemont, Illinois<\/em>. enersol.pk, 315.<\/li>\n<li style=\"text-align: left\">Boudreau, Alan E. 2016. \u201cThe Stillwater Complex, Montana--Overview and the Significance of Volatiles.\u201d <em>Mineralogical Magazine<\/em> 80 (4). Mineralogical Society: 585\u2013637.<\/li>\n<li style=\"text-align: left\">Bromfield, C. S., A. J. Erickson, M. A. Haddadin, and H. H. Mehnert. 1977. \u201cPotassium-Argon Ages of Intrusion, Extrusion, and Associated Ore Deposits, Park City Mining District, Utah.\u201d <em>Economic Geology and the Bulletin of the Society of Economic Geologists<\/em> 72 (5). economicgeology.org: 837\u201348.<\/li>\n<li style=\"text-align: left\">Brown, Valerie J. 2007. \u201cIndustry Issues: Putting the Heat on Gas.\u201d Environmental Health Perspectives 115 (2). ncbi.nlm.nih.gov: A76.<\/li>\n<li style=\"text-align: left\">Cabri, Louis J., Donald C. Harris, and Thorolf W. Weiser. 1996. \u201cMineralogy and Distribution of Platinum-Group Mineral (PGM) Placer Deposits of the World.\u201d <em>Exploration and Mining Geology<\/em> 2 (5). infona.pl: 73\u2013167.<\/li>\n<li style=\"text-align: left\">Crutzen, Paul J., and Jos Lelieveld. 2001. \u201cHuman Impacts on Atmospheric Chemistry.\u201d <em>Annual Review of Earth and Planetary Sciences<\/em> 29 (1). 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Cambridge University Press, 304.<\/li>\n<li style=\"text-align: left\">Einaudi, Marco T., and Donald M. Burt. 1982. \u201cIntroduction; Terminology, Classification, and Composition of Skarn Deposits.\u201d <em>Economic Geology and the Bulletin of the Society of Economic Geologists<\/em> 77 (4). economicgeology.org: 745\u201354.<\/li>\n<li style=\"text-align: left\">Gandossi, Luca. 2013. \u201cAn Overview of Hydraulic Fracturing and Other Formation Stimulation Technologies for Shale Gas Production.\u201d <em>Eur. Commisison Jt. Res. Cent. Tech. Reports<\/em>. skalunudujos.lt. http:\/\/skalunudujos.lt\/wp-content\/uploads\/an-overview-of-hydraulic-fracturing-and-other-stimulation-technologies.pdf.<\/li>\n<li style=\"text-align: left\">Gordon, Mackenzie, Jr, Joshua I. Tracey Jr, and Miller W. Ellis. 1958. \u201cGeology of the Arkansas Bauxite Region.\u201d pubs.er.usgs.gov. https:\/\/pubs.er.usgs.gov\/publication\/pp299.<\/li>\n<li style=\"text-align: left\">Gordon, W. 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It is made of rocks similar to basalt, and as it cools, even become more dense than the upper mantle below.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_247\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_247\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1516\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1516\"><div tabindex=\"-1\"><p>Component of the gravitational force which pushes material downslope.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1698\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1698\"><div tabindex=\"-1\"><p>Ridge of sediment that forms under a glacier by meltwater which forms a river.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1270\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1270\"><div tabindex=\"-1\"><p>A specific layer of rock formed by flowing fluid, either in the lowest part of the lower flow regime or lower part of the upper flow regime.<\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_1937\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_1937\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_493\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_493\"><div tabindex=\"-1\"><p>By Zkeizars (Own work) [<a href=\"http:\/\/www.gnu.org\/copyleft\/fdl.html\">GFDL<\/a> or <a href=\"http:\/\/creativecommons.org\/licenses\/by-sa\/4.0-3.0-2.5-2.0-1.0\">CC BY-SA 4.0-3.0-2.5-2.0-1.0<\/a>], <a href=\"https:\/\/commons.wikimedia.org\/wiki\/File%3AKeizars_TLexplained2.jpg\">via Wikimedia Commons<\/a><\/p>\n<\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><template id=\"term_330_2036\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_330_2036\"><div tabindex=\"-1\"><\/div><button><span aria-hidden=\"true\">&times;<\/span><span class=\"screen-reader-text\">Fermer la d\u00e9finition<\/span><\/button><\/div><\/template><\/div>","protected":false},"author":291,"menu_order":4,"template":"","meta":{"pb_show_title":"","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[49],"contributor":[],"license":[],"class_list":["post-330","chapter","type-chapter","status-publish","hentry","chapter-type-numberless"],"part":19,"_links":{"self":[{"href":"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/wp-json\/pressbooks\/v2\/chapters\/330","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/wp-json\/wp\/v2\/users\/291"}],"version-history":[{"count":2,"href":"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/wp-json\/pressbooks\/v2\/chapters\/330\/revisions"}],"predecessor-version":[{"id":1793,"href":"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/wp-json\/pressbooks\/v2\/chapters\/330\/revisions\/1793"}],"part":[{"href":"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/wp-json\/pressbooks\/v2\/parts\/19"}],"metadata":[{"href":"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/wp-json\/pressbooks\/v2\/chapters\/330\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/wp-json\/wp\/v2\/media?parent=330"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/wp-json\/pressbooks\/v2\/chapter-type?post=330"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/wp-json\/wp\/v2\/contributor?post=330"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/wp-json\/wp\/v2\/license?post=330"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}