{"id":138,"date":"2021-09-16T19:46:12","date_gmt":"2021-09-16T19:46:12","guid":{"rendered":"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/2-plate-tectonics\/"},"modified":"2022-05-18T14:11:26","modified_gmt":"2022-05-18T14:11:26","slug":"2-plate-tectonics","status":"publish","type":"chapter","link":"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/2-plate-tectonics\/","title":{"raw":"2 Plate Tectonics","rendered":"2 Plate Tectonics"},"content":{"raw":"[caption id=\"attachment_2498\" align=\"aligncenter\" width=\"2048\"]<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> 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.[\/caption]\n<h1>2 Plate Tectonics<\/h1>\n<b>KEY CONCEPTS<\/b>\n\n<b>At the end of this chapter, students should be able to:<\/b>\n<ul>\n \t<li>Describe how the ideas behind [pb_glossary id=\"1654\"]plate tectonics[\/pb_glossary] started with Alfred Wegener\u2019s [pb_glossary id=\"1730\"]hypothesis[\/pb_glossary] of [pb_glossary id=\"1653\"]continental[\/pb_glossary]\u00a0drift<\/li>\n \t<li>Describe the physical and chemical layers of the Earth and how they affect [pb_glossary id=\"1669\"]plate[\/pb_glossary] movement<\/li>\n \t<li>Explain how movement at the three types of [pb_glossary id=\"1669\"]plate[\/pb_glossary] boundaries causes earthquakes, [pb_glossary id=\"228\"]volcanoes[\/pb_glossary], and mountain building<\/li>\n \t<li>Identify [pb_glossary id=\"1678\"]convergent[\/pb_glossary] boundaries, including [pb_glossary id=\"1680\"]subduction[\/pb_glossary] and collisions, as places where [pb_glossary id=\"1669\"]plates[\/pb_glossary]\u00a0come together<\/li>\n \t<li>Identify [pb_glossary id=\"1677\"]divergent[\/pb_glossary] boundaries, including [pb_glossary id=\"1702\"]rifts[\/pb_glossary]\u00a0and [pb_glossary id=\"1708\"]mid-ocean ridges[\/pb_glossary], as places where [pb_glossary id=\"1669\"]plates[\/pb_glossary] separate<\/li>\n \t<li>Explain [pb_glossary id=\"1679\"]transform[\/pb_glossary] boundaries as places where adjacent [pb_glossary id=\"1669\"]plates[\/pb_glossary] [pb_glossary id=\"494\"]shear[\/pb_glossary] past each other<\/li>\n \t<li>Describe the [pb_glossary id=\"1715\"]Wilson Cycle[\/pb_glossary], beginning with [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1702\"]rifting[\/pb_glossary], ocean [pb_glossary id=\"508\"]basin[\/pb_glossary] creation, [pb_glossary id=\"1669\"]plate[\/pb_glossary] [pb_glossary id=\"1680\"]subduction[\/pb_glossary], and ending with ocean [pb_glossary id=\"508\"]basin[\/pb_glossary] closure<\/li>\n \t<li>Explain how the tracks of [pb_glossary id=\"1716\"]hotspots[\/pb_glossary], places that have continually rising [pb_glossary id=\"1750\"]magma[\/pb_glossary], is used to calculate [pb_glossary id=\"1669\"]plate[\/pb_glossary] motion<\/li>\n<\/ul>\n[caption id=\"attachment_2499\" align=\"aligncenter\" width=\"4898\"]<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> Detailed map of all known plates, their boundaries, and movements.[\/caption]\n\nRevolution 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.\n\nThe concept of [pb_glossary id=\"1654\"]plate tectonics[\/pb_glossary] was just as revolutionary for geology. The [pb_glossary id=\"1733\"]theory[\/pb_glossary] of [pb_glossary id=\"1654\"]plate tectonics[\/pb_glossary] attributes the movement of [pb_glossary id=\"985\"]massive[\/pb_glossary] sections of the Earth\u2019s outer layers with creating earthquakes, mountains, and [pb_glossary id=\"228\"]volcanoes[\/pb_glossary]. Many earth processes make more sense when viewed through the lens of [pb_glossary id=\"1654\"]plate tectonics[\/pb_glossary]. Because it is so important in understanding how the world works, [pb_glossary id=\"1654\"]plate tectonics[\/pb_glossary] is the first topic of discussion in this textbook.\n<h2><span style=\"font-weight: 400;\">2.1 Alfred Wegener\u2019s Continental Drift Hypothesis<\/span><\/h2>\n[caption id=\"attachment_2500\" align=\"alignleft\" width=\"195\"]<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> Wegener later in his life, ca. 1924-1930.[\/caption]\n\nAlfred 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 [pb_glossary id=\"753\"]isostasy[\/pb_glossary], and that similar land bridges once connected the continents. After reviewing the scientific literature, he published a [pb_glossary id=\"1730\"]hypothesis[\/pb_glossary] stating the continents were originally connected, and then drifted apart. While he did not have the precise mechanism worked out, his [pb_glossary id=\"1730\"]hypothesis[\/pb_glossary] was backed up by a long list of evidence.\n<h3><\/h3>\n<h3><b>2.1.1 Early Evidence for Continental Drift Hypothesis<\/b><\/h3>\n[caption id=\"attachment_2501\" align=\"alignright\" width=\"300\"]<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> Snider-Pellegrini's map showing the continental fit and separation, 1858.[\/caption]\n\nWegener\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 [pb_glossary id=\"1653\"]continental[\/pb_glossary] separation and matching [pb_glossary id=\"1228\"]fossils[\/pb_glossary] in 1858.\n\n[caption id=\"attachment_2502\" align=\"alignleft\" width=\"300\"]<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> 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.[\/caption]\n\nWhat 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 [pb_glossary id=\"1969\"]continental[\/pb_glossary] shelves. This resulted in a better fit than previous efforts that traced the existing coastlines.\n\n[caption id=\"attachment_3259\" align=\"alignright\" width=\"300\"]<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> Image showing fossils that connect the continents of Gondwana (the southern continents of Pangea).[\/caption]\n\n&nbsp;\n\nWegener also compiled evidence by comparing similar rocks, mountains, [pb_glossary id=\"1228\"]fossils[\/pb_glossary], and [pb_glossary id=\"1988\"]glacial[\/pb_glossary] [pb_glossary id=\"2038\"]formations[\/pb_glossary] across oceans. For example, the [pb_glossary id=\"1228\"]fossils[\/pb_glossary] of the primitive aquatic reptile <em>Mesosaurus<\/em> were found on the separate coastlines of Africa and South America. [pb_glossary id=\"1228\"]Fossils[\/pb_glossary] 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.\n\nOpponents of [pb_glossary id=\"1653\"]continental[\/pb_glossary] drift insisted trans-[pb_glossary id=\"1659\"]oceanic [\/pb_glossary] 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 [pb_glossary id=\"1730\"]hypothesis[\/pb_glossary] is the improbability of a land bridge being tall and long enough to stretch across a broad, deep ocean.\n\nMore support for [pb_glossary id=\"1653\"]continental[\/pb_glossary] drift came from the puzzling evidence that [pb_glossary id=\"1516\"]glaciers[\/pb_glossary] once existed in normally very warm areas in southern Africa, India, Australia, and Arabia. These [pb_glossary id=\"757\"]climate[\/pb_glossary] [pb_glossary id=\"765\"]anomalies[\/pb_glossary] could not be explained by land bridges. Wegener found similar evidence when he discovered tropical plant [pb_glossary id=\"1228\"]fossils[\/pb_glossary] in the frozen region of the Arctic Circle. As Wegener collected more data, he realized the explanation that best fit all the [pb_glossary id=\"757\"]climate[\/pb_glossary], rock, and [pb_glossary id=\"1228\"]fossil[\/pb_glossary] observations involved moving continents.\n<h3><b>2.1.2 Proposed Mechanism for Continental Drift<\/b><\/h3>\n[caption id=\"attachment_2504\" align=\"alignleft\" width=\"400\"]<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> 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.[\/caption]\n\n&nbsp;\n\nWegener\u2019s work was considered a fringe science [pb_glossary id=\"1733\"]theory[\/pb_glossary] for his entire life. One of the biggest flaws in his [pb_glossary id=\"1730\"]hypothesis[\/pb_glossary] 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-[pb_glossary id=\"1653\"]continental[\/pb_glossary] drift followers used expansion, contraction, or even the moon\u2019s origin to explain how the continents moved. Wegener used centrifugal forces and [pb_glossary id=\"749\"]precession[\/pb_glossary], but this model was proven wrong. He also speculated about seafloor spreading, with hints of [pb_glossary id=\"1655\"]convection[\/pb_glossary], but could not substantiate these proposals. As it turns out, current scientific knowledge reveals [pb_glossary id=\"1655\"]convection[\/pb_glossary] is one the major forces in driving [pb_glossary id=\"1669\"]plate[\/pb_glossary] movements, along with gravity and density.\n<h3><b>2.1.3 Development of Plate Tectonic Theory<\/b><\/h3>\n[caption id=\"attachment_2505\" align=\"alignright\" width=\"300\"]<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> GPS measurements of plate motions.[\/caption]\n\n&nbsp;\n\nWegener 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 [pb_glossary id=\"1653\"]continental[\/pb_glossary] drift a more viable idea. By the 1960s, scientists had amassed enough evidence to support the missing mechanism\u2014namely, seafloor spreading\u2014for Wegener\u2019s [pb_glossary id=\"1730\"]hypothesis[\/pb_glossary] of [pb_glossary id=\"1653\"]continental[\/pb_glossary] drift to be accepted as the [pb_glossary id=\"1733\"]theory[\/pb_glossary] of [pb_glossary id=\"1654\"]plate tectonics[\/pb_glossary]. Ongoing GPS and earthquake data analyses continue to support this [pb_glossary id=\"1733\"]theory[\/pb_glossary]. The next section provides the pieces of evidence that helped [pb_glossary id=\"1679\"]transform[\/pb_glossary] one man\u2019s wild notion into a scientific [pb_glossary id=\"1733\"]theory[\/pb_glossary].\n<h4><span style=\"font-weight: 400;\">Mapping of the Ocean Floors<\/span><\/h4>\n[caption id=\"attachment_2506\" align=\"alignleft\" width=\"300\"]<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> The complex chemistry around mid-ocean ridges.[\/caption]\n\n&nbsp;\n\nIn 1947 researchers started using an adaptation of [pb_glossary id=\"2442\"]SONAR[\/pb_glossary] 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 [pb_glossary id=\"1963\"]ocean floor[\/pb_glossary] 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-[pb_glossary id=\"508\"]basin[\/pb_glossary] growth [pb_glossary id=\"1730\"]hypotheses[\/pb_glossary]. In 1959, Harry Hess proposed the [pb_glossary id=\"1730\"]hypothesis[\/pb_glossary] of seafloor spreading \u2013 that the [pb_glossary id=\"1708\"]mid-ocean ridges[\/pb_glossary] represented [pb_glossary id=\"1654\"]tectonic[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] factories, where new [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] was issuing from these long [pb_glossary id=\"228\"]volcanic[\/pb_glossary] ridges. Scientists later included [pb_glossary id=\"1679\"]transform[\/pb_glossary] [pb_glossary id=\"3916\"]faults[\/pb_glossary] perpendicular to the ridges to better account for varying rates of movement between the newly formed [pb_glossary id=\"1669\"]plates[\/pb_glossary]. When earthquake [pb_glossary id=\"2163\"]epicenters[\/pb_glossary] were discovered along the ridges, the idea that earthquakes were linked to [pb_glossary id=\"1669\"]plate[\/pb_glossary] movement took hold.\n<div style=\"height: 0; padding-bottom: 56.25%;\">\n\n[embed]https:\/\/youtu.be\/TgfYjS0OTWw[\/embed]\n\n<\/div>\n\n[caption id=\"attachment_3739\" align=\"aligncenter\" width=\"150\"]<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> If you are using the printed version of this OER, access this YouTube video via this QR Code.[\/caption]\n\nSeafloor [pb_glossary id=\"1756\"]sediment[\/pb_glossary], measured by dredging and drilling, provided another clue. Scientists once believed [pb_glossary id=\"1756\"]sediment[\/pb_glossary] accumulated on the ocean floors over a very long time in a static environment. When some studies showed less [pb_glossary id=\"1756\"]sediment[\/pb_glossary] than expected, these results were initially used to argue against [pb_glossary id=\"1653\"]continental[\/pb_glossary] movement. With more time, researchers discovered these thinner [pb_glossary id=\"1756\"]sediment[\/pb_glossary] layers were located close to [pb_glossary id=\"1708\"]mid-ocean ridges[\/pb_glossary], indicating the ridges were younger than the surrounding [pb_glossary id=\"1963\"]ocean floor[\/pb_glossary]. This finding supported the idea that the sea floor was not fixed in one place.\n<h4><span style=\"font-weight: 400;\">Paleomagnetism<\/span><\/h4>\n[caption id=\"attachment_2507\" align=\"alignright\" width=\"300\"]<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> The magnetic field of Earth, simplified as a bar magnet.[\/caption]\n\nThe seafloor was also mapped magnetically. Scientists had long known of strange magnetic [pb_glossary id=\"765\"]anomalies[\/pb_glossary] that formed a striped pattern of symmetrical rows on both sides of mid-[pb_glossary id=\"1659\"]oceanic[\/pb_glossary] 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).\n\n[caption id=\"attachment_2508\" align=\"alignleft\" width=\"351\"]<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> This animation shows how the magnetic poles have moved over 400 years.[\/caption]\n\n[pb_glossary id=\"1657\"]Paleomagnetism[\/pb_glossary] is the study of magnetic fields frozen within rocks, basically a fossilized compass. In fact, the first hard evidence to support [pb_glossary id=\"1669\"]plate[\/pb_glossary] motion came from [pb_glossary id=\"1657\"]paleomagnetism[\/pb_glossary].\n\n[pb_glossary id=\"1753\"]Igneous[\/pb_glossary] rocks containing magnetic [pb_glossary id=\"1765\"]minerals[\/pb_glossary] like magnetite typically provide the most useful data. In their liquid state as [pb_glossary id=\"1750\"]magma[\/pb_glossary] or [pb_glossary id=\"1751\"]lava[\/pb_glossary], the magnetic poles of the [pb_glossary id=\"1765\"]minerals[\/pb_glossary] 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 [pb_glossary id=\"2450\"]latitude[\/pb_glossary], and declination related to magnetic north.\n\n[caption id=\"attachment_2509\" align=\"alignright\" width=\"240\"]<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> The iron in the solidifying rock preserves the current magnetic polarity as new oceanic plates form at mid ocean ridges[\/caption]\n\nScientists 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 [pb_glossary id=\"1653\"]continental[\/pb_glossary] movement explained the data better than pole movement alone.\n<h4><\/h4>\n<h4><\/h4>\n<h4><span style=\"font-weight: 400;\">Wadati-Benioff Zones<\/span><\/h4>\n[caption id=\"attachment_2510\" align=\"alignleft\" width=\"297\"]<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> The Wadati-Benioff zone, showing earthquakes following the subducting slab down.[\/caption]\n\nAround the same time [pb_glossary id=\"1708\"]mid-ocean ridges[\/pb_glossary] were being investigated, other scientists linked the creation of ocean trenches and island arcs to [pb_glossary id=\"2165\"]seismic[\/pb_glossary] activity and [pb_glossary id=\"1654\"]tectonic[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] movement. Several independent research groups recognized earthquake [pb_glossary id=\"2163\"]epicenters[\/pb_glossary] traced the shapes of [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1669\"]plates[\/pb_glossary] sinking into the [pb_glossary id=\"1664\"]mantle[\/pb_glossary]. 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.\n\n[caption id=\"attachment_2511\" align=\"alignright\" width=\"244\"]<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> J. Tuzo Wilson[\/caption]\n\n&nbsp;\n\nBased on the mounting evidence, the [pb_glossary id=\"1733\"]theory[\/pb_glossary] [pb_glossary id=\"1654\"]plate tectonics[\/pb_glossary] 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 [pb_glossary id=\"1669\"]plates[\/pb_glossary] moving with respect to each other, with clear boundaries between them. Others started piecing together complicated histories of [pb_glossary id=\"1654\"]tectonic[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] movement. The [pb_glossary id=\"1669\"]plate[\/pb_glossary] [pb_glossary id=\"1654\"]tectonic[\/pb_glossary] revolution had taken hold.\n\n&nbsp;\n\n&nbsp;\n\n[h5p id=\"8\"]\n\n[caption id=\"attachment_3738\" align=\"aligncenter\" width=\"150\"]<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> 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=\"9\"]\n\n[caption id=\"attachment_3737\" align=\"aligncenter\" width=\"150\"]<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> If you are using the printed version of this OER, access the quiz for section 2.1 via this QR Code.[\/caption]\n<h2><span style=\"font-weight: 400;\">2.2 Layers of the Earth<\/span><\/h2>\n&nbsp;\n\n[caption id=\"attachment_2512\" align=\"alignleft\" width=\"300\"]<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> The layers of the Earth. Physical layers include lithosphere and asthenosphere; chemical layers are crust, mantle, and core.[\/caption]\n\nIn order to understand the details of [pb_glossary id=\"1654\"]plate tectonics[\/pb_glossary], 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 [pb_glossary id=\"2165\"]seismic wave[\/pb_glossary] data and [pb_glossary id=\"1254\"]meteorite[\/pb_glossary] materials. In general, the Earth can be divided into layers based on chemical [pb_glossary id=\"1909\"]composition[\/pb_glossary] and physical characteristics.\n<h3><b>2.2.1 Chemical Layers<\/b><\/h3>\nCertainly the earth is [pb_glossary id=\"1909\"]composed[\/pb_glossary] of a countless combination of [pb_glossary id=\"1778\"]elements[\/pb_glossary]. Regardless of what [pb_glossary id=\"1778\"]elements[\/pb_glossary] are involved two major factors\u2014[pb_glossary id=\"1767\"]temperature[\/pb_glossary] and pressure\u2014are responsible for creating three distinct chemical layers.\n<h4><span style=\"font-weight: 400;\">Crust<\/span><\/h4>\nThe outermost chemical layer and the one we currently reside on, is the [pb_glossary id=\"1658\"]crust[\/pb_glossary]. There are two types of [pb_glossary id=\"1658\"]crust[\/pb_glossary]. [pb_glossary id=\"1653\"]Continental crust[\/pb_glossary] has a relatively low density and [pb_glossary id=\"1909\"]composition[\/pb_glossary] similar to [pb_glossary id=\"1014\"]granite[\/pb_glossary]. [pb_glossary id=\"1659\"]Oceanic crust[\/pb_glossary] has a relatively high density, especially when cold and old, and [pb_glossary id=\"1909\"]composition[\/pb_glossary] similar to [pb_glossary id=\"1013\"]basalt[\/pb_glossary]. The surface levels of [pb_glossary id=\"1658\"]crust[\/pb_glossary] are relatively [pb_glossary id=\"1661\"]brittle[\/pb_glossary]. The deeper parts of the [pb_glossary id=\"1658\"]crust[\/pb_glossary] are subjected to higher temperatures and pressure, which makes them more [pb_glossary id=\"1660\"]ductile[\/pb_glossary]. [pb_glossary id=\"1660\"]Ductile[\/pb_glossary] materials are like soft plastics or putty, they move under force. [pb_glossary id=\"1661\"]Brittle[\/pb_glossary] materials are like solid glass or pottery, they break under force, especially when it is applied quickly. Earthquakes, generally occur in the upper [pb_glossary id=\"1658\"]crust[\/pb_glossary] and are caused by the rapid movement of relatively [pb_glossary id=\"1661\"]brittle[\/pb_glossary] materials.\n\n&nbsp;\n\n[caption id=\"attachment_2513\" align=\"alignleft\" width=\"300\"]<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> The global map of the depth of the moho.[\/caption]\n\nThe base of the [pb_glossary id=\"1658\"]crust[\/pb_glossary] is characterized by a large increase in [pb_glossary id=\"2165\"]seismic[\/pb_glossary] velocity, which measures how fast earthquake waves travel through solid matter. Called the Mohorovi\u010di\u0107 Discontinuity, or [pb_glossary id=\"1662\"]Moho[\/pb_glossary] 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 [pb_glossary id=\"976\"]native[\/pb_glossary] Croatia. The change in wave direction and speed is caused by dramatic chemical differences of the [pb_glossary id=\"1658\"]crust[\/pb_glossary] and [pb_glossary id=\"1664\"]mantle[\/pb_glossary]. Underneath the oceans, the [pb_glossary id=\"1662\"]Moho[\/pb_glossary] is found roughly 5 km below the [pb_glossary id=\"1963\"]ocean floor[\/pb_glossary]. Under the continents, it is located about 30-40 km below the surface. Near certain large mountain-building events known as orogenies, the [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1662\"]Moho[\/pb_glossary] depth is doubled.\n<h4><span style=\"font-weight: 400;\">Mantle<\/span><\/h4>\n[caption id=\"attachment_2514\" align=\"alignright\" width=\"300\"]<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> 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.[\/caption]\n\nThe [pb_glossary id=\"1664\"]mantle[\/pb_glossary] sits below the [pb_glossary id=\"1658\"]crust[\/pb_glossary] and above the [pb_glossary id=\"1667\"]core[\/pb_glossary]. It is the largest chemical layer by volume, extending from the base of the [pb_glossary id=\"1658\"]crust[\/pb_glossary] to a depth of about 2900 km. Most of what we know about the [pb_glossary id=\"1664\"]mantle[\/pb_glossary] comes from [pb_glossary id=\"2165\"]seismic wave[\/pb_glossary] analysis, though information is gathered by studying [pb_glossary id=\"1700\"]ophiolites[\/pb_glossary] and [pb_glossary id=\"1665\"]xenoliths[\/pb_glossary]. [pb_glossary id=\"1700\"]Ophiolites[\/pb_glossary] are pieces of [pb_glossary id=\"1664\"]mantle[\/pb_glossary] that have risen through the [pb_glossary id=\"1658\"]crust[\/pb_glossary] until they are exposed as part of the [pb_glossary id=\"1963\"]ocean floor[\/pb_glossary]. [pb_glossary id=\"1665\"]Xenoliths[\/pb_glossary] are carried within [pb_glossary id=\"1750\"]magma[\/pb_glossary] and brought to the Earth\u2019s surface by volcanic eruptions. Most [pb_glossary id=\"1665\"]xenoliths[\/pb_glossary] are made of [pb_glossary id=\"1666\"]peridotite[\/pb_glossary], an [pb_glossary id=\"1009\"]ultramafic[\/pb_glossary] class of [pb_glossary id=\"1753\"]igneous rock[\/pb_glossary] (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 [pb_glossary id=\"1664\"]mantle[\/pb_glossary] is made of [pb_glossary id=\"1666\"]peridotite[\/pb_glossary].\n<h4><span style=\"font-weight: 400;\">Core<\/span><\/h4>\n[caption id=\"attachment_2515\" align=\"alignleft\" width=\"300\"]<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> A polished fragment of the iron-rich Toluca Meteorite, with octahedral Widmanst\u00e4tten Pattern.[\/caption]\n\n&nbsp;\n\nThe [pb_glossary id=\"1667\"]core[\/pb_glossary] of the Earth, which has both liquid and solid layers, and consists mostly of iron, nickel, and possibly some oxygen. Scientists looking at [pb_glossary id=\"2165\"]seismic[\/pb_glossary] data first discovered this innermost chemical layer in 1906. Through a union of hypothetical modeling, astronomical insight, and hard [pb_glossary id=\"2165\"]seismic[\/pb_glossary] data, they concluded the [pb_glossary id=\"1667\"]core[\/pb_glossary] is mostly [pb_glossary id=\"2423\"]metallic[\/pb_glossary] iron. Scientists studying [pb_glossary id=\"1254\"]meteorites[\/pb_glossary], which typically contain more iron than surface rocks, have proposed the earth was formed from meteoric material. They believe the liquid component of the [pb_glossary id=\"1667\"]core[\/pb_glossary] was created as the iron and nickel sank into the center of the planet, where it was liquefied by intense pressure.\n<h3><b>2.2.2 Physical Layers<\/b><\/h3>\n<span style=\"font-weight: 400;\">The Earth can also be broken down into five distinct physical layers based on how each layer responds to [pb_glossary id=\"1993\"]stress[\/pb_glossary]. While there is some overlap in the chemical and physical designations of layers, specifically the [pb_glossary id=\"1667\"]core[\/pb_glossary]-[pb_glossary id=\"1664\"]mantle[\/pb_glossary] boundary, there are significant differences between the two systems.<\/span>\n<h4><span style=\"font-weight: 400;\">Lithosphere<\/span><\/h4>\n[caption id=\"attachment_2516\" align=\"alignright\" width=\"300\"]<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> Map of the major plates and their motions along boundaries.[\/caption]\n\n<em>Lithos<\/em> is Greek for stone, and the [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] is the outermost physical layer of the Earth. It is grouped into two types: [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] and [pb_glossary id=\"1653\"]continental[\/pb_glossary]. [pb_glossary id=\"1659\"]Oceanic[\/pb_glossary] [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] is thin and relatively rigid. It ranges in thickness from nearly zero in new [pb_glossary id=\"1669\"]plates[\/pb_glossary] found around [pb_glossary id=\"1708\"]mid-ocean ridges[\/pb_glossary], to an average of 140 km in most other locations. [pb_glossary id=\"1653\"]Continental[\/pb_glossary] [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] is generally thicker and considerably more plastic, especially at the deeper levels. Its thickness ranges from 40 to 280 km. The [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] is not continuous. It is broken into segments called [pb_glossary id=\"1669\"]plates[\/pb_glossary]. A [pb_glossary id=\"1670\"]plate boundary[\/pb_glossary] is where two [pb_glossary id=\"1669\"]plates[\/pb_glossary] meet and move relative to each other. [pb_glossary id=\"1669\"]Plate[\/pb_glossary] boundaries are where we see [pb_glossary id=\"1654\"]plate tectonics[\/pb_glossary] in action\u2014mountain building, triggering earthquakes, and generating [pb_glossary id=\"228\"]volcanic[\/pb_glossary] activity.\n<h4><span style=\"font-weight: 400;\">Asthenosphere<\/span><\/h4>\n[caption id=\"attachment_2517\" align=\"alignleft\" width=\"300\"]<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> The lithosphere-asthenosphere boundary changes with certain tectonic situations.[\/caption]\n\n&nbsp;\n\nThe [pb_glossary id=\"1671\"]asthenosphere[\/pb_glossary] is the layer below the [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary]. <em>Astheno-<\/em> means lacking strength, and the most distinctive property of the [pb_glossary id=\"1671\"]asthenosphere[\/pb_glossary] is movement. Because it is mechanically weak, this layer moves and flows due to [pb_glossary id=\"1655\"]convection[\/pb_glossary] currents created by heat coming from the earth\u2019s [pb_glossary id=\"1667\"]core[\/pb_glossary] cause. Unlike the [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] that consists of multiple [pb_glossary id=\"1669\"]plates[\/pb_glossary], the [pb_glossary id=\"1671\"]asthenosphere[\/pb_glossary] is relatively unbroken. Scientists have determined this by analyzing [pb_glossary id=\"2165\"]seismic[\/pb_glossary] waves that pass through the layer. The depth of at which the [pb_glossary id=\"1671\"]asthenosphere[\/pb_glossary] is found is [pb_glossary id=\"1767\"]temperature[\/pb_glossary]-dependent. It tends to lie closer to the earth\u2019s surface around [pb_glossary id=\"1708\"]mid-ocean ridges[\/pb_glossary] and much deeper underneath mountains and the centers of lithospheric [pb_glossary id=\"1669\"]plates[\/pb_glossary].\n<h4><span style=\"font-weight: 400;\">Mesosphere<\/span><\/h4>\n&nbsp;\n\n[caption id=\"attachment_2518\" align=\"alignright\" width=\"300\"]<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> 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.[\/caption]\n\nThe [pb_glossary id=\"1672\"]mesosphere[\/pb_glossary], sometimes known as the lower [pb_glossary id=\"1664\"]mantle[\/pb_glossary], is more rigid and immobile than the [pb_glossary id=\"1671\"]asthenosphere[\/pb_glossary]. Located at a depth of approximately 410 and 660 km below the earth\u2019s surface, the [pb_glossary id=\"1672\"]mesosphere[\/pb_glossary] is subjected to very high pressures and temperatures. These extreme conditions create a transition zone in the upper [pb_glossary id=\"1672\"]mesosphere[\/pb_glossary] where [pb_glossary id=\"1765\"]minerals[\/pb_glossary] continuously change into various forms, or pseudomorphs. Scientists identify this zone by changes in [pb_glossary id=\"2165\"]seismic[\/pb_glossary] velocity and sometimes physical barriers to movement. Below this transitional zone, the [pb_glossary id=\"1672\"]mesosphere[\/pb_glossary] is relatively uniform until it reaches the [pb_glossary id=\"1667\"]core[\/pb_glossary].\n<h4><span style=\"font-weight: 400;\">Inner and Outer Core<\/span><\/h4>\n[caption id=\"attachment_2519\" align=\"alignleft\" width=\"206\"]<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> Lehmann in 1932[\/caption]\n\nThe [pb_glossary id=\"1673\"]outer core[\/pb_glossary] 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 [pb_glossary id=\"2165\"]seismic[\/pb_glossary] data and was the first to prove a solid [pb_glossary id=\"1674\"]inner core[\/pb_glossary] existed within a liquid [pb_glossary id=\"1673\"]outer core[\/pb_glossary] . The solid [pb_glossary id=\"1674\"]inner core[\/pb_glossary] is about 1,220 km thick, and the [pb_glossary id=\"1673\"]outer core[\/pb_glossary] is about 2,300 km thick.\n\nIt seems like a contradiction that the hottest part of the Earth is solid, as the [pb_glossary id=\"1765\"]minerals[\/pb_glossary] making up the [pb_glossary id=\"1667\"]core[\/pb_glossary] should be liquified or vaporized at this [pb_glossary id=\"1767\"]temperature[\/pb_glossary]. Immense pressure keeps the [pb_glossary id=\"1765\"]minerals[\/pb_glossary] of the [pb_glossary id=\"1674\"]inner core[\/pb_glossary] in a solid phase. The [pb_glossary id=\"1674\"]inner core[\/pb_glossary] grows slowly from the lower [pb_glossary id=\"1673\"]outer core[\/pb_glossary] solidifying as heat escapes the interior of the Earth and is dispersed to the outer layers.\n\n[caption id=\"attachment_2520\" align=\"alignright\" width=\"300\"]<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> The outer core's spin causes our protective magnetic field.[\/caption]\n\nThe earth\u2019s liquid [pb_glossary id=\"1673\"]outer core[\/pb_glossary] is critically important in maintaining a breathable [pb_glossary id=\"1745\"]atmosphere[\/pb_glossary] 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 [pb_glossary id=\"1673\"]outer core[\/pb_glossary]. If the [pb_glossary id=\"1673\"]outer core[\/pb_glossary] 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.\n\n&nbsp;\n\n&nbsp;\n\n&nbsp;\n\n&nbsp;\n\n[h5p id=\"10\"]\n\n[caption id=\"attachment_3736\" align=\"aligncenter\" width=\"150\"]<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> If you are using the printed version of this OER, access this interactive activity via this QR Code.[\/caption]\n<h3><b>2.2.3 Plate Tectonic Boundaries<\/b><\/h3>\n[caption id=\"attachment_2521\" align=\"alignleft\" width=\"300\"]<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> Passive margin[\/caption]\n\n&nbsp;\n\nAt passive margins the [pb_glossary id=\"1669\"]plates[\/pb_glossary] don\u2019t move\u2014the [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] transitions into oceanic lithosphere and forms [pb_glossary id=\"1669\"]plates[\/pb_glossary] made of both types. A [pb_glossary id=\"1654\"]tectonic[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] may be made of both [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] and [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] connected by a [pb_glossary id=\"1676\"]passive margin[\/pb_glossary]. North and South America\u2019s eastern coastlines are examples of passive margins. Active margins are places where the [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] and [pb_glossary id=\"1653\"]continental[\/pb_glossary] lithospheric [pb_glossary id=\"1654\"]tectonic[\/pb_glossary] [pb_glossary id=\"1669\"]plates[\/pb_glossary] 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 [pb_glossary id=\"1669\"]plates[\/pb_glossary] and differences in [pb_glossary id=\"1669\"]plate[\/pb_glossary] densities. The majority of mountain-building events, earthquake activity and active [pb_glossary id=\"228\"]volcanism[\/pb_glossary] on the Earth\u2019s surface can be attributed to [pb_glossary id=\"1654\"]tectonic[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] movement at active margins.\n\n&nbsp;\n\n[caption id=\"attachment_2522\" align=\"aligncenter\" width=\"775\"]<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> Schematic of plate boundary types.[\/caption]\n\nIn a simplified model, there are three categories of [pb_glossary id=\"1654\"]tectonic[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] boundaries. [pb_glossary id=\"1678\"]Convergent[\/pb_glossary] boundaries are places where [pb_glossary id=\"1669\"]plates[\/pb_glossary] move toward each other. At [pb_glossary id=\"1677\"]divergent[\/pb_glossary] boundaries, the [pb_glossary id=\"1669\"]plates[\/pb_glossary] move apart. At [pb_glossary id=\"1679\"]transform[\/pb_glossary] boundaries, the [pb_glossary id=\"1669\"]plates[\/pb_glossary] slide past each other.\n\n&nbsp;\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n[h5p id=\"11\"]\n\n[caption id=\"attachment_3735\" align=\"aligncenter\" width=\"150\"]<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> If you are using the printed version of this OER, access the quiz for section 2.2 via this QR Code.[\/caption]\n<h2><span style=\"font-size: 28px;\">2.3 Convergent Boundaries<\/span><\/h2>\n&nbsp;\n\n[caption id=\"attachment_2523\" align=\"alignleft\" width=\"300\"]<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> Geologic provinces with the Shield (orange) and Platform (pink) comprising the Craton, the stable interior of continents.[\/caption]\n\n[pb_glossary id=\"1678\"]Convergent[\/pb_glossary] boundaries, also called destructive boundaries, are places where two or more [pb_glossary id=\"1669\"]plates[\/pb_glossary] move toward each other. . [pb_glossary id=\"1678\"]Convergent[\/pb_glossary] boundary movement is divided into two types, [pb_glossary id=\"1680\"]subduction[\/pb_glossary] and [pb_glossary id=\"1698\"]collision[\/pb_glossary], depending on the density of the involved [pb_glossary id=\"1669\"]plates[\/pb_glossary]. [pb_glossary id=\"1653\"]Continental[\/pb_glossary] [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] is of lower density and thus more buoyant than the underlying [pb_glossary id=\"1671\"]asthenosphere[\/pb_glossary]. [pb_glossary id=\"1659\"]Oceanic[\/pb_glossary] [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] is more dense than [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary], and, when old and cold, may even be more dense than [pb_glossary id=\"1671\"]asthenosphere[\/pb_glossary].\n\nWhen [pb_glossary id=\"1669\"]plates[\/pb_glossary] of different densities converge, the higher density [pb_glossary id=\"1669\"]plate[\/pb_glossary] is pushed beneath the more buoyant [pb_glossary id=\"1669\"]plate[\/pb_glossary] in a process called [pb_glossary id=\"1680\"]subduction[\/pb_glossary]. When [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plates[\/pb_glossary] converge without [pb_glossary id=\"1680\"]subduction[\/pb_glossary] occurring, this process is called [pb_glossary id=\"1698\"]collision[\/pb_glossary].\n<h3><b>2.3.1. Subduction<\/b><\/h3>\n[video width=\"720\" height=\"540\" mp4=\"http:\/\/opengeology.org\/textbook\/wp-content\/uploads\/2016\/07\/Subduction.mp4\"][\/video]\n\n<em><a href=\"http:\/\/emvc.geol.ucsb.edu\/2_infopgs\/IP1GTect\/cSubduction.html\">Video<\/a> showing [pb_glossary id=\"1653\"]<em>continental<\/em>[\/pb_glossary]-[pb_glossary id=\"1659\"]<em>oceanic <\/em>[\/pb_glossary] [pb_glossary id=\"1680\"]<em>subduction<\/em>[\/pb_glossary], causing [pb_glossary id=\"228\"]<em>volcanism<\/em>[\/pb_glossary]. By Tanya Atwater and John Iwerks.<\/em>\n\n[caption id=\"attachment_3734\" align=\"aligncenter\" width=\"150\"]<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> If you are using the printed version of this OER, access this video via this QR Code.[\/caption]\n\n[pb_glossary id=\"1680\"]Subduction[\/pb_glossary] occurs when a dense [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] meets a more buoyant [pb_glossary id=\"1669\"]plate[\/pb_glossary], like a [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] or warmer\/younger [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary], and descends into the [pb_glossary id=\"1664\"]mantle[\/pb_glossary]. The worldwide average rate of [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] [pb_glossary id=\"1680\"]subduction[\/pb_glossary] is 25 miles per million years, about a half-inch per year. As an [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] descends, it pulls the [pb_glossary id=\"1963\"]ocean floor[\/pb_glossary] down into a [pb_glossary id=\"1681\"]trench[\/pb_glossary]. These trenches can be more than twice as deep as the average depth of the adjacent ocean [pb_glossary id=\"508\"]basin[\/pb_glossary], which is usually three to four km. The Mariana [pb_glossary id=\"1681\"]Trench[\/pb_glossary], for example, approaches a staggering 11 km.\n\n&nbsp;\n\n[caption id=\"attachment_2524\" align=\"aligncenter\" width=\"800\"]<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> Diagram of ocean-continent subduction.[\/caption]\n\n[caption id=\"attachment_2525\" align=\"alignright\" width=\"212\"]<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> Microcontinents can become part of the accretionary prism of a subduction zone.[\/caption]\n\nWithin the [pb_glossary id=\"1681\"]trench[\/pb_glossary], [pb_glossary id=\"1963\"]ocean floor[\/pb_glossary] [pb_glossary id=\"1756\"]sediments[\/pb_glossary] are scraped together and compressed between the [pb_glossary id=\"1680\"]subducting[\/pb_glossary] and overriding [pb_glossary id=\"1669\"]plates[\/pb_glossary]. This feature is called the [pb_glossary id=\"1682\"]accretionary wedge[\/pb_glossary], m\u00e9lange, or accretionary prism. Fragments of [pb_glossary id=\"1653\"]continental[\/pb_glossary] material, including microcontinents, riding atop the [pb_glossary id=\"1680\"]subducting[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] may become sutured to the [pb_glossary id=\"1682\"]accretionary wedge [\/pb_glossary] and accumulate into a large area of land called a [pb_glossary id=\"1764\"]terrane[\/pb_glossary]. Vast portions of California are comprised of accreted terranes.\n\n[caption id=\"attachment_2526\" align=\"alignleft\" width=\"179\"]<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> 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.[\/caption]\n\nWhen the [pb_glossary id=\"1680\"]subducting[\/pb_glossary] [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary], or [pb_glossary id=\"1683\"]slab[\/pb_glossary], sinks into the [pb_glossary id=\"1664\"]mantle[\/pb_glossary], the immense heat and pressure pushes volatile materials like water and carbon dioxide into an area below the [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] and above the descending [pb_glossary id=\"1669\"]plate[\/pb_glossary] called the [pb_glossary id=\"1685\"]mantle wedge[\/pb_glossary]. The [pb_glossary id=\"1684\"]volatiles[\/pb_glossary] are released mostly by hydrated [pb_glossary id=\"1765\"]minerals[\/pb_glossary] that revert to non-hydrated [pb_glossary id=\"1765\"]minerals[\/pb_glossary] in these higher [pb_glossary id=\"1767\"]temperature[\/pb_glossary] and pressure conditions. When mixed with asthenospheric material above the [pb_glossary id=\"1669\"]plate[\/pb_glossary], the volatile lower the melting point of the [pb_glossary id=\"1685\"]mantle wedge[\/pb_glossary], and through a process called [pb_glossary id=\"1686\"]flux melting[\/pb_glossary] it becomes liquid [pb_glossary id=\"1750\"]magma[\/pb_glossary]. The molten [pb_glossary id=\"1750\"]magma[\/pb_glossary] is more buoyant than the lithospheric [pb_glossary id=\"1669\"]plate[\/pb_glossary] above it and migrates to the Earth\u2019s surface where it emerges as [pb_glossary id=\"228\"]volcanism[\/pb_glossary]. The resulting [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] frequently appear as curved mountain chains, [pb_glossary id=\"228\"]volcanic[\/pb_glossary] arcs, due to the curvature of the earth. Both [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] and [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plates[\/pb_glossary] can contain [pb_glossary id=\"228\"]volcanic[\/pb_glossary] arcs.\n\n[caption id=\"attachment_2527\" align=\"alignright\" width=\"236\"]<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> Location of the large (Mw 8.5-9.0) 1755 Lisbon Earthquake.[\/caption]\n\nHow [pb_glossary id=\"1680\"]subduction[\/pb_glossary] is initiated is still a matter of scientific debate. It is generally accepted that [pb_glossary id=\"1680\"]subduction[\/pb_glossary] zones start as passive margins, where [pb_glossary id=\"1659\"]oceanic[\/pb_glossary]\u00a0and [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plates[\/pb_glossary] come together, and then gravity initiates [pb_glossary id=\"1680\"]subduction[\/pb_glossary] and converts the [pb_glossary id=\"1676\"]passive margin[\/pb_glossary] into an active one. One [pb_glossary id=\"1730\"]hypothesis[\/pb_glossary] is gravity pulls the denser [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] down or the [pb_glossary id=\"1669\"]plate[\/pb_glossary] can start to flow ductility at a low angle. Scientists seeking to answer this question have collected evidence that suggests a new [pb_glossary id=\"1680\"]subduction[\/pb_glossary] zone is forming off the [pb_glossary id=\"1968\"]coast[\/pb_glossary]\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 [pb_glossary id=\"1680\"]subduction[\/pb_glossary] zone, although the evidence is not definitive. Another [pb_glossary id=\"1730\"]hypothesis[\/pb_glossary] proposes [pb_glossary id=\"1680\"]subduction[\/pb_glossary] happens at [pb_glossary id=\"1679\"]transform[\/pb_glossary] boundaries involving [pb_glossary id=\"1669\"]plates[\/pb_glossary] of different densities.\n\nSome [pb_glossary id=\"1669\"]plate[\/pb_glossary] boundaries look like they should be active, but show no evidence of [pb_glossary id=\"1680\"]subduction[\/pb_glossary]. The [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] lithospheric [pb_glossary id=\"1669\"]plates[\/pb_glossary] on either side of the Atlantic Ocean for example, are denser than the underlying [pb_glossary id=\"1671\"]asthenosphere[\/pb_glossary] and are not [pb_glossary id=\"1680\"]subducting[\/pb_glossary] beneath the [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plates[\/pb_glossary]. One [pb_glossary id=\"1730\"]hypothesis[\/pb_glossary] is the [pb_glossary id=\"1781\"]bond[\/pb_glossary] holding the [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] and [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plates[\/pb_glossary] together is stronger than the downwards force created by the difference in [pb_glossary id=\"1669\"]plate[\/pb_glossary] densities.\n\n[caption id=\"attachment_2528\" align=\"alignleft\" width=\"234\"]<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> 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.[\/caption]\n\n[pb_glossary id=\"1680\"]Subduction[\/pb_glossary] zones are known for having the largest earthquakes and [pb_glossary id=\"2272\"]tsunamis[\/pb_glossary]; they are the only places with [pb_glossary id=\"2143\"]fault[\/pb_glossary] surfaces large enough to create [pb_glossary id=\"2176\"]magnitude[\/pb_glossary]-9 earthquakes. These [pb_glossary id=\"1680\"]subduction[\/pb_glossary]-zone earthquakes not only are very large, but also are very deep. When a [pb_glossary id=\"1680\"]subducting[\/pb_glossary] [pb_glossary id=\"1683\"]slab[\/pb_glossary] becomes stuck and cannot descend, a [pb_glossary id=\"985\"]massive[\/pb_glossary] amount of energy builds up between the stuck [pb_glossary id=\"1669\"]plates[\/pb_glossary]. If this energy is not gradually dispersed, it may force the [pb_glossary id=\"1669\"]plates[\/pb_glossary] to suddenly release along several hundred kilometers of the [pb_glossary id=\"1680\"]subduction[\/pb_glossary] zone. Because [pb_glossary id=\"1680\"]subduction[\/pb_glossary]-zone [pb_glossary id=\"2143\"]faults[\/pb_glossary] are located on the [pb_glossary id=\"1963\"]ocean floor[\/pb_glossary], this [pb_glossary id=\"985\"]massive[\/pb_glossary] amount of movement can generate giant [pb_glossary id=\"2272\"]tsunamis[\/pb_glossary] such as those that followed the 2004 Indian Ocean Earthquake and 2011 T\u014dhoku Earthquake in Japan.\n\n[caption id=\"attachment_2529\" align=\"alignright\" width=\"300\"]<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> Various parts of a subduction zone. This subduction zone is ocean-ocean subduction, though the same features can apply to continent-ocean subduction.[\/caption]\n\nAll [pb_glossary id=\"1680\"]subduction[\/pb_glossary] zones have a [pb_glossary id=\"1692\"]forearc basin[\/pb_glossary], a feature of the overriding [pb_glossary id=\"1669\"]plate[\/pb_glossary] found between the [pb_glossary id=\"1695\"]volcanic arc[\/pb_glossary] and [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1681\"]trench[\/pb_glossary]. The [pb_glossary id=\"1692\"]forearc basin[\/pb_glossary] experiences a lot of [pb_glossary id=\"2143\"]faulting[\/pb_glossary]\u00a0and [pb_glossary id=\"495\"]deformation[\/pb_glossary] activity, particularly within the [pb_glossary id=\"1682\"]accretionary wedge[\/pb_glossary].\n\nIn some [pb_glossary id=\"1680\"]subduction[\/pb_glossary] zones, [pb_glossary id=\"492\"]tensional[\/pb_glossary] forces\u00a0working on the [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] create a backarc [pb_glossary id=\"508\"]basin[\/pb_glossary] on the interior side of the [pb_glossary id=\"1695\"]volcanic arc[\/pb_glossary]. Some scientists have proposed a [pb_glossary id=\"1680\"]subduction[\/pb_glossary] mechanism called [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1683\"]slab[\/pb_glossary] rollback creates [pb_glossary id=\"492\"]extension[\/pb_glossary] [pb_glossary id=\"2143\"]faults[\/pb_glossary] in the overriding [pb_glossary id=\"1669\"]plates[\/pb_glossary]. In this model, the descending [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1683\"]slab[\/pb_glossary] does not slide directly under the overriding [pb_glossary id=\"1669\"]plate[\/pb_glossary] but instead rolls back, pulling the overlying [pb_glossary id=\"1669\"]plate[\/pb_glossary] seaward. The [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] behind the [pb_glossary id=\"1695\"]volcanic arc[\/pb_glossary] gets stretched like pizza dough until the surface cracks and collapses to form a backarc [pb_glossary id=\"508\"]basin[\/pb_glossary]. If the [pb_glossary id=\"492\"]extension[\/pb_glossary] activity is extensive and deep enough, a backarc [pb_glossary id=\"508\"]basin[\/pb_glossary] can develop into a [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1702\"]rifting[\/pb_glossary] zone. These [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1677\"]divergent[\/pb_glossary] boundaries may be less symmetrical than their [pb_glossary id=\"1708\"]mid-ocean ridge[\/pb_glossary] counterparts.\n\nIn places where numerous young buoyant [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1669\"]plates[\/pb_glossary] are converging and [pb_glossary id=\"1680\"]subducting[\/pb_glossary] at a relatively high velocity, they may force the overlying [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] to buckle and crack. This is called [pb_glossary id=\"1688\"]back-arc[\/pb_glossary] [pb_glossary id=\"2143\"]faulting[\/pb_glossary]. [pb_glossary id=\"492\"]Extensional[\/pb_glossary] [pb_glossary id=\"1688\"]back-arc[\/pb_glossary] [pb_glossary id=\"2143\"]faults[\/pb_glossary] pull rocks and chunks of [pb_glossary id=\"1669\"]plates[\/pb_glossary] apart. [pb_glossary id=\"493\"]Compressional[\/pb_glossary] [pb_glossary id=\"1688\"]back-arc[\/pb_glossary] [pb_glossary id=\"2143\"]faults[\/pb_glossary], also known as thrust [pb_glossary id=\"2143\"]faults[\/pb_glossary], push them together.\n\nThe dual spines of the Andes Mountain range include a example of [pb_glossary id=\"493\"]compressional[\/pb_glossary] thrust [pb_glossary id=\"2143\"]faulting[\/pb_glossary]. The western spine is part of a [pb_glossary id=\"1695\"]volcanic arc[\/pb_glossary]. Thrust [pb_glossary id=\"2143\"]faults[\/pb_glossary] have deformed the non-[pb_glossary id=\"228\"]volcanic[\/pb_glossary] eastern spine, \u00a0pushing rocks and pieces of [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] on top of each other.\n\nThere are two styles of [pb_glossary id=\"2152\"]thrust fault[\/pb_glossary] [pb_glossary id=\"495\"]deformation[\/pb_glossary]: [pb_glossary id=\"1689\"]thin-skinned[\/pb_glossary] [pb_glossary id=\"2143\"]faults[\/pb_glossary] that occur in superficial rocks lying on top of the [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] and [pb_glossary id=\"1690\"]thick-skinned[\/pb_glossary] [pb_glossary id=\"2143\"]faults[\/pb_glossary] that reach deeper into the [pb_glossary id=\"1658\"]crust[\/pb_glossary]. The Sevier [pb_glossary id=\"1663\"]Orogeny[\/pb_glossary] in the western U.S. is a notable [pb_glossary id=\"1689\"]thin-skinned[\/pb_glossary] type of [pb_glossary id=\"495\"]deformation[\/pb_glossary] created during the [pb_glossary id=\"487\"]Cretaceous[\/pb_glossary] [pb_glossary id=\"1244\"]Period[\/pb_glossary]. The Laramide [pb_glossary id=\"1663\"]Orogeny[\/pb_glossary], a [pb_glossary id=\"1690\"]thick-skinned[\/pb_glossary] type of [pb_glossary id=\"495\"]deformation[\/pb_glossary], occurred near the end of and slightly after the Sevier [pb_glossary id=\"1663\"]Orogeny[\/pb_glossary] \u00a0in the same region.\n\n[caption id=\"attachment_2530\" align=\"alignleft\" width=\"300\"]<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> Shallow subduction during the Laramide Orogeny.[\/caption]\n\nFlat-[pb_glossary id=\"1683\"]slab[\/pb_glossary], or shallow, [pb_glossary id=\"1680\"]subduction[\/pb_glossary] caused the Laramide [pb_glossary id=\"1663\"]Orogeny[\/pb_glossary]. When the descending [pb_glossary id=\"1683\"]slab[\/pb_glossary] [pb_glossary id=\"1680\"]subducts[\/pb_glossary] at a low angle, there is more contact between the [pb_glossary id=\"1683\"]slab[\/pb_glossary] and the overlying [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] than in a typical [pb_glossary id=\"1680\"]subduction[\/pb_glossary] zone. The shallowly-[pb_glossary id=\"1680\"]subducting[\/pb_glossary] [pb_glossary id=\"1683\"]slab[\/pb_glossary] pushes against the overriding [pb_glossary id=\"1669\"]plate[\/pb_glossary] and creates an area of [pb_glossary id=\"495\"]deformation[\/pb_glossary] on the overriding [pb_glossary id=\"1669\"]plate[\/pb_glossary] many kilometers away from the [pb_glossary id=\"1680\"]subduction[\/pb_glossary] zone.\n<h4><span style=\"font-weight: 400;\">Oceanic-Continental subduction<\/span><\/h4>\n[caption id=\"attachment_2531\" align=\"alignleft\" width=\"300\"]<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> Subduction of an oceanic plate beneath a continental plate, forming a trench and volcanic arc.[\/caption]\n\n[pb_glossary id=\"1694\"]Oceanic-continental subduction[\/pb_glossary] occurs when an [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] dives below a [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary]. This [pb_glossary id=\"1678\"]convergent[\/pb_glossary] boundary has a [pb_glossary id=\"1681\"]trench[\/pb_glossary] and [pb_glossary id=\"1685\"]mantle wedge[\/pb_glossary] and frequently, a [pb_glossary id=\"1695\"]volcanic arc[\/pb_glossary]. Well-known examples of [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1695\"]volcanic arcs[\/pb_glossary] are the Cascade Mountains in the Pacific Northwest and western Andes Mountains in South America.\n<h4><span style=\"font-weight: 400;\">Oceanic-Oceanic Subduction<\/span><\/h4>\n[caption id=\"attachment_2532\" align=\"alignright\" width=\"300\"]<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> Subduction of an oceanic plate beneath another oceanic plate, forming a trench and an island arc.[\/caption]\n\nThe boundaries of [pb_glossary id=\"1696\"]oceanic-oceanic subduction[\/pb_glossary] zones show very different activity from those involving [pb_glossary id=\"1659\"]oceanic[\/pb_glossary]-[pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plates[\/pb_glossary]. Since both [pb_glossary id=\"1669\"]plates[\/pb_glossary] are made of [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary], it is usually the older [pb_glossary id=\"1669\"]plate[\/pb_glossary] that [pb_glossary id=\"1680\"]subducts[\/pb_glossary] because it is colder and denser. The [pb_glossary id=\"228\"]volcanism[\/pb_glossary] on the overlying [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] may remain hidden underwater.. If the [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] rise high enough the reach the ocean surface, the chain of [pb_glossary id=\"228\"]volcanism[\/pb_glossary] forms an [pb_glossary id=\"1697\"]island arc[\/pb_glossary]. 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.\n<h3><b>2.3.2. Collisions<\/b><\/h3>\n[caption id=\"attachment_2533\" align=\"alignleft\" width=\"301\"]<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> Two continental plates colliding.[\/caption]\n\nWhen [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plates[\/pb_glossary] converge, during the closing of an ocean [pb_glossary id=\"508\"]basin[\/pb_glossary] for example, [pb_glossary id=\"1680\"]subduction[\/pb_glossary] is not possible between the equally buoyant [pb_glossary id=\"1669\"]plates[\/pb_glossary]. Instead of one [pb_glossary id=\"1669\"]plate[\/pb_glossary] descending beneath another, the two masses of [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] slam together in a process known as [pb_glossary id=\"1698\"]collision[\/pb_glossary]. Without [pb_glossary id=\"1680\"]subduction[\/pb_glossary], there is no [pb_glossary id=\"1750\"]magma[\/pb_glossary] [pb_glossary id=\"2038\"]formation[\/pb_glossary] and no [pb_glossary id=\"228\"]volcanism[\/pb_glossary]. [pb_glossary id=\"1698\"]Collision[\/pb_glossary] zones are characterized by tall, non-[pb_glossary id=\"228\"]volcanic[\/pb_glossary] mountains; a broad zone of frequent, large earthquakes; and very little [pb_glossary id=\"228\"]volcanism[\/pb_glossary].\n\nWhen [pb_glossary id=\"1659\"]oceanic crust[\/pb_glossary] connected by a [pb_glossary id=\"1676\"]passive margin[\/pb_glossary] to [pb_glossary id=\"1653\"]continental crust[\/pb_glossary] completely [pb_glossary id=\"1680\"]subducts[\/pb_glossary] beneath a [pb_glossary id=\"1653\"]continent[\/pb_glossary], an ocean [pb_glossary id=\"508\"]basin[\/pb_glossary] closes, and [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1698\"]collision[\/pb_glossary] begins. \u00a0Eventually, as ocean basins close, continents join together to form a [pb_glossary id=\"985\"]massive[\/pb_glossary] accumulation of continents called a [pb_glossary id=\"1701\"]supercontinent[\/pb_glossary], a process that has taken place in ~500 million year old cycles over earth\u2019s history.\n\n[caption id=\"attachment_2534\" align=\"alignright\" width=\"267\"]<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> A reconstruction of Pangaea, showing approximate positions of modern continents.[\/caption]\n\n&nbsp;\n\nThe process of [pb_glossary id=\"1698\"]collision[\/pb_glossary] created [pb_glossary id=\"2444\"]Pangea[\/pb_glossary], the supercontinent envisioned by Wegener as the key component of his [pb_glossary id=\"1653\"]continental[\/pb_glossary] drift [pb_glossary id=\"1730\"]hypothesis[\/pb_glossary]. Geologists now have evidence that [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plates[\/pb_glossary] have been continuously converging into [pb_glossary id=\"1701\"]supercontinents[\/pb_glossary] and splitting into smaller [pb_glossary id=\"508\"]basin[\/pb_glossary]-separated continents throughout Earth\u2019s existence, calling this process the [pb_glossary id=\"1701\"]supercontinent[\/pb_glossary] cycle, a process that takes place in approximately 500 million years. For example, they estimate [pb_glossary id=\"2444\"]Pangea[\/pb_glossary] began separating 200 million years ago. [pb_glossary id=\"2444\"]Pangea[\/pb_glossary] was preceded by an earlier [pb_glossary id=\"1701\"]supercontinents[\/pb_glossary], one of which being [pb_glossary id=\"1263\"]Rodinia[\/pb_glossary], which existed 1.1 billion years ago and started breaking apart 800 million to 600 million years ago.\n\n[caption id=\"attachment_2535\" align=\"alignleft\" width=\"300\"]<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> The tectonics of the Zagros Mountains. Note the Persian Gulf foreland basin.[\/caption]\n\n&nbsp;\n\nA foreland [pb_glossary id=\"508\"]basin[\/pb_glossary] is a feature that develops near mountain belts, as the combined mass of the mountains forms a depression in the lithospheric [pb_glossary id=\"1669\"]plate[\/pb_glossary]. While foreland basins may occur at [pb_glossary id=\"1680\"]subduction[\/pb_glossary] zones, they are most commonly found at [pb_glossary id=\"1698\"]collision[\/pb_glossary] boundaries. The Persian Gulf is possibly the best modern example, created entirely by the weight of the nearby Zagros Mountains.\n\n[caption id=\"attachment_2536\" align=\"alignright\" width=\"300\"]<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> Pillow lavas, which only form under water, from an ophiolite in the Apennine Mountains of central Italy.[\/caption]\n\nIf [pb_glossary id=\"1653\"]continental[\/pb_glossary] and [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] are fused on the same [pb_glossary id=\"1669\"]plate[\/pb_glossary], it can partially subduct but its buoyancy prevents it from fully descending. In very rare cases, part of a [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] may become trapped beneath a descending [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] in a process called [pb_glossary id=\"1699\"]obduction[\/pb_glossary]. When a portion of the [pb_glossary id=\"1653\"]continental crust[\/pb_glossary] is driven down into the [pb_glossary id=\"1680\"]subduction[\/pb_glossary] zone, due to its buoyancy it returns to the surface relatively quickly.\n\nAs pieces of the [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] break loose and migrate upward through the [pb_glossary id=\"1699\"]obduction[\/pb_glossary] zone, they bring along bits of the [pb_glossary id=\"1664\"]mantle[\/pb_glossary] and [pb_glossary id=\"1963\"]ocean floor[\/pb_glossary] and amend them on top of the [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary]. Rocks[pb_glossary id=\"1909\"] composed[\/pb_glossary] of this [pb_glossary id=\"1664\"]mantle[\/pb_glossary] and ocean-floor material are called [pb_glossary id=\"1700\"]ophiolites[\/pb_glossary] and they provide valuable information about the [pb_glossary id=\"1909\"]composition[\/pb_glossary] of the [pb_glossary id=\"1664\"]mantle[\/pb_glossary].\n\nThe area of [pb_glossary id=\"1698\"]collision[\/pb_glossary]-zone [pb_glossary id=\"495\"]deformation[\/pb_glossary] and [pb_glossary id=\"2165\"]seismic[\/pb_glossary] activity usually covers a broader area because [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] is plastic and malleable. Unlike [pb_glossary id=\"1680\"]subduction[\/pb_glossary]-zone earthquakes, which tend to be located along a narrow swath near the [pb_glossary id=\"1678\"]convergent[\/pb_glossary] boundary, [pb_glossary id=\"1698\"]collision[\/pb_glossary]-zone earthquakes may occur hundreds of kilometers from the boundary between the [pb_glossary id=\"1669\"]plates[\/pb_glossary].\n\nThe Eurasian [pb_glossary id=\"1653\"]continent[\/pb_glossary] has many examples of [pb_glossary id=\"1698\"]collision[\/pb_glossary]-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.\n\n[video width=\"720\" height=\"478\" mp4=\"http:\/\/opengeology.org\/textbook\/wp-content\/uploads\/2016\/07\/IndiaAsiaCollision.mp4\"][\/video]\n\n<em>Animation of India crashing into Asia, by Tanya Atwater.<\/em>\n\n[caption id=\"attachment_3733\" align=\"aligncenter\" width=\"150\"]<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> If you are using the printed version of this OER, access this animation via this QR Code.[\/caption]\n\n&nbsp;\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n[h5p id=\"12\"]\n\n[caption id=\"attachment_3732\" align=\"aligncenter\" width=\"150\"]<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> If you are using the printed version of this OER, access the quiz for section 2.3 via this QR Code.[\/caption]\n<h2><span style=\"font-weight: 400;\">2.4 Divergent Boundaries<\/span><\/h2>\nAt [pb_glossary id=\"1677\"]divergent[\/pb_glossary] boundaries, sometimes called constructive boundaries, lithospheric [pb_glossary id=\"1669\"]plates[\/pb_glossary] move away from each other. There are two types of [pb_glossary id=\"1677\"]divergent[\/pb_glossary] boundaries, categorized by where they occur: [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1702\"]rift[\/pb_glossary] zones and [pb_glossary id=\"1708\"]mid-ocean ridges[\/pb_glossary]. [pb_glossary id=\"1653\"]Continental[\/pb_glossary] [pb_glossary id=\"1702\"]rift[\/pb_glossary] zones occur in weak spots in the [pb_glossary id=\"1653\"]continental[\/pb_glossary] lithospheric [pb_glossary id=\"1669\"]plate[\/pb_glossary]. A [pb_glossary id=\"1708\"]mid-ocean ridge[\/pb_glossary] usually originates in a [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] as a [pb_glossary id=\"1702\"]rift[\/pb_glossary] zone that expands to the point of splitting the [pb_glossary id=\"1669\"]plate[\/pb_glossary] apart, with seawater filling in the gap. The separate pieces continue to drift apart and become individual continents. This process is known as [pb_glossary id=\"1702\"]rift[\/pb_glossary]-to-drift.\n<h3><b>2.4.1. Continental Rifting<\/b><\/h3>\n[caption id=\"attachment_2537\" align=\"alignleft\" width=\"300\"]<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> Faulting that occurs in divergent boundaries.[\/caption]\n\nIn places where the [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plates[\/pb_glossary] are very thick, they reflect so much heat back into the [pb_glossary id=\"1664\"]mantle[\/pb_glossary] it develops strong [pb_glossary id=\"1655\"]convection[\/pb_glossary] currents that push super-heated [pb_glossary id=\"1664\"]mantle[\/pb_glossary] material up against the overlying [pb_glossary id=\"1669\"]plate[\/pb_glossary], softening it. [pb_glossary id=\"492\"]Tensional[\/pb_glossary] forces created by this convective upwelling begin to pull the weakened [pb_glossary id=\"1669\"]plate[\/pb_glossary] apart. As it stretches, it becomes thinner and develops deep cracks called [pb_glossary id=\"492\"]extension[\/pb_glossary] or normal [pb_glossary id=\"2143\"]faults[\/pb_glossary]. Eventually plate sections located between large faults drop into deep depressions known as [pb_glossary id=\"1702\"]rift[\/pb_glossary] valleys, which often contain keystone-shaped blocks of down-dropped [pb_glossary id=\"1658\"]crust[\/pb_glossary] known as [pb_glossary id=\"1704\"]grabens[\/pb_glossary]. The shoulders of these [pb_glossary id=\"1704\"]grabens[\/pb_glossary] are called [pb_glossary id=\"1703\"]horsts[\/pb_glossary]. If only one side of a section drops, it is called a [pb_glossary id=\"2149\"]half-graben[\/pb_glossary]. Depending on the conditions, [pb_glossary id=\"1702\"]rifts[\/pb_glossary] can grow into very large lakes and even oceans.\n\n[caption id=\"attachment_2538\" align=\"alignright\" width=\"300\"]<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> 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.[\/caption]\n\nWhile seemingly occurring at random, [pb_glossary id=\"1702\"]rifting[\/pb_glossary] is dictated by two factors. [pb_glossary id=\"1702\"]Rifting[\/pb_glossary] does not occur in continents with older and more stable interiors, known as [pb_glossary id=\"1718\"]cratons[\/pb_glossary]. When [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1702\"]rifting[\/pb_glossary] does occur, the break-up pattern resembles the seams of a soccer ball, also called a truncated icosahedron. This is the most common surface-[pb_glossary id=\"986\"]fracture[\/pb_glossary] pattern to develop on an evenly expanding sphere because it uses the least amount of energy.\n\nUsing the soccer ball model, [pb_glossary id=\"1702\"]rifting[\/pb_glossary] tends to lengthen and expand along a particular seam while fizzling out in the other directions. These seams with little or no [pb_glossary id=\"1654\"]tectonic[\/pb_glossary] activity are called failed rift arms. A [pb_glossary id=\"1705\"]failed rift arm[\/pb_glossary] is still a weak spot in the [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary]; even without the presence of active [pb_glossary id=\"492\"]extension[\/pb_glossary] [pb_glossary id=\"2143\"]faults[\/pb_glossary], it may develop into a called an [pb_glossary id=\"1706\"]aulacogen[\/pb_glossary]. One example of a [pb_glossary id=\"1705\"]failed rift arm[\/pb_glossary] is the Mississippi Valley Embayment, a depression through which the upper end of the Mississippi [pb_glossary id=\"2212\"]River[\/pb_glossary] flows. Occasionally connected [pb_glossary id=\"1702\"]rift[\/pb_glossary] arms do develop concurrently, creating multiple boundaries of active [pb_glossary id=\"1702\"]rifting[\/pb_glossary]. In places where the [pb_glossary id=\"1702\"]rift[\/pb_glossary] arms do not fail, for example the Afar Triangle, three [pb_glossary id=\"1677\"]divergent[\/pb_glossary] boundaries can develop near each other forming a [pb_glossary id=\"1707\"]triple junction[\/pb_glossary].\n\n[caption id=\"attachment_2539\" align=\"alignleft\" width=\"300\"]<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> NASA image of the Basin and Range horsts and grabens across central Nevada.[\/caption]\n\n[pb_glossary id=\"1702\"]Rifts[\/pb_glossary] come in two types: narrow and broad. Narrow [pb_glossary id=\"1702\"]rifts[\/pb_glossary] are characterized by a high density of highly active [pb_glossary id=\"1677\"]divergent[\/pb_glossary] boundaries. The East African [pb_glossary id=\"1702\"]Rift[\/pb_glossary] Zone, where the [pb_glossary id=\"1531\"]horn[\/pb_glossary] of Africa is pulling away from the mainland, is an excellent example of an active narrow [pb_glossary id=\"1702\"]rift[\/pb_glossary]. Lake Baikal in Russia is another. Broad [pb_glossary id=\"1702\"]rifts[\/pb_glossary] also have numerous [pb_glossary id=\"2143\"]fault[\/pb_glossary] zones, but they are distributed over wide areas of [pb_glossary id=\"495\"]deformation[\/pb_glossary]. The [pb_glossary id=\"1514\"]Basin and Range[\/pb_glossary] region located in the western United States is a type of broad [pb_glossary id=\"1702\"]rift[\/pb_glossary]. The Wasatch [pb_glossary id=\"2143\"]Fault[\/pb_glossary], which also created the Wasatch Mountain Range in the state of Utah, forms the eastern [pb_glossary id=\"1677\"]divergent[\/pb_glossary] boundary of this broad [pb_glossary id=\"1702\"]rift[\/pb_glossary]\u00a0 (<a href=\"https:\/\/youtu.be\/TvvWqAdNV84\">Animation 1<\/a> and <a href=\"https:\/\/youtu.be\/7DxcAMmNeZk\">Animation 2<\/a>).\n\n&nbsp;\n\n[pb_glossary id=\"1702\"]Rifts[\/pb_glossary] have earthquakes, although not of the [pb_glossary id=\"2176\"]magnitude[\/pb_glossary] and frequency of other boundaries. They may also exhibit [pb_glossary id=\"228\"]volcanism[\/pb_glossary]. Unlike the flux-melted [pb_glossary id=\"1750\"]magma[\/pb_glossary] found in [pb_glossary id=\"1680\"]subduction[\/pb_glossary] zones, [pb_glossary id=\"1702\"]rift[\/pb_glossary]-zone [pb_glossary id=\"1750\"]magma[\/pb_glossary] is created by [pb_glossary id=\"223\"]decompression melting[\/pb_glossary]. As the [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plates[\/pb_glossary] are pulled apart, they create a region of low pressure that melts the [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] and draws it upwards. When this molten [pb_glossary id=\"1750\"]magma[\/pb_glossary] reaches the weakened and [pb_glossary id=\"2143\"]fault[\/pb_glossary]-riddled [pb_glossary id=\"1702\"]rift[\/pb_glossary] zone, it migrates to surface by breaking through the [pb_glossary id=\"1669\"]plate[\/pb_glossary] or escaping via an open [pb_glossary id=\"2143\"]fault[\/pb_glossary]. Examples of young [pb_glossary id=\"1702\"]rift[\/pb_glossary] [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] dot the [pb_glossary id=\"1514\"]Basin and Range[\/pb_glossary] region in the United States. [pb_glossary id=\"1702\"]Rift[\/pb_glossary]-zone activity is responsible for generating some unique [pb_glossary id=\"228\"]volcanism[\/pb_glossary], such as the Ol Doinyo Lengai in Tanzania. This [pb_glossary id=\"228\"]volcano[\/pb_glossary] erupts [pb_glossary id=\"1751\"]lava[\/pb_glossary] consisting largely of [pb_glossary id=\"2443\"]carbonatite[\/pb_glossary], a relatively cold, liquid [pb_glossary id=\"969\"]carbonate[\/pb_glossary] [pb_glossary id=\"1765\"]mineral[\/pb_glossary].\n\n[video width=\"720\" height=\"474\" mp4=\"http:\/\/opengeology.org\/textbook\/wp-content\/uploads\/2016\/07\/SoAtlantic_CutwithConvect.mp4\"][\/video]\n\nSouth America and Africa [pb_glossary id=\"1702\"]rift[\/pb_glossary], forming the Atlantic. <a href=\"http:\/\/emvc.geol.ucsb.edu\/2_infopgs\/IP1GTect\/eSoAtlantic_CutGlobe.html\">Video<\/a> by Tanya Atwater.\n\n[caption id=\"attachment_3731\" align=\"aligncenter\" width=\"150\"]<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> If you are using the printed version of this OER, access this video via this QR Code.[\/caption]\n<h3><b>2.4.2. Mid-ocean ridges<\/b><\/h3>\n[caption id=\"attachment_2541\" align=\"alignleft\" width=\"212\"]<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> Progression from rift to mid-ocean ridge.[\/caption]\n\n&nbsp;\n\n<span style=\"font-weight: 400;\">As [pb_glossary id=\"1702\"]rifting[\/pb_glossary] and [pb_glossary id=\"228\"]volcanic[\/pb_glossary] activity progress, the [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] becomes more [pb_glossary id=\"1008\"]mafic[\/pb_glossary] (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 [pb_glossary id=\"1669\"]plate[\/pb_glossary] under the [pb_glossary id=\"1702\"]rifting[\/pb_glossary] area into [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary]. 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 [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] continues to diverge, a [pb_glossary id=\"1708\"]mid-ocean ridge[\/pb_glossary] is formed.<\/span>\n\n[pb_glossary id=\"1708\"]Mid-ocean ridges[\/pb_glossary], also known as [pb_glossary id=\"1708\"]spreading centers[\/pb_glossary], have several distinctive features. They are the only places on earth that create new [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary]. [pb_glossary id=\"223\"]Decompression melting[\/pb_glossary] in the [pb_glossary id=\"1702\"]rift[\/pb_glossary] zone changes [pb_glossary id=\"1671\"]asthenosphere[\/pb_glossary] material into new [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary], which oozes up through cracks in [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary]. The amount of new [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] being created at [pb_glossary id=\"1708\"]mid-ocean ridges[\/pb_glossary] is highly significant. These undersea [pb_glossary id=\"1702\"]rift[\/pb_glossary] [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] produce more [pb_glossary id=\"1751\"]lava[\/pb_glossary] than all other types of [pb_glossary id=\"228\"]volcanism[\/pb_glossary] combined. Despite this, most mid-[pb_glossary id=\"1659\"]oceanic[\/pb_glossary] ridge [pb_glossary id=\"228\"]volcanism[\/pb_glossary] remains unmapped because the volcanoes are located deep on the [pb_glossary id=\"1963\"]ocean floor[\/pb_glossary].\n\nIn rare cases, such as a few locations in Iceland, [pb_glossary id=\"1702\"]rift[\/pb_glossary] zones display the type of [pb_glossary id=\"228\"]volcanism[\/pb_glossary], spreading, and ridge [pb_glossary id=\"2038\"]formation[\/pb_glossary] found on the [pb_glossary id=\"1963\"]ocean floor[\/pb_glossary].\n\n[caption id=\"attachment_2542\" align=\"alignright\" width=\"300\"]<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> Age of oceanic lithosphere, in millions of years. Notice the differences in the Atlantic Ocean along the coasts of the continents.[\/caption]\n\nThe ridge feature is created by the accumulation of hot [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] material, which is lighter than the dense underlying [pb_glossary id=\"1671\"]asthenosphere[\/pb_glossary]. This chunk of isostatically buoyant [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] sits partially submerged and partially exposed on the [pb_glossary id=\"1671\"]asthenosphere[\/pb_glossary], like an ice cube floating in a glass of water.\n\nAs the ridge continues to spread, the [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] material is pulled away from the area of [pb_glossary id=\"228\"]volcanism[\/pb_glossary] and becomes colder and denser. As it continues to spread and cool, the [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] settles into wide swathes of relatively featureless topography called [pb_glossary id=\"1962\"]abyssal[\/pb_glossary] plains with lower topography.\n\nThis model of ridge [pb_glossary id=\"2038\"]formation[\/pb_glossary] suggests the sections of [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary] furthest away from the [pb_glossary id=\"1708\"]mid-ocean ridges[\/pb_glossary] will be the oldest. Scientists have tested this idea by comparing the age of rocks located in various locations on the [pb_glossary id=\"1963\"]ocean floor[\/pb_glossary]. Rocks found near ridges are younger than those found far away from any ridges. [pb_glossary id=\"1756\"]Sediment[\/pb_glossary] accumulation patterns also confirm the idea of sea-floor spreading. [pb_glossary id=\"1756\"]Sediment[\/pb_glossary] layers tend to be thinner near [pb_glossary id=\"1708\"]mid-ocean ridges[\/pb_glossary], indicating it has had less time to build up.\n\n&nbsp;\n\n[caption id=\"attachment_2543\" align=\"aligncenter\" width=\"600\"]<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> Spreading along several mid-ocean ridges, showing magnetic striping symmetry. By Tanya Atwater.[\/caption]\n\n[caption id=\"attachment_3743\" align=\"aligncenter\" width=\"150\"]<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> If you are using the printed version of this OER, access this animation via this QR Code.[\/caption]\n\nAs mentioned in the section on [pb_glossary id=\"1657\"]paleomagnetism[\/pb_glossary] and the development of [pb_glossary id=\"1669\"]plate[\/pb_glossary] [pb_glossary id=\"1654\"]tectonic[\/pb_glossary] [pb_glossary id=\"1733\"]theory[\/pb_glossary], scientists noticed [pb_glossary id=\"1708\"]mid-ocean ridges[\/pb_glossary] contained unique magnetic [pb_glossary id=\"765\"]anomalies[\/pb_glossary] that show up as symmetrical striping on both sides of the ridge. The Vine-Matthews-Morley [pb_glossary id=\"1730\"]hypothesis[\/pb_glossary] proposes these alternating reversals are created by the earth\u2019s magnetic field being imprinted into [pb_glossary id=\"1750\"]magma[\/pb_glossary]\n\n[caption id=\"attachment_2544\" align=\"alignleft\" width=\"300\"]<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> 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.[\/caption]\n\nafter it emerges from the ridge. Very hot [pb_glossary id=\"1750\"]magma[\/pb_glossary] has no magnetic field. As the [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1669\"]plates[\/pb_glossary] get pulled apart, the [pb_glossary id=\"1750\"]magma[\/pb_glossary] cools below the Curie point, the [pb_glossary id=\"1767\"]temperature[\/pb_glossary] below which a magnetic field gets locked into magnetic [pb_glossary id=\"1765\"]minerals[\/pb_glossary]. 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 [pb_glossary id=\"1654\"]tectonic[\/pb_glossary] activity and determine rates of ridge spreading.\n\n[embed]https:\/\/youtu.be\/6o1HawAOTEI[\/embed]\n\n<em><a href=\"http:\/\/emvc.geol.ucsb.edu\/2_infopgs\/IP3RegTect\/bNoCentAtlantic.html\">Video<\/a> of the breakup of [pb_glossary id=\"2444\"]<em>Pangea<\/em>[\/pb_glossary] and [pb_glossary id=\"2038\"]<em>formation<\/em>[\/pb_glossary] of the northern Atlantic Ocean. By Tanya Atwater.<\/em>\n\n[caption id=\"attachment_3729\" align=\"aligncenter\" width=\"150\"]<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> If you are using the printed version of this OER, access this video via this QR Code.[\/caption]\n\n&nbsp;\n\n[caption id=\"attachment_2545\" align=\"alignright\" width=\"233\"]<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> Black smoker hydrothermal vent with a colony of giant (6'+) tube worms.[\/caption]\n\nThanks to their distinctive geology, [pb_glossary id=\"1708\"]mid-ocean ridges[\/pb_glossary] are home to some of the most unique ecosystems ever discovered. The ridges are often studded with [pb_glossary id=\"1999\"]hydrothermal[\/pb_glossary] vents, deep fissures that allow seawater to circulate through the upper portions of the [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] and interact with hot rock. The super-heated seawater rises back up to the surface of the [pb_glossary id=\"1669\"]plate[\/pb_glossary], carrying [pb_glossary id=\"1893\"]dissolved[\/pb_glossary] gasses and [pb_glossary id=\"1765\"]minerals[\/pb_glossary], and small particulates.\u00a0 The resulting emitted [pb_glossary id=\"1999\"]hydrothermal[\/pb_glossary] water looks like black underwater smoke.\n\nScientists had known about these geothermal areas on the [pb_glossary id=\"1963\"]ocean floor[\/pb_glossary] 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 [pb_glossary id=\"1999\"]hydrothermal[\/pb_glossary] vents. These unique organisms, which include 10-foot-long tube worms taller than people, live in the complete darkness of the [pb_glossary id=\"1963\"]ocean floor [\/pb_glossary] deprived of oxygen and sunlight. They use geothermal energy provided by the vents and a process called bacterial [pb_glossary id=\"231\"]chemosynthesis[\/pb_glossary] 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.\n\n&nbsp;\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n[h5p id=\"13\"]\n\n[caption id=\"attachment_3728\" align=\"aligncenter\" width=\"150\"]<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> If you are using the printed version of this OER, access the quiz for section 2.4 via this QR Code.[\/caption]\n<h2><span style=\"font-weight: 400;\">2.5 Transform Boundaries<\/span><\/h2>\n[caption id=\"attachment_2546\" align=\"alignleft\" width=\"300\"]<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> The two types of transform\/strike slip faults.[\/caption]\n\n&nbsp;\n\nA [pb_glossary id=\"1679\"]transform[\/pb_glossary] boundary, sometimes called a [pb_glossary id=\"2154\"]strike-slip[\/pb_glossary] or conservative boundary, is where the lithospheric [pb_glossary id=\"1669\"]plates[\/pb_glossary] slide past each other in the horizontal plane. This movement is described based on the perspective of an observer standing on one of the [pb_glossary id=\"1669\"]plates[\/pb_glossary], looking across the boundary at the opposing [pb_glossary id=\"1669\"]plate[\/pb_glossary]. [pb_glossary id=\"2155\"]Dextral[\/pb_glossary], also known as [pb_glossary id=\"2155\"]right-lateral[\/pb_glossary], movement describes the opposing [pb_glossary id=\"1669\"]plate[\/pb_glossary] moving to the right. [pb_glossary id=\"1710\"]Sinistral[\/pb_glossary], also known as [pb_glossary id=\"1710\"]left lateral[\/pb_glossary], movement describe the opposing [pb_glossary id=\"1669\"]plate[\/pb_glossary] moving to the left.\n\nMost [pb_glossary id=\"1679\"]transform[\/pb_glossary] boundaries are found on the [pb_glossary id=\"1963\"]ocean floor[\/pb_glossary], around [pb_glossary id=\"1708\"]mid-ocean ridges[\/pb_glossary]. These boundaries form [pb_glossary id=\"2445\"]aseismic[\/pb_glossary] [pb_glossary id=\"986\"]fracture[\/pb_glossary] zones, filled with earthquake-free [pb_glossary id=\"1679\"]transform[\/pb_glossary] [pb_glossary id=\"2143\"]faults[\/pb_glossary], to accommodate different rates of spreading occurring at the ridge.\n\n[caption id=\"attachment_2547\" align=\"alignright\" width=\"217\"]<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> Map of the San Andreas fault, showing relative motion.[\/caption]\n\n&nbsp;\n\nSome [pb_glossary id=\"1679\"]transform[\/pb_glossary] boundaries produce significant [pb_glossary id=\"2165\"]seismic[\/pb_glossary] activity, primarily as earthquakes, with very little mountain-building or [pb_glossary id=\"228\"]volcanism[\/pb_glossary]. This type of [pb_glossary id=\"1679\"]transform[\/pb_glossary] boundary may contain a single [pb_glossary id=\"2143\"]fault[\/pb_glossary] or series of [pb_glossary id=\"2143\"]faults[\/pb_glossary], which develop in places where [pb_glossary id=\"1669\"]plate[\/pb_glossary] [pb_glossary id=\"1654\"]tectonic[\/pb_glossary] [pb_glossary id=\"1993\"]stresses[\/pb_glossary] are transferred to the surface. As with other types of active boundaries, if the [pb_glossary id=\"1669\"]plates[\/pb_glossary] are unable to [pb_glossary id=\"494\"]shear[\/pb_glossary] past each other the [pb_glossary id=\"1654\"]tectonic[\/pb_glossary] forces will continue to build up. If the built up energy between the [pb_glossary id=\"1669\"]plates[\/pb_glossary] is suddenly released, the result is an earthquake.\n\nIn the eyes of humanity, the most significant [pb_glossary id=\"1679\"]transform[\/pb_glossary] [pb_glossary id=\"2143\"]faults[\/pb_glossary] occur within [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plates[\/pb_glossary], and have a [pb_glossary id=\"494\"]shearing[\/pb_glossary] motion that frequently produces moderate-to-large [pb_glossary id=\"2176\"]magnitude[\/pb_glossary] earthquakes. Notable examples include the San Andreas [pb_glossary id=\"2143\"]Fault[\/pb_glossary] in California, Northern and Eastern Anatolian [pb_glossary id=\"2143\"]Faults[\/pb_glossary]\u00a0in Turkey, Altyn Tagh [pb_glossary id=\"2143\"]Fault[\/pb_glossary] in central Asia, and Alpine [pb_glossary id=\"2143\"]Fault[\/pb_glossary] in New Zealand.\n<h3><b>2.5.1. Transpression and Transtension<\/b><\/h3>\n[caption id=\"attachment_2548\" align=\"alignleft\" width=\"150\"]<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> A transpressional strike-slip fault, causing uplift called a restraining bend.[\/caption]\n\n&nbsp;\n\nBends along [pb_glossary id=\"1679\"]transform[\/pb_glossary] [pb_glossary id=\"2143\"]faults[\/pb_glossary] may create [pb_glossary id=\"493\"]compressional[\/pb_glossary] or [pb_glossary id=\"492\"]extensional[\/pb_glossary] forces that cause secondary [pb_glossary id=\"2143\"]faulting[\/pb_glossary] zones. [pb_glossary id=\"1712\"]Transpression[\/pb_glossary] occurs where there is a component of [pb_glossary id=\"493\"]compression[\/pb_glossary] in addition to the [pb_glossary id=\"494\"]shearing[\/pb_glossary] motion. These forces build up around the area of the bend, where the opposing [pb_glossary id=\"1669\"]plates[\/pb_glossary] are restricted from sliding past each other. As the forces continue to build up, they create mountains in the restraining bend around the [pb_glossary id=\"2143\"]fault[\/pb_glossary]. The Big Bend area, located in the southern part of the San Andreas [pb_glossary id=\"2143\"]Fault[\/pb_glossary] includes a large area of [pb_glossary id=\"1712\"]transpression[\/pb_glossary] where many mountains have been built, moved, and even rotated.\n\n&nbsp;\n\n[caption id=\"attachment_2549\" align=\"alignright\" width=\"150\"]<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> A transtensional strike-slip fault, causing a restraining bend. In the center of the fault, a depression with extension would be found.[\/caption]\n\n[pb_glossary id=\"1713\"]Transtension[\/pb_glossary] zones require a [pb_glossary id=\"2143\"]fault[\/pb_glossary] that includes a releasing bend, where the [pb_glossary id=\"1669\"]plates[\/pb_glossary] are being pulled apart by [pb_glossary id=\"492\"]extensional[\/pb_glossary] forces. Depressions and sometimes [pb_glossary id=\"228\"]volcanism[\/pb_glossary] develop in the releasing bend, along the [pb_glossary id=\"2143\"]fault[\/pb_glossary]. The Dead Sea found between Israel and Jordan, and the Salton Sea of California are examples of basins formed by transtensional forces.\n<h3><\/h3>\n<h3><b>2.5.2. Piercing Points<\/b><\/h3>\n[caption id=\"attachment_2550\" align=\"alignleft\" width=\"300\"]<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> 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.[\/caption]\n\n&nbsp;\n\nWhen a geological feature is cut by a [pb_glossary id=\"2143\"]fault[\/pb_glossary], it is called a [pb_glossary id=\"1714\"]piercing point[\/pb_glossary]. Piercing points are very useful for recreating past [pb_glossary id=\"2143\"]fault[\/pb_glossary] movement, especially along [pb_glossary id=\"1679\"]transform[\/pb_glossary] boundaries. [pb_glossary id=\"1679\"]Transform[\/pb_glossary] [pb_glossary id=\"2143\"]faults[\/pb_glossary] are unique because their horizontal motion keeps a geological feature relatively intact, preserving the record of what happened. Other types of [pb_glossary id=\"2143\"]faults[\/pb_glossary]\u2014normal and reverse \u2014tend to be more destructive, obscuring or destroying these features. The best type of [pb_glossary id=\"1714\"]piercing point[\/pb_glossary] includes unique patterns that are used to match the parts of a geological feature separated by [pb_glossary id=\"2143\"]fault[\/pb_glossary] movement. Detailed studies of piercing points show the San Andreas [pb_glossary id=\"2143\"]Fault[\/pb_glossary] has experienced over 225 km of movement in the last 20 million years, and this movement occurred at three different [pb_glossary id=\"2143\"]fault[\/pb_glossary] traces.\n\n[embed]https:\/\/www.youtube.com\/embed\/IDTBY5WDELg[\/embed]\n\n<em>Video of the origin of the San Andreas [pb_glossary id=\"2143\"]<em>fault<\/em>[\/pb_glossary]. As the [pb_glossary id=\"1708\"]<em>mid-ocean ridge<\/em>[\/pb_glossary] [pb_glossary id=\"1680\"]<em>subducts<\/em>[\/pb_glossary], the relative motion between the remaining [pb_glossary id=\"1669\"]<em>plates<\/em>[\/pb_glossary] become [pb_glossary id=\"1679\"]<em>transform<\/em>[\/pb_glossary], forming the [pb_glossary id=\"2143\"]<em>fault<\/em>[\/pb_glossary] [pb_glossary id=\"1742\"]<em>system<\/em>[\/pb_glossary]. Note that because the motion of the [pb_glossary id=\"1669\"]<em>plates<\/em>[\/pb_glossary] is not exactly parallel to the [pb_glossary id=\"2143\"]<em>fault<\/em>[\/pb_glossary], it causes [pb_glossary id=\"1677\"]<em>divergent<\/em>[\/pb_glossary] motion in the interior of North America. By Tanya Atwater.<\/em>\n\n[caption id=\"attachment_3727\" align=\"aligncenter\" width=\"150\"]<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> If you are using the printed version of this OER, access this YouTube video via this QR Code.[\/caption]\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n[h5p id=\"14\"]\n\n[caption id=\"attachment_3726\" align=\"aligncenter\" width=\"150\"]<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> If you are using the printed version of this OER, access the quiz for section 2.5 via this QR Code.[\/caption]\n<h2><span style=\"font-weight: 400;\">2.6 The Wilson Cycle<\/span><\/h2>\n[caption id=\"attachment_2551\" align=\"alignleft\" width=\"300\"]<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> Diagram of the Wilson Cycle, showing rifting and collision phases.[\/caption]\n\n&nbsp;\n\nThe [pb_glossary id=\"1715\"]Wilson Cycle[\/pb_glossary] is named for J. Tuzo Wilson who first described it in 1966, and it outlines the ongoing origin and breakup of [pb_glossary id=\"1701\"]supercontinents[\/pb_glossary], such as [pb_glossary id=\"2444\"]Pangea[\/pb_glossary] and [pb_glossary id=\"1263\"]Rodinia[\/pb_glossary]. Scientists have determined this cycle has been operating for at least three billion years and possibly earlier.\n\nThere are a number of [pb_glossary id=\"1730\"]hypotheses[\/pb_glossary] about how the [pb_glossary id=\"1715\"]Wilson Cycle[\/pb_glossary] works. One mechanism proposes that [pb_glossary id=\"1702\"]rifting[\/pb_glossary] happens because [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plates[\/pb_glossary] reflect the heat much better than [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] [pb_glossary id=\"1669\"]plates[\/pb_glossary]. When continents congregate together, they reflect more of the Earth\u2019s heat back into the [pb_glossary id=\"1664\"]mantle[\/pb_glossary], generating more vigorous [pb_glossary id=\"1655\"]convection[\/pb_glossary] currents that then start the [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1702\"]rifting[\/pb_glossary] process. Some geologists believe [pb_glossary id=\"1664\"]mantle[\/pb_glossary] plumes are remnants of these [pb_glossary id=\"1244\"]periods[\/pb_glossary] of increased [pb_glossary id=\"1664\"]mantle[\/pb_glossary] [pb_glossary id=\"1767\"]temperature[\/pb_glossary] and [pb_glossary id=\"1655\"]convection[\/pb_glossary] upwelling, and study them for clues about the origin of [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1702\"]rifting[\/pb_glossary].\n\nThe mechanism behind how [pb_glossary id=\"1701\"]supercontinents[\/pb_glossary] 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 [pb_glossary id=\"1730\"]hypothesis[\/pb_glossary] suggests after the initial [pb_glossary id=\"1702\"]rifting[\/pb_glossary] event, [pb_glossary id=\"1669\"]plates[\/pb_glossary] continue to be pushed apart by mid-ocean [pb_glossary id=\"1708\"]spreading centers[\/pb_glossary] and their underlying [pb_glossary id=\"1655\"]convection[\/pb_glossary] currents. Slab-pull proposes the [pb_glossary id=\"1669\"]plates[\/pb_glossary] are pulled apart by descending slabs in the [pb_glossary id=\"1680\"]subduction[\/pb_glossary] zones of the [pb_glossary id=\"1659\"]oceanic[\/pb_glossary]-[pb_glossary id=\"1653\"]continental[\/pb_glossary] margins. A third idea, gravitational sliding, attributes the movement to gravitational forces pulling the lithospheric [pb_glossary id=\"1669\"]plates[\/pb_glossary] down from the elevated [pb_glossary id=\"1708\"]mid-ocean ridges[\/pb_glossary] and across the underlying [pb_glossary id=\"1671\"]asthenosphere[\/pb_glossary]. Current evidence seems to support [pb_glossary id=\"1683\"]slab[\/pb_glossary] pull more than ridge push or gravitational sliding.\n<h2><span style=\"font-weight: 400;\">2.7 Hotspots<\/span><\/h2>\n[caption id=\"attachment_2552\" align=\"alignright\" 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&nbsp;\n\nThe [pb_glossary id=\"1715\"]Wilson Cycle[\/pb_glossary] provides a broad overview of [pb_glossary id=\"1654\"]tectonic[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] movement. To analyze [pb_glossary id=\"1669\"]plate[\/pb_glossary] movement more precisely, scientists study [pb_glossary id=\"1716\"]hotspots[\/pb_glossary]. First postulated by J. Tuzo Wilson in 1963, a [pb_glossary id=\"1716\"]hotspot[\/pb_glossary] is an area in the lithospheric [pb_glossary id=\"1669\"]plate[\/pb_glossary] where molten [pb_glossary id=\"1750\"]magma[\/pb_glossary] breaks through and creates a [pb_glossary id=\"228\"]volcanic[\/pb_glossary] center, islands in the ocean and mountains on land. As the [pb_glossary id=\"1669\"]plate[\/pb_glossary] moves across the [pb_glossary id=\"1716\"]hotspot[\/pb_glossary], the [pb_glossary id=\"228\"]volcano[\/pb_glossary] center becomes [pb_glossary id=\"755\"]extinct[\/pb_glossary] because it is no longer over an active [pb_glossary id=\"1750\"]magma[\/pb_glossary] source. Instead, the [pb_glossary id=\"1750\"]magma[\/pb_glossary] emerges through another area in the [pb_glossary id=\"1669\"]plate[\/pb_glossary] to create a new active [pb_glossary id=\"228\"]volcano[\/pb_glossary]. Over time, the combination of moving [pb_glossary id=\"1669\"]plate[\/pb_glossary] and stationary [pb_glossary id=\"1716\"]hotspot[\/pb_glossary] creates a chain of islands or mountains. The classic definition of [pb_glossary id=\"1716\"]hotspots[\/pb_glossary] states they do not move, although recent evidence suggests that there may be exceptions.\n\n[caption id=\"attachment_2553\" align=\"alignleft\" width=\"300\"]<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> Map of world hotspots. Larger circles indicate more active hotspots.[\/caption]\n\n&nbsp;\n\n[pb_glossary id=\"1716\"]Hotspots[\/pb_glossary] are the only types of [pb_glossary id=\"228\"]volcanism[\/pb_glossary] not associated with [pb_glossary id=\"1680\"]subduction[\/pb_glossary] or [pb_glossary id=\"1702\"]rifting[\/pb_glossary] zones at [pb_glossary id=\"1669\"]plate[\/pb_glossary] boundaries; they seem totally disconnected from any [pb_glossary id=\"1654\"]plate tectonics[\/pb_glossary] processes, such as earthquakes. However, there are\u00a0 relationships between [pb_glossary id=\"1716\"]hotspots[\/pb_glossary] and [pb_glossary id=\"1654\"]plate tectonics[\/pb_glossary]. There are several [pb_glossary id=\"1716\"]hotspots[\/pb_glossary], current and former, that are believed to have begun at the time of [pb_glossary id=\"1702\"]rifting[\/pb_glossary]. Also, scientists use the age of [pb_glossary id=\"228\"]volcanic[\/pb_glossary] eruptions and shape of the chain to quantify the rate and direction of [pb_glossary id=\"1669\"]plate[\/pb_glossary] movement relative to the [pb_glossary id=\"1716\"]hotspot[\/pb_glossary].\n\nScientists are divided over how [pb_glossary id=\"1750\"]magma[\/pb_glossary] is generated in [pb_glossary id=\"1716\"]hotspots[\/pb_glossary]. Some suggest that [pb_glossary id=\"1716\"]hotspots[\/pb_glossary] originate from super-heated material from as deep as the [pb_glossary id=\"1667\"]core[\/pb_glossary] that reaches the Earth\u2019s [pb_glossary id=\"1658\"]crust[\/pb_glossary] as a [pb_glossary id=\"1717\"]mantle plume[\/pb_glossary]. Others argue the molten material that feeds [pb_glossary id=\"1716\"]hotspots[\/pb_glossary] is sourced from the [pb_glossary id=\"1664\"]mantle[\/pb_glossary]. Of course, it is difficult to collect data from these deep-Earth features due to the extremely high pressure and [pb_glossary id=\"1767\"]temperature[\/pb_glossary].\n\nHow [pb_glossary id=\"1716\"]hotspots[\/pb_glossary] are initiated is another highly debated subject. The prevailing mechanism has [pb_glossary id=\"1716\"]hotspots[\/pb_glossary] starting in [pb_glossary id=\"1677\"]divergent[\/pb_glossary] boundaries during [pb_glossary id=\"1701\"]supercontinent[\/pb_glossary] [pb_glossary id=\"1702\"]rifting[\/pb_glossary]. Scientists have identified a number of current and past [pb_glossary id=\"1716\"]hotspots[\/pb_glossary] believed to have begun this way. [pb_glossary id=\"1680\"]Subducting[\/pb_glossary] slabs have also been named as causing [pb_glossary id=\"1664\"]mantle[\/pb_glossary] plumes and hot-spot [pb_glossary id=\"228\"]volcanism[\/pb_glossary]. Some geologists have suggested another geological process not involving [pb_glossary id=\"1654\"]plate tectonics[\/pb_glossary] 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 [pb_glossary id=\"1716\"]hotspots[\/pb_glossary]: Hawaii and Yellowstone.\n<h3><b>2.7.1 Hawaiian hotspot<\/b><\/h3>\n[caption id=\"attachment_2554\" align=\"alignright\" 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\n&nbsp;\n\nThe active [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] in Hawaii represent one of the most active [pb_glossary id=\"1716\"]hotspot[\/pb_glossary] sites on earth. Scientific evidence indicates the Hawaiian [pb_glossary id=\"1716\"]hotspot[\/pb_glossary] is at least 80 million years old. Geologists believe it is actually much older; however any rocks with proof of this have been [pb_glossary id=\"1680\"]subducted[\/pb_glossary] under the [pb_glossary id=\"1963\"]ocean floor[\/pb_glossary]. The big island of Hawaii sits atop a large [pb_glossary id=\"1717\"]mantle plume[\/pb_glossary] that marks the active [pb_glossary id=\"1716\"]hotspot[\/pb_glossary]. The Kilauea [pb_glossary id=\"228\"]volcano[\/pb_glossary] is the main [pb_glossary id=\"234\"]vent[\/pb_glossary] for this [pb_glossary id=\"1716\"]hotspot[\/pb_glossary] and has been actively erupting since 1983.\n\nThis enormous [pb_glossary id=\"228\"]volcanic[\/pb_glossary] island chain, much of which is underwater, stretches across the Pacific for almost 6,000 km. The [pb_glossary id=\"1977\"]seamount[\/pb_glossary] chain\u2019s most striking feature is a sharp 60-degree bend located at the midpoint, which marks a significant change in [pb_glossary id=\"1669\"]plate[\/pb_glossary] movement direction that occurred 50 million years ago. The change in direction has been more often linked to a [pb_glossary id=\"1669\"]plate[\/pb_glossary] reconfiguration, but also to other things like plume migration.\n\n[caption id=\"attachment_2555\" align=\"alignleft\" width=\"300\"]<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> Diagram of the Hawaiian hotspot and islands that it formed.[\/caption]\n\n&nbsp;\n\nIn an attempt to map the Hawaiian [pb_glossary id=\"1717\"]mantle plume[\/pb_glossary] as far down as the lower [pb_glossary id=\"1664\"]mantle[\/pb_glossary], scientists have used [pb_glossary id=\"2174\"]tomography[\/pb_glossary], a type of three-dimensional [pb_glossary id=\"2165\"]seismic[\/pb_glossary] 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 [pb_glossary id=\"1716\"]hotspot[\/pb_glossary].\n<h4><b>2.7.2 Yellowstone hotspot<\/b><\/h4>\n[caption id=\"attachment_2556\" 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\n&nbsp;\n\nLike the Hawaiian version, the Yellowstone [pb_glossary id=\"1716\"]hotspot[\/pb_glossary] is formed by [pb_glossary id=\"1750\"]magma[\/pb_glossary] rising through the [pb_glossary id=\"1668\"]lithosphere[\/pb_glossary]. What makes it different is this [pb_glossary id=\"1716\"]hotspot[\/pb_glossary] is located under a thick, [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary]. Hawaii sits on a thin [pb_glossary id=\"1659\"]oceanic[\/pb_glossary]\u00a0[pb_glossary id=\"1669\"]plate[\/pb_glossary], which is easily breached by [pb_glossary id=\"1750\"]magma[\/pb_glossary] coming to the surface. At Yellowstone, the thick [pb_glossary id=\"1653\"]continental[\/pb_glossary] [pb_glossary id=\"1669\"]plate[\/pb_glossary] presents a much more difficult barrier for [pb_glossary id=\"1750\"]magma[\/pb_glossary] to penetrate. When it does emerge, the eruptions are generally much more violent. Thankfully they are also less frequent.\n\nOver 15 million years of eruptions by this [pb_glossary id=\"1716\"]hotspot[\/pb_glossary] have carved a curved path across the western United States. It has been suggested the Yellowstone [pb_glossary id=\"1716\"]hotspot[\/pb_glossary] is connected to the much older Columbia [pb_glossary id=\"2212\"]River[\/pb_glossary] [pb_glossary id=\"244\"]flood basalts[\/pb_glossary] and even to 70 million-year-old [pb_glossary id=\"228\"]volcanism[\/pb_glossary] found in the Yukon region of Canada.\n\n[caption id=\"attachment_2557\" align=\"alignleft\" 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 most recent major eruption of this [pb_glossary id=\"1716\"]hotspot[\/pb_glossary] created the Yellowstone [pb_glossary id=\"235\"]Caldera[\/pb_glossary] and [pb_glossary id=\"1751\"]Lava[\/pb_glossary] Creek [pb_glossary id=\"1005\"]tuff[\/pb_glossary] [pb_glossary id=\"2038\"]formation[\/pb_glossary] approximately 631,000 years ago. The eruption threw 1,000 cubic kilometers of [pb_glossary id=\"1001\"]ash[\/pb_glossary] and [pb_glossary id=\"1750\"]magma[\/pb_glossary] into the [pb_glossary id=\"1745\"]atmosphere[\/pb_glossary], some of which was found as far away as Mississippi. Should the [pb_glossary id=\"1716\"]hotspot[\/pb_glossary] erupt again, scientists predict it will be another [pb_glossary id=\"985\"]massive[\/pb_glossary] event. This would be a calamity reaching far beyond the western United States. These super [pb_glossary id=\"228\"]volcanic[\/pb_glossary] eruptions fill the earth\u2019s [pb_glossary id=\"1745\"]atmosphere[\/pb_glossary] with so much gas and [pb_glossary id=\"1001\"]ash[\/pb_glossary], 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.\n\n&nbsp;\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n[h5p id=\"15\"]\n\n[caption id=\"attachment_3725\" align=\"aligncenter\" width=\"150\"]<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> If you are using the printed version of this OER, access the quiz for sections 2.6 and 2.7 via this QR Code.[\/caption]\n<h2><\/h2>\n<h2>Summary<\/h2>\n[embed]https:\/\/youtu.be\/6wJBOk9xjto[\/embed]\n\n[caption id=\"attachment_3724\" align=\"aligncenter\" width=\"150\"]<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> If you are using the printed version of this OER, access this YouTube video via this QR Code.[\/caption]\n\n[pb_glossary id=\"1654\"]Plate tectonics[\/pb_glossary] is a unifying [pb_glossary id=\"1733\"]theory[\/pb_glossary]; 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 [pb_glossary id=\"1733\"]theory[\/pb_glossary] of [pb_glossary id=\"1654\"]plate tectonics[\/pb_glossary] states the surface layer of the Earth is broken into a network of solid, relatively [pb_glossary id=\"1661\"]brittle[\/pb_glossary] [pb_glossary id=\"1669\"]plates[\/pb_glossary]. Underneath the [pb_glossary id=\"1669\"]plates[\/pb_glossary] is a much hotter and more [pb_glossary id=\"1660\"]ductile[\/pb_glossary] layer that contains zones of convective upwelling generated by the interior heat of Earth. These [pb_glossary id=\"1655\"]convection[\/pb_glossary] currents move the surface [pb_glossary id=\"1669\"]plates[\/pb_glossary] around\u2014bringing them together, pulling them apart, and [pb_glossary id=\"494\"]shearing[\/pb_glossary] them side-by-side. Earthquakes and [pb_glossary id=\"228\"]volcanoes[\/pb_glossary] form at the boundaries where the [pb_glossary id=\"1669\"]plates[\/pb_glossary] interact, with the exception of [pb_glossary id=\"228\"]volcanic[\/pb_glossary] [pb_glossary id=\"1716\"]hotspots[\/pb_glossary], which are not caused by [pb_glossary id=\"1669\"]plate[\/pb_glossary] movement.\n\n&nbsp;\n<h3>Take this quiz to check your comprehension of this Chapter.<\/h3>\n[h5p id=\"16\"]\n\n[caption id=\"attachment_3723\" align=\"aligncenter\" width=\"150\"]<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> If you are using the printed version of this OER, access the review quiz for Chapter 2 via this QR Code.[\/caption]\n<h2>References<\/h2>\n<div class=\"csl-bib-body\">\n<ol>\n \t<li class=\"csl-entry\">Aitta, A., 2006, Iron melting curve with a tricritical point: J. Stat. Mech., v. 2006, no. 12, p. P12015.<\/li>\n \t<li class=\"csl-entry\">Alfe, D., Gillan, M.J., and Price, G.D., 2002, [pb_glossary id=\"1909\"]Composition[\/pb_glossary] and [pb_glossary id=\"1767\"]temperature[\/pb_glossary] of the Earth\u2019s [pb_glossary id=\"1667\"]core[\/pb_glossary] constrained by combining ab initio calculations and [pb_glossary id=\"2165\"]seismic[\/pb_glossary] data: Earth Planet. Sci. Lett., v. 195, no. 1, p. 91\u201398.<\/li>\n \t<li class=\"csl-entry\">Atwater, T., 1970, Implications of [pb_glossary id=\"1654\"]Plate Tectonics[\/pb_glossary] for the [pb_glossary id=\"488\"]Cenozoic[\/pb_glossary] [pb_glossary id=\"1654\"]Tectonic[\/pb_glossary] Evolution of Western North America: Geol. Soc. Am. Bull., v. 81, no. 12, p. 3513\u20133536., doi: <a href=\"https:\/\/doi.org\/10.1130\/0016-7606(1970)81[3513:IOPTFT]2.0.CO;2\">10.1130\/0016-7606(1970)81[3513:IOPTFT]2.0.CO;2<\/a>.<\/li>\n \t<li class=\"csl-entry\">Bacon, F., and Montagu, B., 1848, The Works of Francis Bacon, Lord Chancellor of England: With a Life of the Author: The Works of Francis Bacon, Lord Chancellor of England: With a Life of the Author, Parry &amp; McMillan, The Works of Francis Bacon, Lord Chancellor of England: With a Life of the Author.<\/li>\n \t<li class=\"csl-entry\">Benioff, H., 1949, [pb_glossary id=\"2165\"]Seismic[\/pb_glossary] evidence for the [pb_glossary id=\"2143\"]fault[\/pb_glossary] origin of [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] deeps: Geological Society of America Bulletin, v. 60, no. 12, p. 1837\u20131856., doi: <a href=\"https:\/\/doi.org\/10.1130\/0016-7606(1949)60[1837:SEFTFO]2.0.CO;2\">10.1130\/0016-7606(1949)60[1837:SEFTFO]2.0.CO;2<\/a>.<\/li>\n \t<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 \t<li class=\"csl-entry\">Birch, F., 1964, Density and [pb_glossary id=\"1909\"]composition[\/pb_glossary] of [pb_glossary id=\"1664\"]mantle[\/pb_glossary] and [pb_glossary id=\"1667\"]core[\/pb_glossary]: J. Geophys. Res., v. 69, no. 20, p. 4377\u20134388.<\/li>\n \t<li class=\"csl-entry\">Bott, M.H.P., 1993, Modelling the [pb_glossary id=\"1669\"]plate[\/pb_glossary]-driving mechanism: Journal of the Geological Society, v. 150, no. 5, p. 941\u2013951., doi: <a href=\"https:\/\/doi.org\/10.1144\/gsjgs.150.5.0941\">10.1144\/gsjgs.150.5.0941<\/a>.<\/li>\n \t<li class=\"csl-entry\">Coats, R.R., 1962, [pb_glossary id=\"1750\"]Magma[\/pb_glossary] type and crustal structure in the Aleutian [pb_glossary id=\"1687\"]Arc[\/pb_glossary], <i>in<\/i> The [pb_glossary id=\"1658\"]Crust[\/pb_glossary] of the Pacific [pb_glossary id=\"508\"]Basin[\/pb_glossary]: American Geophysical Union, p. 92\u2013109., doi: <a href=\"https:\/\/doi.org\/10.1029\/GM006p0092\">10.1029\/GM006p0092<\/a>.<\/li>\n \t<li class=\"csl-entry\">Conrad, C.P., and Lithgow-Bertelloni, C., 2002, How [pb_glossary id=\"1664\"]mantle[\/pb_glossary] slabs drive [pb_glossary id=\"1654\"]plate tectonics[\/pb_glossary]: Science (New York, N.Y.), v. 298, no. 5591, p. 207\u2013209., doi: <a href=\"https:\/\/doi.org\/10.1126\/science.1074161\">10.1126\/science.1074161<\/a>.<\/li>\n \t<li class=\"csl-entry\">Corliss, J.B., Dymond, J.G., Gordon, L.I., Edmond, J.M., von Heezen, R.P., Ballard, R.D., Green, K., Williams, D.L., Bainbridge, A., Crane, K., and van Andel, T.H., 1979, Submarine thermal springs on the Galapagos [pb_glossary id=\"1702\"]Rift[\/pb_glossary]: Science, v. 203, p. 107321083.<\/li>\n \t<li class=\"csl-entry\">Davis, E.E., and Lister, C.R.B., 1974, Fundamentals of ridge crest topography: Earth Planet. Sci. Lett., v. 21, no. 4, p. 405\u2013413.<\/li>\n \t<li class=\"csl-entry\">Dawson, J.B., Pinkerton, H., Norton, G.E., and Pyle, D.M., 1990, Physicochemical properties of alkali [pb_glossary id=\"2443\"]carbonatite[\/pb_glossary] lavas:Data from the 1988 eruption of Oldoinyo Lengai, Tanzania: Geology, v. 18, no. 3, p. 260\u2013263.<\/li>\n \t<li class=\"csl-entry\">Drake, E.T., 1976, Alfred Wegener\u2019s reconstruction of [pb_glossary id=\"2444\"]Pangea[\/pb_glossary]: Geology, v. 4, no. 1, p. 41\u201344., doi: &lt;a href=\"https:\/\/doi.org\/10.1130\/0091-7613(1976)42.0.CO;2\"&gt;10.1130\/0091-7613(1976)4&lt;41:AWROP&gt;2.0.CO;2.<\/li>\n \t<li class=\"csl-entry\">Engdahl, E.R., Flynn, E.A., and Masse, R.P., 1974, Differential PkiKP travel times and the radius of the [pb_glossary id=\"1667\"]core[\/pb_glossary]: Geophysical J Royal Astro Soc, v. 40, p. 457\u2013463.<\/li>\n \t<li class=\"csl-entry\">Ewing, M., Ewing, J.I., and Talwani, M., 1964, [pb_glossary id=\"1756\"]Sediment[\/pb_glossary] distribution in the oceans: The Mid-Atlantic Ridge: Geol. Soc. Am. Bull., v. 75, no. 1, p. 17\u201336., doi: <a href=\"https:\/\/doi.org\/10.1130\/0016-7606(1964)75[17:SDITOT]2.0.CO;2\">10.1130\/0016-7606(1964)75[17:SDITOT]2.0.CO;2<\/a>.<\/li>\n \t<li class=\"csl-entry\">Ewing, M., Houtz, R., and Ewing, J., 1969, South Pacific [pb_glossary id=\"1756\"]sediment[\/pb_glossary] distribution: J. Geophys. Res., v. 74, no. 10, p. 2477\u20132493., doi: <a href=\"https:\/\/doi.org\/10.1029\/JB074i010p02477\">10.1029\/JB074i010p02477<\/a>.<\/li>\n \t<li class=\"csl-entry\">Fernandez, L.M., and Careaga, J., 1968, The thickness of the [pb_glossary id=\"1658\"]crust[\/pb_glossary] in central United States and La Paz, Bolivia, from the spectrum of longitudinal [pb_glossary id=\"2165\"]seismic[\/pb_glossary] waves: Bull. Seismol. Soc. Am., v. 58, no. 2, p. 711\u2013741.<\/li>\n \t<li class=\"csl-entry\">Fluegel, von H.W., 1980, Wegener-Ampferer-Schwinner. Ein Beitrag zur Geschichte der Geologie in \u00d6sterreich: Mitt. Oesterr. Geol. Ges., v. 73, p. 237\u2013254.<\/li>\n \t<li class=\"csl-entry\">Forsyth, D.W., 1975, The Early Structural Evolution and Anisotropy of the [pb_glossary id=\"1659\"]Oceanic[\/pb_glossary] Upper [pb_glossary id=\"1664\"]Mantle[\/pb_glossary]: Geophys. J. Int., v. 43, no. 1, p. 103\u2013162., doi: <a href=\"https:\/\/doi.org\/10.1111\/j.1365-246X.1975.tb00630.x\">10.1111\/j.1365-246X.1975.tb00630.x<\/a>.<\/li>\n \t<li class=\"csl-entry\">Frankel, H., 1982, The Development, Reception, and Acceptance of the Vine-Matthews-Morley [pb_glossary id=\"1730\"]Hypothesis[\/pb_glossary]: Hist. Stud. Phys. Biol. Sci., v. 13, no. 1, p. 1\u201339.<\/li>\n \t<li class=\"csl-entry\">Fukao, Y., and Obayashi, M., 2013, [pb_glossary id=\"1680\"]Subducted[\/pb_glossary] slabs stagnant above, penetrating through, and trapped below the 660 km discontinuity: J. Geophys. Res. [Solid Earth], v. 118, no. 11, p. 2013JB010466.<\/li>\n \t<li class=\"csl-entry\">Hagstrum, J.T., 2005, Antipodal [pb_glossary id=\"1716\"]hotspots[\/pb_glossary] and bipolar catastrophes: Were [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] large-body impacts the cause? Earth Planet. Sci. Lett., v. 236, no. 1\u20132, p. 13\u201327.<\/li>\n \t<li class=\"csl-entry\">Hanks, T.C., and Anderson, D.L., 1969, The early thermal history of the earth: Phys. Earth Planet. Inter., v. 2, no. 1, p. 19\u201329.<\/li>\n \t<li class=\"csl-entry\">Heezen, B.C., and Tharp, M., 1965, [pb_glossary id=\"1654\"]Tectonic[\/pb_glossary] Fabric of the Atlantic and Indian Oceans and [pb_glossary id=\"1653\"]Continental[\/pb_glossary] Drift: Philosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences, v. 258, no. 1088, p. 90\u2013106., doi: <a href=\"https:\/\/doi.org\/10.1098\/rsta.1965.0024\">10.1098\/rsta.1965.0024<\/a>.<\/li>\n \t<li class=\"csl-entry\">Heller, P.L., Bowdler, S.S., Chambers, H.P., Coogan, J.C., Hagen, E.S., Shuster, M.W., Winslow, N.S., and Lawton, T.F., 1986, Time of initial [pb_glossary id=\"2152\"]thrusting[\/pb_glossary] in the Sevier orogenic belt, Idaho-Wyoming and Utah: Geology, v. 14, no. 5, p. 388\u2013391.<\/li>\n \t<li class=\"csl-entry\">Herak, D., and Herak, M., 2007, Andrija Mohorovi\u010di\u0107 (1857-1936)\u2014On the occasion of the 150th anniversary of his birth: Seismol. Res. Lett., v. 78, no. 6, p. 671\u2013674.<\/li>\n \t<li class=\"csl-entry\">Hess, H.H., 1962, History of ocean basins: [pb_glossary id=\"220\"]Petrologic[\/pb_glossary] studies, v. 4, p. 599\u2013620.<\/li>\n \t<li class=\"csl-entry\">Hutson, P., Middleton, J., and Miller, D., 2003, [pb_glossary id=\"1698\"]Collision[\/pb_glossary] Zones: Online, <a href=\"http:\/\/www.geosci.usyd.edu.au\/users\/prey\/ACSGT\/EReports\/eR.2003\/GroupD\/Report1\/web%20pages\/contents.html\">http:\/\/www.geosci.usyd.edu.au\/users\/prey\/ACSGT\/EReports\/eR.2003\/GroupD\/Report1\/web%20pages\/contents.html<\/a>, accessed June 2017.<\/li>\n \t<li class=\"csl-entry\">Isacks, B., Oliver, J., and Sykes, L.R., 1968, Seismology and the new global [pb_glossary id=\"1654\"]tectonics[\/pb_glossary]: J. Geophys. Res., v. 73, no. 18, p. 5855\u20135899.<\/li>\n \t<li class=\"csl-entry\">Ito, E., and Takahashi, E., 1989, Postspinel transformations in the [pb_glossary id=\"1742\"]system[\/pb_glossary] Mg2SiO4-Fe2SiO4 and some geophysical implications: J. Geophys. Res. [Solid Earth], v. 94, no. B8, p. 10637\u201310646.<\/li>\n \t<li class=\"csl-entry\">Jacoby, W.R., 1981, Modern concepts of Earth dynamics anticipated by Alfred Wegener in 1912: Geology, v. 9, no. 1, p. 25\u201327., doi: &lt;a href=\"https:\/\/doi.org\/10.1130\/0091-7613(1981)92.0.CO;2\"&gt;10.1130\/0091-7613(1981)9&lt;25:MCOEDA&gt;2.0.CO;2.<\/li>\n \t<li class=\"csl-entry\">Jakosky, B.M., Grebowsky, J.M., Luhmann, J.G., Connerney, J., Eparvier, F., Ergun, R., Halekas, J., Larson, D., Mahaffy, P., McFadden, J., Mitchell, D.F., Schneider, N., Zurek, R., Bougher, S., and others, 2015, MAVEN observations of the response of Mars to an interplanetary coronal mass ejection: Science, v. 350, no. 6261, p. aad0210.<\/li>\n \t<li class=\"csl-entry\">James, D.E., Fouch, M.J., Carlson, R.W., and Roth, J.B., 2011, [pb_glossary id=\"1683\"]Slab[\/pb_glossary] fragmentation, edge flow and the origin of the Yellowstone [pb_glossary id=\"1716\"]hotspot[\/pb_glossary] track: Earth Planet. Sci. Lett., v. 311, no. 1\u20132, p. 124\u2013135.<\/li>\n \t<li class=\"csl-entry\">Ji, Y., and Nataf, H.-C., 1998, Detection of [pb_glossary id=\"1664\"]mantle[\/pb_glossary] plumes in the lower [pb_glossary id=\"1664\"]mantle[\/pb_glossary] by diffraction [pb_glossary id=\"2174\"]tomography[\/pb_glossary]: Hawaii: Earth Planet. Sci. Lett., v. 159, no. 3\u20134, p. 99\u2013115.<\/li>\n \t<li class=\"csl-entry\">Johnston, S.T., Jane Wynne, P., Francis, D., Hart, C.J.R., Enkin, R.J., and Engebretson, D.C., 1996, Yellowstone in Yukon: The Late [pb_glossary id=\"487\"]Cretaceous[\/pb_glossary] Carmacks Group: Geology, v. 24, no. 11, p. 997\u20131000.<\/li>\n \t<li class=\"csl-entry\">Kearey, P., Klepeis, K.A., and Vine, F.J., 2009, Global [pb_glossary id=\"1654\"]Tectonics[\/pb_glossary]: Oxford\u202f; Chichester, West Sussex\u202f; Hoboken, NJ, Wiley-Blackwell, 496 p.<\/li>\n \t<li class=\"csl-entry\">Le Pichon, X., 1968, Sea-floor spreading and [pb_glossary id=\"1653\"]continental[\/pb_glossary] drift: J. Geophys. Res., v. 73, no. 12, p. 3661\u20133697.<\/li>\n \t<li class=\"csl-entry\">Lehmann, I., 1936, P\u2019, Publ: Bur. Centr. Seism. Internat. Serie A, v. 14, p. 87\u2013115.<\/li>\n \t<li class=\"csl-entry\">Mantovani, R., 1889, Les [pb_glossary id=\"986\"]fractures[\/pb_glossary] de l\u2019\u00e9corce terrestre et la th\u00e9orie de Laplace: Bull. Soc. Sc. et Arts R\u00e9union, p. 41\u201353.<\/li>\n \t<li class=\"csl-entry\">Mason, R.G., 1958, A magnetic survey off the west [pb_glossary id=\"1968\"]coast[\/pb_glossary] of the United-States between latitudes 32-degrees-N and 36-degrees-N longitudes 121-degrees-W and 128-degrees-W: Geophysical Journal of the Royal Astronomical Society, v. 1, no. 4, p. 320.<\/li>\n \t<li class=\"csl-entry\">Mason, R.G., and Raff, A.D., 1961, Magnetic Survey Off the West [pb_glossary id=\"1968\"]Coast[\/pb_glossary] of North America, 32\u00b0 N. [pb_glossary id=\"2450\"]Latitude[\/pb_glossary] to 42\u00b0 N. [pb_glossary id=\"2450\"]Latitude[\/pb_glossary]: Geological Society of America Bulletin, v. 72, no. 8, p. 1259\u20131265., doi: <a href=\"https:\/\/doi.org\/10.1130\/0016-7606(1961)72[1259:MSOTWC]2.0.CO;2\">10.1130\/0016-7606(1961)72[1259:MSOTWC]2.0.CO;2<\/a>.<\/li>\n \t<li class=\"csl-entry\">McCollom, T.M., 1999, Methanogenesis as a potential source of chemical energy for primary biomass production by autotrophic organisms in [pb_glossary id=\"1999\"]hydrothermal[\/pb_glossary] systems on Europa: J. Geophys. Res., v. 104, no. E12, p. 30729\u201330742., doi: <a href=\"https:\/\/doi.org\/10.1029\/1999JE001126\">10.1029\/1999JE001126<\/a>.<\/li>\n \t<li class=\"csl-entry\">McKenzie, D.P., and Parker, R.L., 1967, The North Pacific: an Example of [pb_glossary id=\"1654\"]Tectonics[\/pb_glossary] on a Sphere: Nature, v. 216, p. 1276\u20131280., doi: <a href=\"https:\/\/doi.org\/10.1038\/2161276a0\">10.1038\/2161276a0<\/a>.<\/li>\n \t<li class=\"csl-entry\">Miller, A.R., Densmore, C.D., Degens, E.T., Hathaway, J.C., Manheim, F.T., McFarlin, P.F., Pocklington, R., and Jokela, A., 1966, Hot brines and recent iron deposits in deeps of the Red Sea: Geochimica et Cosmochimica Acta, v. 30, no. 3, p. 341\u2013359., doi: <a href=\"https:\/\/doi.org\/10.1016\/0016-7037(66)90007-X\">10.1016\/0016-7037(66)90007-X<\/a>.<\/li>\n \t<li class=\"csl-entry\">Morgan, W.J., 1968, Rises, trenches, great [pb_glossary id=\"2143\"]faults[\/pb_glossary], and crustal blocks: J. Geophys. Res., v. 73, no. 6, p. 1959\u20131982., doi: <a href=\"https:\/\/doi.org\/10.1029\/JB073i006p01959\">10.1029\/JB073i006p01959<\/a>.<\/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\">Oldham, R.D., 1906, The constitution of the interior of the Earth, as revealed by earthquakes: Q. J. Geol. Soc. London, v. 62, no. 1\u20134, p. 456\u2013475.<\/li>\n \t<li class=\"csl-entry\">Pasyanos, M.E., 2010, Lithospheric thickness modeled from long-[pb_glossary id=\"1244\"]period[\/pb_glossary] [pb_glossary id=\"2167\"]surface wave[\/pb_glossary] dispersion: Tectonophysics, v. 481, no. 1\u20134, p. 38\u201350.<\/li>\n \t<li class=\"csl-entry\">Powell, R.E., and Weldon, R.J., 1992, Evolution of the San Andreas [pb_glossary id=\"2143\"]fault[\/pb_glossary]: Annu. Rev. Earth Planet. Sci., v. 20, p. 431.<\/li>\n \t<li class=\"csl-entry\">Raff, A.D., and Mason, R.G., 1961, Magnetic Survey Off the West [pb_glossary id=\"1968\"]Coast[\/pb_glossary] of North America, 40 N. [pb_glossary id=\"2450\"]Latitude[\/pb_glossary] to 52 N. [pb_glossary id=\"2450\"]Latitude[\/pb_glossary]: Geological Society of America Bulletin, v. 72, no. 8, p. 1267\u20131270., doi: <a href=\"https:\/\/doi.org\/10.1130\/0016-7606(1961)72[1267:MSOTWC]2.0.CO;2\">10.1130\/0016-7606(1961)72[1267:MSOTWC]2.0.CO;2<\/a>.<\/li>\n \t<li class=\"csl-entry\">Runcorn, S.K., 1965, Palaeomagnetic comparisons between Europe and North America: Philosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences, v. 258, no. 1088, p. 1\u201311.<\/li>\n \t<li class=\"csl-entry\">Saito, T., Ewing, M., and Burckle, L.H., 1966, Tertiary [pb_glossary id=\"1756\"]sediment[\/pb_glossary] from the mid-atlantic ridge: Science, v. 151, no. 3714, p. 1075\u20131079., doi: <a href=\"https:\/\/doi.org\/10.1126\/science.151.3714.1075\">10.1126\/science.151.3714.1075<\/a>.<\/li>\n \t<li class=\"csl-entry\">Satake, K., and Atwater, B.F., 2007, Long-term perspectives on giant earthquakes and [pb_glossary id=\"2272\"]tsunamis[\/pb_glossary] at [pb_glossary id=\"1680\"]subduction[\/pb_glossary] zones*: Annu. Rev. Earth Planet. Sci., v. 35, p. 349\u2013374.<\/li>\n \t<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 \t<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 \t<li class=\"csl-entry\">Starr, A.M., 2015, Ambient [pb_glossary id=\"2181\"]resonance[\/pb_glossary] of rock arches: Salt Lake City, Utah, University of Utah, 134 p.<\/li>\n \t<li class=\"csl-entry\">Stern, R.J., 1998, A [pb_glossary id=\"1680\"]subduction[\/pb_glossary] primer for instructors of introductory geology courses and authors of introductory-geology textbooks: J. Geosci. Educ., v. 46, p. 221.<\/li>\n \t<li class=\"csl-entry\">Stern, R.J., 2004, [pb_glossary id=\"1680\"]Subduction[\/pb_glossary] initiation: spontaneous and induced: Earth Planet. Sci. Lett., v. 226, no. 3\u20134, p. 275\u2013292.<\/li>\n \t<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 \t<li class=\"csl-entry\">Tatsumi, Y., 2005, The [pb_glossary id=\"1680\"]subduction[\/pb_glossary]\u00a0factory: how it operates in the evolving Earth: GSA Today, v. 15, no. 7, p. 4.<\/li>\n \t<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 \t<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 \t<li class=\"csl-entry\">Vine, F.J., and Matthews, D.H., 1963, Magnetic [pb_glossary id=\"765\"]anomalies[\/pb_glossary] over [pb_glossary id=\"1659\"]oceanic[\/pb_glossary] ridges: Nature, v. 199, no. 4897, p. 947\u2013949.<\/li>\n \t<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 \t<li class=\"csl-entry\">Wadati, K., 1935, On the activity of deep-[pb_glossary id=\"2158\"]focus[\/pb_glossary] earthquakes in the Japan Islands and neighbourhoods: Geophys. Mag., v. 8, no. 3\u20134, p. 305\u2013325.<\/li>\n \t<li class=\"csl-entry\">Waszek, L., Irving, J., and Deuss, A., 2011, Reconciling the hemispherical structure of Earth\/\u2019s [pb_glossary id=\"1674\"]inner core[\/pb_glossary] 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 \t<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 \t<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 \t<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 \t<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 \t<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 [pb_glossary id=\"2446\"]viscosity[\/pb_glossary] of liquid iron at the physical conditions of the Earth\u2019s [pb_glossary id=\"1667\"]core[\/pb_glossary]: Nature, v. 392, no. 6678, p. 805\u2013807., doi: <a href=\"https:\/\/doi.org\/10.1038\/33905\">10.1038\/33905<\/a>.<\/li>\n \t<li class=\"csl-entry\">Wilson, J.T., 1966, Did the Atlantic close and then re-open? Nature.<\/li>\n \t<li class=\"csl-entry\">Wilson, M., 1993, [pb_glossary id=\"1669\"]Plate[\/pb_glossary]-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 \t<li class=\"csl-entry\">Wyllie, P.J., 1970, [pb_glossary id=\"1009\"]Ultramafic[\/pb_glossary] rocks and the upper [pb_glossary id=\"1664\"]mantle[\/pb_glossary], <i>in<\/i> Morgan, B.A., editor, Fiftieth anniversary symposia: Mineralogy and [pb_glossary id=\"220\"]petrology[\/pb_glossary] of the Upper [pb_glossary id=\"1664\"]Mantle[\/pb_glossary]; [pb_glossary id=\"973\"]Sulfides[\/pb_glossary]; Mineralogy and geochemistry of non-[pb_glossary id=\"1961\"]marine[\/pb_glossary] [pb_glossary id=\"1920\"]evaporites[\/pb_glossary]: Washington, DC, Mineralogical Society of America, p. 3\u201332.<\/li>\n \t<li class=\"csl-entry\">Zhou, Z., 2004, The origin and early evolution of birds: discoveries, disputes, and perspectives from [pb_glossary id=\"1228\"]fossil[\/pb_glossary] evidence: Naturwissenschaften, v. 91, no. 10, p. 455\u2013471.<\/li>\n<\/ol>\n<\/div>","rendered":"<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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/09\/MT3.jpg 2048w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/09\/MT3-300x225.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/09\/MT3-1024x768.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/09\/MT3-768x576.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/09\/MT3-1536x1152.jpg 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/09\/MT3-65x49.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/09\/MT3-225x169.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/09\/MT3-350x263.jpg 350w\" sizes=\"auto, (max-width: 2048px) 100vw, 2048px\" \/><\/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_138_1654\">plate tectonics<\/a> started with Alfred Wegener\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1730\">hypothesis<\/a> of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1669\">plate<\/a> boundaries causes earthquakes, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_228\">volcanoes<\/a>, and mountain building<\/li>\n<li>Identify <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1678\">convergent<\/a> boundaries, including <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subduction<\/a> and collisions, as places where <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a>\u00a0come together<\/li>\n<li>Identify <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1677\">divergent<\/a> boundaries, including <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1702\">rifts<\/a>\u00a0and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1708\">mid-ocean ridges<\/a>, as places where <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a> separate<\/li>\n<li>Explain <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1679\">transform<\/a> boundaries as places where adjacent <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_494\">shear<\/a> past each other<\/li>\n<li>Describe the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1715\">Wilson Cycle<\/a>, beginning with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1702\">rifting<\/a>, ocean <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_508\">basin<\/a> creation, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subduction<\/a>, and ending with ocean <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_508\">basin<\/a> closure<\/li>\n<li>Explain how the tracks of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1716\">hotspots<\/a>, places that have continually rising <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1750\">magma<\/a>, is used to calculate <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tectonic_plates_boundaries_detailed-en.svg_.png 4898w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tectonic_plates_boundaries_detailed-en.svg_-300x151.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tectonic_plates_boundaries_detailed-en.svg_-1024x515.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tectonic_plates_boundaries_detailed-en.svg_-768x386.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tectonic_plates_boundaries_detailed-en.svg_-1536x772.png 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tectonic_plates_boundaries_detailed-en.svg_-2048x1029.png 2048w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tectonic_plates_boundaries_detailed-en.svg_-65x33.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tectonic_plates_boundaries_detailed-en.svg_-225x113.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tectonic_plates_boundaries_detailed-en.svg_-350x176.png 350w\" sizes=\"auto, (max-width: 4898px) 100vw, 4898px\" \/><\/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_138_1654\">plate tectonics<\/a> was just as revolutionary for geology. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1733\">theory<\/a> of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1654\">plate tectonics<\/a> attributes the movement of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alfred_Wegener_ca.1924-30-2.jpg 195w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alfred_Wegener_ca.1924-30-2-65x80.jpg 65w\" sizes=\"auto, (max-width: 195px) 100vw, 195px\" \/><\/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_138_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_138_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_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Antonio_Snider-Pellegrini_Opening_of_the_Atlantic-300x177.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Antonio_Snider-Pellegrini_Opening_of_the_Atlantic-65x38.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Antonio_Snider-Pellegrini_Opening_of_the_Atlantic-225x133.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Antonio_Snider-Pellegrini_Opening_of_the_Atlantic-350x206.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Antonio_Snider-Pellegrini_Opening_of_the_Atlantic.jpg 640w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-2501\" class=\"wp-caption-text\">Snider-Pellegrini&rsquo;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_138_1653\">continental<\/a> separation and matching <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ElevationWorld-300x150.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ElevationWorld-1024x512.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ElevationWorld-768x384.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ElevationWorld-1536x768.jpg 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ElevationWorld-65x33.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ElevationWorld-225x113.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ElevationWorld-350x175.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ElevationWorld.jpg 1600w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Wegener_fossil_map.svg_-300x231.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Wegener_fossil_map.svg_-1024x787.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Wegener_fossil_map.svg_-768x591.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Wegener_fossil_map.svg_-65x50.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Wegener_fossil_map.svg_-225x173.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Wegener_fossil_map.svg_-350x269.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Wegener_fossil_map.svg_.png 1160w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_1228\">fossils<\/a>, and glacial formations across oceans. For example, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1653\">continental<\/a> drift insisted trans-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1653\">continental<\/a> drift came from the puzzling evidence that <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_757\">climate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_757\">climate<\/a>, rock, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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_138_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_138_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_138_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_138_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_138_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_138_1655\">convection<\/a> is one the major forces in driving <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Global_plate_motion_2008-04-17-300x212.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Global_plate_motion_2008-04-17-65x46.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Global_plate_motion_2008-04-17-225x159.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Global_plate_motion_2008-04-17-350x248.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Global_plate_motion_2008-04-17.jpg 700w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_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_138_1730\">hypothesis<\/a> of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> drift to be accepted as the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1733\">theory<\/a> of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1679\">transform<\/a> one man\u2019s wild notion into a scientific <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Deep_sea_vent_chemistry_diagram-300x174.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Deep_sea_vent_chemistry_diagram-1024x595.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Deep_sea_vent_chemistry_diagram-768x446.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Deep_sea_vent_chemistry_diagram-1536x893.jpg 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Deep_sea_vent_chemistry_diagram-65x38.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Deep_sea_vent_chemistry_diagram-225x131.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Deep_sea_vent_chemistry_diagram-350x203.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Deep_sea_vent_chemistry_diagram.jpg 1600w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_508\">basin<\/a> growth <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1730\">hypotheses<\/a>. In 1959, Harry Hess proposed the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1730\">hypothesis<\/a> of seafloor spreading \u2013 that the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1708\">mid-ocean ridges<\/a> represented <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1654\">tectonic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> factories, where new <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> was issuing from these long <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_228\">volcanic<\/a> ridges. Scientists later included <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1669\">plate<\/a> movement took hold.<\/p>\n<div style=\"height: 0; padding-bottom: 56.25%;\">\n<p><iframe loading=\"lazy\" id=\"oembed-1\" title=\"Marie Tharp: Uncovering the Secrets of the Ocean Floor - with Helen Czerski\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/TgfYjS0OTWw?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Marie-Tharp-YouTube-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Marie-Tharp-YouTube-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Marie-Tharp-YouTube-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Marie-Tharp-YouTube-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Marie-Tharp-YouTube-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Marie-Tharp-YouTube-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Marie-Tharp-YouTube-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Marie-Tharp-YouTube-QR-Code.png 1155w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/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_138_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_138_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_138_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_138_1653\">continental<\/a> movement. With more time, researchers discovered these thinner <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> layers were located close to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Earths_magnetic_field_schematic.svg_-300x250.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Earths_magnetic_field_schematic.svg_-1024x853.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Earths_magnetic_field_schematic.svg_-768x640.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Earths_magnetic_field_schematic.svg_-65x54.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Earths_magnetic_field_schematic.svg_-225x188.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Earths_magnetic_field_schematic.svg_-350x292.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Earths_magnetic_field_schematic.svg_.png 1200w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_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_138_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 loading=\"lazy\" decoding=\"async\" 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_138_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_138_1669\">plate<\/a> motion came from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1657\">paleomagnetism<\/a>.<\/p>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1753\">Igneous<\/a> rocks containing magnetic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1750\">magma<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1751\">lava<\/a>, the magnetic poles of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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_138_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 loading=\"lazy\" decoding=\"async\" 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_138_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_138_1654\">tectonic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a> sinking into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/John_Tuzo_Wilson_in_1992-2-244x300.jpg 244w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/John_Tuzo_Wilson_in_1992-2-65x80.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/John_Tuzo_Wilson_in_1992-2-225x277.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/John_Tuzo_Wilson_in_1992-2-350x431.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/John_Tuzo_Wilson_in_1992-2.jpg 440w\" sizes=\"auto, (max-width: 244px) 100vw, 244px\" \/><\/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_138_1733\">theory<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1654\">tectonic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> movement. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Continental-Drive-Activity-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Continental-Drive-Activity-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Continental-Drive-Activity-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Continental-Drive-Activity-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Continental-Drive-Activity-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Continental-Drive-Activity-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Continental-Drive-Activity-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Continental-Drive-Activity-QR-Code.png 1147w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.1-Did-I-Get-It-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.1-Did-I-Get-It-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.1-Did-I-Get-It-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.1-Did-I-Get-It-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.1-Did-I-Get-It-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.1-Did-I-Get-It-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.1-Did-I-Get-It-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.1-Did-I-Get-It-QR-Code.png 1147w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Earth-cutaway-schematic-english.svg_-1-300x211.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Earth-cutaway-schematic-english.svg_-1-65x46.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Earth-cutaway-schematic-english.svg_-1-225x158.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Earth-cutaway-schematic-english.svg_-1-350x246.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Earth-cutaway-schematic-english.svg_-1.png 640w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_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_138_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_138_1778\">elements<\/a>. Regardless of what <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1778\">elements<\/a> are involved two major factors\u2014<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1658\">crust<\/a>. There are two types of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1658\">crust<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1014\">granite<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1013\">basalt<\/a>. The surface levels of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1658\">crust<\/a> are relatively <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1661\">brittle<\/a>. The deeper parts of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1660\">ductile<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1658\">crust<\/a> and are caused by the rapid movement of relatively <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MohoDepth-1-300x167.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MohoDepth-1-1024x568.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MohoDepth-1-768x426.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MohoDepth-1-1536x852.png 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MohoDepth-1-65x36.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MohoDepth-1-225x125.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MohoDepth-1-350x194.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MohoDepth-1.png 1600w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_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_138_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_138_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_138_1658\">crust<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1664\">mantle<\/a>. Underneath the oceans, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Iddingsite-300x225.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Iddingsite-65x49.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Iddingsite-225x169.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Iddingsite-350x263.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Iddingsite.jpg 640w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_1664\">mantle<\/a> sits below the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1658\">crust<\/a> and above the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_1700\">ophiolites<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1665\">xenoliths<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1700\">Ophiolites<\/a> are pieces of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1664\">mantle<\/a> that have risen through the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1665\">Xenoliths<\/a> are carried within <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1665\">xenoliths<\/a> are made of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1666\">peridotite<\/a>, an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1009\">ultramafic<\/a> class of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1664\">mantle<\/a> is made of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/02.2_TolucaMeteorite-300x225.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/02.2_TolucaMeteorite-768x576.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/02.2_TolucaMeteorite-65x49.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/02.2_TolucaMeteorite-225x169.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/02.2_TolucaMeteorite-350x263.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/02.2_TolucaMeteorite.jpg 1024w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_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_138_1667\">core<\/a> is mostly metallic iron. Scientists studying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1667\">core<\/a>&#8211;<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plates_tect2_en.svg_-2-300x205.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plates_tect2_en.svg_-2-1024x699.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plates_tect2_en.svg_-2-768x524.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plates_tect2_en.svg_-2-1536x1049.png 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plates_tect2_en.svg_-2-65x44.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plates_tect2_en.svg_-2-225x154.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plates_tect2_en.svg_-2-350x239.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plates_tect2_en.svg_-2.png 2048w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_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_138_1659\">oceanic<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">Oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1669\">plates<\/a> found around <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1653\">Continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1668\">lithosphere<\/a> is not continuous. It is broken into segments called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a>. A <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1670\">plate boundary<\/a> is where two <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a> meet and move relative to each other. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">Plate<\/a> boundaries are where we see <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1654\">plate tectonics<\/a> in action\u2014mountain building, triggering earthquakes, and generating <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Earths_Inner_Layers_denoting_the_LAB-300x207.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Earths_Inner_Layers_denoting_the_LAB-65x45.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Earths_Inner_Layers_denoting_the_LAB-225x155.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Earths_Inner_Layers_denoting_the_LAB-350x242.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Earths_Inner_Layers_denoting_the_LAB.png 766w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_1671\">asthenosphere<\/a> is the layer below the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1655\">convection<\/a> currents created by heat coming from the earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1667\">core<\/a> cause. Unlike the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1668\">lithosphere<\/a> that consists of multiple <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a>, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1671\">asthenosphere<\/a> is found is <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Perovskite-300x288.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Perovskite-65x63.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Perovskite-225x216.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Perovskite-350x337.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Perovskite.jpg 755w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_1672\">mesosphere<\/a>, sometimes known as the lower <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1664\">mantle<\/a>, is more rigid and immobile than the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1672\">mesosphere<\/a> where <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1672\">mesosphere<\/a> is relatively uniform until it reaches the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Inge_Lehmann_1932-206x300.jpg 206w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Inge_Lehmann_1932-65x95.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Inge_Lehmann_1932-225x328.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Inge_Lehmann_1932-350x511.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Inge_Lehmann_1932.jpg 460w\" sizes=\"auto, (max-width: 206px) 100vw, 206px\" \/><\/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_138_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_138_1674\">inner core<\/a> existed within a liquid <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1673\">outer core<\/a> . The solid <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1674\">inner core<\/a> is about 1,220 km thick, and the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">minerals<\/a> making up the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1667\">core<\/a> should be liquified or vaporized at this <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1767\">temperature<\/a>. Immense pressure keeps the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1674\">inner core<\/a> in a solid phase. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1674\">inner core<\/a> grows slowly from the lower <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/02.2_SpinningOuterCore-300x289.gif 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/02.2_SpinningOuterCore-65x63.gif 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/02.2_SpinningOuterCore-225x216.gif 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/02.2_SpinningOuterCore-350x337.gif 350w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-2520\" class=\"wp-caption-text\">The outer core&rsquo;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_138_1673\">outer core<\/a> is critically important in maintaining a breathable <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1673\">outer core<\/a>. If the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Layers-of-Earth-Practice-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Layers-of-Earth-Practice-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Layers-of-Earth-Practice-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Layers-of-Earth-Practice-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Layers-of-Earth-Practice-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Layers-of-Earth-Practice-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Layers-of-Earth-Practice-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Layers-of-Earth-Practice-QR-Code.png 1147w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Passive_Contiental_Margin-300x143.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Passive_Contiental_Margin-1024x490.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Passive_Contiental_Margin-768x367.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Passive_Contiental_Margin-65x31.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Passive_Contiental_Margin-225x108.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Passive_Contiental_Margin-350x167.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Passive_Contiental_Margin.jpg 1146w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_1669\">plates<\/a> don\u2019t move\u2014the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1668\">lithosphere<\/a> transitions into oceanic lithosphere and forms <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a> made of both types. A <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1654\">tectonic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> may be made of both <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1668\">lithosphere<\/a> connected by a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1659\">oceanic<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> lithospheric <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1654\">tectonic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1669\">plates<\/a> and differences in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_228\">volcanism<\/a> on the Earth\u2019s surface can be attributed to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1654\">tectonic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tectonic_plate_boundaries.png 775w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tectonic_plate_boundaries-300x166.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tectonic_plate_boundaries-768x425.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tectonic_plate_boundaries-65x36.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tectonic_plate_boundaries-225x125.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Tectonic_plate_boundaries-350x194.png 350w\" sizes=\"auto, (max-width: 775px) 100vw, 775px\" \/><\/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_138_1654\">tectonic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> boundaries. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1678\">Convergent<\/a> boundaries are places where <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a> move toward each other. At <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1677\">divergent<\/a> boundaries, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a> move apart. At <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1679\">transform<\/a> boundaries, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.2-Did-I-Get-It-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.2-Did-I-Get-It-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.2-Did-I-Get-It-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.2-Did-I-Get-It-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.2-Did-I-Get-It-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.2-Did-I-Get-It-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.2-Did-I-Get-It-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.2-Did-I-Get-It-QR-Code.png 1147w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/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 loading=\"lazy\" decoding=\"async\" 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\" 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: 300px) 100vw, 300px\" \/><\/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_138_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_138_1669\">plates<\/a> move toward each other. . <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1678\">Convergent<\/a> boundary movement is divided into two types, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subduction<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1698\">collision<\/a>, depending on the density of the involved <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">Continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1671\">asthenosphere<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">Oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1668\">lithosphere<\/a> is more dense than <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1671\">asthenosphere<\/a>.<\/p>\n<p>When <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a> of different densities converge, the higher density <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> is pushed beneath the more buoyant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> in a process called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subduction<\/a>. When <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a> converge without <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subduction<\/a> occurring, this process is called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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-138-1\" 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_138_1653\"><em>continental<\/em><\/a>&#8211;<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\"><em>oceanic <\/em><\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\"><em>subduction<\/em><\/a>, causing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Subduction-Animation-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Subduction-Animation-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Subduction-Animation-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Subduction-Animation-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Subduction-Animation-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Subduction-Animation-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Subduction-Animation-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Subduction-Animation-QR-Code.png 1148w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/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_138_1680\">Subduction<\/a> occurs when a dense <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> meets a more buoyant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a>, like a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> or warmer\/younger <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a>, and descends into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1664\">mantle<\/a>. The worldwide average rate of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> descends, it pulls the ocean floor down into a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_508\">basin<\/a>, which is usually three to four km. The Mariana <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Subduction-en.svg_.png 800w, 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\" sizes=\"auto, (max-width: 800px) 100vw, 800px\" \/><\/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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/drawing-212x300.png 212w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/drawing-724x1024.png 724w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/drawing-65x92.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/drawing-225x318.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/drawing-350x495.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/drawing.png 744w\" sizes=\"auto, (max-width: 212px) 100vw, 212px\" \/><\/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_138_1681\">trench<\/a>, ocean floor <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediments<\/a> are scraped together and compressed between the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subducting<\/a> and overriding <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a>. This feature is called the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1682\">accretionary wedge<\/a>, m\u00e9lange, or accretionary prism. Fragments of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> material, including microcontinents, riding atop the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subducting<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> may become sutured to the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/usgs_terranes-179x300.gif 179w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/usgs_terranes-65x109.gif 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/usgs_terranes-225x377.gif 225w\" sizes=\"auto, (max-width: 179px) 100vw, 179px\" \/><\/a><figcaption id=\"caption-attachment-2526\" class=\"wp-caption-text\">Accreted terranes of western North America. Everything that is not the \u00ab\u00a0Ancient continental interior (craton)\u00a0\u00bb 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_138_1680\">subducting<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a>, or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1683\">slab<\/a>, sinks into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> and above the descending <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> called the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1685\">mantle wedge<\/a>. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1684\">volatiles<\/a> are released mostly by hydrated <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> that revert to non-hydrated <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> in these higher <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1669\">plate<\/a>, the volatile lower the melting point of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1685\">mantle wedge<\/a>, and through a process called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1686\">flux melting<\/a> it becomes liquid <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1750\">magma<\/a>. The molten <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1750\">magma<\/a> is more buoyant than the lithospheric <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_228\">volcanism<\/a>. The resulting <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_228\">volcanoes<\/a> frequently appear as curved mountain chains, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_228\">volcanic<\/a> arcs, due to the curvature of the earth. Both <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a> can contain <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/1755_Lisbon_Earthquake_Location-236x300.png 236w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/1755_Lisbon_Earthquake_Location-65x82.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/1755_Lisbon_Earthquake_Location-225x285.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/1755_Lisbon_Earthquake_Location.png 331w\" sizes=\"auto, (max-width: 236px) 100vw, 236px\" \/><\/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_138_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_138_1680\">subduction<\/a> zones start as passive margins, where <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a>\u00a0and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a> come together, and then gravity initiates <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subduction<\/a> and converts the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1676\">passive margin<\/a> into an active one. One <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1730\">hypothesis<\/a> is gravity pulls the denser <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> down or the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1680\">subduction<\/a> zone, although the evidence is not definitive. Another <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1730\">hypothesis<\/a> proposes <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subduction<\/a> happens at <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1679\">transform<\/a> boundaries involving <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a> of different densities.<\/p>\n<p>Some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1680\">subduction<\/a>. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> lithospheric <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1671\">asthenosphere<\/a> and are not <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subducting<\/a> beneath the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a>. One <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1730\">hypothesis<\/a> is the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1781\">bond<\/a> holding the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/SundaMegathrustSeismicity-234x300.png 234w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/SundaMegathrustSeismicity-65x83.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/SundaMegathrustSeismicity-225x289.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/SundaMegathrustSeismicity-350x449.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/SundaMegathrustSeismicity.png 468w\" sizes=\"auto, (max-width: 234px) 100vw, 234px\" \/><\/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_138_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_138_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_138_1680\">subducting<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1683\">slab<\/a> becomes stuck and cannot descend, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_985\">massive<\/a> amount of energy builds up between the stuck <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1669\">plates<\/a> to suddenly release along several hundred kilometers of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subduction<\/a> zone. Because <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subduction<\/a>-zone faults are located on the ocean floor, this <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Forearc-300x258.gif 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Forearc-65x56.gif 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Forearc-225x194.gif 225w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_1680\">subduction<\/a> zones have a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1692\">forearc basin<\/a>, a feature of the overriding <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> found between the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1695\">volcanic arc<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1681\">trench<\/a>. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1692\">forearc basin<\/a> experiences a lot of faulting\u00a0and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_495\">deformation<\/a> activity, particularly within the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1682\">accretionary wedge<\/a>.<\/p>\n<p>In some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subduction<\/a> zones, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_492\">tensional<\/a> forces\u00a0working on the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> create a backarc <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_508\">basin<\/a> on the interior side of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1695\">volcanic arc<\/a>. Some scientists have proposed a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subduction<\/a> mechanism called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1683\">slab<\/a> rollback creates <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_492\">extension<\/a> faults in the overriding <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a>. In this model, the descending <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1683\">slab<\/a> does not slide directly under the overriding <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> but instead rolls back, pulling the overlying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> seaward. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> behind the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_508\">basin<\/a>. If the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_492\">extension<\/a> activity is extensive and deep enough, a backarc <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_508\">basin<\/a> can develop into a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1702\">rifting<\/a> zone. These <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1677\">divergent<\/a> boundaries may be less symmetrical than their <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a> are converging and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> to buckle and crack. This is called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1688\">back-arc<\/a> faulting. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_492\">Extensional<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1688\">back-arc<\/a> faults pull rocks and chunks of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a> apart. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_493\">Compressional<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_493\">compressional<\/a> thrust faulting. The western spine is part of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1695\">volcanic arc<\/a>. Thrust faults have deformed the non-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_228\">volcanic<\/a> eastern spine, \u00a0pushing rocks and pieces of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_495\">deformation<\/a>: <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1690\">thick-skinned<\/a> faults that reach deeper into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1658\">crust<\/a>. The Sevier <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1663\">Orogeny<\/a> in the western U.S. is a notable <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1689\">thin-skinned<\/a> type of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_495\">deformation<\/a> created during the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_487\">Cretaceous<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1244\">Period<\/a>. The Laramide <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1663\">Orogeny<\/a>, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1690\">thick-skinned<\/a> type of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Shallow_subduction_Laramide_orogeny-300x142.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Shallow_subduction_Laramide_orogeny-65x31.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Shallow_subduction_Laramide_orogeny-225x106.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Shallow_subduction_Laramide_orogeny.png 336w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_1683\">slab<\/a>, or shallow, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subduction<\/a> caused the Laramide <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1663\">Orogeny<\/a>. When the descending <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1683\">slab<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1683\">slab<\/a> and the overlying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> than in a typical <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subduction<\/a> zone. The shallowly-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subducting<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1683\">slab<\/a> pushes against the overriding <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> and creates an area of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_495\">deformation<\/a> on the overriding <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> many kilometers away from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/OceanContSub-300x177.gif 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/OceanContSub-65x38.gif 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/OceanContSub-225x133.gif 225w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_1694\">Oceanic-continental subduction<\/a> occurs when an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> dives below a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a>. This <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1678\">convergent<\/a> boundary has a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1681\">trench<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1685\">mantle wedge<\/a> and frequently, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1695\">volcanic arc<\/a>. Well-known examples of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Fig21oceanocean-300x173.gif 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Fig21oceanocean-65x37.gif 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Fig21oceanocean-225x130.gif 225w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_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_138_1659\">oceanic<\/a>&#8211;<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a>. Since both <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a> are made of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1668\">lithosphere<\/a>, it is usually the older <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> that <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subducts<\/a> because it is colder and denser. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_228\">volcanism<\/a> on the overlying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> may remain hidden underwater.. If the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_228\">volcanism<\/a> forms an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a> converge, during the closing of an ocean <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_508\">basin<\/a> for example, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subduction<\/a> is not possible between the equally buoyant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a>. Instead of one <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> descending beneath another, the two masses of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1668\">lithosphere<\/a> slam together in a process known as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1698\">collision<\/a>. Without <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subduction<\/a>, there is no <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1750\">magma<\/a> formation and no <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_228\">volcanism<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1698\">Collision<\/a> zones are characterized by tall, non-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_228\">volcanism<\/a>.<\/p>\n<p>When <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic crust<\/a> connected by a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1676\">passive margin<\/a> to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental crust<\/a> completely <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subducts<\/a> beneath a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continent<\/a>, an ocean <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_508\">basin<\/a> closes, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_985\">massive<\/a> accumulation of continents called a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pangaea_continents-267x300.png 267w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pangaea_continents-65x73.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pangaea_continents-225x253.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pangaea_continents-350x394.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pangaea_continents.png 758w\" sizes=\"auto, (max-width: 267px) 100vw, 267px\" \/><\/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_138_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_138_1653\">continental<\/a> drift <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1730\">hypothesis<\/a>. Geologists now have evidence that <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a> have been continuously converging into <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1701\">supercontinents<\/a> and splitting into smaller <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1701\">supercontinents<\/a>, one of which being <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ZagrosFTB-300x231.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ZagrosFTB-1024x789.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ZagrosFTB-768x592.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ZagrosFTB-65x50.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ZagrosFTB-225x173.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ZagrosFTB-350x270.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ZagrosFTB.png 1184w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_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_138_1669\">plate<\/a>. While foreland basins may occur at <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subduction<\/a> zones, they are most commonly found at <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/02.3_ItalyPillowBasalt-300x225.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/02.3_ItalyPillowBasalt-1024x768.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/02.3_ItalyPillowBasalt-768x576.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/02.3_ItalyPillowBasalt-1536x1152.jpg 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/02.3_ItalyPillowBasalt-65x49.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/02.3_ItalyPillowBasalt-225x169.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/02.3_ItalyPillowBasalt-350x263.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/02.3_ItalyPillowBasalt.jpg 1600w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_1653\">continental<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1668\">lithosphere<\/a> are fused on the same <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> may become trapped beneath a descending <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> in a process called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1699\">obduction<\/a>. When a portion of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental crust<\/a> is driven down into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1668\">lithosphere<\/a> break loose and migrate upward through the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1699\">obduction<\/a> zone, they bring along bits of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a>. Rocks composed of this <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1664\">mantle<\/a> and ocean-floor material are called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1664\">mantle<\/a>.<\/p>\n<p>The area of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1698\">collision<\/a>-zone <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_495\">deformation<\/a> and seismic activity usually covers a broader area because <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1668\">lithosphere<\/a> is plastic and malleable. Unlike <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1678\">convergent<\/a> boundary, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1669\">plates<\/a>.<\/p>\n<p>The Eurasian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continent<\/a> has many examples of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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-138-2\" 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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/India-Asia-Collision-Animation-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/India-Asia-Collision-Animation-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/India-Asia-Collision-Animation-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/India-Asia-Collision-Animation-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/India-Asia-Collision-Animation-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/India-Asia-Collision-Animation-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/India-Asia-Collision-Animation-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/India-Asia-Collision-Animation-QR-Code.png 1125w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.3-Did-I-Get-It-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.3-Did-I-Get-It-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.3-Did-I-Get-It-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.3-Did-I-Get-It-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.3-Did-I-Get-It-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.3-Did-I-Get-It-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.3-Did-I-Get-It-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.3-Did-I-Get-It-QR-Code.png 1147w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/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_138_1677\">divergent<\/a> boundaries, sometimes called constructive boundaries, lithospheric <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1677\">divergent<\/a> boundaries, categorized by where they occur: <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1702\">rift<\/a> zones and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1708\">mid-ocean ridges<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">Continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1702\">rift<\/a> zones occur in weak spots in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> lithospheric <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a>. A <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1708\">mid-ocean ridge<\/a> usually originates in a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> as a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1702\">rift<\/a> zone that expands to the point of splitting the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Horst-Graben.svg_-300x154.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Horst-Graben.svg_-1024x525.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Horst-Graben.svg_-768x394.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Horst-Graben.svg_-65x33.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Horst-Graben.svg_-225x115.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Horst-Graben.svg_-350x180.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Horst-Graben.svg_.png 1068w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1664\">mantle<\/a> it develops strong <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1655\">convection<\/a> currents that push super-heated <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1664\">mantle<\/a> material up against the overlying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a>, softening it. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_1658\">crust<\/a> known as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1704\">grabens<\/a>. The shoulders of these <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1704\">grabens<\/a> are called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/TopographicAfar-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/TopographicAfar-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/TopographicAfar-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/TopographicAfar-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/TopographicAfar-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/TopographicAfar-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/TopographicAfar-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/TopographicAfar.png 1536w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_1702\">rifting<\/a> is dictated by two factors. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1718\">cratons<\/a>. When <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_1654\">tectonic<\/a> activity are called failed rift arms. A <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1705\">failed rift arm<\/a> is still a weak spot in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a>; even without the presence of active <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_492\">extension<\/a> faults, it may develop into a called an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1706\">aulacogen<\/a>. One example of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1702\">rift<\/a> arms do develop concurrently, creating multiple boundaries of active <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1702\">rifting<\/a>. In places where the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1677\">divergent<\/a> boundaries can develop near each other forming a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Basin_range_province-300x240.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Basin_range_province-65x52.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Basin_range_province-225x180.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Basin_range_province-350x280.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Basin_range_province.jpg 640w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_1702\">Rifts<\/a> come in two types: narrow and broad. Narrow <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1702\">rifts<\/a> are characterized by a high density of highly active <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1677\">divergent<\/a> boundaries. The East African <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1702\">Rift<\/a> Zone, where the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1702\">rift<\/a>. Lake Baikal in Russia is another. Broad <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_495\">deformation<\/a>. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1677\">divergent<\/a> boundary of this broad <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_228\">volcanism<\/a>. Unlike the flux-melted <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1750\">magma<\/a> found in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subduction<\/a> zones, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1702\">rift<\/a>-zone <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1750\">magma<\/a> is created by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_223\">decompression melting<\/a>. As the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1668\">lithosphere<\/a> and draws it upwards. When this molten <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1750\">magma<\/a> reaches the weakened and fault-riddled <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1702\">rift<\/a> zone, it migrates to surface by breaking through the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> or escaping via an open fault. Examples of young <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1702\">rift<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_228\">volcanoes<\/a> dot the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1514\">Basin and Range<\/a> region in the United States. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1702\">Rift<\/a>-zone activity is responsible for generating some unique <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_228\">volcanism<\/a>, such as the Ol Doinyo Lengai in Tanzania. This <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_228\">volcano<\/a> erupts <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1751\">lava<\/a> consisting largely of carbonatite, a relatively cold, liquid <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_969\">carbonate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">mineral<\/a>.<\/p>\n<div style=\"width: 720px;\" class=\"wp-video\"><video class=\"wp-video-shortcode\" id=\"video-138-3\" 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_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Rift-Atlantic-Animation-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Rift-Atlantic-Animation-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Rift-Atlantic-Animation-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Rift-Atlantic-Animation-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Rift-Atlantic-Animation-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Rift-Atlantic-Animation-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Rift-Atlantic-Animation-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Rift-Atlantic-Animation-QR-Code.png 1125w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ocean-birth.svg_-212x300.png 212w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ocean-birth.svg_-724x1024.png 724w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ocean-birth.svg_-768x1086.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ocean-birth.svg_-65x92.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ocean-birth.svg_-225x318.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ocean-birth.svg_-350x495.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ocean-birth.svg_.png 848w\" sizes=\"auto, (max-width: 212px) 100vw, 212px\" \/><\/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_138_1702\">rifting<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_228\">volcanic<\/a> activity progress, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1668\">lithosphere<\/a> becomes more <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1669\">plate<\/a> under the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1702\">rifting<\/a> area into <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1668\">lithosphere<\/a> continues to diverge, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1708\">mid-ocean ridge<\/a> is formed.<\/span><\/p>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1708\">Mid-ocean ridges<\/a>, also known as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1668\">lithosphere<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_223\">Decompression melting<\/a> in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1702\">rift<\/a> zone changes <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1671\">asthenosphere<\/a> material into new <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1668\">lithosphere<\/a>, which oozes up through cracks in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a>. The amount of new <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1668\">lithosphere<\/a> being created at <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1708\">mid-ocean ridges<\/a> is highly significant. These undersea <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1702\">rift<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_228\">volcanoes<\/a> produce more <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1751\">lava<\/a> than all other types of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_228\">volcanism<\/a> combined. Despite this, most mid-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> ridge <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1702\">rift<\/a> zones display the type of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/age_oceanic_lith-300x191.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/age_oceanic_lith-1024x653.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/age_oceanic_lith-768x490.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/age_oceanic_lith-1536x980.jpg 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/age_oceanic_lith-65x41.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/age_oceanic_lith-225x144.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/age_oceanic_lith-350x223.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/age_oceanic_lith.jpg 2001w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_1668\">lithosphere<\/a> material, which is lighter than the dense underlying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1671\">asthenosphere<\/a>. This chunk of isostatically buoyant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1668\">lithosphere<\/a> sits partially submerged and partially exposed on the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1668\">lithosphere<\/a> material is pulled away from the area of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1668\">lithosphere<\/a> furthest away from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1756\">Sediment<\/a> layers tend to be thinner near <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Atwater-Spreading-GIF-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Atwater-Spreading-GIF-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Atwater-Spreading-GIF-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Atwater-Spreading-GIF-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Atwater-Spreading-GIF-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Atwater-Spreading-GIF-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Atwater-Spreading-GIF-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Atwater-Spreading-GIF.png 1125w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/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_138_1657\">paleomagnetism<\/a> and the development of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1654\">tectonic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1733\">theory<\/a>, scientists noticed <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1708\">mid-ocean ridges<\/a> contained unique magnetic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Oceanic.Stripe.Magnetic.Anomalies.Scheme.svg_-300x212.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Oceanic.Stripe.Magnetic.Anomalies.Scheme.svg_-65x46.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Oceanic.Stripe.Magnetic.Anomalies.Scheme.svg_-225x159.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Oceanic.Stripe.Magnetic.Anomalies.Scheme.svg_-350x248.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Oceanic.Stripe.Magnetic.Anomalies.Scheme.svg_.png 640w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/a><figcaption id=\"caption-attachment-2544\" class=\"wp-caption-text\">A time progression (with \u00ab\u00a0a\u00a0\u00bb being youngest and \u00ab\u00a0c\u00a0\u00bb 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_138_1750\">magma<\/a> has no magnetic field. As the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a> get pulled apart, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1750\">magma<\/a> cools below the Curie point, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1767\">temperature<\/a> below which a magnetic field gets locked into magnetic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1654\">tectonic<\/a> activity and determine rates of ridge spreading.<\/p>\n<p><iframe loading=\"lazy\" id=\"oembed-2\" title=\"PANGEA Breakup\" width=\"500\" height=\"375\" src=\"https:\/\/www.youtube.com\/embed\/6o1HawAOTEI?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pangea-Animation-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pangea-Animation-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pangea-Animation-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pangea-Animation-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pangea-Animation-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pangea-Animation-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pangea-Animation-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Pangea-Animation-QR-Code.png 1148w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/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 loading=\"lazy\" decoding=\"async\" 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\" 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: 233px) 100vw, 233px\" \/><\/a><figcaption id=\"caption-attachment-2545\" class=\"wp-caption-text\">Black smoker hydrothermal vent with a colony of giant (6&rsquo;+) tube worms.<\/figcaption><\/figure>\n<p>Thanks to their distinctive geology, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1669\">plate<\/a>, carrying dissolved gasses and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.4-Did-I-Get-It-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.4-Did-I-Get-It-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.4-Did-I-Get-It-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.4-Did-I-Get-It-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.4-Did-I-Get-It-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.4-Did-I-Get-It-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.4-Did-I-Get-It-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.4-Did-I-Get-It-QR-Code.png 1147w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Strike_slip_fault-300x137.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Strike_slip_fault-65x30.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Strike_slip_fault-225x103.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Strike_slip_fault-350x160.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Strike_slip_fault.png 437w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_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_138_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_138_1669\">plates<\/a>, looking across the boundary at the opposing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1669\">plate<\/a> moving to the right. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1710\">Sinistral<\/a>, also known as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1710\">left lateral<\/a>, movement describe the opposing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> moving to the left.<\/p>\n<p>Most <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1679\">transform<\/a> boundaries are found on the ocean floor, around <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1708\">mid-ocean ridges<\/a>. These boundaries form aseismic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_986\">fracture<\/a> zones, filled with earthquake-free <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Sanandreas-217x300.jpg 217w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Sanandreas-65x90.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Sanandreas-225x311.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Sanandreas-350x483.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Sanandreas.jpg 362w\" sizes=\"auto, (max-width: 217px) 100vw, 217px\" \/><\/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_138_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_138_228\">volcanism<\/a>. This type of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1669\">plate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1669\">plates<\/a> are unable to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_494\">shear<\/a> past each other the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1679\">transform<\/a> faults occur within <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a>, and have a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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_138_1679\">transform<\/a> faults may create <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_493\">compressional<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_492\">extensional<\/a> forces that cause secondary faulting zones. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1712\">Transpression<\/a> occurs where there is a component of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_493\">compression<\/a> in addition to the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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 loading=\"lazy\" decoding=\"async\" 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_138_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_138_1669\">plates<\/a> are being pulled apart by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_492\">extensional<\/a> forces. Depressions and sometimes <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Wallace_Creek_offset_across_the_San_Andreas_Fault-300x205.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Wallace_Creek_offset_across_the_San_Andreas_Fault-768x524.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Wallace_Creek_offset_across_the_San_Andreas_Fault-65x44.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Wallace_Creek_offset_across_the_San_Andreas_Fault-225x153.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Wallace_Creek_offset_across_the_San_Andreas_Fault-350x239.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Wallace_Creek_offset_across_the_San_Andreas_Fault.png 962w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_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_138_1679\">transform<\/a> boundaries. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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><iframe loading=\"lazy\" id=\"oembed-3\" title=\"Plate Tectonics in a Nutshell (Tanya Atwater)\" width=\"500\" height=\"375\" src=\"https:\/\/www.youtube.com\/embed\/IDTBY5WDELg?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/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_138_1708\"><em>mid-ocean ridge<\/em><\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\"><em>subducts<\/em><\/a>, the relative motion between the remaining <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\"><em>plates<\/em><\/a> become <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1679\"><em>transform<\/em><\/a>, forming the <em>fault<\/em> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1742\"><em>system<\/em><\/a>. Note that because the motion of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plate-Tectonics-YouTube-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plate-Tectonics-YouTube-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plate-Tectonics-YouTube-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plate-Tectonics-YouTube-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plate-Tectonics-YouTube-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plate-Tectonics-YouTube-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plate-Tectonics-YouTube-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plate-Tectonics-YouTube-QR-Code.png 1155w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.5-Did-I-Get-It-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.5-Did-I-Get-It-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.5-Did-I-Get-It-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.5-Did-I-Get-It-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.5-Did-I-Get-It-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.5-Did-I-Get-It-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.5-Did-I-Get-It-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.5-Did-I-Get-It-QR-Code.png 1147w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Wilson-cycle_hg.svg_-300x164.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Wilson-cycle_hg.svg_-1024x559.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Wilson-cycle_hg.svg_-768x419.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Wilson-cycle_hg.svg_-1536x838.png 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Wilson-cycle_hg.svg_-65x35.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Wilson-cycle_hg.svg_-225x123.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Wilson-cycle_hg.svg_-350x191.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Wilson-cycle_hg.svg_.png 1600w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_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_138_1701\">supercontinents<\/a>, such as Pangea and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1730\">hypotheses<\/a> about how the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1715\">Wilson Cycle<\/a> works. One mechanism proposes that <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1702\">rifting<\/a> happens because <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a> reflect the heat much better than <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1664\">mantle<\/a>, generating more vigorous <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1655\">convection<\/a> currents that then start the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1702\">rifting<\/a> process. Some geologists believe <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1664\">mantle<\/a> plumes are remnants of these <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1244\">periods<\/a> of increased <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1664\">mantle<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1767\">temperature<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1702\">rifting<\/a>.<\/p>\n<p>The mechanism behind how <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1730\">hypothesis<\/a> suggests after the initial <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1702\">rifting<\/a> event, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a> continue to be pushed apart by mid-ocean <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1708\">spreading centers<\/a> and their underlying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1655\">convection<\/a> currents. Slab-pull proposes the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a> are pulled apart by descending slabs in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subduction<\/a> zones of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a>&#8211;<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1669\">plates<\/a> down from the elevated <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1708\">mid-ocean ridges<\/a> and across the underlying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1671\">asthenosphere<\/a>. Current evidence seems to support <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 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-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_138_1715\">Wilson Cycle<\/a> provides a broad overview of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1654\">tectonic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> movement. To analyze <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> movement more precisely, scientists study <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1716\">hotspots<\/a>. First postulated by J. Tuzo Wilson in 1963, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1716\">hotspot<\/a> is an area in the lithospheric <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> where molten <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1750\">magma<\/a> breaks through and creates a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1669\">plate<\/a> moves across the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1716\">hotspot<\/a>, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_228\">volcano<\/a> center becomes <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_755\">extinct<\/a> because it is no longer over an active <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1750\">magma<\/a> source. Instead, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1750\">magma<\/a> emerges through another area in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> to create a new active <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_228\">volcano<\/a>. Over time, the combination of moving <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> and stationary <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/HotspotsWorld-300x175.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/HotspotsWorld-65x38.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/HotspotsWorld-225x131.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/HotspotsWorld-350x204.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/HotspotsWorld.png 682w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_1716\">Hotspots<\/a> are the only types of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_228\">volcanism<\/a> not associated with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subduction<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1702\">rifting<\/a> zones at <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> boundaries; they seem totally disconnected from any <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1716\">hotspots<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1654\">plate tectonics<\/a>. There are several <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1702\">rifting<\/a>. Also, scientists use the age of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1669\">plate<\/a> movement relative to the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1716\">hotspot<\/a>.<\/p>\n<p>Scientists are divided over how <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1750\">magma<\/a> is generated in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1716\">hotspots<\/a>. Some suggest that <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1667\">core<\/a> that reaches the Earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1658\">crust<\/a> as a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1717\">mantle plume<\/a>. Others argue the molten material that feeds <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1716\">hotspots<\/a> is sourced from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1767\">temperature<\/a>.<\/p>\n<p>How <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1716\">hotspots<\/a> starting in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1677\">divergent<\/a> boundaries during <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1701\">supercontinent<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1702\">rifting<\/a>. Scientists have identified a number of current and past <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1716\">hotspots<\/a> believed to have begun this way. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">Subducting<\/a> slabs have also been named as causing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1664\">mantle<\/a> plumes and hot-spot <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_228\">volcanism<\/a>. Some geologists have suggested another geological process not involving <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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 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-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_138_228\">volcanoes<\/a> in Hawaii represent one of the most active <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1716\">hotspot<\/a> sites on earth. Scientific evidence indicates the Hawaiian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1717\">mantle plume<\/a> that marks the active <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1716\">hotspot<\/a>. The Kilauea <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_228\">volcano<\/a> is the main <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_234\">vent<\/a> for this <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hawaii_hotspot_cross-sectional_diagram-300x159.jpg 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hawaii_hotspot_cross-sectional_diagram-1024x543.jpg 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hawaii_hotspot_cross-sectional_diagram-768x407.jpg 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hawaii_hotspot_cross-sectional_diagram-1536x814.jpg 1536w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hawaii_hotspot_cross-sectional_diagram-65x34.jpg 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hawaii_hotspot_cross-sectional_diagram-225x119.jpg 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hawaii_hotspot_cross-sectional_diagram-350x186.jpg 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Hawaii_hotspot_cross-sectional_diagram.jpg 1600w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><\/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_138_1717\">mantle plume<\/a> as far down as the lower <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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 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-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_138_1716\">hotspot<\/a> is formed by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1750\">magma<\/a> rising through the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1668\">lithosphere<\/a>. What makes it different is this <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1716\">hotspot<\/a> is located under a thick, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a>. Hawaii sits on a thin <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a>\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a>, which is easily breached by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1750\">magma<\/a> coming to the surface. At Yellowstone, the thick <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> presents a much more difficult barrier for <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1716\">hotspot<\/a> is connected to the much older Columbia River <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_244\">flood basalts<\/a> and even to 70 million-year-old <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 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-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_138_1716\">hotspot<\/a> created the Yellowstone <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_235\">Caldera<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1751\">Lava<\/a> Creek <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1001\">ash<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1750\">magma<\/a> into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1716\">hotspot<\/a> erupt again, scientists predict it will be another <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_228\">volcanic<\/a> eruptions fill the earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1745\">atmosphere<\/a> with so much gas and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.6-7-Did-I-Get-It-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.6-7-Did-I-Get-It-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.6-7-Did-I-Get-It-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.6-7-Did-I-Get-It-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.6-7-Did-I-Get-It-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.6-7-Did-I-Get-It-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.6-7-Did-I-Get-It-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/2.6-7-Did-I-Get-It-QR-Code.png 1147w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/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<p><iframe loading=\"lazy\" id=\"oembed-4\" title=\"Plate Tectonics Basics 1\" width=\"500\" height=\"281\" src=\"https:\/\/www.youtube.com\/embed\/6wJBOk9xjto?feature=oembed&#38;rel=0\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"><\/iframe><\/p>\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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plate-Tectonics-Basics-YouTube-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plate-Tectonics-Basics-YouTube-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plate-Tectonics-Basics-YouTube-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plate-Tectonics-Basics-YouTube-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plate-Tectonics-Basics-YouTube-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plate-Tectonics-Basics-YouTube-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plate-Tectonics-Basics-YouTube-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Plate-Tectonics-Basics-YouTube-QR-Code.png 1155w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/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_138_1654\">Plate tectonics<\/a> is a unifying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1733\">theory<\/a> of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1661\">brittle<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a>. Underneath the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a> is a much hotter and more <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1655\">convection<\/a> currents move the surface <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a> around\u2014bringing them together, pulling them apart, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_494\">shearing<\/a> them side-by-side. Earthquakes and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_228\">volcanoes<\/a> form at the boundaries where the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a> interact, with the exception of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_228\">volcanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1716\">hotspots<\/a>, which are not caused by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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 loading=\"lazy\" decoding=\"async\" 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\" srcset=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ch.2-Review-QR-Code-150x150.png 150w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ch.2-Review-QR-Code-300x300.png 300w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ch.2-Review-QR-Code-1024x1024.png 1024w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ch.2-Review-QR-Code-768x768.png 768w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ch.2-Review-QR-Code-65x65.png 65w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ch.2-Review-QR-Code-225x225.png 225w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ch.2-Review-QR-Code-350x350.png 350w, https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ch.2-Review-QR-Code.png 1147w\" sizes=\"auto, (max-width: 150px) 100vw, 150px\" \/><\/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. Stat. Mech., v. 2006, no. 12, p. P12015.<\/li>\n<li class=\"csl-entry\">Alfe, D., Gillan, M.J., and Price, G.D., 2002, Composition and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1767\">temperature<\/a> of the Earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1667\">core<\/a> 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\">Atwater, T., 1970, Implications of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1654\">Plate Tectonics<\/a> for the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_488\">Cenozoic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1654\">Tectonic<\/a> Evolution of Western North America: Geol. Soc. Am. Bull., v. 81, no. 12, p. 3513\u20133536., doi: <a href=\"https:\/\/doi.org\/10.1130\/0016-7606(1970)81[3513:IOPTFT]2.0.CO;2\">10.1130\/0016-7606(1970)81[3513:IOPTFT]2.0.CO;2<\/a>.<\/li>\n<li class=\"csl-entry\">Bacon, F., and Montagu, B., 1848, The Works of Francis Bacon, Lord Chancellor of England: With a Life of the Author: The Works of Francis Bacon, Lord Chancellor of England: With a Life of the Author, Parry &amp; McMillan, The Works of Francis Bacon, Lord Chancellor of England: With a Life of the Author.<\/li>\n<li class=\"csl-entry\">Benioff, H., 1949, Seismic evidence for the fault origin of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> deeps: Geological Society of America Bulletin, v. 60, no. 12, p. 1837\u20131856., doi: <a href=\"https:\/\/doi.org\/10.1130\/0016-7606(1949)60[1837:SEFTFO]2.0.CO;2\">10.1130\/0016-7606(1949)60[1837:SEFTFO]2.0.CO;2<\/a>.<\/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\">Birch, F., 1964, Density and composition of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1664\">mantle<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1667\">core<\/a>: J. Geophys. Res., v. 69, no. 20, p. 4377\u20134388.<\/li>\n<li class=\"csl-entry\">Bott, M.H.P., 1993, Modelling the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a>-driving mechanism: Journal of the Geological Society, v. 150, no. 5, p. 941\u2013951., doi: <a href=\"https:\/\/doi.org\/10.1144\/gsjgs.150.5.0941\">10.1144\/gsjgs.150.5.0941<\/a>.<\/li>\n<li class=\"csl-entry\">Coats, R.R., 1962, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1750\">Magma<\/a> type and crustal structure in the Aleutian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1687\">Arc<\/a>, <i>in<\/i> The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1658\">Crust<\/a> of the Pacific <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_508\">Basin<\/a>: American Geophysical Union, p. 92\u2013109., doi: <a href=\"https:\/\/doi.org\/10.1029\/GM006p0092\">10.1029\/GM006p0092<\/a>.<\/li>\n<li class=\"csl-entry\">Conrad, C.P., and Lithgow-Bertelloni, C., 2002, How <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1664\">mantle<\/a> slabs drive <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1654\">plate tectonics<\/a>: Science (New York, N.Y.), v. 298, no. 5591, p. 207\u2013209., doi: <a href=\"https:\/\/doi.org\/10.1126\/science.1074161\">10.1126\/science.1074161<\/a>.<\/li>\n<li class=\"csl-entry\">Corliss, J.B., Dymond, J.G., Gordon, L.I., Edmond, J.M., von Heezen, R.P., Ballard, R.D., Green, K., Williams, D.L., Bainbridge, A., Crane, K., and van Andel, T.H., 1979, Submarine thermal springs on the Galapagos <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1702\">Rift<\/a>: Science, v. 203, p. 107321083.<\/li>\n<li class=\"csl-entry\">Davis, E.E., and Lister, C.R.B., 1974, Fundamentals of ridge crest topography: Earth Planet. Sci. Lett., v. 21, no. 4, p. 405\u2013413.<\/li>\n<li class=\"csl-entry\">Dawson, J.B., Pinkerton, H., Norton, G.E., and Pyle, D.M., 1990, Physicochemical properties of alkali carbonatite lavas:Data from the 1988 eruption of Oldoinyo Lengai, Tanzania: Geology, v. 18, no. 3, p. 260\u2013263.<\/li>\n<li class=\"csl-entry\">Drake, E.T., 1976, Alfred Wegener\u2019s reconstruction of Pangea: Geology, v. 4, no. 1, p. 41\u201344., doi: &lt;a href=\u00a0\u00bbhttps:\/\/doi.org\/10.1130\/0091-7613(1976)42.0.CO;2&Prime;&gt;10.1130\/0091-7613(1976)4&lt;41:AWROP&gt;2.0.CO;2.<\/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 <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1667\">core<\/a>: Geophysical J Royal Astro Soc, v. 40, p. 457\u2013463.<\/li>\n<li class=\"csl-entry\">Ewing, M., Ewing, J.I., and Talwani, M., 1964, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">Sediment<\/a> distribution in the oceans: The Mid-Atlantic Ridge: Geol. Soc. Am. Bull., v. 75, no. 1, p. 17\u201336., doi: <a href=\"https:\/\/doi.org\/10.1130\/0016-7606(1964)75[17:SDITOT]2.0.CO;2\">10.1130\/0016-7606(1964)75[17:SDITOT]2.0.CO;2<\/a>.<\/li>\n<li class=\"csl-entry\">Ewing, M., Houtz, R., and Ewing, J., 1969, South Pacific <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> distribution: J. Geophys. Res., v. 74, no. 10, p. 2477\u20132493., doi: <a href=\"https:\/\/doi.org\/10.1029\/JB074i010p02477\">10.1029\/JB074i010p02477<\/a>.<\/li>\n<li class=\"csl-entry\">Fernandez, L.M., and Careaga, J., 1968, The thickness of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1658\">crust<\/a> in central United States and La Paz, Bolivia, from the spectrum of longitudinal seismic waves: Bull. Seismol. Soc. Am., v. 58, no. 2, p. 711\u2013741.<\/li>\n<li class=\"csl-entry\">Fluegel, von H.W., 1980, Wegener-Ampferer-Schwinner. Ein Beitrag zur Geschichte der Geologie in \u00d6sterreich: Mitt. Oesterr. Geol. Ges., v. 73, p. 237\u2013254.<\/li>\n<li class=\"csl-entry\">Forsyth, D.W., 1975, The Early Structural Evolution and Anisotropy of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">Oceanic<\/a> Upper <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1664\">Mantle<\/a>: Geophys. J. Int., v. 43, no. 1, p. 103\u2013162., doi: <a href=\"https:\/\/doi.org\/10.1111\/j.1365-246X.1975.tb00630.x\">10.1111\/j.1365-246X.1975.tb00630.x<\/a>.<\/li>\n<li class=\"csl-entry\">Frankel, H., 1982, The Development, Reception, and Acceptance of the Vine-Matthews-Morley <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1730\">Hypothesis<\/a>: Hist. Stud. Phys. Biol. Sci., v. 13, no. 1, p. 1\u201339.<\/li>\n<li class=\"csl-entry\">Fukao, Y., and Obayashi, M., 2013, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">Subducted<\/a> slabs stagnant above, penetrating through, and trapped below the 660 km discontinuity: J. Geophys. Res. [Solid Earth], v. 118, no. 11, p. 2013JB010466.<\/li>\n<li class=\"csl-entry\">Hagstrum, J.T., 2005, Antipodal <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1716\">hotspots<\/a> and bipolar catastrophes: Were <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> large-body impacts the cause? Earth Planet. Sci. Lett., v. 236, no. 1\u20132, p. 13\u201327.<\/li>\n<li class=\"csl-entry\">Hanks, T.C., and Anderson, D.L., 1969, The early thermal history of the earth: Phys. Earth Planet. Inter., v. 2, no. 1, p. 19\u201329.<\/li>\n<li class=\"csl-entry\">Heezen, B.C., and Tharp, M., 1965, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1654\">Tectonic<\/a> Fabric of the Atlantic and Indian Oceans and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">Continental<\/a> Drift: Philosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences, v. 258, no. 1088, p. 90\u2013106., doi: <a href=\"https:\/\/doi.org\/10.1098\/rsta.1965.0024\">10.1098\/rsta.1965.0024<\/a>.<\/li>\n<li class=\"csl-entry\">Heller, P.L., Bowdler, S.S., Chambers, H.P., Coogan, J.C., Hagen, E.S., Shuster, M.W., Winslow, N.S., and Lawton, T.F., 1986, Time of initial thrusting in the Sevier orogenic belt, Idaho-Wyoming and Utah: Geology, v. 14, no. 5, p. 388\u2013391.<\/li>\n<li class=\"csl-entry\">Herak, D., and Herak, M., 2007, Andrija Mohorovi\u010di\u0107 (1857-1936)\u2014On the occasion of the 150th anniversary of his birth: Seismol. Res. Lett., v. 78, no. 6, p. 671\u2013674.<\/li>\n<li class=\"csl-entry\">Hess, H.H., 1962, History of ocean basins: <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_220\">Petrologic<\/a> studies, v. 4, p. 599\u2013620.<\/li>\n<li class=\"csl-entry\">Hutson, P., Middleton, J., and Miller, D., 2003, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1698\">Collision<\/a> Zones: Online, <a href=\"http:\/\/www.geosci.usyd.edu.au\/users\/prey\/ACSGT\/EReports\/eR.2003\/GroupD\/Report1\/web%20pages\/contents.html\">http:\/\/www.geosci.usyd.edu.au\/users\/prey\/ACSGT\/EReports\/eR.2003\/GroupD\/Report1\/web%20pages\/contents.html<\/a>, accessed June 2017.<\/li>\n<li class=\"csl-entry\">Isacks, B., Oliver, J., and Sykes, L.R., 1968, Seismology and the new global <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1654\">tectonics<\/a>: J. Geophys. Res., v. 73, no. 18, p. 5855\u20135899.<\/li>\n<li class=\"csl-entry\">Ito, E., and Takahashi, E., 1989, Postspinel transformations in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1742\">system<\/a> Mg2SiO4-Fe2SiO4 and some geophysical implications: J. Geophys. Res. [Solid Earth], v. 94, no. B8, p. 10637\u201310646.<\/li>\n<li class=\"csl-entry\">Jacoby, W.R., 1981, Modern concepts of Earth dynamics anticipated by Alfred Wegener in 1912: Geology, v. 9, no. 1, p. 25\u201327., doi: &lt;a href=\u00a0\u00bbhttps:\/\/doi.org\/10.1130\/0091-7613(1981)92.0.CO;2&Prime;&gt;10.1130\/0091-7613(1981)9&lt;25:MCOEDA&gt;2.0.CO;2.<\/li>\n<li class=\"csl-entry\">Jakosky, B.M., Grebowsky, J.M., Luhmann, J.G., Connerney, J., Eparvier, F., Ergun, R., Halekas, J., Larson, D., Mahaffy, P., McFadden, J., Mitchell, D.F., Schneider, N., Zurek, R., Bougher, S., and others, 2015, MAVEN observations of the response of Mars to an interplanetary coronal mass ejection: Science, v. 350, no. 6261, p. aad0210.<\/li>\n<li class=\"csl-entry\">James, D.E., Fouch, M.J., Carlson, R.W., and Roth, J.B., 2011, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1683\">Slab<\/a> fragmentation, edge flow and the origin of the Yellowstone <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1716\">hotspot<\/a> track: Earth Planet. Sci. Lett., v. 311, no. 1\u20132, p. 124\u2013135.<\/li>\n<li class=\"csl-entry\">Ji, Y., and Nataf, H.-C., 1998, Detection of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1664\">mantle<\/a> plumes in the lower <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1664\">mantle<\/a> by diffraction tomography: Hawaii: Earth Planet. Sci. Lett., v. 159, no. 3\u20134, p. 99\u2013115.<\/li>\n<li class=\"csl-entry\">Johnston, S.T., Jane Wynne, P., Francis, D., Hart, C.J.R., Enkin, R.J., and Engebretson, D.C., 1996, Yellowstone in Yukon: The Late <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_487\">Cretaceous<\/a> Carmacks Group: Geology, v. 24, no. 11, p. 997\u20131000.<\/li>\n<li class=\"csl-entry\">Kearey, P., Klepeis, K.A., and Vine, F.J., 2009, Global <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1654\">Tectonics<\/a>: Oxford\u202f; Chichester, West Sussex\u202f; Hoboken, NJ, Wiley-Blackwell, 496 p.<\/li>\n<li class=\"csl-entry\">Le Pichon, X., 1968, Sea-floor spreading and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> drift: J. Geophys. Res., v. 73, no. 12, p. 3661\u20133697.<\/li>\n<li class=\"csl-entry\">Lehmann, I., 1936, P\u2019, Publ: Bur. Centr. Seism. Internat. Serie A, v. 14, p. 87\u2013115.<\/li>\n<li class=\"csl-entry\">Mantovani, R., 1889, Les <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_986\">fractures<\/a> de l\u2019\u00e9corce terrestre et la th\u00e9orie de Laplace: Bull. Soc. Sc. et Arts R\u00e9union, p. 41\u201353.<\/li>\n<li class=\"csl-entry\">Mason, R.G., 1958, A magnetic survey off the west coast of the United-States between latitudes 32-degrees-N and 36-degrees-N longitudes 121-degrees-W and 128-degrees-W: Geophysical Journal of the Royal Astronomical Society, v. 1, no. 4, p. 320.<\/li>\n<li class=\"csl-entry\">Mason, R.G., and Raff, A.D., 1961, Magnetic Survey Off the West Coast of North America, 32\u00b0 N. Latitude to 42\u00b0 N. Latitude: Geological Society of America Bulletin, v. 72, no. 8, p. 1259\u20131265., doi: <a href=\"https:\/\/doi.org\/10.1130\/0016-7606(1961)72[1259:MSOTWC]2.0.CO;2\">10.1130\/0016-7606(1961)72[1259:MSOTWC]2.0.CO;2<\/a>.<\/li>\n<li class=\"csl-entry\">McCollom, T.M., 1999, Methanogenesis as a potential source of chemical energy for primary biomass production by autotrophic organisms in hydrothermal systems on Europa: J. Geophys. Res., v. 104, no. E12, p. 30729\u201330742., doi: <a href=\"https:\/\/doi.org\/10.1029\/1999JE001126\">10.1029\/1999JE001126<\/a>.<\/li>\n<li class=\"csl-entry\">McKenzie, D.P., and Parker, R.L., 1967, The North Pacific: an Example of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1654\">Tectonics<\/a> on a Sphere: Nature, v. 216, p. 1276\u20131280., doi: <a href=\"https:\/\/doi.org\/10.1038\/2161276a0\">10.1038\/2161276a0<\/a>.<\/li>\n<li class=\"csl-entry\">Miller, A.R., Densmore, C.D., Degens, E.T., Hathaway, J.C., Manheim, F.T., McFarlin, P.F., Pocklington, R., and Jokela, A., 1966, Hot brines and recent iron deposits in deeps of the Red Sea: Geochimica et Cosmochimica Acta, v. 30, no. 3, p. 341\u2013359., doi: <a href=\"https:\/\/doi.org\/10.1016\/0016-7037(66)90007-X\">10.1016\/0016-7037(66)90007-X<\/a>.<\/li>\n<li class=\"csl-entry\">Morgan, W.J., 1968, Rises, trenches, great faults, and crustal blocks: J. Geophys. Res., v. 73, no. 6, p. 1959\u20131982., doi: <a href=\"https:\/\/doi.org\/10.1029\/JB073i006p01959\">10.1029\/JB073i006p01959<\/a>.<\/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_138_1680\">subduction<\/a>: J. Geophys. Res. [Solid Earth], v. 96, no. B1, p. 651\u2013665.<\/li>\n<li class=\"csl-entry\">Oldham, R.D., 1906, The constitution of the interior of the Earth, as revealed by earthquakes: Q. J. Geol. Soc. London, v. 62, no. 1\u20134, p. 456\u2013475.<\/li>\n<li class=\"csl-entry\">Pasyanos, M.E., 2010, Lithospheric thickness modeled from long-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1244\">period<\/a> surface wave dispersion: Tectonophysics, v. 481, no. 1\u20134, p. 38\u201350.<\/li>\n<li class=\"csl-entry\">Powell, R.E., and Weldon, R.J., 1992, Evolution of the San Andreas fault: Annu. Rev. Earth Planet. Sci., v. 20, p. 431.<\/li>\n<li class=\"csl-entry\">Raff, A.D., and Mason, R.G., 1961, Magnetic Survey Off the West Coast of North America, 40 N. Latitude to 52 N. Latitude: Geological Society of America Bulletin, v. 72, no. 8, p. 1267\u20131270., doi: <a href=\"https:\/\/doi.org\/10.1130\/0016-7606(1961)72[1267:MSOTWC]2.0.CO;2\">10.1130\/0016-7606(1961)72[1267:MSOTWC]2.0.CO;2<\/a>.<\/li>\n<li class=\"csl-entry\">Runcorn, S.K., 1965, Palaeomagnetic comparisons between Europe and North America: Philosophical Transactions of the Royal Society of London A: Mathematical, Physical and Engineering Sciences, v. 258, no. 1088, p. 1\u201311.<\/li>\n<li class=\"csl-entry\">Saito, T., Ewing, M., and Burckle, L.H., 1966, Tertiary <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> from the mid-atlantic ridge: Science, v. 151, no. 3714, p. 1075\u20131079., doi: <a href=\"https:\/\/doi.org\/10.1126\/science.151.3714.1075\">10.1126\/science.151.3714.1075<\/a>.<\/li>\n<li class=\"csl-entry\">Satake, K., and Atwater, B.F., 2007, Long-term perspectives on giant earthquakes and tsunamis at <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subduction<\/a> zones*: Annu. 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_138_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_138_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_138_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_138_765\">anomalies<\/a> over <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_1009\">Ultramafic<\/a> rocks and the upper <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_220\">petrology<\/a> of the Upper <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1664\">Mantle<\/a>; <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1228\">fossil<\/a> evidence: Naturwissenschaften, v. 91, no. 10, p. 455\u2013471.<\/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 >SunRiver       <\/li><li >Tectonic_plates_boundaries_detailed-en.svg       <\/li><li >Alfred_Wegener_ca.1924-30       <\/li><li >_Antonio_Snider-Pellegrini_Opening_of_the_Atlantic       <\/li><li >ElevationWorld       <\/li><li >Wegener_fossil_map.svg       <\/li><li >Convection       <\/li><li >Global plate motion 2008-04-17       <\/li><li >Deep sea vent chemistry diagram       <\/li><li >Marie Tharp YouTube QR Code       <\/li><li >Earths magnetic field schematic       <\/li><li >Earth Magnetic Field Declination from 1590 to 1990       <\/li><li >magnetic stripes       <\/li><li >Benioff zone       <\/li><li >John Tuzo Wilson in 1992       <\/li><li >Continental Drive Activity QR Code       <\/li><li >2.1 Did I Get It QR Code       <\/li><li >Earth cutaway schematic-en       <\/li><li >MohoDepth       <\/li><li >Iddingsite       <\/li><li >TolucaMeteorite       <\/li><li >Plates tect2 en       <\/li><li >Earth&rsquo;s Inner Layers denoting the LAB       <\/li><li >Perovskite       <\/li><li >Inge Lehmann 1932       <\/li><li >Spinning Outer Core       <\/li><li >Layers of Earth Practice QR Code       <\/li><li >Passive Contiental Margin       <\/li><li >Tectonic_plate_boundaries       <\/li><li >2.2 Did I Get It QR Code       <\/li><li >World geologic provinces       <\/li><li >Subduction Animation QR Code       <\/li><li >Subduction-en       <\/li><li >Terrane       <\/li><li >USGS Terranes       <\/li><li >1755 Lisbon Earthquake Location       <\/li><li >SundaMegathrustSeismicity       <\/li><li >Forearc       <\/li><li >Shallow subduction Laramide orogeny       <\/li><li >OceanContSub       <\/li><li >OceanSub       <\/li><li >ContCollision       <\/li><li >Pangaea continents       <\/li><li >ZagrosFTB       <\/li><li >ItalyPillowBasalt       <\/li><li >India-Asia Collision Animation QR Code       <\/li><li >2.3 Did I Get It QR Code       <\/li><li >Horst-Graben       <\/li><li >Topographic Afar       <\/li><li >Basin range province       <\/li><li >Rift Atlantic Animation QR Code       <\/li><li >02.4_Ocean-birth.svg       <\/li><li >Age Oceanic Lith       <\/li><li >atwater_mag_reversal_mid_ocean_ridge       <\/li><li >Atwater &#8211; Spreading along several mid-ocean ridges GIF       <\/li><li >Oceanic.Stripe.Magnetic.Anomalies.Scheme       <\/li><li >Pangea Animation QR Code       <\/li><li >BlackSmoker       <\/li><li >2.4 Did I Get It QR Code       <\/li><li >Strike slip fault       <\/li><li >Sanandreas       <\/li><li >Restraining Bend       <\/li><li >Releasing bend       <\/li><li >Wallace Creek offset across the San Andreas Fault       <\/li><li >Plate Tectonics YouTube QR Code       <\/li><li >2.5 Did I Get It QR Code       <\/li><li >Wilson-cycle hg       <\/li><li >Hotspot(geology)-1       <\/li><li >CourtHotspots       <\/li><li >Hawaii-Emperor engl       <\/li><li >Hawaii hotspot cross-sectional diagram       <\/li><li >HotspotsSRP update2013       <\/li><li >Yellowstone volcano-ash beds       <\/li><li >2.6-7 Did I Get It QR Code       <\/li><li >Plate Tectonics Basics YouTube QR Code       <\/li><li >Ch.2 Review QR Code       <\/li><\/ul><\/div><div class=\"glossary\"><span class=\"screen-reader-text\" id=\"definition\">d\u00e9finition<\/span><template id=\"term_138_1654\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1730\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1653\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1669\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_228\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1678\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1680\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1677\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1702\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1708\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1679\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1679\"><div tabindex=\"-1\"><p>Groves scratched in rock 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_138_494\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_494\"><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_138_1715\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1715\"><div tabindex=\"-1\"><p>The amount of light that is reflected off of an object like the Earth.<\/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_138_508\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1716\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1750\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1733\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_985\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_985\"><div tabindex=\"-1\"><p>The thin, outer layer of the Earth which makes up the rocky bottom of the ocean basins. 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_138_753\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_753\"><div tabindex=\"-1\"><p>By USGS (unknown photographer) [Public domain], <a href=\"https:\/\/commons.wikimedia.org\/wiki\/File%3ASanJoaquinDrop.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_138_1228\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1228\"><div tabindex=\"-1\"><p>Lowest layer of the soil (C), which is mechanically weathered (not chemically weathered) bedrock.<\/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_138_1969\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1969\"><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_138_1988\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1988\"><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_138_2038\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1659\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1516\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_757\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_757\"><div tabindex=\"-1\"><p>Photo credit to Louis J. Maher, Jr.<\/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_138_765\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_765\"><div tabindex=\"-1\"><figure id=\"attachment_3413\" aria-describedby=\"caption-attachment-3413\" style=\"width: 1024px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/bend2.jpg\"><img class=\"wp-image-699 size-large\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/12\/bend2-1024x436.jpg\" alt=\"Entrenched meander of the Colorado River, downstream of Page, Arizona. High cliffs, that lead down to a river with narrow shores.\" width=\"1024\" height=\"436\"><\/a><figcaption id=\"caption-attachment-3413\" class=\"wp-caption-text\">Entrenched meander of the Colorado River, downstream of Page, Arizona.<\/figcaption><\/figure>\n<h1>11 Water<\/h1>\n<h4><b>KEY CONCEPTS<\/b><\/h4>\n<ul>\n<li style=\"font-weight: 400;\">\n<figure id=\"attachment_3414\" aria-describedby=\"caption-attachment-3414\" style=\"width: 364px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/640px-Aqueduct_of_Segovia_08.jpg\"><img class=\"wp-image-700\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/640px-Aqueduct_of_Segovia_08-300x225.jpg\" alt=\"\" width=\"364\" height=\"273\"><\/a><figcaption id=\"caption-attachment-3414\" class=\"wp-caption-text\">Example of a Roman aqueduct in Segovia, Spain.<\/figcaption><\/figure>\n<p><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW38754758\"><span class=\"TextRun BCX0 SCXW38754758\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW38754758\">Describe the\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW38754758\"><span class=\"TextRun BCX0 SCXW38754758\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW38754758\">processes<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW38754758\"><span class=\"TextRun BCX0 SCXW38754758\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW38754758\">\u00a0of the water cycle<\/span><\/span><\/span><\/li>\n<li style=\"font-weight: 400;\"><span class=\"TextRun BCX0 SCXW197926192\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW197926192\">Describe drainage basins, watershed protection, and water budget<\/span><\/span><\/li>\n<li style=\"font-weight: 400;\"><span class=\"TextRun SCXW76897045 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW76897045 BCX0\">Describe reasons for water laws, who controls them, and how water is shared in the western U.S.<\/span><\/span><\/li>\n<li style=\"font-weight: 400;\"><span class=\"TextRun BCX0 SCXW36017110\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW36017110\">Describe zone of transport, zone of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> production, zone of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1757\">deposition<\/a>, and equilibrium<\/span><\/span><\/li>\n<li style=\"font-weight: 400;\"><span class=\"TextRun BCX0 SCXW97979262\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW97979262\">Describe stream landforms: channel types, alluvial fans, floodplains, natural levees, deltas, entrenched meanders, and terraces<\/span><\/span><\/li>\n<li style=\"font-weight: 400;\"><span class=\"TextRun SCXW13072825 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW13072825 BCX0\">Describe the properties required for a good aquifer; define confining layer water table<\/span><\/span><\/li>\n<li><span class=\"TextRun SCXW108299043 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW108299043 BCX0\">Describe three major groups of water contamination and three types of remediation<\/span><\/span><\/li>\n<li><span class=\"TrackChangeTextInsertion TrackedChange SCXW51411932 BCX0\"><span class=\"TextRun SCXW51411932 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW51411932 BCX0\">Describ<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW51411932 BCX0\"><span class=\"TextRun SCXW51411932 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW51411932 BCX0\">e<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW51411932 BCX0\"><span class=\"TextRun SCXW51411932 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW51411932 BCX0\"> karst topography<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW51411932 BCX0\"><span class=\"TextRun SCXW51411932 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW51411932 BCX0\">, how\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW51411932 BCX0\"><span class=\"TextRun SCXW51411932 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW51411932 BCX0\">it is\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW51411932 BCX0\"><span class=\"TextRun SCXW51411932 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW51411932 BCX0\">created,\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW51411932 BCX0\"><span class=\"TextRun SCXW51411932 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW51411932 BCX0\">and\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW51411932 BCX0\"><span class=\"TextRun SCXW51411932 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW51411932 BCX0\">the landforms that characterize it<\/span><\/span><\/span><\/li>\n<\/ul>\n<p><span style=\"font-weight: 400;\">All life on Earth requires water. \u00a0The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1744\">hydrosphere<\/a> (Earth\u2019s water) is an important agent of geologic change. Water shapes our planet by depositing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a>, aiding <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1760\">lithification<\/a>, and altering rocks after they are lithified. Water carried by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1680\">subducted<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plates<\/a> causes <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1686\">flux\u00a0melting<\/a> of upper <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1664\">mantle<\/a> material. Water is among the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1684\">volatiles<\/a> in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1750\">magma<\/a> and emerges at the surface as steam in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_228\">volcanoes<\/a>.<\/span><\/p>\n<figure id=\"attachment_3415\" aria-describedby=\"caption-attachment-3415\" style=\"width: 199px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/4650720277_e5ff788fc0_z.jpg\"><img class=\"size-medium wp-image-701\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/4650720277_e5ff788fc0_z-199x300.jpg\" alt=\"Mayan stone figure with a long elephant-like nose representing a water deity.\" width=\"199\" height=\"300\"><\/a><figcaption id=\"caption-attachment-3415\" class=\"wp-caption-text\">Chac mask in Mexico.<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400;\">Humans rely on suitable water sources for consumption, agriculture, power generation, and many other purposes. In pre-industrial civilizations, the powerful controlled water resources <span class=\"NormalTextRun BCX0 SCXW10523279\">[<\/span><span class=\"NormalTextRun BCX0 SCXW10523279\">1<\/span><span class=\"NormalTextRun BCX0 SCXW10523279\">,<\/span><span class=\"NormalTextRun BCX0 SCXW10523279\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW10523279\">2<\/span><span class=\"NormalTextRun BCX0 SCXW10523279\">]<\/span><\/span><span style=\"font-weight: 400;\">.\u00a0 As shown in the figures, two thousand year old Roman aqueducts still grace European, Middle Eastern, and North African skylines<\/span><span style=\"font-weight: 400;\">. \u00a0Ancient Mayan architecture depicts water imagery such as frogs, water-lilies, water fowl to illustrate the importance of water in their societies <span class=\"NormalTextRun BCX0 SCXW10523279\">[<\/span><span class=\"NormalTextRun BCX0 SCXW10523279\">3<\/span><span class=\"NormalTextRun BCX0 SCXW10523279\">]<\/span><\/span><span style=\"font-weight: 400;\">.\u00a0 In the drier lowlands of the Yucatan Peninsula, mask facades of the hooked-nosed rain god, <\/span><i><span style=\"font-weight: 400;\">Chac <\/span><\/i><span style=\"font-weight: 400;\">(or <em>Chaac)<\/em><\/span>\u00a0<span style=\"font-weight: 400;\">are prominent on Mayan buildings such as the Kodz Poop (Temple of the Masks, sometimes spelled <span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW77517608\"><span class=\"TextRun BCX0 SCXW77517608\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW77517608\">Coodz<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW77517608\"><span class=\"TextRun BCX0 SCXW77517608\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW77517608\">\u00a0Poop<\/span><\/span><\/span>) at the ceremonial site of Kabah. To this day government c<\/span><span style=\"font-weight: 400;\">ontrolled water continues to be an integral part of most modern societies.\u00a0\u00a0<\/span><\/p>\n<h2><span style=\"font-weight: 400;\">11.1 Water Cycle<\/span><\/h2>\n<figure id=\"attachment_3416\" aria-describedby=\"caption-attachment-3416\" style=\"width: 385px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/11.2watercycle-page.jpg\"><img class=\"wp-image-702\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/11.2watercycle-page-300x209.jpg\" alt=\"The water cycle.\" width=\"385\" height=\"268\"><\/a><figcaption id=\"caption-attachment-3416\" class=\"wp-caption-text\">The water cycle.<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400;\">The water cycle is the continuous circulation of water in the Earth's <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1745\">atmosphere<\/a>. During circulation, water\u00a0 changes between solid, liquid, and gas (water vapor) and changes location. <span class=\"TrackChangeTextInsertion TrackedChange SCXW39602649 BCX0\"><span class=\"TextRun SCXW39602649 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW39602649 BCX0\">The processes involved\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW39602649 BCX0\"><span class=\"TextRun SCXW39602649 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW39602649 BCX0\">in the water cycle\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW39602649 BCX0\"><span class=\"TextRun SCXW39602649 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW39602649 BCX0\">are evaporation, transpiration, condensation, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1785\">precipitation<\/a>, and runoff.\u00a0<\/span><\/span><\/span><span class=\"EOP TrackedChange SCXW39602649 BCX0\" data-ccp-props=\"{&quot;201341983&quot;:2,&quot;335559739&quot;:120,&quot;335559740&quot;:240}\">\u00a0<\/span><\/span><\/p>\n<p><span style=\"font-weight: 400;\">Evaporation is the process by which a liquid is converted to a gas. Water evaporates when solar energy warms the water sufficiently to excite the water molecules to the point of vaporization. Evaporation occurs from oceans, lakes, and streams\u00a0and the land surface. Plants <span class=\"TextRun BCX0 SCXW207464996\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW207464996\">contribute significant amounts of water vapor as a byproduct of photosynthesis called transpiration <\/span><\/span>that occurs through the minute pores of plant leaves<\/span><span style=\"font-weight: 400;\">. <span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW207464996\"><span class=\"TextRun BCX0 SCXW207464996\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW207464996\">The term\u00a0<\/span><\/span><\/span><strong><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW207464996\"><span class=\"TextRun BCX0 SCXW207464996\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW207464996\">evapotranspiration<\/span><\/span><\/span><\/strong><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW207464996\"><span class=\"TextRun BCX0 SCXW207464996\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW207464996\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW207464996\"><span class=\"TextRun BCX0 SCXW207464996\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW207464996\">refers to<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW207464996\"><span class=\"TextRun BCX0 SCXW207464996\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW207464996\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW207464996\"><span class=\"TextRun BCX0 SCXW207464996\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW207464996\">these two sources of water entering the<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW207464996\"><span class=\"TextRun BCX0 SCXW207464996\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW207464996\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW207464996\"><span class=\"TextRun BCX0 SCXW207464996\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW207464996\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1745\">atmosphere<\/a><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW207464996\"><span class=\"TextRun BCX0 SCXW207464996\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW207464996\">\u00a0and is\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW207464996\"><span class=\"TextRun BCX0 SCXW207464996\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW207464996\">commonly used by g<\/span><\/span><\/span>eologists.<\/span><\/p>\n<p><span style=\"font-weight: 400;\"><span class=\"TrackChangeTextInsertion TrackedChange SCXW11741361 BCX0\"><span class=\"TextRun SCXW11741361 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart SCXW11741361 BCX0\">Water vapor is invisible. Condensation is the process of <\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW11741361 BCX0\"><span class=\"TextRun SCXW11741361 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW11741361 BCX0\">w<\/span><\/span><\/span><span class=\"TextRun SCXW11741361 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW11741361 BCX0\">ater vapor\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW11741361 BCX0\"><span class=\"TextRun SCXW11741361 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW11741361 BCX0\">transitioning to a liq<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW11741361 BCX0\"><span class=\"TextRun SCXW11741361 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW11741361 BCX0\">uid<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW11741361 BCX0\"><span class=\"TextRun SCXW11741361 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW11741361 BCX0\">. <\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW11741361 BCX0\"><span class=\"TextRun SCXW11741361 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW11741361 BCX0\">Winds carry<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW11741361 BCX0\"><span class=\"TextRun SCXW11741361 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW11741361 BCX0\"> water vapor <\/span><\/span><\/span>in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1745\">atmosphere<\/a> long distances. <span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW11741361\"><span class=\"TextRun BCX0 SCXW11741361\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW11741361\">When\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW11741361\"><span class=\"TextRun BCX0 SCXW11741361\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW11741361\">water\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW11741361\"><span class=\"TextRun BCX0 SCXW11741361\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW11741361\">vapor<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW11741361\"><span class=\"TextRun BCX0 SCXW11741361\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW11741361\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW11741361\"><span class=\"TextRun BCX0 SCXW11741361\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW11741361\">cools or\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW11741361\"><span class=\"TextRun BCX0 SCXW11741361\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW11741361\">when air masses of different temperatures mix<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW11741361\"><span class=\"TextRun BCX0 SCXW11741361\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW11741361\">,<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW11741361\"><span class=\"TextRun BCX0 SCXW11741361\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW11741361\"> water vapor may condense back into droplets of liquid water. <\/span><\/span><\/span>These water droplets usually form around a microscopic piece of dust or salt called condensation nuclei.<span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW215532585\"><span class=\"TextRun BCX0 SCXW215532585\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart BCX0 SCXW215532585\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW215532585\"><span class=\"TextRun BCX0 SCXW215532585\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW215532585\">T<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW215532585\"><span class=\"TextRun BCX0 SCXW215532585\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW215532585\">he<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW215532585\"><span class=\"TextRun BCX0 SCXW215532585\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW215532585\">se<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW215532585\"><span class=\"TextRun BCX0 SCXW215532585\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW215532585\"> small d<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW215532585\"><span class=\"TextRun BCX0 SCXW215532585\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW215532585\">roplets of liquid\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW215532585\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW215532585\">water\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW215532585\"><span class=\"TextRun BCX0 SCXW215532585\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW215532585\">suspended in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1745\">atmosphere<\/a> become<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW215532585\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW215532585\"> visible <\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW215532585\"><span class=\"TextRun BCX0 SCXW215532585\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW215532585\">as<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW215532585\"><span class=\"TextRun BCX0 SCXW215532585\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW215532585\">\u00a0in\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW215532585\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW215532585\">a cloud.<\/span><\/span> <span class=\"TrackChangeTextInsertion TrackedChange SCXW82462577 BCX0\"><span class=\"TextRun SCXW82462577 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart SCXW82462577 BCX0\">Water droplets inside c<\/span><\/span><\/span><span class=\"TextRun SCXW82462577 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW82462577 BCX0\">louds\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW82462577 BCX0\"><span class=\"TextRun SCXW82462577 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW82462577 BCX0\">collide and stick<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW82462577 BCX0\"><span class=\"TextRun SCXW82462577 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW82462577 BCX0\">\u00a0together<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW82462577 BCX0\"><span class=\"TextRun SCXW82462577 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW82462577 BCX0\">, growing into larger<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW82462577 BCX0\"><span class=\"TextRun SCXW82462577 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW82462577 BCX0\"> droplets. O<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW82462577 BCX0\"><span class=\"TextRun SCXW82462577 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW82462577 BCX0\">nce<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW82462577 BCX0\"><span class=\"TextRun SCXW82462577 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW82462577 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW82462577 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW82462577 BCX0\">the\u00a0<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW82462577 BCX0\"><span class=\"TextRun SCXW82462577 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart SCXW82462577 BCX0\">water\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW82462577 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW82462577 BCX0\">droplets\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW82462577 BCX0\"><span class=\"TextRun SCXW82462577 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW82462577 BCX0\">become <\/span><\/span><\/span><span class=\"TextRun SCXW82462577 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW82462577 BCX0\">big enough, they fall to\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW82462577 BCX0\"><span class=\"TextRun SCXW82462577 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW82462577 BCX0\">E<\/span><\/span><\/span><span class=\"TextRun SCXW82462577 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW82462577 BCX0\">arth as<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW82462577 BCX0\"><span class=\"TextRun SCXW82462577 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW82462577 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW82462577 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW82462577 BCX0\">rain, snow, hail, or sleet.<\/span><\/span><span class=\"EOP SCXW82462577 BCX0\" data-ccp-props=\"{&quot;201341983&quot;:2,&quot;335559739&quot;:120,&quot;335559740&quot;:240}\">\u00a0<\/span><\/span><\/p>\n<p><span style=\"font-weight: 400;\">Once <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1785\">precipitation<\/a> has reached the Earth's surface, it can evaporate or flow as <strong>runoff<\/strong> into streams, lakes, and eventually back to the oceans. \u00a0Water in streams and lakes is called surface water.\u00a0 Or water can also <strong>infiltrate<\/strong> into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_250\">soil<\/a> and fill the pore spaces in the rock or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> underground to become <strong>groundwater<\/strong>. Groundwater slowly moves through rock and unconsolidated materials. Some groundwater may reach the surface again, where it discharges as springs, streams, lakes, and\u00a0 the ocean. Also, surface water in streams and lakes can infiltrate again to recharge groundwater. \u00a0Therefore, the surface water and groundwater systems are connected.<\/span><\/p>\n<figure id=\"attachment_4554\" aria-describedby=\"caption-attachment-4554\" style=\"width: 150px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/The-Water-Cycle-Youtube-QR-Code.png\"><img class=\"size-medium wp-image-703\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/The-Water-Cycle-Youtube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4554\" 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<p><i><\/i><\/p>\n<div id=\"h5p-75\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-75\" class=\"h5p-iframe\" data-content-id=\"75\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"11.2 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_4536\" aria-describedby=\"caption-attachment-4536\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/11.1-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-704\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/11.1-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4536\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 11.1 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-weight: 400;\">11.2 Water Basins and Budgets<\/span><\/h2>\n<figure id=\"attachment_3417\" aria-describedby=\"caption-attachment-3417\" style=\"width: 226px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/11.6-Hydrographic_basin.svg_.png\"><img class=\"wp-image-705\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/11.6-Hydrographic_basin.svg_-300x296.png\" alt=\"Map view of a drainage basin with main trunk streams and many tributaries with drainage divide in dashed red line.\" width=\"226\" height=\"223\"><\/a><figcaption id=\"caption-attachment-3417\" class=\"wp-caption-text\">Map view of a drainage basin with main trunk streams and many tributaries with drainage divide in dashed red line.<\/figcaption><\/figure>\n<p>The basic unit of division of the landscape is the <b>drainage basin<\/b>, also known as a\u00a0<b>catchment<\/b>\u00a0or <b>watershed. It<\/b> is the area of land that captures <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1785\">precipitation<\/a> and contributes runoff to a stream or stream segment <span class=\"FindHit BCX0 SCXW83290690\">[<\/span><span class=\"NormalTextRun BCX0 SCXW83290690\">4]<\/span>. <strong>Drainage divides<\/strong> are local topographic high points that separate one drainage basin from another <span class=\"FindHit BCX0 SCXW190510073\">[<\/span><span class=\"NormalTextRun BCX0 SCXW190510073\">5<\/span><span class=\"NormalTextRun BCX0 SCXW190510073\">]<\/span>. Water that falls on one side of the divide goes to one stream, and water that falls on the other side of the divide goes to a different stream. Each stream, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1774\">tributary<\/a> and streamlet has its own drainage basin. In areas with flatter topography, drainage divides are not as easily identified but they still exist<span class=\"NormalTextRun BCX0 SCXW26145523\">\u00a0<\/span><span class=\"FindHit BCX0 SCXW26145523\">[<\/span><span class=\"NormalTextRun BCX0 SCXW26145523\">6<\/span><span class=\"NormalTextRun BCX0 SCXW26145523\">]<\/span>.<\/p>\n<figure id=\"attachment_3418\" aria-describedby=\"caption-attachment-3418\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/1024px-EN_Bazinul_hidrografic_al_Raului_Latorita_Romania.jpg\"><img class=\"wp-image-706 size-medium\" title=\"By Asybaris01\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/1024px-EN_Bazinul_hidrografic_al_Raului_Latorita_Romania-300x214.jpg\" alt=\"Oblique view of the drainage basin and divide of the Latorita River, Romania.\" width=\"300\" height=\"214\"><\/a><figcaption id=\"caption-attachment-3418\" class=\"wp-caption-text\">Oblique view of the drainage basin and divide of the Latorita River, Romania.<\/figcaption><\/figure>\n<p>The headwater is where the stream begins. Smaller <b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1774\">tributary<\/a> <\/b>streams combine downhill to make the larger trunk of the stream. The <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1776\">mouth<\/a><\/strong> is where the stream finally reaches its end. The mouth of most streams is at the ocean. However, a rare number of streams do not flow to the ocean, but rather end in a <b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1777\">closed basin<\/a><\/b> (or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1777\">endorheic basin<\/a>) where the only outlet is evaporation. Most streams in the Great <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_508\">Basin<\/a> of Western North America end in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1777\">endorheic basins<\/a>. For example, in Salt Lake County, Utah, Little Cottonwood Creek and the Jordan River flow into the endorheic Great Salt Lake where the water evaporates.<\/p>\n<figure id=\"attachment_3419\" aria-describedby=\"caption-attachment-3419\" style=\"width: 1024px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Ocean_drainage.png\"><img class=\"wp-image-707 size-full\" title=\"By Citynoise at English Wikipedia \" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ocean_drainage.png\" alt=\"Major drainage basins color coded to match the related ocean. Closed basins (or endorheic basins) are shown in gray.\" width=\"1024\" height=\"535\"><\/a><figcaption id=\"caption-attachment-3419\" class=\"wp-caption-text\">Major drainage basins color coded to match the related ocean. Closed basins (or endorheic basins) are shown in gray.<\/figcaption><\/figure>\n<p><span class=\"TextRun SCXW135665434 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart SCXW135665434 BCX0\">Perennial streams flow all year round. <\/span><\/span><b>Perennial streams<\/b> occur in humid or temperate climates where there is sufficient rainfall and low evaporation rates. \u00a0Water levels rise and fall with the seasons, depending on the discharge. <b>Ephemeral streams<\/b> flow only during rain events or the wet season. <span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW135665434\"><span class=\"TextRun BCX0 SCXW135665434\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW135665434\">I<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW135665434\"><span class=\"TextRun BCX0 SCXW135665434\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW135665434\">n arid climates<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW135665434\"><span class=\"TextRun BCX0 SCXW135665434\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW135665434\">,<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW135665434\"><span class=\"TextRun BCX0 SCXW135665434\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW135665434\">\u00a0like Utah, many<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW135665434\"><span class=\"TextRun BCX0 SCXW135665434\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW135665434\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW135665434\"><span class=\"TextRun BCX0 SCXW135665434\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW135665434\">streams<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW135665434\"><span class=\"TextRun BCX0 SCXW135665434\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW135665434\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW135665434\"><span class=\"TextRun BCX0 SCXW135665434\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW135665434\">are<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW135665434\"><span class=\"TextRun BCX0 SCXW135665434\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW135665434\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW135665434\"><span class=\"TextRun BCX0 SCXW135665434\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW135665434\">ephemeral.\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW135665434\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW135665434\">These\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW135665434\"><span class=\"TextRun BCX0 SCXW135665434\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW135665434\">streams\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW135665434\"><span class=\"TextRun BCX0 SCXW135665434\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW135665434\">occur in dry climates with low amounts of rainfall and high evaporation rates. Their channels are <span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW135665434\">often<\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW135665434\">\u00a0<\/span>dry washes\u00a0or\u00a0arroyos\u00a0for much of the year and t<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW135665434\"><span class=\"TextRun BCX0 SCXW135665434\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW135665434\">heir sudden flow causes <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1506\">flash floods<\/a> <span class=\"FindHit BCX0 SCXW92545693\">[<\/span><span class=\"NormalTextRun BCX0 SCXW92545693\">7<\/span><span class=\"NormalTextRun BCX0 SCXW92545693\">]<\/span>.<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW135665434\"><span class=\"TextRun BCX0 SCXW135665434\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW135665434\">\u00a0<\/span><\/span><\/span><\/p>\n<p>Along Utah\u2019s Wasatch Front,\u00a0<span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW73071915\"><span class=\"TextRun BCX0 SCXW73071915\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW73071915\">the urban area extending north<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW73071915\"><span class=\"TextRun BCX0 SCXW73071915\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW73071915\">\u00a0to\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW73071915\"><span class=\"TextRun BCX0 SCXW73071915\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW73071915\">south from Brigham City to Provo,\u00a0<\/span><\/span><\/span>there are several watersheds that are designated as \u201cwatershed protection areas\u201d that limit the type of use allowed in those drainages in order to protect culinary water. \u00a0Dogs and swimming are limited in those watersheds because of the possibility of contamination by harmful bacteria and substances to the drinking supply of Salt Lake City and surrounding municipalities.<\/p>\n<p><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart SCXW230395698 BCX0\">Water\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">in the water cycle\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">is very much like money in a personal budget. I<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">ncome\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">includes<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1785\">precipitation<\/a><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">\u00a0and\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">stream<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">and<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">groundwater<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">inflow<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">.<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">E<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">xpenses\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">include<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">groundwater<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">withdrawal, evaporation, and<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">stream<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">and<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">groundwater<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">outflow. If the expenses outweigh the income, the water budget is not balanced<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">. In this case, <\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">water\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">is\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">removed from\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">savings<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">, i.e. <\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">water\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">storage<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">,<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">if available.<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">Reservoirs, snow<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">,\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">ice,<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_250\">soil<\/a><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">moisture, and<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">aquifers<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">all\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">serve<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">a<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">s\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">storage in a water budget.<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">\u00a0In\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">dry regions, the water is critical for sustaining human activities<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">. U<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">nderstanding and managing\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\">the water budget<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW230395698 BCX0\"><span class=\"TextRun SCXW230395698 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW230395698 BCX0\"> is an ongoing political and social challenge.<\/span><\/span><\/span><span class=\"EOP TrackedChange SCXW230395698 BCX0\" data-ccp-props=\"{&quot;201341983&quot;:2,&quot;335559739&quot;:120,&quot;335559740&quot;:240}\">\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Hydrologists create groundwater budgets within any designated area, but they are generally made for watershed (<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_508\">basin<\/a>) boundaries, because groundwater and surface water are easier to account for within these boundaries. Water budgets can be created for state, county, or aquifer extent boundaries as well. \u00a0The groundwater budget is an essential component of the hydrologic model; hydrologists use measured data with a conceptual workflow of the model to better understand the water <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1742\">system<\/a>.<\/span><\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-78\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-78\" class=\"h5p-iframe\" data-content-id=\"78\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"11.6 Map of Mississippi River meander channels\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_4537\" aria-describedby=\"caption-attachment-4537\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/11.2-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-708\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/11.2-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4537\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 11.2 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-weight: 400;\">11.3 Water Use and Distribution<\/span><\/h2>\n<figure id=\"attachment_3420\" aria-describedby=\"caption-attachment-3420\" style=\"width: 431px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/11.4_Earth111Mod1Fig11.png\"><img class=\"wp-image-709\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/11.4_Earth111Mod1Fig11-300x274.png\" alt=\"Agricultural water use in the United States by state.\" width=\"431\" height=\"393\"><\/a><figcaption id=\"caption-attachment-3420\" class=\"wp-caption-text\">Agricultural water use in the United States by state.<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400;\">In the United States, <span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW140405130\"><span class=\"TrackedChange BCX0 SCXW140405130\"><span class=\"TextRun Highlight BCX0 SCXW140405130\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW140405130\">1,<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW140405130\"><span class=\"TrackedChange BCX0 SCXW140405130\"><span class=\"TextRun Highlight BCX0 SCXW140405130\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW140405130\">34<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW140405130\"><span class=\"TextRun Highlight BCX0 SCXW140405130\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW140405130\">4 billion<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW140405130\"><span class=\"TrackedChange BCX0 SCXW140405130\"><span class=\"TextRun Highlight BCX0 SCXW140405130\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW140405130\">\u00a0<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW140405130\"><span class=\"TextRun Highlight BCX0 SCXW140405130\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW140405130\">L<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW140405130\"><span class=\"TrackedChange BCX0 SCXW140405130\"><span class=\"TextRun Highlight BCX0 SCXW140405130\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW140405130\">\u00a0(<\/span><\/span><\/span><\/span>355 billion gallons) of ground and surface water are used each day, of which <span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW140405130\"><span class=\"TrackedChange BCX0 SCXW140405130\"><span class=\"TextRun Highlight BCX0 SCXW140405130\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW140405130\">2<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW140405130\"><span class=\"TrackedChange BCX0 SCXW140405130\"><span class=\"TextRun Highlight BCX0 SCXW140405130\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW140405130\">8<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW140405130\"><span class=\"TrackedChange BCX0 SCXW140405130\"><span class=\"TextRun Highlight BCX0 SCXW140405130\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW140405130\">8 billion<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW140405130\"><span class=\"TrackedChange BCX0 SCXW140405130\"><span class=\"TextRun Highlight BCX0 SCXW140405130\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW140405130\">\u00a0<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW140405130\"><span class=\"TrackedChange BCX0 SCXW140405130\"><span class=\"TextRun Highlight BCX0 SCXW140405130\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW140405130\">L<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW140405130\"><span class=\"TextRun BCX0 SCXW140405130\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW140405130\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW140405130\"><span class=\"TrackedChange BCX0 SCXW140405130\"><span class=\"TextRun Highlight BCX0 SCXW140405130\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW140405130\">(<\/span><\/span><\/span><\/span>76 billion gallons) are fresh groundwater. \u00a0The state of California uses 16% of national groundwater <span class=\"FindHit BCX0 SCXW70803371\">[<\/span><span class=\"NormalTextRun BCX0 SCXW70803371\">8<\/span><span class=\"NormalTextRun BCX0 SCXW70803371\">]<\/span><\/span><span style=\"font-weight: 400;\">.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Utah is the second driest state in the United States. Nevada, having a mean statewide <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1785\">precipitation<\/a> of\u00a0<span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW225581329\"><span class=\"TrackedChange BCX0 SCXW225581329\"><span class=\"TextRun Highlight BCX0 SCXW225581329\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW225581329\">31\u00a0<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW225581329\"><span class=\"TextRun Highlight BCX0 SCXW225581329\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW225581329\">c<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW225581329\"><span class=\"TrackedChange BCX0 SCXW225581329\"><span class=\"TextRun Highlight BCX0 SCXW225581329\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW225581329\">m<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW225581329\"><span class=\"TextRun BCX0 SCXW225581329\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW225581329\">\u00a0(<\/span><\/span><\/span>12.2 inches) per year, is the driest. \u00a0Utah also has the second highest per capita rate of total domestic water use <\/span><span style=\"font-weight: 400;\">of <span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW225581329\"><span class=\"TrackedChange BCX0 SCXW225581329\"><span class=\"TextRun Highlight BCX0 SCXW225581329\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW225581329\">632.16\u00a0<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW225581329\"><span class=\"TrackedChange BCX0 SCXW225581329\"><span class=\"TextRun Highlight BCX0 SCXW225581329\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW225581329\">L<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW225581329\"><span class=\"TextRun BCX0 SCXW225581329\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW225581329\">\u00a0(<\/span><\/span><\/span>167 gallonsL per <\/span><span style=\"font-weight: 400;\">day per person <span class=\"FindHit BCX0 SCXW70803371\">[<\/span><span class=\"NormalTextRun BCX0 SCXW70803371\">8<\/span><span class=\"NormalTextRun BCX0 SCXW70803371\">]<\/span>. \u00a0With the combination of relatively high demand and limited quantity, Utah is at risk for water budget deficits.<\/span><\/p>\n<figure id=\"attachment_3421\" aria-describedby=\"caption-attachment-3421\" style=\"width: 610px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/11.4_trends-bar-2010.png\"><img class=\"size-full wp-image-710\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/11.4_trends-bar-2010.png\" alt=\"Trends in water use by source\" width=\"610\" height=\"357\"><\/a><figcaption id=\"caption-attachment-3421\" class=\"wp-caption-text\">Trends in water use by source<\/figcaption><\/figure>\n<h3><b>11.3.1 Surface Water Distribution<\/b><\/h3>\n<p><span style=\"font-weight: 400;\"><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW10965646\"><span class=\"TextRun BCX0 SCXW10965646\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW10965646\">Fresh water is a precious resource and should not be taken for granted, especially in dry<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW10965646\"><span class=\"TextRun BCX0 SCXW10965646\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW10965646\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW10965646\"><span class=\"TextRun BCX0 SCXW10965646\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW10965646\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_757\">climate<\/a><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW10965646\"><span class=\"TextRun BCX0 SCXW10965646\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW10965646\">s<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW10965646\"><span class=\"TextRun BCX0 SCXW10965646\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW10965646\">. <\/span><\/span><\/span>Surface water makes up only 1.2% of the fresh water available on the planet, and 69% of that surface water is trapped in ground ice and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_760\">permafrost<\/a>. \u00a0Stream water accounts for only 0.006% of all freshwater and lakes contain only 0.26% of the world\u2019s fresh water <span class=\"FindHit BCX0 SCXW253398420\">[<\/span><span class=\"NormalTextRun BCX0 SCXW253398420\">9<\/span><span class=\"NormalTextRun BCX0 SCXW253398420\">]<\/span><\/span><span style=\"font-weight: 400;\">.\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Global circulation patterns are the most important factor in <span class=\"TextRun BCX0 SCXW37402210\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW37402210\">\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW37402210\"><span class=\"TextRun BCX0 SCXW37402210\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart BCX0 SCXW37402210\">distributi<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW37402210\"><span class=\"TextRun BCX0 SCXW37402210\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW37402210\">ng<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW37402210\"><span class=\"TextRun BCX0 SCXW37402210\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW37402210\">\u00a0surface water\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW37402210\"><span class=\"TextRun BCX0 SCXW37402210\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW37402210\">through\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW37402210\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW37402210\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1785\">precipitation<\/a><\/span><\/span>. D<\/span><span style=\"font-weight: 400;\">ue to the Coriolis effect and the uneven heating of the Earth, air rises near the equator and near latitudes 60\u00b0 north and south. A<\/span><span style=\"font-weight: 400;\">ir sinks at the poles and latitudes 30\u00b0 north and south\u00a0 (see <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/13-deserts\/\" target=\"_blank\" rel=\"noopener\"><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW234167386\"><span class=\"FieldRange BCX0 SCXW234167386\"><span class=\"TextRun Underlined BCX0 SCXW234167386\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"none\"><span class=\"NormalTextRun BCX0 SCXW234167386\" data-ccp-charstyle=\"Hyperlink\">Chapter 13<\/span><\/span><\/span><\/span><\/a>). <span class=\"TextRun BCX0 SCXW234167386\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234167386\">\u00a0Land masses near rising air are\u00a0<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW234167386\"><span class=\"TextRun BCX0 SCXW234167386\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234167386\">more\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW234167386\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234167386\">prone to humid and wet climates<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW234167386\"><span class=\"TextRun BCX0 SCXW234167386\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234167386\">. Land masses near<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW234167386\"><span class=\"TextRun BCX0 SCXW234167386\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234167386\">\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW234167386\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234167386\">sinking air<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW234167386\"><span class=\"TextRun BCX0 SCXW234167386\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234167386\">, which<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW234167386\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234167386\">\u00a0inhibits<\/span><span class=\"NormalTextRun BCX0 SCXW234167386\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW234167386\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1785\">precipitation<\/a><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW234167386\"><span class=\"TextRun BCX0 SCXW234167386\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234167386\">,<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW234167386\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234167386\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW234167386\">a<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW234167386\"><span class=\"TextRun BCX0 SCXW234167386\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234167386\">re prone to <\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW234167386\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234167386\">dry conditions <span class=\"FindHit BCX0 SCXW166247515\">[<\/span><span class=\"NormalTextRun BCX0 SCXW166247515\">10<\/span><span class=\"NormalTextRun BCX0 SCXW166247515\">,<\/span><span class=\"NormalTextRun BCX0 SCXW166247515\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW166247515\">11<\/span><span class=\"NormalTextRun BCX0 SCXW166247515\">]<\/span><\/span><\/span><\/span><span style=\"font-weight: 400;\">. Prevailing winds, ocean circulation patterns such as the Gulf Stream\u2019s effects on eastern North America, rain shadows (the dry leeward sides of mountains), and even the proximity of bodies of water can affect local <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_757\">climate<\/a> patterns. <span class=\"TrackChangeTextInsertion TrackedChange SCXW133046679 BCX0\"><span class=\"TextRun SCXW133046679 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart SCXW133046679 BCX0\">When\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW133046679 BCX0\"><span class=\"TextRun SCXW133046679 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133046679 BCX0\">this moist\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW133046679 BCX0\"><span class=\"TextRun SCXW133046679 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133046679 BCX0\">air <\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW133046679 BCX0\"><span class=\"TextRun SCXW133046679 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133046679 BCX0\">collides with the nearby moun<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW133046679 BCX0\"><span class=\"TextRun SCXW133046679 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133046679 BCX0\">tains causing it to rise and cool, the<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW133046679 BCX0\"><span class=\"TextRun SCXW133046679 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133046679 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW133046679 BCX0\"><span class=\"TextRun SCXW133046679 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133046679 BCX0\">moisture\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW133046679 BCX0\"><span class=\"TextRun SCXW133046679 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133046679 BCX0\">may <\/span><\/span><\/span><span class=\"TextRun SCXW133046679 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133046679 BCX0\">fall<\/span><\/span><span class=\"TextRun SCXW133046679 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133046679 BCX0\">\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW133046679 BCX0\"><span class=\"TextRun SCXW133046679 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133046679 BCX0\">out\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW133046679 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133046679 BCX0\">as snow or rain on nearby areas<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW133046679 BCX0\"><span class=\"TextRun SCXW133046679 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133046679 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW133046679 BCX0\"><span class=\"TextRun SCXW133046679 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133046679 BCX0\">in\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW133046679 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133046679 BCX0\">a phenomenon known as\u00a0<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW133046679 BCX0\"><span class=\"TextRun SCXW133046679 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133046679 BCX0\">\u201c<\/span><\/span><\/span><span class=\"TextRun SCXW133046679 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133046679 BCX0\">lake-effect<\/span><span class=\"NormalTextRun SCXW133046679 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW133046679 BCX0\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1785\">precipitation<\/a>.<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW133046679 BCX0\"><span class=\"TextRun SCXW133046679 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133046679 BCX0\">\u201d <span class=\"FindHit BCX0 SCXW2109339\">[<\/span><span class=\"NormalTextRun BCX0 SCXW2109339\">12<\/span><span class=\"NormalTextRun BCX0 SCXW2109339\">]<\/span><\/span><\/span><\/span><\/span><\/p>\n<figure id=\"attachment_3422\" aria-describedby=\"caption-attachment-3422\" style=\"width: 1024px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/pageprecip_us3.png\"><img class=\"size-large wp-image-711\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/pageprecip_us3-1024x789.png\" alt=\"Distribution of precipitation in the United States.\" width=\"1024\" height=\"789\"><\/a><figcaption id=\"caption-attachment-3422\" class=\"wp-caption-text\">Distribution of precipitation in the United States. The 100th Meridian is approximately where the average precipitation transitions from relatively wet to dry. (Source: U.S. Geological Survey)<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400;\">In the United States, the 100th meridian <\/span><span style=\"font-weight: 400;\">roughly marks the boundary between the humid and arid parts of the country. Growing crops west of the 100th meridian requires irrigation <span class=\"FindHit BCX0 SCXW93504855\">[<\/span><span class=\"NormalTextRun BCX0 SCXW93504855\">13<\/span><span class=\"NormalTextRun BCX0 SCXW93504855\">]<\/span><\/span><span style=\"font-weight: 400;\">. In the west, surface water is stored in reservoirs and mountain snowpacks <span class=\"FindHit BCX0 SCXW59410485\">[<\/span><span class=\"NormalTextRun BCX0 SCXW59410485\">14<\/span><span class=\"NormalTextRun BCX0 SCXW59410485\">]<\/span><\/span><span style=\"font-weight: 400;\">, then strategically released through a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1742\">system<\/a> of canals during times of high water use.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Some of the driest parts of the western United States are in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1514\">Basin and Range<\/a> Province. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1514\">Basin and Range<\/a> has multiple mountain ranges that are oriented north to south. \u00a0Most of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_508\">basin<\/a> valleys in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1514\">Basin and Range<\/a> are dry, receiving less than <span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW239353099\"><span class=\"TrackedChange BCX0 SCXW239353099\"><span class=\"TextRun Highlight BCX0 SCXW239353099\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW239353099\">30\u00a0<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW239353099\"><span class=\"TextRun Highlight BCX0 SCXW239353099\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW239353099\">c<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW239353099\"><span class=\"TrackedChange BCX0 SCXW239353099\"><span class=\"TextRun Highlight BCX0 SCXW239353099\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW239353099\">m\u00a0<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW239353099\"><span class=\"TrackedChange BCX0 SCXW239353099\"><span class=\"TextRun Highlight BCX0 SCXW239353099\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW239353099\">(<\/span><\/span><\/span><\/span>12 inches) of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1785\">precipitation<\/a> per year. However, some of the mountain ranges can receive more than 1<span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW239353099\"><span class=\"TrackedChange BCX0 SCXW239353099\"><span class=\"TextRun Highlight BCX0 SCXW239353099\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart BCX0 SCXW239353099\">.52 m\u00a0<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW239353099\"><span class=\"TrackedChange BCX0 SCXW239353099\"><span class=\"TextRun Highlight BCX0 SCXW239353099\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW239353099\">(<\/span><\/span><\/span><\/span>60 inches) of water as snow or snow-water-equivalent. The snow-water equivalent is the amount of water that would result if the snow were melted, as the snowpack is generally much thicker than the equivalent amount of water that it would produce <span class=\"FindHit BCX0 SCXW74073591\">[<\/span><span class=\"NormalTextRun BCX0 SCXW74073591\">12<\/span><span class=\"NormalTextRun BCX0 SCXW74073591\">]<\/span><\/span><span style=\"font-weight: 400;\">. <\/span><\/p>\n<h3><b>11.3.2 Groundwater Distribution<\/b><\/h3>\n<table class=\"center\" style=\"width: 723px;\" summary=\"Data table showing one estimate of global water distribution. Where and how much water is located in, on, and above the earth.\">\n<thead>\n<tr style=\"height: 86.7969px; background-color: #b8f2e8; border-color: #030303;\">\n<th style=\"height: 86.7969px; width: 253px; text-align: center;\">Water source<\/th>\n<th style=\"height: 86.7969px; width: 179px; text-align: center;\">Water volume<\/p>\n<p>(cubic miles)<\/th>\n<th style=\"height: 86.7969px; width: 123px; text-align: center;\">Fresh water (%)<\/th>\n<th style=\"height: 86.7969px; width: 113px; text-align: center;\">Total water (%)<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr style=\"height: 28px;\">\n<td style=\"height: 28px; width: 253px; text-align: left;\">Oceans, Seas, &amp; Bays<\/td>\n<td style=\"height: 28px; width: 179px; text-align: center;\">321,000,000<\/td>\n<td style=\"height: 28px; width: 123px; text-align: center;\">--<\/td>\n<td style=\"height: 28px; width: 113px; text-align: center;\">96.5<\/td>\n<\/tr>\n<tr class=\"even\" style=\"height: 56px;\">\n<td style=\"height: 56px; width: 253px; text-align: left;\">Ice caps, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1516\">Glaciers<\/a>, &amp; Permanent Snow<\/td>\n<td style=\"height: 56px; width: 179px; text-align: center;\">5,773,000<\/td>\n<td style=\"height: 56px; width: 123px; text-align: center;\">68.7<\/td>\n<td style=\"height: 56px; width: 113px; text-align: center;\">1.74<\/td>\n<\/tr>\n<tr style=\"height: 28px;\">\n<td style=\"height: 28px; width: 253px; text-align: left;\">Groundwater<\/td>\n<td style=\"height: 28px; width: 179px; text-align: center;\">5,614,000<\/td>\n<td style=\"height: 28px; width: 123px; text-align: center;\">--<\/td>\n<td style=\"height: 28px; width: 113px; text-align: center;\">1.69<\/td>\n<\/tr>\n<tr class=\"even\" style=\"height: 28px;\">\n<td style=\"height: 28px; width: 253px; text-align: left;\">\u00a0 \u00a0 \u00a0 -- Fresh<\/td>\n<td style=\"height: 28px; width: 179px; text-align: center;\">2,526,000<\/td>\n<td style=\"height: 28px; width: 123px; text-align: center;\">30.1<\/td>\n<td style=\"height: 28px; width: 113px; text-align: center;\">\u00a0\u00a00.76<\/td>\n<\/tr>\n<tr style=\"height: 28px;\">\n<td style=\"height: 28px; width: 253px; text-align: left;\">\u00a0 \u00a0 \u00a0 -- Saline<\/td>\n<td style=\"height: 28px; width: 179px; text-align: center;\">3,088,000<\/td>\n<td style=\"height: 28px; width: 123px; text-align: center;\">--<\/td>\n<td style=\"height: 28px; width: 113px; text-align: center;\">\u00a0\u00a00.93<\/td>\n<\/tr>\n<tr class=\"even\" style=\"height: 28px;\">\n<td style=\"height: 28px; width: 253px; text-align: left;\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_250\">Soil<\/a> Moisture<\/td>\n<td style=\"height: 28px; width: 179px; text-align: center;\">3,959<\/td>\n<td style=\"height: 28px; width: 123px; text-align: center;\">0.05<\/td>\n<td style=\"height: 28px; width: 113px; text-align: center;\">0.001<\/td>\n<\/tr>\n<tr style=\"height: 28px;\">\n<td style=\"height: 28px; width: 253px; text-align: left;\">Ground Ice &amp; <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_760\">Permafrost<\/a><\/td>\n<td style=\"height: 28px; width: 179px; text-align: center;\">71,970<\/td>\n<td style=\"height: 28px; width: 123px; text-align: center;\">0.86<\/td>\n<td style=\"height: 28px; width: 113px; text-align: center;\">0.022<\/td>\n<\/tr>\n<tr class=\"even\" style=\"height: 28px;\">\n<td style=\"height: 28px; width: 253px; text-align: left;\">Lakes<\/td>\n<td style=\"height: 28px; width: 179px; text-align: center;\">42,320<\/td>\n<td style=\"height: 28px; width: 123px; text-align: center;\">--<\/td>\n<td style=\"height: 28px; width: 113px; text-align: center;\">0.013<\/td>\n<\/tr>\n<tr style=\"height: 28px;\">\n<td style=\"height: 28px; width: 253px; text-align: left;\">\u00a0 \u00a0 \u00a0 -- Fresh<\/td>\n<td style=\"height: 28px; width: 179px; text-align: center;\">21,830<\/td>\n<td style=\"height: 28px; width: 123px; text-align: center;\">0.26<\/td>\n<td style=\"height: 28px; width: 113px; text-align: center;\">0.007<\/td>\n<\/tr>\n<tr class=\"even\" style=\"height: 28px;\">\n<td style=\"height: 28px; width: 253px; text-align: left;\">\u00a0 \u00a0 \u00a0 -- Saline<\/td>\n<td style=\"height: 28px; width: 179px; text-align: center;\">20,490<\/td>\n<td style=\"height: 28px; width: 123px; text-align: center;\">--<\/td>\n<td style=\"height: 28px; width: 113px; text-align: center;\">0.006<\/td>\n<\/tr>\n<tr style=\"height: 28px;\">\n<td style=\"height: 28px; width: 253px; text-align: left;\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1745\">Atmosphere<\/a><\/td>\n<td style=\"height: 28px; width: 179px; text-align: center;\">3,095<\/td>\n<td style=\"height: 28px; width: 123px; text-align: center;\">0.04<\/td>\n<td style=\"height: 28px; width: 113px; text-align: center;\">0.001<\/td>\n<\/tr>\n<tr class=\"even\" style=\"height: 28px;\">\n<td style=\"height: 28px; width: 253px; text-align: left;\">Swamp Water<\/td>\n<td style=\"height: 28px; width: 179px; text-align: center;\">2,752<\/td>\n<td style=\"height: 28px; width: 123px; text-align: center;\">0.03<\/td>\n<td style=\"height: 28px; width: 113px; text-align: center;\">0.0008<\/td>\n<\/tr>\n<tr style=\"height: 28px;\">\n<td style=\"height: 28px; width: 253px; text-align: left;\">Rivers<\/td>\n<td style=\"height: 28px; width: 179px; text-align: center;\">509<\/td>\n<td style=\"height: 28px; width: 123px; text-align: center;\">0.006<\/td>\n<td style=\"height: 28px; width: 113px; text-align: center;\">0.0002<\/td>\n<\/tr>\n<tr class=\"even\" style=\"height: 28px;\">\n<td style=\"height: 28px; width: 253px; text-align: left;\">Biological Water<\/td>\n<td style=\"height: 28px; width: 179px; text-align: center;\">269<\/td>\n<td style=\"height: 28px; width: 123px; text-align: center;\">0.003<\/td>\n<td style=\"height: 28px; width: 113px; text-align: center;\">0.0001<\/td>\n<\/tr>\n<tr style=\"height: 56px;\">\n<td style=\"height: 56px; width: 668px;\" colspan=\"4\"><span class=\"smaller\" style=\"font-size: 8pt;\">Source: Igor Shiklomanov's chapter \"World fresh water resources\" in Peter H. Gleick (editor), 1993, Water in Crisis: A Guide to the World's Fresh Water Resources (Oxford University Press, New York)[zotpressInText item=\"{P7VGIQT4}\" format=\"%num%\" brackets=\"yes\" separator=\"comma\"]<\/span><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p><span style=\"font-weight: 400;\">Groundwater makes up 30.1% of the fresh water on the planet, making it the most abundant reservoir of fresh water accessible to most humans. \u00a0The majority of freshwater, 68.7%, is stored in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1516\">glaciers<\/a> and ice caps as ice<span class=\"NormalTextRun BCX0 SCXW74300989\">\u00a0<\/span><span class=\"FindHit BCX0 SCXW74300989\">[<\/span><span class=\"NormalTextRun BCX0 SCXW74300989\">9<\/span><span class=\"NormalTextRun BCX0 SCXW74300989\">]<\/span><\/span><span style=\"font-weight: 400;\">.\u00a0 As the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1516\">glaciers<\/a> and ice caps melt due to global warming, this fresh water is lost as it flows into the oceans.<\/span><\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-79\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-79\" class=\"h5p-iframe\" data-content-id=\"79\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"11.6_MissDelt.jpg\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_4538\" aria-describedby=\"caption-attachment-4538\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/11.3-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-712\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/11.3-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4538\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 11.3 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-weight: 400;\">11.4 Water Law<\/span><\/h2>\n<p><span style=\"font-weight: 400;\">Federal and state governments have put laws in place to ensure the fair and equitable use of water. In the United States, the states are tasked with creating a fair and legal <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1742\">system<\/a> for sharing water. <\/span><\/p>\n<h3><b>11.4.1 Water Rights<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">Because of the limited supply of water, especially in the western United States, states disperse a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1742\">system<\/a> of legal <strong>water rights<\/strong> defined as a claim to a portion or all of a water source, such as a spring, stream, well, or lake<\/span><span style=\"font-weight: 400;\">. \u00a0Federal law mandates that states control water rights, with the special exception of federally reserved water rights, such as those associated with national parks and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_976\">Native<\/a> American tribes, and navigation servitude that maintains navigable water bodies. Each state in the United States has a different way to disperse and manage water rights. <\/span><\/p>\n<p><span style=\"font-weight: 400;\">A person, entity, company, or organization, must have a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1773\">water right<\/a> to legally extract or use surface or groundwater in their state. \u00a0Water rights in some western states are dictated by the concept of prior appropriation, or \u201cfirst in time, first in right,\u201d where the person with the oldest <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1773\">water right<\/a> gets priority water use during times when there is not enough water to fulfill every <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1773\">water right<\/a>. <\/span><\/p>\n<p><span style=\"font-weight: 400;\">The Colorado River and its tributaries pass through a desert region, including seven states (Wyoming, Colorado, Utah, New Mexico, Arizona, Nevada, California), <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_976\">Native<\/a> American reservations, and Mexico. As the western United States became more populated and while California was becoming a key agricultural producer, the states along the Colorado River realized that the river was important to sustaining life in the West. \u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\"><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW184366708\"><span class=\"TextRun BCX0 SCXW184366708\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW184366708\">T<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW184366708\"><span class=\"TextRun BCX0 SCXW184366708\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW184366708\">o guarantee\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW184366708\"><span class=\"TextRun BCX0 SCXW184366708\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW184366708\">certain\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW184366708\"><span class=\"TrackedChange BCX0 SCXW184366708\"><span class=\"TextRun BCX0 SCXW184366708\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW184366708\"><em>perceived<\/em>\u00a0<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW184366708\"><span class=\"TextRun BCX0 SCXW184366708\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW184366708\">water rights<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW184366708\"><span class=\"TextRun BCX0 SCXW184366708\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW184366708\">, the<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW184366708\"><span class=\"TextRun BCX0 SCXW184366708\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW184366708\">se western states<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW184366708\"><span class=\"TextRun BCX0 SCXW184366708\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW184366708\">\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW184366708\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW184366708\">recognized\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW184366708\"><span class=\"TextRun BCX0 SCXW184366708\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW184366708\">that<\/span><\/span><\/span> a water budget was necesary for the Colorado River <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_508\">Basin<\/a>. Thus was enacted the Colorado River Compact in 1922 to ensure that each state got a fair share of the river water. The Compact granted each state a specific volume of water based on the total measured flow at the time. \u00a0However, in 1922, the flow of the river was higher than its long-term average flow, consequently, more water was allocated to each state than is typically available in the river <span class=\"FindHit BCX0 SCXW136464619\">[<\/span><span class=\"NormalTextRun BCX0 SCXW136464619\">16<\/span><span class=\"NormalTextRun BCX0 SCXW136464619\">]<\/span><\/span><span style=\"font-weight: 400;\">. <\/span><\/p>\n<p><span style=\"font-weight: 400;\"><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW112536447\"><span class=\"TextRun BCX0 SCXW112536447\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW112536447\">Over the next several decades<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW112536447\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW112536447\">,\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW112536447\"><span class=\"TextRun BCX0 SCXW112536447\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW112536447\">lawmakers\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW112536447\"><span class=\"TextRun BCX0 SCXW112536447\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW112536447\">have\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW112536447\"><span class=\"TextRun BCX0 SCXW112536447\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW112536447\">made\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW112536447\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW112536447\">many other agreements and modifications\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW112536447\"><span class=\"TextRun BCX0 SCXW112536447\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW112536447\">regarding <\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW112536447\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW112536447\">the Colorado<\/span><span class=\"NormalTextRun BCX0 SCXW112536447\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW112536447\">River<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW112536447\"><span class=\"TextRun BCX0 SCXW112536447\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW112536447\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW112536447\"><span class=\"TextRun BCX0 SCXW112536447\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW112536447\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW112536447\"><span class=\"TextRun BCX0 SCXW112536447\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW112536447\">Compact,\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW112536447\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW112536447\">including\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW112536447\"><span class=\"TextRun BCX0 SCXW112536447\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW112536447\">those\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW112536447\"><span class=\"TextRun BCX0 SCXW112536447\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW112536447\">agreements\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW112536447\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW112536447\">that brought about the Hoover\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW112536447\"><span class=\"TextRun BCX0 SCXW112536447\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW112536447\">Dam\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW112536447\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW112536447\">(formerly Boulder Dam)<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW112536447\"><span class=\"TextRun BCX0 SCXW112536447\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW112536447\">,<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW112536447\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW112536447\">\u00a0<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW112536447\"><span class=\"TextRun BCX0 SCXW112536447\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW112536447\">and\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW112536447\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW112536447\">Glen Canyon Dam<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW112536447\"><span class=\"TextRun BCX0 SCXW112536447\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW112536447\">,<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW112536447\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW112536447\"> and a treaty between the American and Mexican governments. <span class=\"NormalTextRun CommentStart BCX0 SCXW112536447\">Co<\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW112536447\">llectively<\/span>, the agreements\u00a0<span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW112536447\">are referred to <\/span>as\u00a0<span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW112536447\">\u201c<\/span>The Law of the\u00a0River\"<span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW112536447\">\u00a0<\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW112536447\">by the United States Bureau of\u00a0<\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW112536447\"><span class=\"NormalTextRun CommentStart BCX0 SCXW112536447\">Reclamation<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW112536447\">.<\/span><\/span><\/span>\u00a0 <span class=\"TextRun BCX0 SCXW8127879\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8127879\">Despite adjustments to the\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8127879\"><span class=\"TrackedChange BCX0 SCXW8127879\"><span class=\"TextRun BCX0 SCXW8127879\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8127879\">Colorado River Compact<\/span><\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW8127879\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8127879\">,<\/span><span class=\"NormalTextRun BCX0 SCXW8127879\">\u00a0many believe that\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8127879\"><span class=\"TextRun BCX0 SCXW8127879\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8127879\">the\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8127879\"><span class=\"TextRun BCX0 SCXW8127879\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8127879\">Colorado<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8127879\"><span class=\"TextRun BCX0 SCXW8127879\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8127879\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8127879\"><span class=\"TextRun BCX0 SCXW8127879\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8127879\">River<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8127879\"><span class=\"TextRun BCX0 SCXW8127879\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8127879\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8127879\"><span class=\"TextRun BCX0 SCXW8127879\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8127879\">is still <\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW8127879\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8127879\">over-allocat<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8127879\"><span class=\"TextRun BCX0 SCXW8127879\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8127879\">ed<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8127879\"><span class=\"TextRun BCX0 SCXW8127879\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8127879\">,<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW8127879\"><span class=\"TextRun BCX0 SCXW8127879\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8127879\">\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW8127879\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8127879\">as the <\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW8127879\"><span class=\"TextRun BCX0 SCXW8127879\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8127879\">Colorado<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW8127879\"><span class=\"TextRun BCX0 SCXW8127879\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8127879\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW8127879\"><span class=\"TextRun BCX0 SCXW8127879\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8127879\">River <span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8127879\">flow<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW8127879\"><span class=\"TextRun BCX0 SCXW8127879\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8127879\">\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW8127879\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8127879\">no longer reaches the Pacific Ocean, its original terminus (base level).<\/span><span class=\"NormalTextRun BCX0 SCXW8127879\">\u00a0<\/span><\/span> <span class=\"TextRun BCX0 SCXW247511937\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW247511937\">Dams along<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\"><span class=\"TextRun BCX0 SCXW247511937\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW247511937\">\u00a0the<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW247511937\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW247511937\">\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\"><span class=\"TextRun BCX0 SCXW247511937\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW247511937\">Colorado<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\"><span class=\"TextRun BCX0 SCXW247511937\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW247511937\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\"><span class=\"TextRun BCX0 SCXW247511937\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW247511937\">River<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\"><span class=\"TextRun BCX0 SCXW247511937\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW247511937\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\"><span class=\"TextRun BCX0 SCXW247511937\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW247511937\">have <\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW247511937\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW247511937\">caus<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\"><span class=\"TextRun BCX0 SCXW247511937\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW247511937\">ed water to<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW247511937\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW247511937\">\u00a0diver<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\"><span class=\"TextRun BCX0 SCXW247511937\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW247511937\">t<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW247511937\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW247511937\">\u00a0and evaporat<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\"><span class=\"TextRun BCX0 SCXW247511937\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW247511937\">e<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\"><span class=\"TextRun BCX0 SCXW247511937\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW247511937\">, creating<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW247511937\"><span class=\"TextRun BCX0 SCXW247511937\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW247511937\">\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW247511937\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW247511937\">serious water budget concerns in the Colorado<\/span><span class=\"NormalTextRun BCX0 SCXW247511937\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW247511937\">River<\/span><span class=\"NormalTextRun BCX0 SCXW247511937\">\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\"><span class=\"TextRun BCX0 SCXW247511937\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW247511937\">B<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW247511937\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW247511937\">asin. Predicted drought associated with global warming\u00a0<span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\">is\u00a0<\/span>caus<span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\">ing<\/span>\u00a0additional concerns about\u00a0<span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\">over-allocati<\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\">ng<\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\">\u00a0<\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\">the\u00a0<\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\">Colorado<\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\">\u00a0<\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\">River<\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\">\u00a0<\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\">flow<\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\">\u00a0<\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\">in the future<\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\">.<\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW247511937\">\u00a0<\/span><\/span><\/span><\/span><\/p>\n<p style=\"text-align: left;\"><span style=\"font-weight: 400;\">The Law of the River highlights the complex and prolonged nature of interstate water rights agreements, as well as the importance of water.<\/span><\/p>\n<figure id=\"attachment_4552\" aria-describedby=\"caption-attachment-4552\" style=\"width: 150px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/The-Colorado-River-Compact-of-1922-Youtube-QR-Code.png\"><img class=\"size-thumbnail wp-image-713\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/The-Colorado-River-Compact-of-1922-Youtube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4552\" 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 style=\"text-align: left;\"><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW156675929\"><span class=\"TextRun BCX0 SCXW156675929\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart BCX0 SCXW156675929\">The\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW156675929\"><span class=\"TextRun BCX0 SCXW156675929\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW156675929\">Snake Valley straddles the border of Utah and Nevada with<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW156675929\"><span class=\"TextRun BCX0 SCXW156675929\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW156675929\"> m<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW156675929\"><span class=\"TextRun BCX0 SCXW156675929\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW156675929\">ore of the irrigable land area lying on the Utah side of the border.<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW156675929\"><span class=\"TextRun BCX0 SCXW156675929\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW156675929\"> <span class=\"NormalTextRun CommentStart BCX0 SCXW156675929\">In 1989, the Southern Nevada Water Authority (SNWA) submitted applications for water rights to pipe<\/span>\u00a0up to\u00a0<span class=\"TrackedChange BCX0 SCXW156675929\"><span class=\"TextRun Highlight BCX0 SCXW156675929\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\">191<\/span><\/span><span class=\"TrackedChange BCX0 SCXW156675929\"><span class=\"TextRun Highlight BCX0 SCXW156675929\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\">,<\/span><\/span><span class=\"TrackedChange BCX0 SCXW156675929\"><span class=\"TextRun Highlight BCX0 SCXW156675929\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\">189<\/span><\/span><span class=\"TrackedChange BCX0 SCXW156675929\"><span class=\"TextRun Highlight BCX0 SCXW156675929\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\">,<\/span><\/span><span class=\"TrackedChange BCX0 SCXW156675929\"><span class=\"TextRun Highlight BCX0 SCXW156675929\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\">70<\/span><\/span><span class=\"TrackedChange BCX0 SCXW156675929\"><span class=\"TextRun Highlight BCX0 SCXW156675929\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\">7<\/span><\/span><span class=\"TrackedChange BCX0 SCXW156675929\"><span class=\"TextRun Highlight BCX0 SCXW156675929\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\">\u00a0<\/span><\/span><span class=\"TrackedChange BCX0 SCXW156675929\"><span class=\"TextRun Highlight BCX0 SCXW156675929\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\">cu m<\/span><\/span>\u00a0(<span class=\"TrackedChange BCX0 SCXW156675929\"><span class=\"TextRun Highlight BCX0 SCXW156675929\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\">155,000 ac<span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW156675929\">-ft<\/span><\/span><\/span><span class=\"TextRun Highlight BCX0 SCXW156675929\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\">)<\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW156675929\">\u00a0<\/span>of water per year\u00a0<span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW156675929\">(an acre-foot of water is one acre covered with water one foot deep)\u00a0<\/span>from\u00a0Spring, Snake,\u00a0Delamar, Dry Lake, and Cave <span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW156675929\">v<\/span>alleys to southern Nevada,\u00a0 mostly for Las Vegas<span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW15730741\"><span class=\"TextRun BCX0 SCXW15730741\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW15730741\">\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW15730741\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"FindHit BCX0 SCXW15730741\">[<\/span><span class=\"NormalTextRun BCX0 SCXW15730741\">17<\/span><span class=\"NormalTextRun BCX0 SCXW15730741\">]<\/span><\/span>. <span class=\"TextRun BCX0 SCXW130227827\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW130227827\">Nevada and Utah have attempted a comprehensive agreement, but negotiations have not yet been settled.<\/span><\/span><span class=\"LineBreakBlob BlobObject DragDrop BCX0 SCXW130227827\"><span class=\"BCX0 SCXW130227827\">\u00a0<\/span><\/span><\/span><\/span><\/span><\/p>\n<p><iframe src=\"https:\/\/www.arcgis.com\/apps\/MapJournal\/index.html?appid=79199afd183e459596e6e21315159354\" width=\"100%\" height=\"800px\" frameborder=\"0\"><\/iframe><\/p>\n<figure id=\"attachment_4560\" aria-describedby=\"caption-attachment-4560\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Groundwater-Issues-Story-Map-QR-Code.png\"><img class=\"size-thumbnail wp-image-714\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Groundwater-Issues-Story-Map-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4560\" 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<h4><\/h4>\n<p>&nbsp;<\/p>\n<p><a href=\"http:\/\/www.npr.org\/templates\/story\/story.php?storyId=10953190\"><span style=\"font-weight: 400;\">NPR story on Snake Valley<\/span><\/a><\/p>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_4551\" aria-describedby=\"caption-attachment-4551\" style=\"width: 150px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Snake-Valley-NPR-Story-QR-Code.png\"><img class=\"size-thumbnail wp-image-715\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Snake-Valley-NPR-Story-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4551\" class=\"wp-caption-text\">If you are using the printed version of this OER, access this NPR Story via this QR Code.<\/figcaption><\/figure>\n<p><iframe title=\"NPR embedded audio player\" src=\"https:\/\/www.npr.org\/player\/embed\/10953190\/10956967\" width=\"100%\" height=\"290\" frameborder=\"0\" scrolling=\"no\"><\/iframe><br \/>\n<a href=\"https:\/\/www.youtube.com\/watch?v=C-bE-gOOJlU\"><span style=\"font-weight: 400;\">SNWA History<\/span><\/a><\/p>\n<p><a href=\"https:\/\/www.youtube.com\/watch?v=eCZ8KLrmUXo\"><span style=\"font-weight: 400;\">Dean Baker Story<\/span><\/a><\/p>\n<figure id=\"attachment_4553\" aria-describedby=\"caption-attachment-4553\" style=\"width: 150px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/The-Consequences-Youtube-QR-Code.png\"><img class=\"size-thumbnail wp-image-716\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/The-Consequences-Youtube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4553\" 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><b>11.4.2 Water Quality and Protection<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">Two major federal laws that protect water quality in the United States are the Clean Water Act and the Safe Drinking Water Act. \u00a0The Clean Water Act, an amendment of the Federal Water Pollution Control Act, protects navigable waters from dumping and point-source pollution. The Safe Drinking Water Act ensures that water that is provided by public water suppliers, like cities and towns, is safe to drink <span class=\"FindHit BCX0 SCXW47373929\">[<\/span><span class=\"NormalTextRun BCX0 SCXW47373929\">18<\/span><span class=\"NormalTextRun BCX0 SCXW47373929\">]<\/span>.\u00a0<\/span><\/p>\n<p><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">The<\/span><span class=\"NormalTextRun BCX0 SCXW193906268\">\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart BCX0 SCXW193906268\">U.S. Environmental Protection Agency\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">Superfund<\/span><span class=\"NormalTextRun BCX0 SCXW193906268\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW193906268\">program ensures the cleanup of hazardous contamination<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">,<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">\u00a0and can be applied to situations of surface water and<\/span><span class=\"NormalTextRun BCX0 SCXW193906268\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW193906268\">groundwater<\/span><span class=\"NormalTextRun BCX0 SCXW193906268\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW193906268\">contamination. It is part of the Comprehensive Environmental Response, Compensation, and Liability Act of 1980.\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">Under this act, <\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">state governments and<\/span><\/span><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">\u00a0the U.S. Environmental Protection Agency\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">can\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">use the superfund to\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">pay for <\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">remediat<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">ion <\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">of a <\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">contaminated\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">site<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">\u00a0and then file a lawsuit against the polluter\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">to recoup\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">the costs<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart BCX0 SCXW193906268\">.\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">Or to avoid being sued, the <\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">pollut<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">e<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">r <\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW193906268\"><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">that caused the contamination may<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW193906268\"><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">\u00a0<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">take direct action\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">or provide funds <\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">to\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">remediat<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">e<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\"> the\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">contamination<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">.<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW193906268\"><span class=\"TextRun BCX0 SCXW193906268\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW193906268\">\u00a0<\/span><\/span><\/span><\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-80\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-80\" class=\"h5p-iframe\" data-content-id=\"80\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"11.5 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_4539\" aria-describedby=\"caption-attachment-4539\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/11.4-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-717\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/11.4-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4539\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 11.4 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-weight: 400;\">11.5 Surface Water<\/span><\/h2>\n<p><span style=\"font-weight: 400;\">Geologically, a <\/span><b>stream <\/b><span style=\"font-weight: 400;\">is a body of flowing surface water confined to a channel. Terms such as river, creek and brook are social terms not used in geology. <span class=\"TextRun BCX0 SCXW52289593\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart BCX0 SCXW52289593\">Streams<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW52289593\"><span class=\"TextRun BCX0 SCXW52289593\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW52289593\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW52289593\"><span class=\"TextRun BCX0 SCXW52289593\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW52289593\">ero<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW52289593\"><span class=\"TextRun BCX0 SCXW52289593\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW52289593\">d<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW52289593\"><span class=\"TextRun BCX0 SCXW52289593\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW52289593\">e<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW52289593\"><span class=\"TextRun BCX0 SCXW52289593\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW52289593\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW52289593\"><span class=\"TextRun BCX0 SCXW52289593\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW52289593\">and transport <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediments<\/a><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW52289593\"><span class=\"TextRun BCX0 SCXW52289593\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW52289593\">, making<\/span><\/span><\/span> <span class=\"TextRun BCX0 SCXW52289593\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW52289593\">the<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW52289593\"><span class=\"TextRun BCX0 SCXW52289593\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW52289593\">m the<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW52289593\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW52289593\">\u00a0most important agents\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW52289593\">of\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW52289593\">the earth\u2019s surface<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW52289593\"><span class=\"TextRun BCX0 SCXW52289593\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW52289593\">,\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW52289593\"><span class=\"TextRun BCX0 SCXW52289593\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW52289593\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW52289593\"><span class=\"TextRun BCX0 SCXW52289593\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW52289593\">along with wave action <span class=\"TextRun BCX0 SCXW201920896\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW201920896\">(see <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/12-shorelines\/\" target=\"_blank\" rel=\"noopener\">Chapter 12<\/a>)<\/span><\/span> <\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW52289593\"><span class=\"TextRun BCX0 SCXW52289593\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW52289593\">in<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW52289593\"><span class=\"TextRun BCX0 SCXW52289593\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW52289593\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW52289593\"><span class=\"TextRun BCX0 SCXW52289593\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW52289593\">ero<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW52289593\"><span class=\"TextRun BCX0 SCXW52289593\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW52289593\">ding\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW52289593\"><span class=\"TextRun BCX0 SCXW52289593\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW52289593\">and transport<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW52289593\"><span class=\"TextRun BCX0 SCXW52289593\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW52289593\">ing<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW52289593\"><span class=\"TextRun BCX0 SCXW52289593\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW52289593\">\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediments<\/a><\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW52289593\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW52289593\">.\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW52289593\">They create much of the surface topography and are an important water resource<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW52289593\"><span class=\"TextRun BCX0 SCXW52289593\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW52289593\">.\u00a0<\/span><\/span><\/span><\/span><\/p>\n<p><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart SCXW266511203 BCX0\">Several factors cause<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">streams<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">to erode and transport<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a>, but the two main factors are<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">stream<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">-<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">channel gradient and velocity.\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">Stream<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">-<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">channel\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">gradient is the slope of the<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\"> stream usually expressed in meters per kilometer or feet per mile<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">. A steeper\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">channel\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">gradie<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">nt\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">promotes <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1755\">erosion<\/a>. When<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1654\">tectonic<\/a><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">forces\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun AdvancedProofingIssueV2 SCXW266511203 BCX0\">elevate<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">\u00a0a mountain, the stream<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">gradient<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">\u00a0increases,\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">caus<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">ing<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">\u00a0the<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\"> mountain <\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">stream<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">to erode downward and deepen its channel eventually forming a valley.<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">Stream<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">-<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">channel\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">velocity<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">is the speed\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">at which channel water\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">flow<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">s. Factors affecting channel v<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">elocity<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\"> include channel gradient which decreases downstream, discharge and channel size which <\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">increase<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\"> as tributaries coalesce, and channel roughness which decreases as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> lining the channel walls decreases in size thus<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">reducing friction<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW266511203 BCX0\"><span class=\"TextRun SCXW266511203 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW266511203 BCX0\">.<\/span><\/span><\/span><span class=\"EOP TrackedChange SCXW266511203 BCX0\" data-ccp-props=\"{&quot;201341983&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:259}\"> The combined effect of these factors is that channel velocity actually increases from mountain brooks to the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1776\">mouth<\/a> of the stream.<\/span><\/p>\n<h3><b>11.5.1 Discharge<\/b><\/h3>\n<p>Stream size is measured in terms of <strong>discharge,<\/strong>\u00a0 the volume of water flowing past a point in the stream over a defined time interval. <span style=\"font-weight: 400;\">Volume is commonly measured in cubic units (length x width x depth), shown as feet<sup>3<\/sup><\/span><span style=\"font-weight: 400;\"> (ft<sup>3<\/sup>) or meter<sup>3<\/sup> (m<sup>3<\/sup>)<\/span><span style=\"font-weight: 400;\">. \u00a0Therefore, the units of discharge are cubic feet per second (<\/span><span style=\"font-weight: 400;\">ft<\/span><sub><span style=\"font-weight: 400;\">3<\/span><\/sub><span style=\"font-weight: 400;\">\/sec<\/span><span style=\"font-weight: 400;\"> or cfs). <span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">Therefore, the units of<\/span><span class=\"NormalTextRun BCX0 SCXW114151887\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW114151887\">discharge<\/span><span class=\"NormalTextRun BCX0 SCXW114151887\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW114151887\">are\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">cubic meters per second, (<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">m<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">\u00b3<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">\/s or<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SpellingErrorV2 BCX0 SCXW114151887\">cms, or <\/span><\/span><\/span><\/span><span class=\"TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">cubic feet per second (ft<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">\u00b3<\/span><\/span><\/span><span class=\"TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">\/s<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW114151887\"><span class=\"TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">ec<\/span><\/span><\/span><\/span><span class=\"TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">\u00a0or\u00a0<\/span><\/span><\/span><span class=\"TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SpellingErrorV2 BCX0 DefaultHighlightTransition SCXW114151887\">cfs<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">). <\/span><\/span>Stream discharge increases downstream<b>.<\/b> Smaller streams have less discharge than larger streams. For example, the Mississippi River is the largest river in North America, with an average flow of about\u00a0<span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">16<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">,<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">990.1<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">1<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">\u00a0<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SpellingErrorV2 BCX0 SCXW114151887\">cms<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">(<\/span><\/span><\/span><span class=\"TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">600,000\u00a0<\/span><\/span><\/span><span class=\"TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SpellingErrorV2 BCX0 SCXW114151887\">cfs<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">) <span class=\"FindHit BCX0 SCXW148589328\">[<\/span><span class=\"NormalTextRun BCX0 SCXW148589328\">19]<\/span><\/span><\/span><\/span><\/span><span style=\"font-weight: 400;\">. <span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">For comparison, the average<\/span><span class=\"NormalTextRun BCX0 SCXW114151887\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW114151887\">discharge<\/span><span class=\"NormalTextRun BCX0 SCXW114151887\">\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">of<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">\u00a0the Jordan<\/span><span class=\"NormalTextRun BCX0 SCXW114151887\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW114151887\">River<\/span><span class=\"NormalTextRun BCX0 SCXW114151887\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW114151887\">at Utah Lake is about\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">16.25<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">\u00a0<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SpellingErrorV2 BCX0 SCXW114151887\">cms<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">(<\/span><\/span><\/span><span class=\"TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">574\u00a0<\/span><\/span><\/span><span class=\"TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SpellingErrorV2 BCX0 SCXW114151887\">cfs<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">) <span class=\"FindHit BCX0 SCXW117893300\">[<\/span><span class=\"NormalTextRun BCX0 SCXW117893300\">20<\/span><span class=\"NormalTextRun BCX0 SCXW117893300\">]<\/span><span class=\"NormalTextRun BCX0 SCXW117893300\">\u00a0<\/span> <\/span><\/span><\/span><\/span><span style=\"font-weight: 400;\">and<span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">\u00a0<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">for\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">the\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">annual<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">discharge<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">\u00a0of the\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">Amazon<\/span><span class=\"NormalTextRun BCX0 SCXW114151887\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW114151887\">River<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">,\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">(<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">the world\u2019s largest<\/span><span class=\"NormalTextRun BCX0 SCXW114151887\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW114151887\">river<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">)<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">,\u00a0<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">annual<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">discharge<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">is about\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">175,56<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">5<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SpellingErrorV2 BCX0 SCXW114151887\">cms<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">(<\/span><\/span><\/span><span class=\"TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">6,200,000\u00a0<\/span><\/span><\/span><span class=\"TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun Highlight BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SpellingErrorV2 BCX0 DefaultHighlightTransition SCXW114151887\">cfs<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW114151887\"><span class=\"TextRun BCX0 SCXW114151887\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW114151887\">)<span class=\"NormalTextRun BCX0 SCXW23375202\">\u00a0<\/span><span class=\"FindHit BCX0 SCXW23375202\">[<\/span><span class=\"NormalTextRun BCX0 SCXW23375202\">21<\/span><span class=\"NormalTextRun BCX0 SCXW23375202\">]<\/span><\/span><\/span><\/span><\/span><span style=\"font-weight: 400;\">. \u00a0\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Discharge can be expressed by the following equation: <\/span><\/p>\n<p><b><span data-contrast=\"auto\">Q = V A<\/span><\/b><span data-ccp-props=\"{&quot;201341983&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:259}\">\u00a0<\/span><\/p>\n<ul>\n<li data-leveltext=\"\uf0b7\" data-font=\"Symbol\" data-listid=\"21\" data-aria-posinset=\"1\" data-aria-level=\"1\"><span data-contrast=\"auto\">Q =\u00a0discharge\u00a0<\/span><span data-contrast=\"auto\">cms<\/span><span data-contrast=\"auto\">\u00a0<\/span><span data-contrast=\"auto\">(or <\/span><span data-contrast=\"auto\">ft<sup>3<\/sup><\/span><span data-contrast=\"auto\">\/sec),<\/span><span data-ccp-props=\"{&quot;201341983&quot;:2,&quot;335559739&quot;:120,&quot;335559740&quot;:240}\">\u00a0<\/span><\/li>\n<li data-leveltext=\"\uf0b7\" data-font=\"Symbol\" data-listid=\"21\" data-aria-posinset=\"2\" data-aria-level=\"1\"><span data-contrast=\"auto\">A = cross-sectional area of the\u00a0stream\u00a0channel [width times average depth]<\/span><span data-contrast=\"auto\"> as <\/span><span data-contrast=\"auto\">m<\/span><sup><span data-contrast=\"auto\">2<\/span><\/sup><span data-contrast=\"auto\">\u00a0<\/span><span data-contrast=\"auto\">(or in<sup>2<\/sup> or ft<\/span><sup><span data-contrast=\"auto\">2<\/span><\/sup><span data-contrast=\"auto\">),<\/span><span data-ccp-props=\"{&quot;201341983&quot;:2,&quot;335559739&quot;:120,&quot;335559740&quot;:240}\">\u00a0<\/span><\/li>\n<li data-leveltext=\"\uf0b7\" data-font=\"Symbol\" data-listid=\"21\" data-aria-posinset=\"3\" data-aria-level=\"1\"><span data-contrast=\"auto\">V = average channel velocity <\/span><span data-contrast=\"auto\">m\/s<\/span><span data-contrast=\"auto\">\u00a0<\/span><span data-contrast=\"auto\">(or ft\/sec) <span class=\"FindHit BCX0 SCXW36958835\">[<\/span><span class=\"NormalTextRun BCX0 SCXW36958835\">7<\/span><span class=\"NormalTextRun BCX0 SCXW36958835\">]<\/span><\/span><\/li>\n<\/ul>\n<p><span class=\"TrackChangeTextInsertion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart SCXW25992323 BCX0\">At a given location along the stream, velocity varies <\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">with\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">stream<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">width<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">, s<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">hape<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">, and depth <\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW25992323 BCX0\"><span class=\"TrackChangeTextInsertion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">within the stream<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW25992323 BCX0\"><span class=\"TrackChangeTextInsertion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">\u00a0<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW25992323 BCX0\"><span class=\"TrackChangeTextInsertion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">channel<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW25992323 BCX0\"><span class=\"TrackChangeTextInsertion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">\u00a0as well<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">.\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">When<\/span><\/span> <span class=\"TrackChangeTextDeletion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">the<\/span><\/span><\/span><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">stream <\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">channel<\/span><\/span><\/span><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">\u00a0narrows but<\/span><span class=\"NormalTextRun SCXW25992323 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW25992323 BCX0\">discharge<\/span><span class=\"NormalTextRun SCXW25992323 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW25992323 BCX0\">remains constant, the same volume of water\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">must\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">flow<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">s<\/span><\/span><\/span><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">\u00a0through\u00a0<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">a<\/span><\/span><\/span><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">\u00a0na<\/span><span class=\"NormalTextRun SCXW25992323 BCX0\">rrower space causing\u00a0<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">the\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">velocity to increase, similar to putting a thumb over the end of a backyard water hose<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">. <\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">\u00a0In addition,\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">d<\/span><\/span><\/span><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">uring\u00a0<\/span><span class=\"NormalTextRun ContextualSpellingAndGrammarErrorV2 SCXW25992323 BCX0\">rain storms<\/span><span class=\"NormalTextRun SCXW25992323 BCX0\">\u00a0or heavy snow melt,<\/span><span class=\"NormalTextRun SCXW25992323 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW25992323 BCX0\">runoff<\/span> <\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">increase<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">s<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW25992323 BCX0\"><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">,<\/span><\/span><\/span><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">\u00a0which increases<\/span><span class=\"NormalTextRun SCXW25992323 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW25992323 BCX0\">stream<\/span><span class=\"NormalTextRun SCXW25992323 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW25992323 BCX0\">discharge<\/span><span class=\"NormalTextRun SCXW25992323 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW25992323 BCX0\">and<\/span><\/span><span class=\"TextRun SCXW25992323 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW25992323 BCX0\">\u00a0velocity.<\/span><\/span><\/p>\n<p><span class=\"TrackChangeTextInsertion TrackedChange SCXW133448488 BCX0\"><span class=\"TextRun SCXW133448488 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart SCXW133448488 BCX0\">When the\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW133448488 BCX0\"><span class=\"TextRun SCXW133448488 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133448488 BCX0\">stream <\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW133448488 BCX0\"><span class=\"TrackChangeTextInsertion TrackedChange SCXW133448488 BCX0\"><span class=\"TextRun SCXW133448488 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133448488 BCX0\">channel<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW133448488 BCX0\"><span class=\"TextRun SCXW133448488 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133448488 BCX0\">\u00a0curves, the highest velocity will be on the outside of the bend.<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW133448488 BCX0\"><span class=\"TextRun SCXW133448488 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133448488 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW133448488 BCX0\"><span class=\"TextRun SCXW133448488 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133448488 BCX0\">W<\/span><\/span><\/span><span class=\"TextRun SCXW133448488 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133448488 BCX0\">hen the\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW133448488 BCX0\"><span class=\"TextRun SCXW133448488 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133448488 BCX0\">stream <\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW133448488 BCX0\"><span class=\"TextRun SCXW133448488 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133448488 BCX0\">channel<\/span><\/span><\/span><span class=\"TextRun SCXW133448488 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133448488 BCX0\">\u00a0is straight and uniform<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW133448488 BCX0\"><span class=\"TextRun SCXW133448488 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133448488 BCX0\">ly dee<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW133448488 BCX0\"><span class=\"TextRun SCXW133448488 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133448488 BCX0\">p<\/span><\/span><\/span><span class=\"TextRun SCXW133448488 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133448488 BCX0\">, the highest velocity is in the channel center <\/span><\/span><span class=\"TextRun SCXW133448488 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133448488 BCX0\">at the top of the water where it is the farthest from frictional contact with the <\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW133448488 BCX0\"><span class=\"TextRun SCXW133448488 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133448488 BCX0\">stream\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW133448488 BCX0\"><span class=\"TextRun SCXW133448488 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133448488 BCX0\">channel\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW133448488 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133448488 BCX0\">bottom and sides. <\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW133448488 BCX0\"><span class=\"TextRun SCXW133448488 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart SCXW133448488 BCX0\">In hydrology, the <em>thalweg<\/em> of a rive<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW133448488 BCX0\"><span class=\"TextRun SCXW133448488 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133448488 BCX0\">r is the\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW133448488 BCX0\"><span class=\"TextRun SCXW133448488 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133448488 BCX0\">line drawn that shows its natural progression<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW133448488 BCX0\"><span class=\"TextRun SCXW133448488 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133448488 BCX0\">\u00a0and deepest channel<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW133448488 BCX0\"><span class=\"TextRun SCXW133448488 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW133448488 BCX0\">, as is shown in the diagram.<\/span><\/span><\/span><span class=\"EOP SCXW133448488 BCX0\" data-ccp-props=\"{&quot;201341983&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:259}\">\u00a0<\/span><\/p>\n<figure id=\"attachment_3423\" aria-describedby=\"caption-attachment-3423\" style=\"width: 1024px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/meandering.png\"><img class=\"size-large wp-image-718\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/meandering-1024x376.png\" alt=\"Stream velocity is higher on the outside bend and the surface which is farthest from the friction of the stream bed. The inside of the bend is a shorter distance than the outside. Longer arrows indicate faster velocity. In a river bend, the fastest moving particles are on the outside of the bend, near the cutbank.\" width=\"1024\" height=\"376\"><\/a><figcaption id=\"caption-attachment-3423\" class=\"wp-caption-text\">Thalweg of a river. In a river bend, the fastest moving water is on the outside of the bend, near the cutbank. Stream velocity is higher on the outside bend and the water surface which is farthest from the friction of the stream bed. Longer arrows indicate faster velocity (Earle 2015).<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<h3><b>11.5.2 Runoff vs. Infiltration<\/b><\/h3>\n<p><span style=\"font-weight: 400;\"><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW241541500\"><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">F<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">actors\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW241541500\"><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">that\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">dictat<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW241541500\"><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">e<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0whether water will<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">infiltrate<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">into the ground or run off over the land <\/span><\/span><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">include <\/span><\/span><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">the amount, type, and intensity of<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1785\">precipitation<\/a><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW241541500\"><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">;<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0the type and amount of vegeta<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW241541500\"><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">t<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW241541500\"><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">ion<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW241541500\"><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0cover<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW241541500\"><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">;<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0the slope of the land<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW241541500\"><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">;<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0the<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1767\">temperature<\/a><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW241541500\"><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">and aspect of the land<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW241541500\"><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">;<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0preexisting conditions<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW241541500\"><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">;<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0and the type of<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_250\">soil<\/a><\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">in the\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW241541500\"><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">i<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW241541500\"><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">nfiltrated\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">area<\/span><\/span>. <span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">High<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW241541500\"><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">-<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW241541500\"><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">intensity<\/span> <\/span><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">rain will cause more<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">runoff<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">than the same amount of rain spread out over a longer duration.<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">If the rain<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">falls<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">faster than the\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW241541500\"><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_250\">soil<\/a>\u2019s\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">properties <\/span><\/span><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">allow it to<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">infiltrate, then the water that cannot<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">infiltrate<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">becomes<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">runoff.<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\"> Dense vegetation can increase\u00a0infiltration, as the vegetative cover slows\u00a0<span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW241541500\">the\u00a0<\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW241541500\">water particle<\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW241541500\">\u2019<\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW241541500\">s\u00a0<\/span>overland flow giving them more time to infiltrate.\u00a0<\/span><\/span>If a parcel of land has more direct solar radiation or higher seasonal temperatures, there will be less infiltration and runoff, as evapotranspiration rates will be higher.\u00a0 <span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">As the\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW241541500\"><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">land<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW241541500\"><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">\u2019s\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">slope <\/span><\/span><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">increases, so does<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">runoff,\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW241541500\"><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">because<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW241541500\"><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">the\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW241541500\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW241541500\">water is more inclined to move downslope than<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">infiltrate<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">into the ground.<\/span><span class=\"NormalTextRun BCX0 SCXW241541500\">\u00a0<\/span><\/span>Extreme examples are a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_508\">basin<\/a> and a cliff, where water infiltrates much quicker into a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_508\">basin<\/a> than a cliff that has the same <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_250\">soil<\/a> properties. \u00a0Because saturated soil does not have the capacity to take more water, runoff is generally greater over saturated soil. Clay-rich <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_250\">soil<\/a> cannot accept infiltration as quickly as gravel-rich <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_250\">soil<\/a>.<\/span><\/p>\n<h3><b>11.5.3 <\/b><span style=\"font-weight: 400;\">Drainage Patterns<\/span><\/h3>\n<p><span style=\"font-weight: 400;\">The pattern of tributaries within a region is called <strong>drainage pattern<\/strong>. They depend largely on the type of rock beneath, and on structures within that rock (such as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_502\">folds<\/a> and faults). The main types of drainage patterns are dendritic, trellis, rectangular, radial, and deranged. <\/span><b>Dendritic patterns <\/b><span style=\"font-weight: 400;\">are the most common and develop in areas where the underlying rock or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediments<\/a> are uniform in character, mostly flat lying, and can be eroded equally easily in all directions<\/span><span style=\"font-weight: 400;\">. Examples are alluvial <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediments<\/a> or flat lying sedimentary rocks. <\/span><b>Trellis patterns<\/b><span style=\"font-weight: 400;\"> typically develop where sedimentary rocks have been folded or tilted and then eroded to varying degrees depending on their strength. The Appalachian Mountains in eastern United States have many good examples of trellis drainage<\/span><span style=\"font-weight: 400;\">. <\/span><b>Rectangular patterns<\/b><span style=\"font-weight: 400;\"> develop in areas that have very little topography and a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1742\">system<\/a> of bedding planes, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_986\">joints<\/a><\/span><span style=\"font-weight: 400;\">, or faults that form a rectangular network. A <\/span><b>radial pattern<\/b><span style=\"font-weight: 400;\"> forms when streams flow away from a central high point such as a mountain top or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_228\">volcano<\/a>, with the individual streams typically having dendritic drainage patterns<\/span><span style=\"font-weight: 400;\">. In places with extensive limestone deposits, streams can disappear into the groundwater via caves and subterranean drainage and this creates a <\/span><b>deranged pattern <span class=\"FindHit BCX0 SCXW69782112\">[<\/span><span class=\"NormalTextRun BCX0 SCXW69782112\">4]<\/span><\/b><span style=\"font-weight: 400;\">.<\/span><\/p>\n<figure id=\"attachment_3424\" aria-describedby=\"caption-attachment-3424\" style=\"width: 1024px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/DrainagePattern.png\"><img class=\"size-large wp-image-719\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/DrainagePattern-1024x199.png\" alt=\"Various stream drainage patterns.\" width=\"1024\" height=\"199\"><\/a><figcaption id=\"caption-attachment-3424\" class=\"wp-caption-text\">Various stream drainage patterns.<\/figcaption><\/figure>\n<h3><b>11.5.4 Fluvial Processes<\/b><\/h3>\n<p><span style=\"font-weight: 400;\"><strong>Fluvial<\/strong> processes dictate how a stream behaves and include factors controlling fluvial <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> production, transport, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1757\">deposition<\/a>. Fluvial processes include velocity, slope and gradient, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1755\">erosion<\/a>, transportation, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1757\">deposition<\/a>, stream equilibrium, and base level. <\/span><\/p>\n<p><span style=\"font-weight: 400;\">Streams can be divided into three main zones: the many smaller tributaries in the source area, the main trunk stream in the floodplain and the distributaries at the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1776\">mouth<\/a> of the stream. Major stream systems like the Mississippi are composed of many source areas, many tributaries and trunk streams, all coalescing into the one main stream draining the region. The zones of a stream are defined as 1) the zone of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> production (erosion), 2) the zone of transport, and 3) the zone of deposition. The <\/span>zone of sediment production<span style=\"font-weight: 400;\"> is located in the <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1775\">headwaters<\/a><\/strong> of the stream. In t<\/span><span style=\"font-weight: 400;\">he zone of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> transport, there is a general balance between <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1755\">erosion<\/a> of the finer <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> in its channel and transport of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> across the floodplain<\/span><span style=\"font-weight: 400;\">. Streams eventually flow into the ocean or end in quiet water with a delta which is a z<\/span>one of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1757\">deposition<\/a> <span style=\"font-weight: 400;\">located at the <\/span><b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1776\">mouth<\/a> <\/b><span style=\"font-weight: 400;\">of a stream<span class=\"NormalTextRun BCX0 SCXW234245023\">\u00a0<\/span><span class=\"FindHit BCX0 SCXW234245023\">[<\/span><span class=\"NormalTextRun BCX0 SCXW234245023\">6]<\/span><\/span><span style=\"font-weight: 400;\">. The <\/span><b>longitudinal profile<\/b><span style=\"font-weight: 400;\"> of a stream is a plot of the elevation of the stream channel at all points along its course and illustrates the location of the three zones <span class=\"FindHit BCX0 SCXW40744565\">[<\/span><span class=\"NormalTextRun BCX0 SCXW40744565\">22]<\/span><\/span><\/p>\n<h4><span style=\"font-weight: 400;\">Zone of Sediment Production\u00a0<\/span><\/h4>\n<p><span style=\"font-weight: 400;\">The zone of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> production is located in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1775\">headwaters<\/a> of a stream where rills and gullies erode <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> and contribute to larger <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1774\">tributary<\/a> streams. These tributaries carry <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> and water further downstream to the main trunk of the stream. Tributaries at the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1775\">headwaters<\/a> have the steepest gradient;\u00a0 <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1755\">erosion<\/a> there produces considerable <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> carried b the stream. Headwater streams tend to be narrow and straight with small or non-existent floodplains adjacent to the channel. Since the zone of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> production is generally the steepest part of the stream, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1775\">headwaters<\/a> are generally located in relatively high elevations. The Rocky Mountains of Wyoming and Colorado west of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">Continental<\/a> Divide contain much of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1775\">headwaters<\/a> for the Colorado River which then flows from Colorado through Utah and Arizona to Mexico.\u00a0 <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1775\">Headwaters<\/a> of the Mississippi river <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1742\">system<\/a> lie east of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">Continental<\/a> Divide in the Rocky Mountains and west of the Appalachian Divide.<\/span><\/p>\n<h4><span style=\"font-weight: 400;\">Zone of Sediment TransPORT\u00a0<\/span><\/h4>\n<figure id=\"attachment_3425\" aria-describedby=\"caption-attachment-3425\" style=\"width: 466px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Stream_Load.gif\"><img class=\"wp-image-720\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Stream_Load-300x161.gif\" alt=\"A stream carries dissolved load, suspended load, and bedload.\" width=\"466\" height=\"250\"><\/a><figcaption id=\"caption-attachment-3425\" class=\"wp-caption-text\">A stream carries dissolved load, suspended load, and bedload.<\/figcaption><\/figure>\n<p style=\"text-align: left;\"><span style=\"font-weight: 400;\">Streams transport <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> great distances from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1775\">headwaters<\/a> to the ocean, the ultimate depositional basins. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">Sediment<\/a> transportation is directly related to stream gradient and velocity. Faster and steeper streams can transport larger <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> grains. When velocity slows down, larger <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediments<\/a> settle to the channel bottom. When the velocity increases, those larger <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediments<\/a> are entrained and move again. <\/span><\/p>\n<p><span style=\"font-weight: 400;\">Transported <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediments<\/a> are grouped into <\/span>bedload<span style=\"font-weight: 400;\">, <\/span>suspended load<span style=\"font-weight: 400;\">, and <\/span>dissolved load as illustrated in the above image<span style=\"font-weight: 400;\">. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">Sediments<\/a> moved along the channel bottom are the <\/span><b>bedload <span style=\"font-weight: 400;\">that<\/span><\/b><span style=\"font-weight: 400;\"> typically consists of the largest and densest particles. Bedload is moved by <\/span><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1498\">saltation<\/a> <span style=\"font-weight: 400;\">(bouncing) and <\/span>traction <span style=\"font-weight: 400;\">(being pushed or rolled along by the force of the flow)<\/span><span style=\"font-weight: 400;\">. Smaller\u00a0 particles are picked up by flowing water and carried in suspension as <\/span><b>suspended load<\/b><span style=\"font-weight: 400;\">. The particle size that is carried in suspended and bedload depends on the flow velocity of the stream. <\/span><b>Dissolved load<\/b><span style=\"font-weight: 400;\"> in a stream is the total of the ions in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1783\">solution<\/a> from chemical weathering, including such common ions such as bicarbonate (-HCO<sup>3<\/sup><sub>-<\/sub><span style=\"font-size: 16px;\">),<\/span><sub>\u00a0<\/sub>calcium (Ca<\/span><sub><span style=\"font-weight: 400;\">+2<\/span><\/sub><span style=\"font-weight: 400;\">), chloride (Cl<\/span><sub><span style=\"font-weight: 400;\">-1<\/span><\/sub><span style=\"font-weight: 400;\">), potassium (K<\/span><sub><span style=\"font-weight: 400;\">+1<\/span><\/sub><span style=\"font-weight: 400;\">), and sodium (Na<\/span><sub><span style=\"font-weight: 400;\">+1<\/span><\/sub><span style=\"font-weight: 400;\">). The amounts of these ions are not affected by flow velocity.<\/span><\/p>\n<figure id=\"attachment_4546\" aria-describedby=\"caption-attachment-4546\" style=\"width: 150px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Bed-Load-Sediment-Transport-Youtube-QR-Code.png\"><img class=\"size-thumbnail wp-image-721\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Bed-Load-Sediment-Transport-Youtube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4546\" 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_3459\" aria-describedby=\"caption-attachment-3459\" style=\"width: 329px\" class=\"wp-caption alignright\"><a href=\"http:\/\/opengeology.org\/textbook\/wp-content\/uploads\/2016\/07\/natural-lev\u00e9es.png\"><img class=\"wp-image-871\" title=\"Source: Physical Geology, Steven Earle https:\/\/opentextbc.ca\/geology\/wp-content\/uploads\/sites\/110\/2015\/08\/natural-lev%C3%A9es.png\" src=\"http:\/\/opengeology.org\/textbook\/wp-content\/uploads\/2016\/07\/natural-lev\u00e9es.png#fixme#fixme\" alt=\"Profile of stream channel at bankfull stage, flood stage, and deposition of natural levee (Earle 2015).\" width=\"329\" height=\"324\"><\/a><figcaption id=\"caption-attachment-3459\" class=\"wp-caption-text\">Profile of stream channel at bankfull stage, flood stage, and deposition of natural levee [zotpressInText item=\"{R6VDH77A}\" format=\"%num%\" brackets=\"yes\" separator=\"comma\"].<\/figcaption><\/figure>\n<p style=\"text-align: left;\"><span style=\"font-weight: 400;\">A <\/span><b>floodplain <\/b><span style=\"font-weight: 400;\">is the flat area of land adjacent to a stream channel inundated with flood water on a regular basis. Stream flooding is a natural process that adds <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> to floodplains. A stream typically reaches its greatest velocity when it is close to flooding, known as the <\/span><b>bankfull stage<\/b><span style=\"font-weight: 400;\">. As soon as the flooding stream overtops its banks and flows onto its floodplain, the velocity decreases. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">Sediment<\/a> that was being carried by the swiftly moving water is deposited at the edge of the channel, forming a low ridge or <\/span><b>natural lev\u00e9e. <\/b><span style=\"font-weight: 400;\">In addition, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediments<\/a> are added to the floodplain during this flooding process contributing to fertile <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_250\">soils<\/a> <span class=\"NormalTextRun BCX0 SCXW137018927\">[<\/span><span class=\"NormalTextRun BCX0 SCXW137018927\">4]<\/span>.<\/span><\/p>\n<h4><span style=\"font-weight: 400;\">Zone of SEDIMENT Deposition<\/span><\/h4>\n<p><strong>D<\/strong><b>eposition <\/b><span style=\"font-weight: 400;\">occurs when bedload and suspended load come to rest on the bottom of the stream channel, lake, or ocean due to decrease in stream gradient and reduction in velocity. While both <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1757\">deposition<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1755\">erosion<\/a> occur in the zone of transport such as on <strong>point bars<\/strong> and <strong>cut banks<\/strong>, ultimate <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1757\">deposition<\/a> where the stream reaches a lake or ocean. L<\/span><span style=\"font-weight: 400;\">andforms called <\/span><b>deltas <\/b>form where the stream enters quiet water <span style=\"font-weight: 400;\">composed of the finest <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> such as fine sand, silt, and clay. <\/span><\/p>\n<h4><span style=\"font-weight: 400;\">Equilibrium and Base Level<\/span><\/h4>\n<figure id=\"attachment_3426\" aria-describedby=\"caption-attachment-3426\" style=\"width: 434px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/HalfwayCreek_Long_Profile-1.jpg\"><img class=\"wp-image-722\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/HalfwayCreek_Long_Profile-1-300x190.jpg\" alt=\"Longitudinal Profile of a creek in Indiana, showing steep gradient in its headwaters and shallower gradients toward its mouth.\" width=\"434\" height=\"275\"><\/a><figcaption id=\"caption-attachment-3426\" class=\"wp-caption-text\">Example of a longitudinal profile of a stream; Halfway Creek, Indiana<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400;\">All three stream zones are present in the typical\u00a0<\/span><b>longitudinal profile<\/b><span style=\"font-weight: 400;\"> of a stream which plots the elevation of the channel at all points along its course (see figure). All streams have a long profile. The long profile shows the stream gradient from headwater to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1776\">mouth<\/a>. All streams attempt to achieve an energetic balance among <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1755\">erosion<\/a>, transport, gradient, velocity, discharge, and channel characteristics along the stream\u2019s profile. This balance is called <\/span><strong>equilibrium, <\/strong>a state called <strong>grade<\/strong><span style=\"font-weight: 400;\">.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Another factor influencing equilibrium is <\/span><b>base level<\/b>, the<span style=\"font-weight: 400;\"> elevation of the stream's <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1776\">mouth<\/a> representing<\/span><span style=\"font-weight: 400;\"> the lowest level to which a stream can erode. The ultimate base level is, of course, sea-level. A lake or reservoir may also represent base level for a stream entering it.\u00a0 The Great <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_508\">Basin<\/a> of western Utah, Nevada, and parts of some surrounding states contains no outlets to the sea and provides internal base levels for streams within it.\u00a0 Base level for a stream entering the ocean changes if sea-level rises or falls. Base level also changes if a natural or human-made dam is added along a stream's profile. When base level is lowered, a stream will cut down and deepen its channel. When base level rises, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1757\">deposition<\/a> increases as the stream adjusts attempting to establish a new state of equilibrium<\/span><span style=\"font-weight: 400;\">. A stream that has approximately achieved equilibrium is called a <strong>graded stream<\/strong>.<\/span><\/p>\n<h3><b>11.5.5 Fluvial Landforms <\/b><\/h3>\n<p><span style=\"font-weight: 400;\">Stream landforms are the land features formed on the surface by either <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1755\">erosion<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1757\">deposition<\/a>. The stream-related landforms described here are primarily related to channel types. <\/span><\/p>\n<h4><span style=\"font-weight: 400;\">Channel Types<\/span><\/h4>\n<figure id=\"attachment_3126\" aria-describedby=\"caption-attachment-3126\" style=\"width: 465px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/BraidedWaimakariri.jpg\"><img class=\"wp-image-422\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/BraidedWaimakariri-300x225.jpg\" alt=\"The river has many inter-braided channels.\" width=\"465\" height=\"349\"><\/a><figcaption id=\"caption-attachment-3126\" class=\"wp-caption-text\">The braided Waimakariri river in New Zealand.<\/figcaption><\/figure>\n<figure id=\"attachment_3124\" aria-describedby=\"caption-attachment-3124\" style=\"width: 466px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/MeanderingRio-cauto-cuba.jpg\"><img class=\"wp-image-421\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/MeanderingRio-cauto-cuba-300x225.jpg\" alt=\"The river wiggles back and forth.\" width=\"466\" height=\"350\"><\/a><figcaption id=\"caption-attachment-3124\" class=\"wp-caption-text\">Air photo of the meandering river, R\u00edo Cauto, Cuba.<\/figcaption><\/figure>\n<p style=\"text-align: left;\"><span style=\"font-weight: 400;\">Stream channels can be straight, braided, meandering, or entrenched. The gradient, sediment load, discharge, and location of base level all influence channel type. <\/span><b>Straight channels<\/b><span style=\"font-weight: 400;\"> are relatively straight, located near the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1775\">headwaters<\/a>, have steep gradients, low discharge, and narrow V-shaped valleys. Examples of these are located in mountainous areas.\u00a0<\/span><\/p>\n<p><b>Braided streams<\/b><span style=\"font-weight: 400;\"> have multiple channels splitting and recombining around numerous mid-channel bars<\/span><span style=\"font-weight: 400;\">. These are found in floodplains with low gradients in areas with near sources of coarse <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> such as trunk streams draining mountains or in front of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1516\">glaciers<\/a>. <\/span><\/p>\n<p><b>Meandering streams<\/b><span style=\"font-weight: 400;\"> have a single channel that curves back and forth like a snake within its <\/span>floodplain <span style=\"font-weight: 400;\">where it emerges from its <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1775\">headwaters<\/a> into the zone of transport<\/span><span style=\"font-weight: 400;\">. Meandering streams are dynamic creating a wide floodplain by eroding and extending meander loops side-to-side. The highest velocity water is located on the outside of a meander bend. \u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1755\">Erosion<\/a> of the outside of the curve creates a feature called a <b>cut bank<\/b> and the meander extends its loop wider by this <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1755\">erosion<\/a>.<\/span><\/p>\n<figure id=\"attachment_3429\" aria-describedby=\"caption-attachment-3429\" style=\"width: 406px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/11.6_CirqueMadeleine.jpg\"><img class=\"wp-image-723\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/11.6_CirqueMadeleine-300x225.jpg\" alt=\"Sandy deposition at the inside of a bend (point bar) and erosion on the outside of the bend (cut bank) of a river in France.\" width=\"406\" height=\"305\"><\/a><figcaption id=\"caption-attachment-3429\" class=\"wp-caption-text\">Point bar and cut bank on the Cirque de la Madeleine in France.<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400;\">The <b>thalweg <\/b>of the stream is the deepest part of the stream channel. In the straight parts of the channel, the thalweg and highest velocity are in the center of the channel. But at the bend of a meandering stream, the thalweg shifts toward the cut bank. Opposite the cutbank on the inside bend of the channel is the lowest stream velocity and is an area of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1757\">deposition<\/a> called a <b>point bar<\/b>.<\/span><span style=\"font-weight: 400;\">\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">In areas of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1654\">tectonic<\/a> uplift such as on the Colorado Plateau, meandering streams that once flowed on the plateau surface have become entrenched or incised as uplift occurred and the stream cut its meandering channel down into <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1023\">bedrock<\/a>. Over the past several million years, the Colorado River and its tributaries have incised into the flat lying rocks of the plateau by hundreds, even thousands of feet creating deep canyons including the Grand Canyon in Arizona.<\/span><\/p>\n<figure id=\"attachment_3413\" aria-describedby=\"caption-attachment-3413\" style=\"width: 1024px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/bend2.jpg\"><img class=\"wp-image-699 size-large\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2021\/12\/bend2-1024x436.jpg\" alt=\"Entrenched meander of the Colorado River, downstream of Page, Arizona. High cliffs, that lead down to a river with narrow shores.\" width=\"1024\" height=\"436\"><\/a><figcaption id=\"caption-attachment-3413\" class=\"wp-caption-text\">An entrenched meander on the Colorado River in the eastern entrance to the Grand Canyon.<\/figcaption><\/figure>\n<figure id=\"attachment_3431\" aria-describedby=\"caption-attachment-3431\" style=\"width: 1024px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/1024px-GooseNeckStateParkPanorama.jpg\"><img class=\"size-full wp-image-724\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/1024px-GooseNeckStateParkPanorama.jpg\" alt=\"Panoramic view of incised meanders of the San Juan River at Gooseneck State Park, Utah.\" width=\"1024\" height=\"286\"><\/a><figcaption id=\"caption-attachment-3431\" class=\"wp-caption-text\">Panoramic view of incised meanders of the San Juan River at Gooseneck State Park, Utah.<\/figcaption><\/figure>\n<figure id=\"attachment_3432\" aria-describedby=\"caption-attachment-3432\" style=\"width: 452px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Lake_Powell_and_The_Rincon_Utah_-_NASA_Earth_Observatory.jpg\"><img class=\"wp-image-725\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Lake_Powell_and_The_Rincon_Utah_-_NASA_Earth_Observatory-300x200.jpg\" alt=\"The Rincon is an abandoned meander loop on the entrenched Colorado River in Lake Powell.\" width=\"452\" height=\"301\"><\/a><figcaption id=\"caption-attachment-3432\" class=\"wp-caption-text\">The Rincon is an abandoned meaner loop on the entrenched Colorado River in Lake Powell.<\/figcaption><\/figure>\n<figure id=\"attachment_3433\" aria-describedby=\"caption-attachment-3433\" style=\"width: 332px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Landsat-image-of-lower-Mississippi-River-floodplain.jpg\"><img class=\"wp-image-726\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Landsat-image-of-lower-Mississippi-River-floodplain-254x300.jpg\" alt=\"Satellite image of lower Mississippi River floodplain\" width=\"332\" height=\"393\"><\/a><figcaption id=\"caption-attachment-3433\" class=\"wp-caption-text\">Landsat image of lower Mississippi River flodplain<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400;\">Many fluvial landforms occur on a floodplain associated with a meandering stream. Meander activity and r<\/span><span style=\"font-weight: 400;\">egular flooding contribute to widening the floodplain by eroding adjacent uplands. The stream channels are confined by <\/span><b>natural levees<\/b><span style=\"font-weight: 400;\"> that have been built up over many years of regular flooding.<\/span><span style=\"font-weight: 400;\"> Natural levees can isolate and direct flow from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1774\">tributary<\/a> channels on the floodplain from immediately reaching the main channel. \u00a0These isolated streams are called <\/span><b>yazoo streams<\/b> and<span style=\"font-weight: 400;\"> flow parallel to the main trunk stream until there is an opening in the levee to allow for a belated confluence<\/span><span style=\"font-weight: 400;\">.<\/span><\/p>\n<figure id=\"attachment_4548\" aria-describedby=\"caption-attachment-4548\" style=\"width: 150px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/How-Is-A-Levee-Formed-Youtube-QR-Code.png\"><img class=\"size-thumbnail wp-image-727\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/How-Is-A-Levee-Formed-Youtube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4548\" 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><span style=\"font-weight: 400;\">To limit flooding, humans build artificial levees on flood plains. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">Sediment<\/a> that breaches the levees during flood stage is called <\/span><b>crevasse splays<\/b><span style=\"font-weight: 400;\"> and delivers silt and clay onto the floodplain. These deposits are rich in nutrients and often make good farm land. When floodwaters crest over human-made levees, the levees quickly erode with potentially catastrophic impacts.\u00a0 Because of the good <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_250\">soils<\/a>, farmers regularly return after floods and rebuild year after year.<\/span><\/p>\n<figure id=\"attachment_3434\" aria-describedby=\"caption-attachment-3434\" style=\"width: 456px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Nowitna_river-with-approaching-cutoff.jpg\"><img class=\"wp-image-728\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Nowitna_river-with-approaching-cutoff-300x211.jpg\" alt=\"Meander nearing cutoff on the Nowitna River in Alaska\" width=\"456\" height=\"321\"><\/a><figcaption id=\"caption-attachment-3434\" class=\"wp-caption-text\">Meander nearing cutoff on the Nowitna River in Alaska<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400;\">Through <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1755\">erosion<\/a> on the outsides of the meanders and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1757\">deposition<\/a> on the insides, the channels of meandering streams move back and forth across their floodplain over time<\/span><span style=\"font-weight: 400;\">. On very broad floodplains with very low gradients, the meander bends can become so extreme that they cut across themselves at a narrow neck (see figure) called a <strong>cutoff<\/strong>. The former channel becomes isolated and forms an <\/span><b>oxbow lake<\/b> seen on the right of the figure<span style=\"font-weight: 400;\">.<\/span><span style=\"font-weight: 400;\">\u00a0Eventually the oxbow lake fills in with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> and becomes a <\/span>wetland <span style=\"font-weight: 400;\">and eventually a <\/span><b>meander scar<\/b><span style=\"font-weight: 400;\">. <\/span><span style=\"font-weight: 400;\">S<\/span><span style=\"font-weight: 400;\">tream meanders can migrate\u00a0and form oxbow lakes in a relatively short amount of time. Where stream channels form geographic and political boundaries, this shifting of channels can cause conflicts.<\/span><\/p>\n<figure id=\"attachment_4557\" aria-describedby=\"caption-attachment-4557\" style=\"width: 150px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Why-Do-Rivers-Curve-Youtube-QR-Code.png\"><img class=\"size-thumbnail wp-image-729\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Why-Do-Rivers-Curve-Youtube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4557\" 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_3435\" aria-describedby=\"caption-attachment-3435\" style=\"width: 356px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Alluvial_fan_in_Iran.jpg\"><img class=\"wp-image-730\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Alluvial_fan_in_Iran-300x200.jpg\" alt=\"Satellite image of alluvial fan in Iraq.\" width=\"356\" height=\"237\"><\/a><figcaption id=\"caption-attachment-3435\" class=\"wp-caption-text\">Alluvial fan in Iraq seen by NASA satellite. A stream emerges from the canyon and creates this cone-shaped deposit.<\/figcaption><\/figure>\n<p><strong>Alluvial fans<\/strong> are a depositional landform created where streams emerge from mountain canyons into a valley. The channel that had been confined by the canyon walls is no longer confined, slows down and spreads out, dropping its bedload of all sizes, forming a delta in the air of the valley.\u00a0 As distributary channels fill with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a>, the stream is diverted laterally, and the alluvial fan develops into a cone shaped landform with distributaries radiating from the canyon <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1776\">mouth<\/a>. Alluvial fans are common in the dry climates of the West where ephemeral streams emerge from canyons in the ranges of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1514\">Basin and Range<\/a>.<\/p>\n<div id=\"h5p-76\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-76\" class=\"h5p-iframe\" data-content-id=\"76\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"11.3 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_4541\" aria-describedby=\"caption-attachment-4541\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/11.5-Interactive-Map-of-Mississipi-River-QR-Code.png\"><img class=\"size-thumbnail wp-image-731\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/11.5-Interactive-Map-of-Mississipi-River-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4541\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 11.5 via this QR Code.<\/figcaption><\/figure>\n<figure id=\"attachment_3436\" aria-describedby=\"caption-attachment-3436\" style=\"width: 417px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/11.6_Mississippiriver-new-01.png\"><img class=\"wp-image-732\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/11.6_Mississippiriver-new-01-300x275.png\" alt=\"The area that contributes to the tributaries of the Mississippi River.\" width=\"417\" height=\"382\"><\/a><figcaption id=\"caption-attachment-3436\" class=\"wp-caption-text\">Location of the Mississippi River drainage basin and Mississippi River delta.<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400;\">\u00a0A <strong>delta<\/strong> is formedwhen a stream reaches a quieter body of water such as a lake or the ocean and the bedload and suspended load is deposited<\/span><span style=\"font-weight: 400;\">. If wave <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1755\">erosion<\/a> from the water body is greater than <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1757\">deposition<\/a> from the river, a delta will not form. The largest and most famous delta in the United States is the Mississippi River delta formed where the Mississippi River flows into the Gulf of Mexico. The Mississippi River drainage basin is the largest in North America, draining 41%<\/span> <span style=\"font-weight: 400;\">of the contiguous United States <span class=\"NormalTextRun BCX0 SCXW57176381\">[<\/span><span class=\"NormalTextRun BCX0 SCXW57176381\">24]<\/span><\/span><span style=\"font-weight: 400;\">. Because of the large drainage area, the river carries a large amount of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a>. The Mississippi River is a major shipping route and human engineering has ensured that the channel has been artificially straightened and remains fixed within the floodplain. The river\u00a0 is now 229 km shorter than it was before humans began engineering it <span class=\"NormalTextRun BCX0 SCXW57176381\">[<\/span><span class=\"NormalTextRun BCX0 SCXW57176381\">24]<\/span><\/span><span style=\"font-weight: 400;\">. Because of these restraints, the delta is now focused on one trunk channel and has created a \u201cbird\u2019s foot\u201d pattern<\/span><span style=\"font-weight: 400;\">. The two <\/span><a href=\"http:\/\/earthobservatory.nasa.gov\/IOTD\/view.php?id=8103&amp;eocn=image&amp;eoci=related_image\"><span style=\"font-weight: 400;\">NASA images<\/span><\/a><span style=\"font-weight: 400;\"> below of the delta show how the shoreline has retreated and land was inundated with water while <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1757\">deposition<\/a> of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> was focused at end of the distributaries. These images have changed over a 25 year <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1244\">period<\/a> from 1976 to 2001. These are stark changes illustrating sea-level rise and land <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_511\">subsidence<\/a> from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1758\">compaction<\/a> of peat due to the lack of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> resupply <span class=\"NormalTextRun SCXW213676927 BCX0\">[<\/span><span class=\"NormalTextRun SCXW213676927 BCX0\">25]<\/span><\/span><span style=\"font-weight: 400;\">.<\/span><\/p>\n<div id=\"h5p-77\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-77\" class=\"h5p-iframe\" data-content-id=\"77\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"11.4 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_4542\" aria-describedby=\"caption-attachment-4542\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/11.5-June-10-1976-Landsat-QR-Code.png\"><img class=\"size-thumbnail wp-image-733\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/11.5-June-10-1976-Landsat-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4542\" 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 formation of the Mississippi River delta started about 7500 years ago when postglacial sea level stopped rising<\/span><span style=\"font-weight: 400;\">. In the past 7000 years, prior to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_764\">anthropogenic<\/a> modifications, the Mississippi River delta formed several sequential lobes. The river abandoned each lobe for a more preferred route to the Gulf of Mexico. These delta lobes were reworked by the ocean waves of the Gulf of Mexico <span class=\"NormalTextRun BCX0 SCXW144287476\">[<\/span><span class=\"NormalTextRun BCX0 SCXW144287476\">26]<\/span><\/span><span style=\"font-weight: 400;\">. \u00a0After each lobe was abandoned by the river, isostatic depression and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1758\">compaction<\/a> of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediments<\/a> caused <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_508\">basin<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_511\">subsidence<\/a> and the land to sink.\u00a0<\/span><\/p>\n<figure id=\"attachment_3437\" aria-describedby=\"caption-attachment-3437\" style=\"width: 464px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/11.6_QuakeLake.jpg\"><img class=\"wp-image-734\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/11.6_QuakeLake-300x200.jpg\" alt=\"Delta in Quake Lake Montana. Deposition of this delta began in 1959, when the Madison river was dammed by the landslide caused by the 7.5 magnitude earthquake.\" width=\"464\" height=\"309\"><\/a><figcaption id=\"caption-attachment-3437\" class=\"wp-caption-text\">Delta in Quake Lake Montana. Deposition of this delta began in 1959, when the Madison river was dammed by the landslide caused by the 7.5 magnitude earthquake.<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400;\">A clear example of how deltas form came from an earthquake. During the 1959 Madison Canyon 7.5 magnitude earthquake in Montana, a large <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_246\">landslide<\/a> dammed the Madison River forming Quake Lake <\/span><span style=\"font-weight: 400;\">still there today <span class=\"NormalTextRun BCX0 SCXW11982677\">[<\/span><span class=\"NormalTextRun BCX0 SCXW11982677\">27]<\/span>. A small <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1774\">tributary<\/a> stream that once flowed into the Madison River, now flows into Quake Lake forming a delta c<\/span><span style=\"font-weight: 400;\">omposed of coarse <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> actively eroded from the mountainous upthrown block to the north. <\/span><\/p>\n<p><span style=\"font-weight: 400;\">Deltas can be further categorized as wave-dominated or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1480\">tide<\/a>-dominated. Wave-dominated deltas occur where the tides are small and wave energy dominates. An example is the Nile River delta in the Mediterranean Sea that has the classic shape of the Greek character (\u0394) from which the landform is named<\/span><span style=\"font-weight: 400;\">. A <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1480\">tide<\/a>-dominated delta forms when ocean tides are powerful and influence the shape of the delta. For example, Ganges-Brahmaputra Delta in the Bay of Bengal (near India and Bangladesh) is the world\u2019s largest delta and mangrove swamp called the Sundarban <span class=\"NormalTextRun BCX0 SCXW49111969\">[<\/span><span class=\"NormalTextRun BCX0 SCXW49111969\">29]<\/span>.\u00a0<\/span><\/p>\n<figure id=\"attachment_3438\" aria-describedby=\"caption-attachment-3438\" style=\"width: 221px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Sundarban-Delta-Bangladesh.png\"><img class=\"wp-image-735 size-medium\" style=\"font-weight: bold; background-color: transparent; text-align: inherit;\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Sundarban-Delta-Bangladesh-221x300.png\" alt=\"Tide-dominated delta of the Ganges River\" width=\"221\" height=\"300\"><\/a><figcaption id=\"caption-attachment-3438\" class=\"wp-caption-text\">Sundarban Delta in Bangladesh, a tide-dominated delta of the Ganges River<\/figcaption><\/figure>\n<p>At the Sundarban Delta in Bangladesh, t<span style=\"font-weight: 400;\">idal forces create linear intrusions of seawater into the delta. This delta also holds the world\u2019s largest mangrove swamp<\/span><span style=\"font-weight: 400;\">. \u00a0<\/span><\/p>\n<figure id=\"attachment_3439\" aria-describedby=\"caption-attachment-3439\" style=\"width: 698px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Nile_River_and_delta_from_orbit-e1491789834381.jpg\"><img class=\"size-full wp-image-736\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Nile_River_and_delta_from_orbit-e1491789834381.jpg\" alt=\"The Nile Delta is a triangular patch of green in an otherwise sandy brown area.\" width=\"698\" height=\"259\"><\/a><figcaption id=\"caption-attachment-3439\" class=\"wp-caption-text\">Nile Delta showing its classic \u201cdelta\u201d shape.<\/figcaption><\/figure>\n<figure id=\"attachment_3440\" aria-describedby=\"caption-attachment-3440\" style=\"width: 420px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/11.6_Logan_Bonneville_Delta.jpg\"><img class=\"wp-image-737\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/11.6_Logan_Bonneville_Delta-237x300.jpg\" alt=\"Contours of the Logan Delta, incised by the Logan River.\" width=\"420\" height=\"531\"><\/a><figcaption id=\"caption-attachment-3440\" class=\"wp-caption-text\">Map of the Logan Delta (Gilbert 1890).<\/figcaption><\/figure>\n<p style=\"text-align: left;\"><span style=\"font-weight: 400;\">Lake Bonneville was a large, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_746\">pluvial lake<\/a> that occupied the western half of Utah and parts of eastern Nevada from about 30,000 to 12,000 years ago<\/span><span style=\"font-weight: 400;\">. The lake filled to a maximum elevation as great as approximately 5100 feet above mean sea level, filling the basins, leaving the mountains exposed, many as islands. The presence of the lake allowed for <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1757\">deposition<\/a> of both fine grained lake mud and silt and coarse gravels from the mountains. Variations in lake level were controlled by regional <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_757\">climate<\/a> and a catastrophic failure of Lake Bonneville\u2019s main outlet, Red Rock Pass\u00a0<span class=\"TextRun Strikethrough BCX0 SCXW10377017\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW10377017\">[<\/span><span class=\"NormalTextRun BCX0 SCXW10377017\">31]<\/span><\/span><\/span><span style=\"font-weight: 400;\">.\u00a0 during extended <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1244\">periods<\/a> of time in which the lake level remained stable, wave-cut terraces were produced that can be seen today on the flanks of many mountains in the region.\u00a0 Significant deltas formed at the mouths of major canyons in Salt Lake, Cache, and other Utah valleys. \u00a0The Great Salt Lake is the remnant of Lake Bonneville and cities have built up on these delta deposits.<\/span><\/p>\n<figure id=\"attachment_3441\" aria-describedby=\"caption-attachment-3441\" style=\"width: 1024px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/ggk03413-scaled.jpg\"><img class=\"size-large wp-image-3441\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/ggk03413-scaled-1.jpg\" alt=\"Deltaic deposits of Lake Bonneville near Logan, Utah.\" width=\"1024\" height=\"665\"><\/a><figcaption id=\"caption-attachment-3441\" class=\"wp-caption-text\">Deltaic deposits of Lake Bonneville near Logan, Utah; wave cut terraces can be seen on the mountain slope.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p><b>Stream terraces<\/b><span style=\"font-weight: 400;\"> are remnants of older floodplains located above the existing floodplain and river. Like entrenched meanders, stream terraces form when uplift occurs or base level drops and streams erode downward, their meanders widening a new flood plain. Stream terraces can also form from extreme flood events associated with retreating <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1516\">glaciers<\/a>. A classic example of multiple stream terraces are along the Snake River in Grand Teton National Park in Wyoming <span class=\"NormalTextRun BCX0 SCXW162599196\">[3<\/span><span class=\"NormalTextRun BCX0 SCXW162599196\">2; 33]<\/span><\/span><span style=\"font-weight: 400;\">.<\/span><\/p>\n<table style=\"border-collapse: collapse; width: 100%;\" border=\"0\">\n<tbody>\n<tr>\n<td style=\"width: 50%;\">\n<figure id=\"attachment_3443\" aria-describedby=\"caption-attachment-3443\" style=\"width: 375px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/11.6_TetonTerraceDSC_0076-scaled.jpg\"><img class=\"wp-image-3443\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/11.6_TetonTerraceDSC_0076-scaled-1.jpg\" alt=\"Landscape with river cutting into plane. Three different levels of flat surfaces that represent different base levels.\" width=\"375\" height=\"250\"><\/a><figcaption id=\"caption-attachment-3443\" class=\"wp-caption-text\">Terraces along the Snake River, Wyoming.<\/figcaption><\/figure>\n<\/td>\n<td style=\"width: 50%;\">\n<figure id=\"attachment_3444\" aria-describedby=\"caption-attachment-3444\" style=\"width: 333px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/11.6_StreamTerrace_IMGP4422.jpg\"><img class=\"wp-image-740\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/11.6_StreamTerrace_IMGP4422-300x225.jpg\" alt=\"River along several different levels of flat floodplains\" width=\"333\" height=\"250\"><\/a><figcaption id=\"caption-attachment-3444\" class=\"wp-caption-text\">Terraces in Glen Roy, Scotland<\/figcaption><\/figure>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>&nbsp;<\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-81\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-81\" class=\"h5p-iframe\" data-content-id=\"81\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"11.6 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_4540\" aria-describedby=\"caption-attachment-4540\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/11.5-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-741\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/11.5-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4540\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 11.5 via this QR Code.<\/figcaption><\/figure>\n<h2><span style=\"font-weight: 400;\">11.6 Groundwater<\/span><\/h2>\n<p><span style=\"font-weight: 400;\">Groundwater is an important source of freshwater. \u00a0It can be found at varying depths in all places under the ground, but is limited by extractable quantity and quality.<\/span><\/p>\n<figure id=\"attachment_4555\" aria-describedby=\"caption-attachment-4555\" style=\"width: 150px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/What-is-an-Aquifer-Youtube-QR-Code.png\"><img class=\"size-thumbnail wp-image-742\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/What-is-an-Aquifer-Youtube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4555\" 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>11.6.1 Porosity and Permeability<\/b><\/h3>\n<p><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW254024023\"><span class=\"TextRun BCX0 SCXW254024023\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart BCX0 SCXW254024023\">An\u00a0<\/span><\/span><\/span><strong><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW254024023\"><span class=\"TextRun BCX0 SCXW254024023\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW254024023\">aquifer<\/span><\/span><\/span><\/strong><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW254024023\"><span class=\"TextRun BCX0 SCXW254024023\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW254024023\">\u00a0is a\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW254024023\"><span class=\"TextRun BCX0 SCXW254024023\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW254024023\">rock unit<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW254024023\"><span class=\"TextRun BCX0 SCXW254024023\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW254024023\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW254024023\"><span class=\"TextRun BCX0 SCXW254024023\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW254024023\">that contains extractable<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW254024023\"><span class=\"TextRun BCX0 SCXW254024023\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW254024023\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW254024023\"><span class=\"TextRun BCX0 SCXW254024023\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW254024023\">ground<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW254024023\"><span class=\"TextRun BCX0 SCXW254024023\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW254024023\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW254024023\"><span class=\"TextRun BCX0 SCXW254024023\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW254024023\">water.<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW254024023\"><span class=\"TextRun BCX0 SCXW254024023\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW254024023\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW254024023\"><span class=\"TextRun BCX0 SCXW254024023\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW254024023\">A good aquifer must be both <strong>porous<\/strong> and <strong>permeable<\/strong>. P<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW254024023\"><span class=\"TextRun BCX0 SCXW254024023\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW254024023\">orosity<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW254024023\"><span class=\"TextRun BCX0 SCXW254024023\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW254024023\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW254024023\"><span class=\"TextRun BCX0 SCXW254024023\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW254024023\">is the <\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW254024023\"><span class=\"TextRun BCX0 SCXW254024023\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW254024023\">space between grains <\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW254024023\"><span class=\"TextRun BCX0 SCXW254024023\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW254024023\">that can hold <\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW254024023\"><span class=\"TextRun BCX0 SCXW254024023\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW254024023\">water, <span style=\"font-weight: 400;\">expressed as the percentage of open space in the total volume of the rock<\/span>.<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW254024023\"><span class=\"TextRun BCX0 SCXW254024023\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW254024023\"> P<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW254024023\"><span class=\"TextRun BCX0 SCXW254024023\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW254024023\">ermeability comes from connectivity of the spaces that <\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW254024023\"><span class=\"TextRun BCX0 SCXW254024023\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW254024023\">allows water to\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW254024023\"><span class=\"TextRun BCX0 SCXW254024023\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW254024023\">move in the aquifer<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW254024023\"><span class=\"TextRun BCX0 SCXW254024023\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW254024023\">. <\/span><\/span><\/span><span style=\"font-weight: 400;\">Porosity can occur as primary porosity, as space between sand grains or vesicles in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_228\">volcanic<\/a> rocks, or secondary porosity as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_986\">fractures<\/a> or dissolved spaces in\u00a0 rock). <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1758\">Compaction<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1759\">cementation<\/a> during <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1760\">lithification<\/a> of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediments<\/a> reduces porosity (see chapter <a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/5-weathering-erosion-and-sedimentary-rocks\/\" target=\"_blank\" rel=\"noopener\">5.3<\/a>).\u00a0<\/span><\/p>\n<p><span style=\"font-weight: 400;\">A combination of a place to contain water (porosity) and the ability to move water (permeability) makes a good <strong>aquifer<\/strong>\u2014a rock unit or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> that allows extraction of groundwater. \u00a0Well-sorted <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediments<\/a> have higher porosity because there are not smaller <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> particles filling in the spaces between the larger particles. Shales made of clays generally have high porosity, but the pores are poorly connected, thereby causing low permeability. \u00a0<\/span><\/p>\n<figure id=\"attachment_4549\" aria-describedby=\"caption-attachment-4549\" style=\"width: 150px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Porosity-and-Permeability-Youtube-QR-Code.png\"><img class=\"size-thumbnail wp-image-743\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Porosity-and-Permeability-Youtube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4549\" 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><span style=\"font-weight: 400;\"><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW26704983\"><span class=\"TextRun BCX0 SCXW26704983\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart BCX0 SCXW26704983\">Wh<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW26704983\"><span class=\"TextRun BCX0 SCXW26704983\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW26704983\">ile permeability is a<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW26704983\"><span class=\"TextRun BCX0 SCXW26704983\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW26704983\">n important<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW26704983\"><span class=\"TextRun BCX0 SCXW26704983\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW26704983\">\u00a0measure of\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW26704983\"><span class=\"TextRun BCX0 SCXW26704983\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW26704983\">a\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW26704983\"><span class=\"TextRun BCX0 SCXW26704983\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW26704983\">porous<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW26704983\"><span class=\"TextRun BCX0 SCXW26704983\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW26704983\">\u00a0material<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW26704983\"><span class=\"TextRun BCX0 SCXW26704983\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW26704983\">\u2019s ability to trans<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW26704983\"><span class=\"TextRun BCX0 SCXW26704983\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW26704983\">mit<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW26704983\"><span class=\"TextRun BCX0 SCXW26704983\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW26704983\">\u00a0water<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW26704983\"><span class=\"TextRun BCX0 SCXW26704983\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW26704983\">,\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW26704983\"><span class=\"TextRun BCX0 SCXW26704983\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW26704983\">hydraulic conductivity is\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW26704983\"><span class=\"TextRun BCX0 SCXW26704983\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW26704983\">more commonly use<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW26704983\"><span class=\"TextRun BCX0 SCXW26704983\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW26704983\">d by geologists<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW26704983\"><span class=\"TextRun BCX0 SCXW26704983\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW26704983\">\u00a0to measure\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW26704983\"><span class=\"TextRun BCX0 SCXW26704983\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW26704983\">how easily a fluid is transmitted<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW26704983\"><span class=\"TextRun BCX0 SCXW26704983\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW26704983\">. <\/span><\/span><\/span><\/span><b>Hydraulic conductivity<\/b><span style=\"font-weight: 400;\"> <span class=\"TextRun BCX0 SCXW234101823\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234101823\">measure<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW234101823\"><span class=\"TextRun BCX0 SCXW234101823\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234101823\">s both the\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW234101823\"><span class=\"TextRun BCX0 SCXW234101823\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234101823\">permeability of <\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW234101823\"><span class=\"TextRun BCX0 SCXW234101823\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234101823\">the\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW234101823\"><span class=\"TextRun BCX0 SCXW234101823\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234101823\">porous\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW234101823\"><span class=\"TextRun BCX0 SCXW234101823\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234101823\">material\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW234101823\"><span class=\"TextRun BCX0 SCXW234101823\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234101823\">and\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW234101823\"><span class=\"TextRun BCX0 SCXW234101823\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234101823\">the properties\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW234101823\"><span class=\"TextRun BCX0 SCXW234101823\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234101823\">of the\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW234101823\"><span class=\"TextRun BCX0 SCXW234101823\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234101823\">water, or whate<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW234101823\"><span class=\"TextRun BCX0 SCXW234101823\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234101823\">ver\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW234101823\"><span class=\"TextRun BCX0 SCXW234101823\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234101823\">fluid<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW234101823\"><span class=\"TextRun BCX0 SCXW234101823\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234101823\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW234101823\"><span class=\"TextRun BCX0 SCXW234101823\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234101823\">is\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW234101823\"><span class=\"TextRun BCX0 SCXW234101823\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234101823\">being transmitted like oil or gas<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW234101823\"><span class=\"TextRun BCX0 SCXW234101823\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW234101823\">.<\/span><\/span><\/span> <span class=\"TextRun SCXW70667293 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW70667293 BCX0\">Because\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW70667293 BCX0\"><span class=\"TextRun SCXW70667293 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW70667293 BCX0\">hydraulic conductivity<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW70667293 BCX0\"><span class=\"TextRun SCXW70667293 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW70667293 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW70667293 BCX0\"><span class=\"TextRun SCXW70667293 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW70667293 BCX0\">also measures the properties of the<\/span><\/span><\/span><span class=\"TextRun SCXW70667293 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW70667293 BCX0\">\u00a0fluid<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW70667293 BCX0\"><span class=\"TextRun SCXW70667293 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW70667293 BCX0\">, such as viscosity<\/span><\/span><\/span><span class=\"TextRun SCXW70667293 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW70667293 BCX0\">,<\/span><span class=\"NormalTextRun SCXW70667293 BCX0\">\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW70667293 BCX0\"><span class=\"TextRun SCXW70667293 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW70667293 BCX0\">it <\/span><\/span><\/span><span class=\"TextRun SCXW70667293 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW70667293 BCX0\">is used by <\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW70667293 BCX0\"><span class=\"TextRun SCXW70667293 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW70667293 BCX0\">both<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW70667293 BCX0\"><span class=\"TextRun SCXW70667293 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW70667293 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW70667293 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW70667293 BCX0\">petroleum<\/span><span class=\"NormalTextRun SCXW70667293 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW70667293 BCX0\">geologists and\u00a0<\/span><span class=\"NormalTextRun SCXW70667293 BCX0\">hydrogeologists to describe\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW70667293 BCX0\"><span class=\"TextRun SCXW70667293 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW70667293 BCX0\">both<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW70667293 BCX0\"><span class=\"TextRun SCXW70667293 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW70667293 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW70667293 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW70667293 BCX0\">the production capability of<\/span><span class=\"NormalTextRun SCXW70667293 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW70667293 BCX0\">oil<\/span><span class=\"NormalTextRun SCXW70667293 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW70667293 BCX0\">reservoirs<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW70667293 BCX0\"><span class=\"TextRun SCXW70667293 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW70667293 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW70667293 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW70667293 BCX0\">and<\/span><span class=\"NormalTextRun SCXW70667293 BCX0\">\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW70667293 BCX0\"><span class=\"TextRun SCXW70667293 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW70667293 BCX0\">of\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW70667293 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW70667293 BCX0\">aquifers. High<\/span><span class=\"NormalTextRun SCXW70667293 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW70667293 BCX0\">hydraulic conductivity<\/span><span class=\"NormalTextRun SCXW70667293 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW70667293 BCX0\">indicates\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW70667293 BCX0\"><span class=\"TextRun SCXW70667293 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW70667293 BCX0\">that fluid transmits rapidly <\/span><\/span><\/span><span class=\"TextRun SCXW70667293 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW70667293 BCX0\">through an<\/span><span class=\"NormalTextRun SCXW70667293 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW70667293 BCX0\">aquifer.\u00a0<\/span><\/span><\/span><\/p>\n<h3><b>11.6.2 Aquifers\u00a0<\/b><\/h3>\n<p><span style=\"font-weight: 400;\"><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW76684060\"><span class=\"TextRun BCX0 SCXW76684060\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart BCX0 SCXW76684060\">Aquifers are rock layers with sufficient porosity and permeability to allow water to be both contained and move within them. For rock or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a><\/span><\/span><\/span> to be considered an aquifer, its pores must be at least partially filled with water and it must be permeable enough to transmit water. Drinking water aquifers must also contain <strong>potable <\/strong>water. Aquifers can vary dramatically in scale, from spanning several formations covering large regions to being a local formation in a limited area. Aquifers adequate for water supply are both permeable, porous, and potable.<\/span><\/p>\n<h3><b>11.6.3 Groundwater Flow<\/b><\/h3>\n<figure id=\"attachment_3445\" aria-describedby=\"caption-attachment-3445\" style=\"width: 320px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Vadose_zone.gif\"><img class=\"size-full wp-image-744\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Vadose_zone.gif\" alt=\"The groundwater table is where the pores in an aquifer are completely saturated.\" width=\"320\" height=\"243\"><\/a><figcaption id=\"caption-attachment-3445\" class=\"wp-caption-text\">Zone of saturation.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p style=\"text-align: left;\"><span style=\"font-weight: 400;\">When surface water infiltrates or seeps into the ground, it usually enters the unsaturated zone also called the vadose zone, or zone of aeration. \u00a0The <\/span><b>vadose zone<\/b><span style=\"font-weight: 400;\"> is the volume of geologic material between the land surface and the zone of saturation <\/span><span style=\"font-weight: 400;\">where the pore spaces are not completely filled with water <span class=\"NormalTextRun BCX0 SCXW263278408\">[<\/span><span class=\"NormalTextRun BCX0 SCXW263278408\">34<\/span><span class=\"NormalTextRun BCX0 SCXW263278408\">]<\/span><\/span><span style=\"font-weight: 400;\">. Plant roots inhabit the upper vadose zone and fluid pressure in the pores is less than atmospheric pressure. \u00a0Below the vadose zone is the capillary fringe. \u00a0Capillary fringe is the usually thin zone below the vadose zone where the pores are completely filled with water (<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1784\">saturation<\/a>), but the fluid pressure is less than atmospheric pressure. \u00a0The pores in the capillary fringe are filled because of capillary action, which occurs because of a combination of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1771\">adhesion<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1770\">cohesion<\/a>. Below the capillary fringe is the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1784\">saturated<\/a> zone or phreatic zone, where the pores are completely <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1784\">saturated<\/a> and the fluid in the pores is at or above atmospheric pressure<\/span><span style=\"font-weight: 400;\">. The interface between the capillary fringe and the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1784\">saturated<\/a> zone marks the location of the water table.<\/span><\/p>\n<p><strong>W<\/strong><b>ells<\/b>\u00a0are conduits that extend into the ground with openings to the aquifers, to extract from, measure, and sometimes add water to the aquifer. Wells are generally the way that geologists and hydrologist measure the depth to groundwater from the land surface as well as withdraw water from aquifers.<\/p>\n<p>Water is found throughout the pore spaces in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediments<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1023\">bedrock<\/a>. The <b>water table<\/b> is the area below which the pores are fully <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1784\">saturated<\/a> with water. The simplest case of a water table is when the aquifer is unconfined, meaning it does not have a confining layer above it. Confining layers can pressurize aquifers by trapping water that is recharged at a higher elevation underneath the confining layer, allowing for a potentiometric surface higher than the top of the aquifer, and sometimes higher than the land surface.<\/p>\n<figure id=\"attachment_3446\" aria-describedby=\"caption-attachment-3446\" style=\"width: 550px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/wa-aquifer_types-1.gif\"><img class=\"size-full wp-image-745\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/wa-aquifer_types-1.gif\" alt=\"In a confined aquifer, the potentiometric surface can rise above the ground.\" width=\"550\" height=\"325\"><\/a><figcaption id=\"caption-attachment-3446\" class=\"wp-caption-text\">Potentiometric surface and water table in an aquifer system.<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400;\">A <\/span><b>confining layer<\/b><span style=\"font-weight: 400;\"> is a low permeability layer above and\/or below an aquifer that restricts the water from moving in and out of the aquifer. \u00a0Confining layers include <\/span><b>aquicludes<\/b><span style=\"font-weight: 400;\">, which are so impermeable that no water travels through them, and <\/span><b>aquitards<\/b><span style=\"font-weight: 400;\">, which significantly decrease the speed at which water travels through them. <\/span>The <b>potentiometric surface<\/b> represents the height that water would rise in a well penetrating the pressurized aquifer <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1742\">system<\/a>. Breaches in the pressurized aquifer <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1742\">system<\/a>, like faults or wells, can cause <b>springs<\/b> or <b>flowing wells<\/b>, also known as <b>artesian wells<\/b>.<\/p>\n<p><span style=\"font-weight: 400;\">The water table will generally mirror surface topography, though more subdued, because hydrostatic pressure is equal to atmospheric pressure along the surface of the water table. \u00a0If the water table intersects the ground surface the result will be water at the surface in the form of a gaining stream, spring, lake, or wetland. The water table intersects the channel for <strong>gaining streams<\/strong> which then gains water from the water table.\u00a0 The channels for <strong>losing streams<\/strong> lie below the water table, thus losing streams lose water to the water table.\u00a0 Losing streams may be seasonal during a dry season or <strong>ephemeral<\/strong> in dry climates where they may normally be dry and carry water only after rain storms. Ephemeral streams pose a serious danger of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1506\">flash flooding<\/a>\u00a0in dry climates.<\/span><\/p>\n<figure id=\"attachment_4556\" aria-describedby=\"caption-attachment-4556\" style=\"width: 150px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Where-is-the-Water-Table-Youtube-QR-Code.png\"><img class=\"size-thumbnail wp-image-746\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Where-is-the-Water-Table-Youtube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4556\" 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><span style=\"font-weight: 400;\">Mentioned in the video is the <a href=\"https:\/\/groundwaterwatch.usgs.gov\/default.asp\">USGS Groundwater Watch<\/a> site.\u00a0<\/span><\/p>\n<p><i><\/i><span style=\"font-weight: 400;\"><span class=\"TrackChangeTextInsertion TrackedChange SCXW96173255 BCX0\"><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart SCXW96173255 BCX0\">Using wells, g<\/span><\/span><\/span><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">eologists measure the\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW96173255 BCX0\"><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">water table<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW96173255 BCX0\"><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">\u2019s\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">hei<\/span><\/span><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">ght <\/span><\/span><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">and<\/span><span class=\"NormalTextRun SCXW96173255 BCX0\">\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW96173255 BCX0\"><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">the\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">potentiometric surface<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW96173255 BCX0\"><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">.<\/span><\/span><\/span><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">\u00a0<\/span><\/span><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">Graphs of\u00a0<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW96173255 BCX0\"><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">the\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">depth <\/span><\/span><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">to <\/span><\/span><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">groundwater<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW96173255 BCX0\"><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW96173255 BCX0\"><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">over<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW96173255 BCX0\"><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW96173255 BCX0\"><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">time<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW96173255 BCX0\"><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">,<\/span><\/span><\/span><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">\u00a0<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW96173255 BCX0\"><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">are\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">known as <strong>hydrographs<\/strong> and<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW96173255 BCX0\"><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW96173255 BCX0\"><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">sho<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW96173255 BCX0\"><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">w <\/span><\/span><\/span><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">changes in the<\/span><span class=\"NormalTextRun SCXW96173255 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW96173255 BCX0\">water table<\/span><span class=\"NormalTextRun SCXW96173255 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW96173255 BCX0\">over time.\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW96173255 BCX0\"><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">W<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW96173255 BCX0\"><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">ell<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW96173255 BCX0\"><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">-<\/span><\/span><\/span><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">water level\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW96173255 BCX0\"><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">is\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW96173255 BCX0\"><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">controlled by many factors <\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW96173255 BCX0\"><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">and <\/span><\/span><\/span><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">can change very frequently, even <\/span><\/span><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">every minute<\/span><\/span><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">, seasonally, and over longer<\/span><span class=\"NormalTextRun SCXW96173255 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW96173255 BCX0\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1244\">periods<\/a><\/span><span class=\"NormalTextRun SCXW96173255 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW96173255 BCX0\">of time<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW96173255 BCX0\"><span class=\"TextRun SCXW96173255 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW96173255 BCX0\">.<\/span><\/span><\/span> \u00a0<\/span><\/p>\n<figure id=\"attachment_3448\" aria-describedby=\"caption-attachment-3448\" style=\"width: 432px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/USGS.404356111503901.143976.72019.00002.19750718.19890930..0..pres-1.png\"><img class=\"wp-image-747\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/USGS.404356111503901.143976.72019.00002.19750718.19890930..0..pres-1.png\" alt=\"A hydrograph is a line graph that shows depth to water with time.\" width=\"432\" height=\"320\"><\/a><figcaption id=\"caption-attachment-3448\" class=\"wp-caption-text\">Example of a hydrograph<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400;\"><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW257587516\"><span class=\"TextRun BCX0 SCXW257587516\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart BCX0 SCXW257587516\">In 1856,\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW257587516\"><span class=\"TextRun BCX0 SCXW257587516\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW257587516\">French engineer\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW257587516\"><span class=\"TextRun BCX0 SCXW257587516\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW257587516\">Henry Darcy developed a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1730\">hypothesis<\/a> to <\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW257587516\"><span class=\"TextRun BCX0 SCXW257587516\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW257587516\">show <\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW257587516\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW257587516\">how discharge through a porous medium is controlled by permeability, pressure, and cross<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW257587516\"><span class=\"TextRun BCX0 SCXW257587516\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW257587516\">-<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW257587516\"><span class=\"TextRun BCX0 SCXW257587516\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW257587516\">\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW257587516\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW257587516\">sectional area.\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW257587516\"><span class=\"TextRun BCX0 SCXW257587516\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW257587516\">To\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW257587516\"><span class=\"TextRun BCX0 SCXW257587516\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW257587516\">prove<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW257587516\"><span class=\"TextRun BCX0 SCXW257587516\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW257587516\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW257587516\"><span class=\"TextRun BCX0 SCXW257587516\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW257587516\">this<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW257587516\"><span class=\"TextRun BCX0 SCXW257587516\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW257587516\">\u00a0relationship<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW257587516\"><span class=\"TextRun BCX0 SCXW257587516\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW257587516\">,\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW257587516\"><span class=\"TextRun BCX0 SCXW257587516\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW257587516\">Darcy <\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW257587516\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW257587516\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1731\">experiment<\/a><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW257587516\"><span class=\"TextRun BCX0 SCXW257587516\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW257587516\">ed with<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW257587516\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW257587516\"> tubes of packed <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> with water running through them<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW257587516\"><span class=\"TextRun BCX0 SCXW257587516\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW257587516\">. <span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW38581994\"><span class=\"TextRun BCX0 SCXW38581994\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW38581994\">The results<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW38581994\"><span class=\"TextRun BCX0 SCXW38581994\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW38581994\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW38581994\"><span class=\"TextRun BCX0 SCXW38581994\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW38581994\">o<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW38581994\"><span class=\"TextRun BCX0 SCXW38581994\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW38581994\">f his experiments<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW38581994\"><span class=\"TextRun BCX0 SCXW38581994\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW38581994\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW38581994\"><span class=\"TextRun BCX0 SCXW38581994\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW38581994\">empirica<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW38581994\"><span class=\"TextRun BCX0 SCXW38581994\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW38581994\">l<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW38581994\"><span class=\"TextRun BCX0 SCXW38581994\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW38581994\">ly\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW38581994\"><span class=\"TextRun BCX0 SCXW38581994\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW38581994\">established<\/span><\/span><\/span> <span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW38581994\"><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW38581994\"><span class=\"TextRun BCX0 SCXW38581994\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW38581994\">a\u00a0<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW38581994\"><span class=\"TextRun BCX0 SCXW38581994\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW38581994\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1724\">quantitative<\/a> measure of hydraulic conductivity and discharge<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW38581994\"><span class=\"TextRun BCX0 SCXW38581994\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW38581994\">\u00a0that is known as Darcy\u2019s <\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW38581994\"><span class=\"TextRun BCX0 SCXW38581994\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW38581994\">l<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW38581994\"><span class=\"TextRun BCX0 SCXW38581994\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW38581994\">aw. <\/span><\/span><\/span><\/span><\/span><\/span>The relationships described by Darcy\u2019s Law have close similarities to Fourier's law in the field of heat conduction, Ohm's law in the field of electrical networks, or Fick's law in diffusion <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1733\">theory<\/a>.\u00a0<\/span><\/p>\n<p style=\"text-align: center;\"><strong>Q=KA(<span style=\"font-weight: 400;\">\u0394<strong>h\/<\/strong><\/span>L)<\/strong><\/p>\n<figure id=\"attachment_3449\" aria-describedby=\"caption-attachment-3449\" style=\"width: 431px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Darcys_Law.png\"><img class=\"wp-image-748\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Darcys_Law.png\" alt=\"Cylinder with a length (L), cross-sectional area (A), which is filled with a material of a specific hydraulic conductivity.\" width=\"431\" height=\"215\"><\/a><figcaption id=\"caption-attachment-3449\" class=\"wp-caption-text\">Pipe showing apparatus that would demonstrate Darcy\u2019s Law. \u0394h would be measured across L from a to b.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<ul>\n<li><span style=\"font-weight: 400;\">Q = flow (volume\/time)<\/span><\/li>\n<li><span style=\"font-weight: 400;\">K = hydraulic conductivity (length\/time<\/span><span style=\"font-weight: 400;\">)<\/span><\/li>\n<li><span style=\"font-weight: 400;\">A = cross-sectional area of flow (area)<\/span><\/li>\n<li><span style=\"font-weight: 400;\">\u0394h = change in pressure head (pressure difference)<\/span><\/li>\n<li><span style=\"font-weight: 400;\">L = distance between pressure (h) measurements (length)<\/span><\/li>\n<li><strong><span style=\"font-weight: 400;\">\u0394h\/<\/span><\/strong><span style=\"font-weight: 400;\">L is commonly referred to as the hydraulic gradient<\/span><\/li>\n<\/ul>\n<p><span class=\"TextRun SCXW247876017 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart SCXW247876017 BCX0\">Pumping water from an<\/span><span class=\"NormalTextRun SCXW247876017 BCX0\">\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW247876017 BCX0\"><span class=\"TextRun SCXW247876017 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW247876017 BCX0\">unconfi<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW247876017 BCX0\"><span class=\"TextRun SCXW247876017 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW247876017 BCX0\">ned\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW247876017 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW247876017 BCX0\">aquifer<\/span><span class=\"NormalTextRun SCXW247876017 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW247876017 BCX0\">lowers the<\/span><span class=\"NormalTextRun SCXW247876017 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW247876017 BCX0\">water table<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW247876017 BCX0\"><span class=\"TextRun SCXW247876017 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW247876017 BCX0\">. Pumping water from a confined aquifer lowers the\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW247876017 BCX0\"><span class=\"TextRun SCXW247876017 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW247876017 BCX0\">pressure and\/<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW247876017 BCX0\"><span class=\"TextRun SCXW247876017 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW247876017 BCX0\">or<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW247876017 BCX0\"><span class=\"TextRun SCXW247876017 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW247876017 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW247876017 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW247876017 BCX0\">potentiometric surface<\/span><span class=\"NormalTextRun SCXW247876017 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW247876017 BCX0\">around the well.\u00a0<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW247876017 BCX0\"><span class=\"TextRun SCXW247876017 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW247876017 BCX0\">In an unconfined<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW247876017 BCX0\"><span class=\"TextRun SCXW247876017 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW247876017 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW247876017 BCX0\"><span class=\"TextRun SCXW247876017 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW247876017 BCX0\">aquifer, the<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW247876017 BCX0\"><span class=\"TextRun SCXW247876017 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW247876017 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW247876017 BCX0\"><span class=\"TextRun SCXW247876017 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW247876017 BCX0\">water table<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW247876017 BCX0\"><span class=\"TextRun SCXW247876017 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW247876017 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW247876017 BCX0\"><span class=\"TextRun SCXW247876017 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW247876017 BCX0\">is lowered as water is removed from the<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW247876017 BCX0\"><span class=\"TextRun SCXW247876017 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW247876017 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW247876017 BCX0\"><span class=\"TextRun SCXW247876017 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW247876017 BCX0\">aquifer<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW247876017 BCX0\"><span class=\"TextRun SCXW247876017 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW247876017 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW247876017 BCX0\"><span class=\"TextRun SCXW247876017 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW247876017 BCX0\">near the well producing <strong>drawdown <\/strong>and a <strong>cone of depression<\/strong> (see figure). In a confined<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW247876017 BCX0\"><span class=\"TextRun SCXW247876017 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW247876017 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW247876017 BCX0\"><span class=\"TextRun SCXW247876017 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW247876017 BCX0\">aquifer, pumping on an artesian well reduces the pressure or potentiometric surface around the well.<\/span><\/span><\/span> <span class=\"EOP SCXW247876017 BCX0\" data-ccp-props=\"{&quot;201341983&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:259}\">\u00a0<\/span><\/p>\n<figure id=\"attachment_892\" aria-describedby=\"caption-attachment-892\" style=\"width: 3104px\" class=\"wp-caption alignright\"><a href=\"http:\/\/opengeology.org\/textbook\/wp-content\/uploads\/2016\/07\/Cone_of_Depression_WSP2220.png\"><img class=\"wp-image-749 size-full\" title=\"Source: Heath, 1983, USGS\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Cone_of_Depression_WSP2220.png\" alt=\"The shape of the potentiometric surface or water table around a pumping well is cone-shaped, where groundwater level has the greatest drawdown near the well.\" width=\"3104\" height=\"1353\"><\/a><figcaption id=\"caption-attachment-892\" class=\"wp-caption-text\">Cones of depression (Heath 1983).<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400;\">When one cone of depression intersects another cone of depression or a barrier feature like an impermeable mountain block, drawdown is intensified. When a cone of depression intersects a recharge zone, the cone of depression is lessened.<\/span><\/p>\n<h3><b>11.6.4 Recharge<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">The\u00a0<\/span><b>recharge <\/b>area<span style=\"font-weight: 400;\"> is where surface water enters an aquifer through the process of infiltration. Recharge areas are generally topographically high locations of an aquifer. \u00a0They are characterized by losing streams and permeable rock that allows infiltration into the aquifer. Recharge areas mark the beginning of groundwater flow paths.<\/span><\/p>\n<p><span style=\"font-weight: 400;\"><span class=\"TextRun BCX0 SCXW51221263\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW51221263\">In the<\/span><span class=\"NormalTextRun BCX0 SCXW51221263\">\u00a0<\/span><span class=\"NormalTextRun CommentStart BCX0 SCXW51221263\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1514\">Basin and Range<\/a><\/span><span class=\"NormalTextRun BCX0 SCXW51221263\">\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW51221263\"><span class=\"TextRun BCX0 SCXW51221263\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW51221263\">Province<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW51221263\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW51221263\">, <\/span><span class=\"NormalTextRun BCX0 SCXW51221263\">recharge<\/span><span class=\"NormalTextRun BCX0 SCXW51221263\">\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW51221263\"><span class=\"TextRun BCX0 SCXW51221263\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW51221263\">areas<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW51221263\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW51221263\">\u00a0for\u00a0<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW51221263\"><span class=\"TextRun BCX0 SCXW51221263\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW51221263\">the\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW51221263\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW51221263\">unconsolidated<\/span><span class=\"NormalTextRun BCX0 SCXW51221263\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW51221263\">aquifers<\/span><span class=\"NormalTextRun BCX0 SCXW51221263\">\u00a0<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW51221263\"><span class=\"TextRun BCX0 SCXW51221263\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW51221263\">of the valleys <\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW51221263\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW51221263\">are along <\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW51221263\"><span class=\"TextRun BCX0 SCXW51221263\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW51221263\">mountain\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW51221263\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW51221263\">foothills<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW51221263\"><span class=\"TextRun BCX0 SCXW51221263\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW51221263\">. <\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW51221263\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW51221263\">In\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW51221263\"><span class=\"TextRun BCX0 SCXW51221263\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW51221263\">the foothills of\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW51221263\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW51221263\">Salt Lake Valley, <\/span><\/span>losing streams contribute water to the gravel-rich deltaic deposits of ancient Lake Bonneville, in some cases feeding artesian wells in the Salt Lake Valley.<\/span><\/p>\n<p><span style=\"font-weight: 400;\"><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart BCX0 SCXW103813114\">An\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">aquifer<\/span><span class=\"NormalTextRun BCX0 SCXW103813114\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW103813114\">management practice<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">is to induce <\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">r<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">echarge<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\"> through storage and recovery<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">.<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">Geologists and hydrologists<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">can<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">\u00a0increase the\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">recharge\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">rate<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">into an<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">aquifer<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1742\">system<\/a>\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">using<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">\u00a0i<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">njection wells and<\/span><span class=\"NormalTextRun BCX0 SCXW103813114\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW103813114\">infiltration<\/span><span class=\"NormalTextRun BCX0 SCXW103813114\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW103813114\">galleries<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">\u00a0or\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">basins<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">[<\/span><span class=\"NormalTextRun BCX0 SCXW103813114\">35<\/span><span class=\"NormalTextRun BCX0 SCXW103813114\">].\u00a0<\/span><\/span> <span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">Injection wells pump water into an<\/span><span class=\"NormalTextRun BCX0 SCXW103813114\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW103813114\">aquifer<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">\u00a0where it\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">can be<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW103813114\"><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">\u00a0stored<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW103813114\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW103813114\">.<\/span><span class=\"NormalTextRun BCX0 SCXW103813114\">\u00a0<\/span><\/span>Injection wells are regulated by state and federal governments to ensure that the injected water is not negatively impacting the quality or supply of the existing groundwater in the aquifer. \u00a0Some aquifers can store significant quantities of water, allowing water managers to use the aquifer <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1742\">system<\/a> like a surface reservoir. Water is stored in the aquifer during <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1244\">periods<\/a> of low water demand and high water supply and later extracted during times of high water demand and low water supply.<\/span><\/p>\n<figure id=\"attachment_3451\" aria-describedby=\"caption-attachment-3451\" style=\"width: 550px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/wcartificialrecharge.gif\"><img class=\"wp-image-750\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/wcartificialrecharge.gif\" alt=\"Different ways an aquifer can be recharged. Rivers, injection wells, and infiltration can all contribute to aquifer recharge.\" width=\"550\" height=\"271\"><\/a><figcaption id=\"caption-attachment-3451\" class=\"wp-caption-text\">Different ways an aquifer can be recharged.<\/figcaption><\/figure>\n<h3><b>11.6.5 Discharge<\/b><\/h3>\n<p><span class=\"TextRun BCX0 SCXW180141458\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW180141458\"><strong>Discharge<\/strong> areas are where\u00a0the<\/span><\/span><span class=\"TextRun BCX0 SCXW180141458\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW180141458\">\u00a0<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW180141458\"><span class=\"TextRun BCX0 SCXW180141458\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW180141458\">water table or potentiometric surface<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW180141458\"><span class=\"TextRun BCX0 SCXW180141458\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW180141458\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW180141458\"><span class=\"TextRun BCX0 SCXW180141458\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW180141458\">intersects the land surface.<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW180141458\"><span class=\"TextRun BCX0 SCXW180141458\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW180141458\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW180141458\"><span class=\"TextRun BCX0 SCXW180141458\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW180141458\">Discharge<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW180141458\"><span class=\"TextRun BCX0 SCXW180141458\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW180141458\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW180141458\"><span class=\"TextRun BCX0 SCXW180141458\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW180141458\">areas mark the end of<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW180141458\"><span class=\"TextRun BCX0 SCXW180141458\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW180141458\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW180141458\"><span class=\"TextRun BCX0 SCXW180141458\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW180141458\">groundwater<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW180141458\"><span class=\"TextRun BCX0 SCXW180141458\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW180141458\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW180141458\"><span class=\"TextRun BCX0 SCXW180141458\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW180141458\">flow paths<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW180141458\"><span class=\"TextRun BCX0 SCXW180141458\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW180141458\">.<span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW87410731\"><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW87410731\"><span class=\"TextRun BCX0 SCXW87410731\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW87410731\">\u00a0<\/span><\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW87410731\"><span class=\"TextRun BCX0 SCXW87410731\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW87410731\">These areas\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW87410731\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW87410731\">are characterized by springs,\u00a0<\/span><span class=\"NormalTextRun CommentStart BCX0 SCXW87410731\">flowing\u00a0<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW87410731\"><span class=\"TextRun BCX0 SCXW87410731\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW87410731\">(<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW87410731\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW87410731\">artesian<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW87410731\"><span class=\"TextRun BCX0 SCXW87410731\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW87410731\">)<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW87410731\"><span class=\"TextRun BCX0 SCXW87410731\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW87410731\">\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW87410731\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW87410731\">wells, gaining<\/span><span class=\"NormalTextRun BCX0 SCXW87410731\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW87410731\">streams, and<\/span><span class=\"NormalTextRun BCX0 SCXW87410731\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW87410731\">playas<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW87410731\"><span class=\"TextRun BCX0 SCXW87410731\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW87410731\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW87410731\"><span class=\"TextRun BCX0 SCXW87410731\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW87410731\">i<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW87410731\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW87410731\">n the<\/span><span class=\"NormalTextRun BCX0 SCXW87410731\"> dry<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW87410731\"><span class=\"TextRun BCX0 SCXW87410731\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW87410731\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW87410731\"><span class=\"TextRun BCX0 SCXW87410731\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW87410731\">valley<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW87410731\"><span class=\"TextRun BCX0 SCXW87410731\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW87410731\">\u00a0basins<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW87410731\"><span class=\"TextRun BCX0 SCXW87410731\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW87410731\">\u00a0of\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW87410731\"><span class=\"TextRun BCX0 SCXW87410731\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW87410731\">the\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW87410731\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW87410731\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1514\">Basin and Range<\/a><\/span><span class=\"NormalTextRun BCX0 SCXW87410731\">\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW87410731\"><span class=\"TextRun BCX0 SCXW87410731\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW87410731\">Province\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW87410731\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW87410731\">of\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW87410731\">the western United States<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW87410731\"><span class=\"TextRun BCX0 SCXW87410731\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW87410731\">.<\/span><\/span><\/span><\/span><\/span><\/span><\/p>\n<h3><b>11.6.6 Groundwater mining and subsidence<\/b><\/h3>\n<p><span style=\"font-weight: 400;\">Like other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1738\">natural resources<\/a> on our planet, the quantity of fresh and potable water is finite.\u00a0 The only natural source of water on land is from the sky in the form of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1785\">precipitation<\/a>.\u00a0 <span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW169962721\"><span class=\"TextRun BCX0 SCXW169962721\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW169962721\">I<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW169962721\"><span class=\"TextRun BCX0 SCXW169962721\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW169962721\">n many places<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW169962721\"><span class=\"TextRun BCX0 SCXW169962721\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW169962721\">,<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW169962721\"><span class=\"TextRun BCX0 SCXW169962721\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW169962721\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW169962721\"><span class=\"TextRun BCX0 SCXW169962721\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW169962721\">groundwater<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW169962721\"><span class=\"TextRun BCX0 SCXW169962721\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW169962721\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW169962721\"><span class=\"TextRun BCX0 SCXW169962721\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW169962721\">is being extracted faster than it is being replenished<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW169962721\"><span class=\"TextRun BCX0 SCXW169962721\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW169962721\">. <span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">When<\/span><span class=\"NormalTextRun BCX0 SCXW8772542\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW8772542\">groundwater<\/span><span class=\"NormalTextRun BCX0 SCXW8772542\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW8772542\">is extracted faster than<\/span><span class=\"NormalTextRun BCX0 SCXW8772542\">\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">it is\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">recharge<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">d<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">,<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">groundwater<\/span><span class=\"NormalTextRun BCX0 SCXW8772542\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW8772542\">levels\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">and<\/span><\/span><\/span> <span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">potentiometric surfaces<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">decline<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">,\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">and\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">discharge<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">areas <\/span><\/span><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">diminish\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW8772542\">or dry up completely.\u00a0<\/span><\/span><\/span><\/span><\/span>Regional pumping-induced groundwater decline is known as <\/span><b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1772\">groundwater mining<\/a><\/b><span style=\"font-weight: 400;\"> or groundwater overdraft. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1772\">Groundwater mining<\/a> is a serious situation and can lead to dry wells, reduced spring and stream flow, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_511\">subsidence<\/a>. <span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart BCX0 SCXW8772542\">G<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">roundwater mining<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">is happening<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\"> is places <\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">w<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">here<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">\u00a0more water is\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">extract<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">ed<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">\u00a0by pumping\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">than\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">is being\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">replenish<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">ed<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">\u00a0by<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1785\">precipitation<\/a><\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">, and\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">the<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">water table <\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">is continual<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">l<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">y<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">\u00a0lower<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">ed<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW8772542\"><span class=\"TextRun BCX0 SCXW8772542\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW8772542\">. In these situations, groundwater must be viewed as a ore body and in its depletion, the possibility of producing ghost towns.<\/span><\/span><\/span><\/span><\/p>\n<figure id=\"attachment_4550\" aria-describedby=\"caption-attachment-4550\" style=\"width: 150px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Science-Today-Groundwater-Youtube-QR-Code.png\"><img class=\"size-thumbnail wp-image-751\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Science-Today-Groundwater-Youtube-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4550\" 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><span class=\"TextRun SCXW193209130 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW193209130 BCX0\">In many places, water <\/span><span class=\"NormalTextRun AdvancedProofingIssueV2 SCXW193209130 BCX0\">actually helps<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\">\u00a0hold up<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW193209130 BCX0\"><span class=\"TextRun SCXW193209130 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW193209130 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW193209130 BCX0\"><span class=\"TextRun SCXW193209130 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart SCXW193209130 BCX0\">an<\/span><\/span><\/span><span class=\"TextRun SCXW193209130 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW193209130 BCX0\">\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW193209130 BCX0\"><span class=\"TextRun SCXW193209130 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW193209130 BCX0\">aquifer<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW193209130 BCX0\"><span class=\"TextRun SCXW193209130 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW193209130 BCX0\">\u2019s<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW193209130 BCX0\"><span class=\"TextRun SCXW193209130 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW193209130 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW193209130 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW193209130 BCX0\">skeleton\u00a0<\/span><\/span><span class=\"TextRun SCXW193209130 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW193209130 BCX0\">by the water pressure exerted on the grains in an<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\">aquifer.<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\"> This pressure is called <strong>pore <\/strong><\/span><span class=\"NormalTextRun SCXW193209130 BCX0\"><strong>pressure<\/strong> and comes from the weight of overlying water. If pore pressure decreases because of<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1772\">groundwater mining<\/a>, the<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\">aquifer<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\">can compact, causing the surface of the ground to sink.<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\">Areas especially susceptible to this effect are<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\">aquifers<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\">made of unconsolidated<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediments<\/a>.<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\">Unconsolidated<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediments<\/a><\/span><span class=\"NormalTextRun SCXW193209130 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\">with multiple layers of clay and other fine-grained material are at higher risk because\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW193209130 BCX0\"><span class=\"TextRun SCXW193209130 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW193209130 BCX0\">when water is<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW193209130 BCX0\"><span class=\"TextRun SCXW193209130 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW193209130 BCX0\">\u00a0drained,\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW193209130 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW193209130 BCX0\">clay\u00a0<\/span><\/span><span class=\"TextRun SCXW193209130 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW193209130 BCX0\">compact<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW193209130 BCX0\"><span class=\"TextRun SCXW193209130 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW193209130 BCX0\">s<\/span><\/span><\/span><span class=\"TextRun SCXW193209130 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW193209130 BCX0\"> considerably<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW193209130 BCX0\"><span class=\"TextRun SCXW193209130 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW193209130 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW193209130 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW193209130 BCX0\">[<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\">36<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\">;<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\">37<\/span><span class=\"NormalTextRun SCXW193209130 BCX0\">].<\/span><\/span><span class=\"EOP SCXW193209130 BCX0\" data-ccp-props=\"{&quot;201341983&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:259}\">\u00a0<\/span><\/p>\n<figure id=\"attachment_3452\" aria-describedby=\"caption-attachment-3452\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/100_4902-scaled.jpg\"><img class=\"wp-image-3452 size-medium\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/100_4902-scaled-1.jpg\" alt=\"The author stands in a large ditch-like\" width=\"300\" height=\"225\"><\/a><figcaption id=\"caption-attachment-3452\" class=\"wp-caption-text\">Example of an earth fissure in Cedar City.<\/figcaption><\/figure>\n<p><b><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_511\">Subsidence<\/a><\/b><span style=\"font-weight: 400;\"> from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1772\">groundwater mining<\/a> has been documented in southwestern Utah, notably Cedar Valley, Iron County, Utah. \u00a0Groundwater levels have declined more than 100 feet in certain parts of Cedar Valley, causing earth fissures and measurable amounts of land <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_511\">subsidence<\/a>.<\/span><\/p>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_3453\" aria-describedby=\"caption-attachment-3453\" style=\"width: 174px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/land-subsidence-poland-calif.jpg\"><img class=\"wp-image-753\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/land-subsidence-poland-calif.jpg\" alt=\"Eivdence of land subsidence from pumping of groundwater shown by dates on a pole\" width=\"174\" height=\"435\"><\/a><figcaption id=\"caption-attachment-3453\" class=\"wp-caption-text\">Evidence of land subsidence from pumping of groundwater shown by dates on a pole<\/figcaption><\/figure>\n<p>This photo shows documentation of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_511\">subsidence<\/a> from pumping of groundwater for irrigation in the Central Valley in California. The pole shows <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_511\">subsidence<\/a> from groundwater pumping over a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1244\">period<\/a> of time.<\/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<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-82\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-82\" class=\"h5p-iframe\" data-content-id=\"82\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"11.7 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_4543\" aria-describedby=\"caption-attachment-4543\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/11.6-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-754\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/11.6-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4543\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 11.6 via this QR Code.<\/figcaption><\/figure>\n<h2><b>11.7 Water Contamination and Remediation<\/b><\/h2>\n<p><span class=\"TextRun SCXW125219294 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW125219294 BCX0\">Water can be contaminated by <\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW125219294 BCX0\"><span class=\"TextRun SCXW125219294 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart SCXW125219294 BCX0\">natural features like<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW125219294 BCX0\"><span class=\"TextRun SCXW125219294 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW125219294 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW125219294 BCX0\"><span class=\"TextRun SCXW125219294 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW125219294 BCX0\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">mineral<\/a>-rich geologic<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW125219294 BCX0\"><span class=\"TextRun SCXW125219294 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW125219294 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW125219294 BCX0\"><span class=\"TextRun SCXW125219294 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW125219294 BCX0\">formations\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW125219294 BCX0\"><span class=\"TextRun SCXW125219294 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW125219294 BCX0\">and by <\/span><\/span><\/span><span class=\"TextRun SCXW125219294 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW125219294 BCX0\">human <\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW125219294 BCX0\"><span class=\"TextRun SCXW125219294 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW125219294 BCX0\">activities <\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW125219294 BCX0\"><span class=\"TextRun SCXW125219294 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW125219294 BCX0\">such as a<\/span><\/span><\/span><span class=\"TextRun SCXW125219294 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW125219294 BCX0\">griculture, industrial <\/span><span class=\"NormalTextRun SCXW125219294 BCX0\">operations, landfills, animal operations, and <\/span><\/span><span class=\"TextRun SCXW125219294 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW125219294 BCX0\">sewage treatment processes, among many other things<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW125219294 BCX0\"><span class=\"TextRun SCXW125219294 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart SCXW125219294 BCX0\">.\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW125219294 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW125219294 BCX0\">As water runs over the land or<\/span><span class=\"NormalTextRun SCXW125219294 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW125219294 BCX0\">infiltrates<\/span><span class=\"NormalTextRun SCXW125219294 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW125219294 BCX0\">into the ground, it dissolves material left behind by these potential contaminant sources. There are three major groups of contamination:\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW125219294 BCX0\"><span class=\"TextRun SCXW125219294 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW125219294 BCX0\">organic and <\/span><\/span><\/span><span class=\"TextRun SCXW125219294 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW125219294 BCX0\">inorganic chemicals<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW125219294 BCX0\"><span class=\"TextRun SCXW125219294 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW125219294 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW125219294 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW125219294 BCX0\">and biological agents. Small<\/span><span class=\"NormalTextRun SCXW125219294 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW125219294 BCX0\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediments<\/a><\/span><span class=\"NormalTextRun SCXW125219294 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW125219294 BCX0\">that cloud<\/span><\/span> <span class=\"TextRun SCXW125219294 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW125219294 BCX0\">water<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW125219294 BCX0\"><span class=\"TextRun SCXW125219294 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW125219294 BCX0\">,<\/span><\/span><\/span><span class=\"TextRun SCXW125219294 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW125219294 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW125219294 BCX0\">causing turbidity<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW125219294 BCX0\"><span class=\"TextRun SCXW125219294 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW125219294 BCX0\">,<\/span><\/span><\/span><span class=\"TextRun SCXW125219294 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW125219294 BCX0\">\u00a0is also an issue with some wells, but it is not considered contamination. The risks and<\/span><span class=\"NormalTextRun SCXW125219294 BCX0\">\u00a0type of<\/span><span class=\"NormalTextRun SCXW125219294 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW125219294 BCX0\">remediation<\/span><span class=\"NormalTextRun SCXW125219294 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW125219294 BCX0\">for a contaminant depends on the type of chemicals present.<\/span><\/span><span class=\"EOP SCXW125219294 BCX0\" data-ccp-props=\"{&quot;201341983&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:259}\">\u00a0<\/span><\/p>\n<p><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW16454995\"><span class=\"TextRun BCX0 SCXW16454995\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW16454995\">Contamination occurs as point<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW16454995\"><span class=\"TextRun BCX0 SCXW16454995\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW16454995\">-<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW16454995\"><span class=\"TextRun BCX0 SCXW16454995\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW16454995\">source and non<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW16454995\"><span class=\"TextRun BCX0 SCXW16454995\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW16454995\">point<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW16454995\"><span class=\"TextRun BCX0 SCXW16454995\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW16454995\">-<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW16454995\"><span class=\"TextRun BCX0 SCXW16454995\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW16454995\">source pollution.\u00a0<\/span><\/span><\/span><b>Point source<\/b><span style=\"font-weight: 400;\"> pollution can be attributed to a single, definable source, while<\/span><b> nonpoint source <\/b><span style=\"font-weight: 400;\">pollution is from multiple dispersed sources. Point sources include waste disposal sites, storage tanks, sewage treatment plants, and chemical spills. Nonpoint sources are dispersed and indiscreet, where the whole of the contribution of pollutants is harmful, but the individual components do not have harmful concentrations of pollutants. \u00a0A good example of nonpoint pollution is residential areas, where lawn fertilizer on one person\u2019s yard may not contribute much pollution to the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1742\">system<\/a>, but the combined effect of many residents using fertilizer can lead to significant nonpoint pollution. \u00a0Other nonpoint sources include nutrients (nitrate and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_975\">phosphate<\/a>), herbicides, pesticides contributed by farming, nitrate contributed by animal operations, and nitrate contributed by septic systems. \u00a0<\/span><\/p>\n<p>Organic chemicals<span style=\"font-weight: 400;\">\u00a0are common pollutants. They consist of strands and rings of carbon atoms, usually connected by covalent <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1781\">bonds<\/a>. Other types of atoms, like chlorine, and molecules, like hydroxide (OH<\/span><sub><span style=\"font-weight: 400;\">-<\/span><\/sub><span style=\"font-weight: 400;\">), are attached to the strands and rings. The number and arrangement of atoms will decide how the chemical behaves in the environment, its danger to humans or ecosystems, and where the chemical ends up in the environment. The different arrangements of carbon allow for tens of thousands of organic chemicals, many of which have never been studied for negative effects on human health or the environment. \u00a0Common organic pollutants are herbicides and pesticides, pharmaceuticals, fuel, and industrial solvents and cleansers. <\/span><\/p>\n<p><span style=\"font-weight: 400;\">Organic chemicals include surfactants<span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW79227683\"><span class=\"TextRun BCX0 SCXW79227683\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW79227683\">\u00a0such as<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW79227683\"><span class=\"TextRun BCX0 SCXW79227683\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW79227683\">\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW79227683\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW79227683\">cleaning agents<\/span><\/span>\u00a0and synthetic hormones associated with pharmaceuticals, which can act as endocrine disruptors. Endocrine disruptors mimic hormones, and can cause long-term effects in developing sexual reproduction systems in developing animals. Only very small quantities of endocrine disruptors are needed to cause significant changes in animal populations.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">An example of organic chemical contamination is the Love Canal, Niagara Falls, New York. From 1942 to 1952, the Hooker Chemical Company disposed of over <span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW131021485\"><span class=\"TextRun BCX0 SCXW131021485\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW131021485\">21,337 mt (<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW131021485\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW131021485\">21,000 t<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW131021485\"><span class=\"TextRun BCX0 SCXW131021485\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW131021485\">)<\/span><\/span><\/span> of chemical waste, including chlorinated hydrocarbons, into a canal and covered it with a thin layer of clay. \u00a0Chlorinated hydrocarbons are a large group of organic chemicals that have chlorine functional groups, most of which are toxic and carcinogenic to humans. The company sold the land to the New York School Board, who developed it into a neighborhood. After residents began to suffer from serious health ailments and pools of oily fluid started rising into residents\u2019 basements, the neighborhood had to be evacuated. \u00a0This site became a U.S. Environmental Protection Agency <\/span><b>Superfund site<\/b><span style=\"font-weight: 400;\">, a site with federal funding and oversight to ensure its cleanup. \u00a0\u00a0<\/span><\/p>\n<p>Inorganic chemicals<span style=\"font-weight: 400;\">\u00a0are another set of chemical pollutants. They can contain carbon atoms, but not in long strands or links. Inorganic contaminants include chloride, arsenic, and nitrate (NO<\/span><sub><span style=\"font-weight: 400;\">3<\/span><\/sub><span style=\"font-weight: 400;\">). \u00a0Nutrients can be from geologic material, like phosphorous-rich rock, but are most often sourced from fertilizer and animal and human waste. \u00a0Untreated sewage and agricultural runoff contain concentrates of nitrogen and phosphorus which are essential for the growth of microorganisms. Nutrients like nitrate and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_975\">phosphate<\/a> in surface water can promote growth of microbes, like blue-green algae (cyanobacteria), which in turn use oxygen and create toxins (microcystins and anatoxins) in lakes <span class=\"NormalTextRun BCX0 SCXW72694573\">[<\/span><span class=\"NormalTextRun BCX0 SCXW72694573\">38<\/span><span class=\"NormalTextRun BCX0 SCXW72694573\">]<\/span><\/span><span style=\"font-weight: 400;\">. This process is known as eutrophication.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Metals are common inorganic contaminants. Lead, mercury, and arsenic are some of the more problematic inorganic groundwater contaminants. \u00a0Bangladesh has a well documented case of arsenic contamination from natural geologic material dissolving into the groundwater. <span class=\"TextRun BCX0 SCXW94984786\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW94984786\">Acid<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW94984786\"><span class=\"TextRun BCX0 SCXW94984786\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW94984786\">-<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW94984786\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW94984786\">mine drainage<\/span><span class=\"NormalTextRun BCX0 SCXW94984786\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW94984786\">can also cause significant inorganic contamination<\/span><\/span> <span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW94984786\"><span class=\"TextRun BCX0 SCXW94984786\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW94984786\">(<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW94984786\"><span class=\"TextRun BCX0 SCXW94984786\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW94984786\">s<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW94984786\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW94984786\">ee <\/span><\/span><a href=\"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/chapter\/16-energy-and-mineral-resources\/\" target=\"_blank\" rel=\"noopener\"><span class=\"TextRun BCX0 SCXW94984786\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW94984786\"><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW94984786\">Chap<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW94984786\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW94984786\"><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW94984786\">ter\u00a0<\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW94984786\">16<\/span><\/span><\/span><\/a><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW94984786\"><span class=\"TextRun BCX0 SCXW94984786\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW94984786\">)<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW94984786\"><span class=\"TextRun BCX0 SCXW94984786\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW94984786\">.<\/span><\/span><\/span><\/span><\/p>\n<p><span style=\"font-weight: 400;\">Salt, typically sodium chloride, is a common inorganic contaminant. \u00a0It can be introduced into groundwater from natural sources, such as evaporite deposits like the Arapien Shale of Utah, or from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_764\">anthropogenic<\/a> sources like the salts applied to roads in the winter to keep ice from forming. \u00a0Salt contamination can also occur <span class=\"TrackChangeTextInsertion TrackedChange SCXW153366638 BCX0\"><span class=\"TextRun SCXW153366638 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW153366638 BCX0\">near ocean coasts\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW153366638 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW153366638 BCX0\">from saltwater intru<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW153366638 BCX0\"><span class=\"TextRun SCXW153366638 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW153366638 BCX0\">ding into the <\/span><\/span><\/span><span class=\"TextRun SCXW153366638 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW153366638 BCX0\">cones of depression around fresh<\/span><span class=\"NormalTextRun SCXW153366638 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW153366638 BCX0\">groundwater<\/span><span class=\"NormalTextRun SCXW153366638 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW153366638 BCX0\">pumping<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW153366638 BCX0\"><span class=\"TextRun SCXW153366638 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW153366638 BCX0\">, <\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW153366638 BCX0\"><span class=\"TextRun SCXW153366638 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW153366638 BCX0\">inducing the encroachment of <\/span><\/span><\/span><span class=\"TextRun SCXW153366638 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW153366638 BCX0\">saltwater into the freshwater body.<\/span><\/span><\/span><\/p>\n<p><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW14358776\"><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun CommentStart BCX0 SCXW14358776\">Biological agents are\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW14358776\"><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\">a<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\">nother common<\/span><span class=\"NormalTextRun BCX0 SCXW14358776\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW14358776\">groundwater<\/span><span class=\"NormalTextRun BCX0 SCXW14358776\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW14358776\">contaminant<\/span><\/span><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\">\u00a0which includes harmful bacteria and viruses. A common bacteria contaminant is<\/span><span class=\"NormalTextRun BCX0 SCXW14358776\">\u00a0<\/span><\/span><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\"><em>Escherichia coli<\/em> (<em>E. coli<\/em>)<\/span><\/span><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\">. Generally, harmful bacteria are not present in<\/span><span class=\"NormalTextRun BCX0 SCXW14358776\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW14358776\">groundwater<\/span><span class=\"NormalTextRun BCX0 SCXW14358776\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW14358776\">unless the\u00a0<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW14358776\"><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\">groundwater<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW14358776\"><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\">\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\">source <\/span><\/span><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\">is closely connected with a contaminated surface source, such as a septic<\/span><span class=\"NormalTextRun BCX0 SCXW14358776\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW14358776\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1742\">system<\/a><\/span><span class=\"NormalTextRun CommentStart BCX0 SCXW14358776\">.<\/span><span class=\"NormalTextRun BCX0 SCXW14358776\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW14358776\">Karst<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW14358776\"><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\">,<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW14358776\"><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW14358776\"><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\">landforms created from\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW14358776\"><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\">dissolved<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW14358776\"><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW14358776\"><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\">limestone<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW14358776\"><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\">,<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW14358776\"><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\">\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\">i<\/span><span class=\"NormalTextRun BCX0 SCXW14358776\">s especially susceptible to this form of contamination<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW14358776\"><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\">,<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\">\u00a0because water moves relatively quickly through the<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW14358776\"><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\"> conduits o<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW14358776\"><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\">f dissolved<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW14358776\"><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW14358776\"><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\">limestone<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange BCX0 SCXW14358776\"><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\">.\u00a0<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\">Bacteria can also be used for<\/span><span class=\"NormalTextRun BCX0 SCXW14358776\">\u00a0<\/span><span class=\"NormalTextRun BCX0 SCXW14358776\">remediation<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW14358776\"><span class=\"TextRun BCX0 SCXW14358776\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW14358776\">.<\/span><\/span><\/span><\/p>\n<p><a href=\"http:\/\/water.usgs.gov\/edu\/groundwater-contaminants.html\"><i><span style=\"font-weight: 400;\">Table. Groundwater contaminants.<\/span><\/i><\/a><\/p>\n<p><span style=\"font-weight: 400;\"><strong>Remediation<\/strong> is the act of cleaning contamination. <span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW244500733\"><span class=\"TextRun BCX0 SCXW244500733\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW244500733\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW244500733\"><span class=\"TextRun BCX0 SCXW244500733\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW244500733\">Hydrologists use<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW244500733\"><span class=\"TextRun BCX0 SCXW244500733\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW244500733\">\u00a0three\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW244500733\"><span class=\"TextRun BCX0 SCXW244500733\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW244500733\">types<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW244500733\"><span class=\"TextRun BCX0 SCXW244500733\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW244500733\">\u00a0of remediation:\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW244500733\"><span class=\"TextRun BCX0 SCXW244500733\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW244500733\">b<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW244500733\"><span class=\"TextRun BCX0 SCXW244500733\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW244500733\">iological, chemical, and physical.<\/span><\/span><\/span><span class=\"TextRun BCX0 SCXW244500733\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW244500733\">\u00a0<\/span><\/span>Biological remediation uses specific strains of bacteria to break down a contaminant into safer chemicals. \u00a0This type of remediation is usually used on organic chemicals, but also works on reducing or oxidizing inorganic chemicals like nitrate. Phytoremediation is a type of bioremediation that uses plants to absorb the chemicals over time.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Chemical remediation uses chemicals to remove the contaminant or make it less harmful. \u00a0One example is to use a reactive barrier, a permeable wall in the ground or at a discharge point that chemically reacts with contaminants in the water. Reactive barriers made of limestone can increase the pH of acid mine drainage, making the water less acidic and more basic, which removes dissolved contaminants by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1785\">precipitation<\/a> into solid form.<\/span><\/p>\n<p><span style=\"font-weight: 400;\">Physical remediation consists of removing the contaminated water and either treating it with filtration<span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW260675278\"><span class=\"TextRun BCX0 SCXW260675278\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW260675278\">, called<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW260675278\"><span class=\"TextRun BCX0 SCXW260675278\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW260675278\">\u00a0pump<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW260675278\"><span class=\"TextRun BCX0 SCXW260675278\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW260675278\">-<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW260675278\"><span class=\"TextRun BCX0 SCXW260675278\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW260675278\">and<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW260675278\"><span class=\"TextRun BCX0 SCXW260675278\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW260675278\">-<\/span><\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange BCX0 SCXW260675278\"><span class=\"TextRun BCX0 SCXW260675278\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun BCX0 SCXW260675278\">treat,<\/span><\/span><\/span> or disposing of it. \u00a0All of these options are technically complex, expensive, and difficult, with physical remediation typically being the most costly.<\/span><\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-83\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-83\" class=\"h5p-iframe\" data-content-id=\"83\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"11.8 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_4544\" aria-describedby=\"caption-attachment-4544\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/11.7-Did-I-Get-It-QR-Youtube.png\"><img class=\"size-thumbnail wp-image-755\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/11.7-Did-I-Get-It-QR-Youtube-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4544\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 11.7 via this QR Code.<\/figcaption><\/figure>\n<h2><b>11.8 Karst<\/b><\/h2>\n<figure id=\"attachment_3454\" aria-describedby=\"caption-attachment-3454\" style=\"width: 300px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Karst-Towers-in-China.jpg\"><img class=\"wp-image-756 size-medium\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Karst-Towers-in-China-300x205.jpg\" alt=\"Steep rock towers left as remnants of limestone layers dissolved away by acidic rainwater.\" width=\"300\" height=\"205\"><\/a><figcaption id=\"caption-attachment-3454\" class=\"wp-caption-text\">Steep karst towers in China left as remnants as limestone is dissolved away by acidic rain and groundwater.<\/figcaption><\/figure>\n<p><span class=\"TextRun SCXW177943039 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW177943039 BCX0\"><strong>Karst<\/strong> refers to landscapes and hydrologic features created\u00a0<\/span><span class=\"NormalTextRun CommentStart SCXW177943039 BCX0\">by\u00a0<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW177943039 BCX0\"><span class=\"TextRun SCXW177943039 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW177943039 BCX0\">the\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW177943039 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW177943039 BCX0\">dissolving<\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW177943039 BCX0\"><span class=\"TextRun SCXW177943039 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW177943039 BCX0\">\u00a0of <\/span><\/span><\/span><span class=\"TextRun SCXW177943039 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW177943039 BCX0\">limestone. Karst can be<\/span><span class=\"NormalTextRun SCXW177943039 BCX0\">\u00a0found anywhere<\/span><\/span> <span class=\"TextRun SCXW177943039 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW177943039 BCX0\">there is<\/span><span class=\"NormalTextRun SCXW177943039 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW177943039 BCX0\">limestone<\/span><span class=\"NormalTextRun SCXW177943039 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW177943039 BCX0\">and other soluble subterranean substances like salt deposits.<\/span><span class=\"NormalTextRun SCXW177943039 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW177943039 BCX0\">Dissol<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW177943039 BCX0\"><span class=\"TextRun SCXW177943039 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW177943039 BCX0\">ving<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW177943039 BCX0\"><span class=\"TextRun SCXW177943039 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW177943039 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TrackChangeTextDeletion TrackedChange SCXW177943039 BCX0\"><span class=\"TextRun SCXW177943039 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW177943039 BCX0\">of <\/span><\/span><\/span><span class=\"TextRun SCXW177943039 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW177943039 BCX0\">limestone<\/span><\/span><span class=\"TrackChangeTextInsertion TrackedChange SCXW177943039 BCX0\"><span class=\"TextRun SCXW177943039 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW177943039 BCX0\">\u00a0<\/span><\/span><\/span><span class=\"TextRun SCXW177943039 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW177943039 BCX0\">creates features like sinkholes, caverns, disappearing<\/span><span class=\"NormalTextRun SCXW177943039 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW177943039 BCX0\">streams, and\u00a0<\/span><span class=\"NormalTextRun SCXW177943039 BCX0\">towers.<\/span><\/span><span class=\"EOP SCXW177943039 BCX0\" data-ccp-props=\"{&quot;201341983&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:259}\">\u00a0<\/span><\/p>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_3455\" aria-describedby=\"caption-attachment-3455\" style=\"width: 300px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Sinkholes-in-Kaibab-Ls-from-solution-of-salt.jpg\"><img class=\"wp-image-757 size-medium\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Sinkholes-in-Kaibab-Ls-from-solution-of-salt-300x204.jpg\" alt=\"Sinkholes of the McCauley Sink in Northern Arizona, produced by collapse of Kaibab Limestone into caverns caused by solution of underlying salt deposits\" width=\"300\" height=\"204\"><\/a><figcaption id=\"caption-attachment-3455\" class=\"wp-caption-text\">Sinkholes of the McCauley Sink in Northern Arizona, produced by collapse of Kaibab Limestone into caverns caused by solution of underlying salt deposits .<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400;\">Dissolving of underlying salt deposits has caused sinkholes to form in the Kaibab Limestone on the Colorado Plateau in Arizona.<\/span><\/p>\n<figure id=\"attachment_3456\" aria-describedby=\"caption-attachment-3456\" style=\"width: 439px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Sinkhole.jpg\"><img class=\"wp-image-758\" style=\"font-weight: bold; background-color: transparent; text-align: inherit;\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Sinkhole-300x196.jpg\" alt=\"Sinkhole that appeared in Florida in the front yard of a home.\" width=\"439\" height=\"288\"><\/a><figcaption id=\"caption-attachment-3456\" class=\"wp-caption-text\">This sinkhole from collapse of surface into a underground cavern appeared in the front yard of this home in Florida.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p><span class=\"TrackChangeTextInsertion TrackedChange SCXW56751174 BCX0\"><span class=\"TextRun SCXW56751174 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW56751174 BCX0\">Collapse of the surface into an underground cavern caused this s<\/span><\/span><\/span><span class=\"TextRun SCXW56751174 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW56751174 BCX0\">inkhole <\/span><\/span><span class=\"TextRun SCXW56751174 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW56751174 BCX0\">in the front yard of a home in Florida.<\/span><\/span><span class=\"EOP SCXW56751174 BCX0\" data-ccp-props=\"{&quot;201341983&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:259}\">\u00a0<\/span><\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p><span class=\"TextRun SCXW178914480 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW178914480 BCX0\">CO<sub><span class=\"NormalTextRun Superscript SCXW178914480 BCX0\" data-fontsize=\"11\">2<\/span><\/sub>\u00a0in the\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1745\">atmosphere<\/a>\u00a0dissolves readily in the water droplets that form clouds\u00a0from which\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1785\">precipitation<\/a>\u00a0comes in the form of rain and snow. This\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1785\">precipitation<\/a>\u00a0is slightly acidic with\u00a0carbonic acid.<span class=\"EOP SCXW178914480 BCX0\" data-ccp-props=\"{&quot;201341983&quot;:0,&quot;335559739&quot;:160,&quot;335559740&quot;:259}\">\u00a0<\/span>Karst<\/span><span class=\"NormalTextRun SCXW178914480 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW178914480 BCX0\">forms when<\/span><\/span><span class=\"TextRun SCXW178914480 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW178914480 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW178914480 BCX0\">carbonic acid <\/span><\/span><span class=\"TextRun SCXW178914480 BCX0\" lang=\"EN-US\" xml:lang=\"EN-US\" data-contrast=\"auto\"><span class=\"NormalTextRun SCXW178914480 BCX0\">dissolves<\/span><span class=\"NormalTextRun SCXW178914480 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW178914480 BCX0\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_970\">calcite<\/a><\/span><span class=\"NormalTextRun SCXW178914480 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW178914480 BCX0\">(calcium<\/span><span class=\"NormalTextRun SCXW178914480 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW178914480 BCX0\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_969\">carbonate<\/a>) in<\/span><span class=\"NormalTextRun SCXW178914480 BCX0\">\u00a0<\/span><span class=\"NormalTextRun SCXW178914480 BCX0\">limestone.\u00a0<\/span><\/span><\/p>\n<p style=\"text-align: center;\"><strong>H<sub>2<\/sub>O + CO<sub>2<\/sub>\u00a0= H<sub>2<\/sub>CO<sub>3<\/sub><\/strong><\/p>\n<p style=\"text-align: center;\"><strong>Water + Carbon Dioxide Gas equals Carbonic Acid in Water<\/strong><\/p>\n<p style=\"text-align: center;\"><strong>CaCO<sub>3<\/sub> + H<sub>2<\/sub>CO<sub>3<\/sub>\u00a0= Ca<sup>2+<\/sup>+ 2HCO<sub>3<\/sub> <sup>-1<\/sup><\/strong><\/p>\n<p style=\"text-align: center;\"><strong>Solid <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_970\">Calcite<\/a> + Carbonic Acid in Water Dissolved equals Calcium Ion + Dissolved Bicarbonate Ion<\/strong><\/p>\n<figure id=\"attachment_3457\" aria-describedby=\"caption-attachment-3457\" style=\"width: 385px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/1024px-Dead_trees_at_Mammoth_Hot_Springs.jpg\"><img class=\"wp-image-759\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/1024px-Dead_trees_at_Mammoth_Hot_Springs-300x198.jpg\" alt=\"Calcium carbonate deposited at Mammoth hot springs encapsulates trees.\" width=\"385\" height=\"255\"><\/a><figcaption id=\"caption-attachment-3457\" class=\"wp-caption-text\">Mammoth hot springs, Yellowstone National Park.<\/figcaption><\/figure>\n<p style=\"text-align: left;\"><span style=\"font-weight: 400;\">After the slightly acidic water dissolves the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_970\">calcite<\/a>, changes in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1767\">temperature<\/a> or gas content in the water can cause the water to redeposit the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_970\">calcite<\/a> in a different place as tufa (travertine), often deposited by a spring<\/span><span style=\"font-weight: 400;\"> or in a cave. \u00a0Speleothems are secondary deposits, typically made of travertine, deposited in a cave<\/span><span style=\"font-weight: 400;\">. \u00a0Travertine speleothems form by water dripping through cracks and dissolved openings in caves and evaporating, leaving behind the travertine deposits. \u00a0Speleothems commonly occur in the form of stalactites, when extending from the ceiling, and stalagmites, when standing up from the floor.<\/span><\/p>\n<figure id=\"attachment_3458\" aria-describedby=\"caption-attachment-3458\" style=\"width: 490px\" class=\"wp-caption alignright\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/640px-Labeled_speleothems.jpg\"><img class=\"wp-image-760\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/640px-Labeled_speleothems-300x214.jpg\" alt=\"Cave deposits hanging and protruding from the base of a cave.\" width=\"490\" height=\"350\"><\/a><figcaption id=\"caption-attachment-3458\" class=\"wp-caption-text\">Varieties of speleotherms.<\/figcaption><\/figure>\n<p>&nbsp;<\/p>\n<figure id=\"attachment_3459\" aria-describedby=\"caption-attachment-3459\" style=\"width: 472px\" class=\"wp-caption alignleft\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2021\/12\/Disappearing-stream.jpg\"><img class=\"wp-image-761\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Disappearing-stream-300x224.jpg\" alt=\"Stream disappears into subterranean cavern system.\" width=\"472\" height=\"352\"><\/a><figcaption id=\"caption-attachment-3459\" class=\"wp-caption-text\">This stream disappears into a subterranean cavern system to re-emerge a few hundred yards downstream.<\/figcaption><\/figure>\n<p><span style=\"font-weight: 400;\">Surface water enters the karst <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1742\">system<\/a> through sinkholes, losing streams, and disappearing streams. \u00a0Changes in base level can cause rivers running over limestone to dissolve the limestone and sink into the ground. \u00a0As the water continues to dissolve its way through the limestone, it can leave behind intricate networks of caves and narrow passages. \u00a0Often dissolution will follow and expand <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_986\">fractures<\/a> in the limestone. \u00a0Water exits the karst <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1742\">system<\/a> as springs and rises. <\/span><span style=\"font-weight: 400;\">In mountainous <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1764\">terrane<\/a>, dissolution can extend all the way through the vertical profile of the mountain, with caverns dropping thousands of feet.<\/span><\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<h3>Take this quiz to check your comprehension of this section.<\/h3>\n<div id=\"h5p-84\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-84\" class=\"h5p-iframe\" data-content-id=\"84\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Chapter 11 Review\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_4545\" aria-describedby=\"caption-attachment-4545\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/11.8-Did-I-Get-It-QR-Code.png\"><img class=\"size-thumbnail wp-image-762\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/11.8-Did-I-Get-It-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4545\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the quiz for section 11.8 via this QR Code.<\/figcaption><\/figure>\n<h2>Summary<\/h2>\n<p><span style=\"font-weight: 400;\">Water is essential for all living things. It continuously cycles through the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1745\">atmosphere<\/a>, over land, and through the ground. In much of the United States and other countries, water is managed through a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1742\">system<\/a> of regional laws and regulations and distributed on paper in a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1742\">system<\/a> collectively known as \u201cwater rights\u201d. Surface water follows a watershed, which is separate from other areas by its divides (highest ridges). Groundwater exists in the pores within rocks and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a>.\u00a0 It moves predominantly due to pressure and gravitational gradients through the rock. Human and natural causes can make water unsuitable for consumption.\u00a0 There are different ways to deal with this contamination. Karst is when limestone is dissolved by water, forming caves and sinkholes.<\/span><\/p>\n<h3>Take this quiz to check your comprehension of this Chapter.<\/h3>\n<div id=\"h5p-85\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-85\" class=\"h5p-iframe\" data-content-id=\"85\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"12.1 Did I Get It?\"><\/iframe><\/div>\n<\/div>\n<figure id=\"attachment_4547\" aria-describedby=\"caption-attachment-4547\" style=\"width: 150px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/slcc.pressbooks.pub\/app\/uploads\/sites\/35\/2022\/02\/Ch.11-Review-QR-Code.png\"><img class=\"size-thumbnail wp-image-763\" src=\"https:\/\/integrations.pressbooks.network\/app\/uploads\/sites\/516\/2022\/05\/Ch.11-Review-QR-Code-150x150.png\" alt=\"\" width=\"150\" height=\"150\"><\/a><figcaption id=\"caption-attachment-4547\" class=\"wp-caption-text\">If you are using the printed version of this OER, access the review quiz for Chapter 11 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\">Brush, L.M., Jr, 1961, Drainage basins, channels, and flow characteristics of selected streams in central Pennsylvania: pubs.er.usgs.gov.<\/li>\n<li class=\"csl-entry\">Charlton, R., 2007, Fundamentals of fluvial geomorphology: Taylor &amp; Francis.<\/li>\n<li class=\"csl-entry\">Cirrus Ecological <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1783\">Solutions<\/a>, 2009, Jordan River TMDL: Utah State Division of Water Quality.<\/li>\n<li class=\"csl-entry\">Earle, S., 2015, Physical geology OER textbook: BC Campus OpenEd.<\/li>\n<li class=\"csl-entry\">EPA, 2009, Water on Tap-What You Need to Know: U.S. Environmental Protection Agency.<\/li>\n<li class=\"csl-entry\">Fagan, B., 2012, Elixir: A history of water and humankind: Bloomsbury Press.<\/li>\n<li class=\"csl-entry\">Fairbridge, R.W., 1968, Yazoo rivers or streams, <i>in<\/i> Geomorphology: Springer Berlin Heidelberg Encyclopedia of Earth Science, p. 1238\u20131239.<\/li>\n<li class=\"csl-entry\">Freeze, A.R., and Cherry, J.A., 1979, Groundwater: Prentice Hall.<\/li>\n<li class=\"csl-entry\">Galloway, D., Jones, D.R., and Ingebritsen, S.E., 1999, Land <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_511\">subsidence<\/a> in the United States: U.S. Geological Survey Circular 1182.<\/li>\n<li class=\"csl-entry\">Galloway, W.E., Whiteaker, T.L., and Ganey-Curry, P., 2011, History of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_488\">Cenozoic<\/a> North American drainage basin evolution, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> yield, and accumulation in the Gulf of Mexico <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_508\">basin<\/a>: <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1743\">Geosphere<\/a>, v. 7, no. 4, p. 938\u2013973.<\/li>\n<li class=\"csl-entry\">Gilbert, G.K., 1890, Lake Bonneville: United States Geological Survey, 438 p.<\/li>\n<li class=\"csl-entry\">Gleick, P.H., 1993, Water in Crisis: A Guide to the World\u2019s Fresh Water Resources: Oxford University Press.<\/li>\n<li class=\"csl-entry\">Hadley, G., 1735, Concerning the cause of the general trade-winds: By Geo. Hadley, Esq; FRS: Philosophical Transactions, v. 39, no. 436\u2013444, p. 58\u201362.<\/li>\n<li class=\"csl-entry\">Halvorson, S.F., and James Steenburgh, W., 1999, Climatology of lake-effect snowstorms of the Great Salt Lake: University of Utah.<\/li>\n<li class=\"csl-entry\">Heath, R.C., 1983, Basic ground-water hydrology: U.S. Geological Survey Water-Supply Paper 2220, 91 p.<\/li>\n<li class=\"csl-entry\">Hobbs, W.H., and Fisk, H.N., 1947, Geological Investigation of the Alluvial Valley of the Lower Mississippi River: JSTOR.<\/li>\n<li class=\"csl-entry\">Knudsen, T., Inkenbrandt, P., Lund, W., Lowe, M., and Bowman, S., 2014, Investigation of land <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_511\">subsidence<\/a> and earth fissures in Cedar Valley, Iron County, Utah: Utah Geological Survey Special Study 150.<\/li>\n<li class=\"csl-entry\">Lorenz, E.N., 1955, Available potential energy and the maintenance of the general circulation: Tell\u2019Us, v. 7, no. 2, p. 157\u2013167.<\/li>\n<li class=\"csl-entry\">Marston, R.A., Mills, J.D., Wrazien, D.R., Bassett, B., and Splinter, D.K., 2005, Effects of Jackson lake dam on the Snake River and its floodplain, Grand Teton National Park, Wyoming, USA: Geomorphology, v. 71, no. 1\u20132, p. 79\u201398.<\/li>\n<li class=\"csl-entry\">Maupin, M.A., Kenny, J.F., Hutson, S.S., Lovelace, J.K., Barber, N.L., and Linsey, K.S., 2014, Estimated use of water in the United States in 2010: US Geological Survey.<\/li>\n<li class=\"csl-entry\">Myers, W.B., and Hamilton, W., 1964, The Hebgen Lake, Montana, earthquake of August 17, 1959: U.S. Geol. Surv. Prof. Pap., v. 435, p. 51.<\/li>\n<li class=\"csl-entry\">Oviatt, C.G., 2015, Chronology of Lake Bonneville, 30,000 to 10,000 yr B.P: Quat. Sci. Rev., v. 110, p. 166\u2013171.<\/li>\n<li class=\"csl-entry\">Powell, J.W., 1879, Report on the lands of the arid region of the United States with a more detailed account of the land of Utah with maps: Monograph.<\/li>\n<li class=\"csl-entry\">Reed, J.C., Love, D., and Pierce, K., 2003, Creation of the Teton landscape: a geologic chronicle of Jackson Hole and the Teton Range: pubs.er.usgs.gov.<\/li>\n<li class=\"csl-entry\">Reese, R.S., 2014, Review of Aquifer Storage and Recovery in the Floridan Aquifer <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1742\">System<\/a> of Southern Florida:<\/li>\n<li class=\"csl-entry\">Schele, L., Miller, M.E., Kerr, J., Coe, M.D., and Sano, E.J., 1992, The Blood of Kings: Dynasty and Ritual in Maya Art: George Braziller Inc.<\/li>\n<li class=\"csl-entry\">Seaber, P.R., Kapinos, F.P., and Knapp, G.L., 1987, Hydrologic unit maps:<\/li>\n<li class=\"csl-entry\">Solomon, S., 2011, Water: The Epic Struggle for Wealth, Power, and Civilization: Harper Perennial.<\/li>\n<li class=\"csl-entry\">T\u00f6rnqvist, T.E., Wallace, D.J., Storms, J.E.A., Wallinga, J., Van Dam, R.L., Blaauw, M., Derksen, M.S., Klerks, C.J.W., Meijneken, C., and Snijders, E.M.A., 2008, Mississippi Delta <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_511\">subsidence<\/a> primarily caused by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1758\">compaction<\/a> of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_490\">Holocene<\/a> strata: Nat. Geosci., v. 1, no. 3, p. 173\u2013176.<\/li>\n<li class=\"csl-entry\">Turner, R.E., and Rabalais, N.N., 1991, Changes in Mississippi River water quality this century: Bioscience, v. 41, no. 3, p. 140\u2013147.<\/li>\n<li class=\"csl-entry\">United States Geological Survey, 1967, The Amazon: Measuring a Mighty River: United States Geological Survey O-245-247.<\/li>\n<li class=\"csl-entry\">U.S. Environmental Protection Agency, 2014, Cyanobacteria\/Cyanotoxins<\/li>\n<li class=\"csl-entry\">U.S. Geological Survey, 2012, Snowmelt - The Water Cycle, from USGS Water-Science School<\/li>\n<li class=\"csl-entry\">Utah\/Nevada Draft Snake Valley Agreement, 2013<\/li>\n<\/ol>\n<\/div>\n<p><span style=\"font-family: 'courier new', courier, monospace;\">\u00a0<\/span><\/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_138_749\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_749\"><div tabindex=\"-1\"><p>Heath, R. C. (1983). Basic ground-water hydrology (No. Water-Supply Paper 2220). [Washington, D.C.]; Alexandria, Va.: U.S. Geological Survey. Retrieved from http:\/\/pubs.usgs.gov\/wsp\/2220\/report.pdf<\/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_138_1655\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_2442\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_2442\"><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_138_1963\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_3916\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_3916\"><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_138_2163\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_2163\"><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_138_1756\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1657\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1657\"><div tabindex=\"-1\"><p>Isolated piece of bedrock which sticks above an alluvial 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_138_1753\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1765\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1751\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_2450\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_2450\"><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_138_2165\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1664\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1254\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1254\"><div tabindex=\"-1\"><p>Chemical sedimentary rocks that have a biologic component to their origin. Many limestones are biochemical.<\/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_138_1909\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1778\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1767\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1658\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1014\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1013\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1661\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1661\"><div tabindex=\"-1\"><p>A sedimentary structure that has inclined layers within an overall layer. Forms commonly in dunes, larger in eolian dunes.<\/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_138_1660\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1660\"><div tabindex=\"-1\"><p>A vast stretch of sand dunes.<\/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_138_1662\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1662\"><div tabindex=\"-1\"><p>Crescent-shaped dune formed by consistent wind and limited sediment.<\/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_138_976\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1667\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1700\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1700\"><div tabindex=\"-1\"><p>Series of lakes between moraines within an alpine glacier basin, typically a cirque.<\/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_138_1665\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1666\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1009\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_2423\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_2423\"><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_138_1993\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1993\"><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_138_1668\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1670\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1671\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1672\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1672\"><div tabindex=\"-1\"><p>Snow which has been compressed, and is starting to turn into ice.<\/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_138_1673\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1674\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1674\"><div tabindex=\"-1\"><p>The net gain or loss of ice within 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_138_1745\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1676\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1676\"><div tabindex=\"-1\"><p>Part of a glacier which has a net loss of material over the course of a year.<\/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_138_1698\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1681\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1681\"><div tabindex=\"-1\"><p>A ridge that is carved between two glacial valleys.<\/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_138_1682\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1682\"><div tabindex=\"-1\"><p>Glacially-carved, bowl-shaped 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_138_1764\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1764\"><div tabindex=\"-1\"><p>Possesses properties of both acid and base<\/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_138_1683\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1685\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1685\"><div tabindex=\"-1\"><p>A feature formed by a tributary glacier going into a main glacier, forming a tributary valley floor higher in elevation than the main valley floor.<\/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_138_1684\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1686\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1968\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1968\"><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_138_1781\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_2272\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_2143\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_2143\"><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_138_2176\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_2176\"><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_138_1692\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1692\"><div tabindex=\"-1\"><p>A place where two or more glaciers combine, and the lateral moraines combine to form a moraine within 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_138_1695\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_495\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_495\"><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_138_492\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1688\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1688\"><div tabindex=\"-1\"><p>Accumulation of sediment at the margins of glaciers, including the base, sides, and end.<\/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_138_493\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_2152\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_2152\"><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_138_1689\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1689\"><div tabindex=\"-1\"><p>Moraine that forms at the end of 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_138_1690\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1690\"><div tabindex=\"-1\"><p>A terminal moraine that forms as a glacier melts.<\/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_138_1663\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1663\"><div tabindex=\"-1\"><p>Dunes that are much longer than wide, forming from wind that varies in two opposite 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_138_487\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_487\"><div tabindex=\"-1\"><p>This is a copyrighted image from the CAMECA Archives<br \/>\nReproduction is authorized, 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_138_1244\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1694\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1694\"><div tabindex=\"-1\"><p>Accumulation of fine-grained sediment formed downhill of the terminal moraine.<\/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_138_1696\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1696\"><div tabindex=\"-1\"><p>Depression formed by ice resting in sediment, then preserved after the ice melts and the sediment lithifies.<\/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_138_1697\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1697\"><div tabindex=\"-1\"><p>Lake that forms in a kettle.<\/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_138_1701\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1701\"><div tabindex=\"-1\"><p>Lake that fills a glacial 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_138_2444\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_2444\"><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_138_1263\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1263\"><div tabindex=\"-1\"><p>The study of rock layers and their relationships to each other within a specific area.<\/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_138_1699\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1699\"><div tabindex=\"-1\"><p>Ridge of sediment that forms under a glacier, with a steep uphill (with respect to the glacier) side and gentle downhill side.<\/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_138_1704\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1704\"><div tabindex=\"-1\"><p>A period of cooler temperatures on Earth in which ice sheets can grow on continents.<\/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_138_1703\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1703\"><div tabindex=\"-1\"><p>Lakes that form via increased precipitation with glacial climate shifts.<\/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_138_2149\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_2149\"><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_138_1718\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1718\"><div tabindex=\"-1\"><p>A system which reverts back to a baseline when it deviates.<\/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_138_986\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1705\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1705\"><div tabindex=\"-1\"><p>A series of changes to the Earth's orbit which can fluctuate climate.<\/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_138_1706\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1706\"><div tabindex=\"-1\"><p>Wobbles in the Earth's axis.<\/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_138_2212\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1707\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1707\"><div tabindex=\"-1\"><p>The angle of the Earth's axis with respect to the plane of rotation.<\/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_138_1531\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1531\"><div tabindex=\"-1\"><p>Water that flows over 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_138_1514\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_223\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_2443\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_969\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1008\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1962\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1962\"><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_138_1999\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1893\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_231\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_2154\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_2154\"><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_138_2155\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_2155\"><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_138_1710\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1710\"><div tabindex=\"-1\"><p>Relative balance of an object based on how it floats.<\/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_138_2445\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_2445\"><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_138_1712\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1712\"><div tabindex=\"-1\"><p>When a species no longer exists.<\/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_138_1713\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1713\"><div tabindex=\"-1\"><p>Current conditions within the atmosphere.<\/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_138_1714\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1714\"><div tabindex=\"-1\"><p>Long term averages and variations within the conditions of the atmosphere.<\/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_138_1742\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_755\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1717\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_234\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_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_138_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_138_1781\">bonding<\/a> related to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1788\">silicon-oxygen tetrahedron<\/a> and how it forms common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_971\">oxide<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_973\">sulfide<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_974\">sulfate<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_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_138_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_138_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_138_1767\">temperature<\/a>. Both are considered <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> because they were classified before the room-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1767\">temperature<\/a> rule was accepted as part of the definition. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1765\">mineral<\/a> is an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_970\">calcite<\/a> is considered a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">mineral<\/a>. Typically, substances like coal, pearl, opal, or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_999\">obsidian<\/a> that do not fit the definition of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1765\">minerals<\/a>: <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_251\">mechanical weathering<\/a> (sand, gravel, etc.) and chemical weathering (things <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1785\">precipitated<\/a> from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">minerals<\/a> that have a specific chemical composition.\u00a0 To understand <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_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_138_1778\">elements<\/a>, a tabular arrangement of all known <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_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_138_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_138_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_138_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_138_1779\">isotope<\/a><strong>.\u00a0<\/strong><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1779\">Isotopes<\/a> <\/strong>are forms of an <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1779\">isotopes<\/a> for a particular <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_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_138_1778\">elements<\/a> are found in the most common rock forming <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1778\">Elements<\/a> in the Earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1778\">elements<\/a>. Chemical <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_1765\">minerals<\/a> are also compounds of more than one <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1778\">element<\/a>. The common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">mineral<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1781\">bonds<\/a> to form a <strong>molecular ion<\/strong>, called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">mineral<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_970\">calcite<\/a>, CaCO3. The name of the chemical compound is calcium <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_969\">carbonate<\/a>, where calcium is Ca and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">mineral<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_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_138_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_138_1778\">elements<\/a> in order of atomic number and the columns organize <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_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_138_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_138_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_138_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_138_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_138_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_138_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_138_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_138_1781\">bonds<\/a> with other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_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_138_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_138_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_138_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_138_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_138_1781\">bonds<\/a>, also called electron-transfer <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_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_138_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_138_1781\">bond<\/a>, commonly occurs between nonmetals. Covalent <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1765\">Minerals<\/a> form when atoms <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1785\">precipitation<\/a> directly from an aqueous (water) <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1783\">solution<\/a> with a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1767\">temperature<\/a> change, 2) <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1752\">crystallization<\/a> from a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1750\">magma<\/a> with a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1767\">temperature<\/a> change, and 3) biological <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_1783\">solution<\/a>.<\/p>\n<p><strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1785\">Precipitation<\/a><\/strong> is the reverse process, in which ions in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1783\">solution<\/a> come together to form solid <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1785\">Precipitation<\/a> is dependent on the concentration of ions in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1783\">solution<\/a> and other factors such as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1784\">saturation<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1785\">Precipitation<\/a> can occur when the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1767\">temperature<\/a> of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1783\">solution<\/a>. An example of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1765\">minerals<\/a> dissolved in water to form <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1781\">bonds<\/a> and grow into crystals or cement grains of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediment<\/a> together. In Utah, deposits of tufa formed from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">mineral<\/a>-rich springs that emerged into the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_970\">calcite<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1784\">saturation<\/a> is reached and the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1785\">precipitate<\/a> out as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_1750\">Magma<\/a> is molten rock with freely moving ions. When <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1751\">lava<\/a>), it starts to cool and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">minerals<\/a> biologically. The most common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">mineral<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1785\">precipitated<\/a> by organisms is <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_970\">calcite<\/a>, or calcium <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_969\">carbonate<\/a> (CaCO3). <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_970\">Calcite<\/a> is often <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1785\">precipitate<\/a> aragonite or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1756\">sediments<\/a>, and eventually may become the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1761\">sedimentary rock<\/a> chert. An example of biologic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1785\">precipitation<\/a> from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">mineral<\/a> in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">minerals<\/a> until the organism dies and these hard parts become <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">Minerals<\/a> are categorized based on their composition and structure. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1787\">Silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> are built around a molecular ion called the <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1787\">Silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> form the largest group of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1664\">mantle<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1658\">crust<\/a>. Of the nearly four thousand known <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_1788\">silicon-oxygen tetrahedron<\/a> an ionic charge of -4. This <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1788\">silicon-oxygen tetrahedron<\/a> has chemically active corners available to form <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1781\">bonds<\/a> with other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1750\">magma<\/a> chemistry, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1789\">Olivine<\/a> Family<\/b><\/span><\/p>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1789\">Olivine<\/a> is the primary <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">mineral<\/a> component in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1664\">mantle<\/a> rock such as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1666\">peridotite<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1778\">elements<\/a> occur in a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1783\">solution<\/a>, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1786\">solid solution<\/a> occurs when two or more <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1789\">Olivine<\/a> is referred to as a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1789\">olivine<\/a> family indicates a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1786\">solid solution<\/a> forming a compositional series within the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1789\">olivine<\/a> series of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a>, the iron and magnesium ions in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1750\">magma<\/a>, the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">mineral<\/a> crystals continue to grow until they solidify into <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1750\">magma<\/a> determine which <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> in the series form. Other rarer <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1789\">olivine<\/a> crystalline structure in small amounts. Such ionic substitutions in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">mineral<\/a> crystals give rise to the great variety of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">minerals<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1008\">mafic<\/a><\/strong> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a>, a contraction of their chemical symbols Ma and Fe. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1008\">Mafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> are also referred to as dark-colored ferromagnesian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1787\">silicates<\/a> tend to be more dense than non-ferromagnesian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1753\">igneous<\/a> rocks that are built from these <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a>: whether a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1654\">tectonic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1789\">olivine<\/a> is built from independent <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1788\">silica tetrahedra<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1789\">olivine<\/a>, other common neosilicate <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> include garnet, topaz, kyanite, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1765\">minerals<\/a> that share one oxygen between two tetrahedra, and include <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1790\">Pyroxene<\/a> is another family of dark ferromagnesian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1778\">elements<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1781\">bonded<\/a> to polymerized <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1008\">mafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1753\">igneous<\/a> rocks such as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1666\">peridotite<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1013\">basalt<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_1790\">pyroxene<\/a> family is augite, itself containing several <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">mineral<\/a> names.<\/p>\n<p>This single-chain crystalline structure <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1781\">bonds<\/a> with many <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_1791\">Amphibole<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_980\">crystal habit<\/a><\/strong>. The most common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1762\">metamorphic rock<\/a>, amphibolite, is primarily composed of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1791\">amphibole<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1780\">cations<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1781\">bonded<\/a> with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1788\">silica tetrahedra<\/a>. These dark ferromagnesian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> are commonly found in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1016\">gabbro<\/a>, baslt, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1015\">diorite<\/a>, and often form the black specks in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_1765\">minerals<\/a> and water dissolved in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_1787\">silicates<\/a>, also known as phyllosilicates. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_966\">Mica<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> are usually found in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1753\">igneous<\/a> and metamorphic rocks, while clay <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_966\">biotite<\/a>, frequently found in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1014\">granite<\/a>, and light-colored <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_966\">muscovite<\/a>, found in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_966\">Biotite<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">mineral<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_966\">Muscovite<\/a> micas belong to the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1006\">felsic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1006\">Felsic<\/a> is a contraction formed from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_968\">feldspar<\/a>, the dominant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">mineral<\/a> in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_966\">mica<\/a> shows the corner O atoms <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_1781\">bonds<\/a> are weak compared to the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1765\">minerals<\/a> occur in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediments<\/a> formed by the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1754\">weathering<\/a> of rocks and are another family of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> with a tetrahedral sheet structure. Clay <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1765\">minerals<\/a> are composed of hydrous aluminum <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_967\">Quartz<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_968\">feldspar<\/a> are the two most abundant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental crust<\/a>. In fact, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_968\">feldspar<\/a> itself is the single most abundant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">mineral<\/a> in the Earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1658\">crust<\/a>. There are two types of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_968\">feldspar<\/a>, one containing potassium and abundant in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1006\">felsic<\/a> rocks of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1008\">mafic<\/a> rocks of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1659\">oceanic crust<\/a>.\u00a0 Together with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_967\">quartz<\/a>, these <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> are classified as framework <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1787\">silicates<\/a>. They are built with a three-dimensional framework of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1765\">mineral<\/a> compositions and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_968\">Feldspars<\/a> are usually found in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1753\">igneous<\/a> rocks, such as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1014\">granite<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1010\">rhyolite<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1754\">weathering<\/a>. While <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_967\">quartz<\/a> is the most abundant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_968\">feldspar<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> are the most abundant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> in the Earth's <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1658\">crust<\/a>, comprising roughly 50% of the total <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> that make up the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_967\">quartz<\/a> among which are gemstones like amethyst, rose <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_967\">quartz<\/a>, and citrine.\u00a0 <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_968\">feldspar<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_968\">K-spar<\/a>, is made of silica, aluminum, and potassium. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_967\">Quartz<\/a> and orthoclase <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_968\">feldspar<\/a> are <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1006\">felsic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1006\">Felsic<\/a> is the compositional term applied to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1653\">continental<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1753\">igneous<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> and rocks that contain an abundance of silica. Another <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_968\">feldspar<\/a> is <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1786\">solid solution<\/a> (Ca,Na) indicating a series of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1765\">Minerals<\/a> in this solid solution series have different <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_968\">feldspar<\/a>, orthoclase and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_968\">plagioclase<\/a> respectively.\u00a0Framework <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> (see table) does not contain <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1788\">silica-oxygen tetrahedra<\/a>. Many non-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_976\">Native<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_969\">Carbonates<\/a><\/span><\/td>\n<td><span style=\"font-weight: 400\"><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_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_138_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_138_1787\"><em>silicate<\/em><\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_969\">carbonate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_969\">carbonate<\/a> rocks, such <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_970\">calcite<\/a> and dolomite, are formed via evaporation and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1785\">precipitation<\/a>. However, most <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_969\">carbonate<\/a>-rich rocks, such as limestone, are created by the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_969\">carbonate<\/a> hard parts become included in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1756\">sediments<\/a>, eventually becoming the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_970\">calcite<\/a> crystals are used in special petrographic microscopes for studying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> and rocks.<\/p>\n<p>Many non-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1783\">solution<\/a> of carbon dioxide in water. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_969\">Carbonate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> are salts built around the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_1765\">mineral<\/a> identification section below, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_969\">carbonate<\/a> unit consists of carbon atoms (tiny white dots) covalently <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_969\">carbonate<\/a> unit forms an ionic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_969\">carbonates<\/a>, the next most common non-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> are the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_971\">oxides<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_972\">halides<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_973\">sulfides<\/a>.<\/p>\n<p><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_971\">Oxides<\/a> consist of metal ions covalently <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1781\">bonded<\/a> with oxygen. The most familiar <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_971\">oxide<\/a> is rust, which is a combination of iron <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_971\">oxides<\/a>. Hydrated <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_971\">oxides<\/a> are important for producing metallic iron. When iron <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_967\">quartz<\/a> coated with iron <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_971\">oxide<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_1781\">bonded<\/a> with sodium or other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_972\">Halide<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_972\">halide<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_973\">sulfide<\/a>), <\/span>sphalerite<span style=\"font-weight: 400\"> (zinc <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_973\">sulfide<\/a>).<\/span><span style=\"font-weight: 400\">\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_973\">Sulfides<\/a> are well known for being important ore <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_974\">Sulfate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> contain a metal ion, such as calcium, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1781\">bonded<\/a> to a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_974\">sulfate<\/a> ion. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_974\">sulfate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">minerals<\/a> like <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_974\">sulfate<\/a> without water is a different <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_975\">Phosphate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> have a tetrahedral <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1782\">anions<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_975\">phosphate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_975\">phosphate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_976\">native<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1778\">element<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">mineral<\/a>; it is not very reactive and rarely <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1781\">bonds<\/a> with other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">mineral<\/a> carbon is often found as a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_976\">native<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1781\">bond<\/a> to other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1778\">elements<\/a> and are rarely found in a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1765\">minerals<\/a> by testing several physical properties: <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_977\">luster<\/a> and color, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_978\">streak<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_979\">hardness<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_980\">crystal habit<\/a>, cleavage and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_986\">fracture<\/a>, and some special properties. Only a few common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_1765\">mineral<\/a> is its surface appearance, specifically <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_977\">luster<\/a> and color. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_977\">Luster<\/a> describes how the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">mineral<\/a> looks. Metallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_977\">luster<\/a> has a duller appearance. Pewter, for example, shows submetallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_977\">luster<\/a>. See the table for descriptions and examples of nonmetallic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_1765\">minerals<\/a> because of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">minerals<\/a>, although it can be quite variable within the same <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">mineral<\/a> family. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">Mineral<\/a> colors are affected by the main <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1765\">mineral<\/a> formula. For example, the incorporation of water molecules gives <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_1786\">solid solution<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_968\">Feldspars<\/a>, the most abundant <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> in the earth\u2019s <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1658\">crust<\/a>, are complex, have <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1778\">elements<\/a>. The same <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1778\">element<\/a> may show up as different colors, in different <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">minerals<\/a>. For identifying many <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a>. a more reliable indicator is <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_978\">streak<\/a>, which is the color of the powdered <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_978\">Streak<\/a> examines the color of a powdered <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">mineral<\/a>, and can be seen when a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">mineral<\/a> sample is scratched or scraped on an unglazed porcelain <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_978\">streak<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_978\">streak<\/a> of some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">Minerals<\/a> that are harder than the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_978\">streak<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> will not show <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_978\">streak<\/a>, but will scratch the porcelain. For these <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a>, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_978\">streak<\/a> test can be obtained by powdering the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">mineral<\/a> with a hammer and smearing the powder across a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_978\">streak<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1669\">plate<\/a> or notebook paper.<\/p>\n<p>While <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">mineral<\/a> surface colors and appearances may vary, their <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_971\">oxide<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_979\">Hardness<\/a> measures the ability of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">mineral<\/a> to scratch other substances. The Mohs <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">minerals<\/a> when compared to a standardized set of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">minerals<\/a> by <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_979\">hardness<\/a> goes back thousands of years. Mohs <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_979\">hardness<\/a> values are determined by the strength of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">mineral<\/a>\u2019s atomic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1781\">bonds<\/a>.<\/p>\n<p>The figure shows the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> associated with specific <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">mineral<\/a> identification. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_979\">hardness<\/a> value of 5.5, separates between hard and soft <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> on many <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">Minerals<\/a> can be identified by <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">mineral<\/a> crystal. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">minerals<\/a> crystallizing in the same rock. When <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> are constrained so they do not develop their typical <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_980\">crystal habit<\/a>, they are called <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_981\">anhedral<\/a><\/strong>. <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_982\">Subhedral<\/a><\/strong> crystals are partially formed shapes. For some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> characteristic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_983\">euhedral<\/a><\/strong> crystal has a perfectly formed, unconstrained shape. Some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_980\">crystal habit<\/a> to the naked eye. Other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_985\">massive<\/a>. The table lists typical crystal habits of various <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_967\">quartz<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_1789\">olivine<\/a>, garnet, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_966\">mica <\/a>(<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_966\">biotite<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_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_138_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_138_968\">feldspar<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1790\">pyroxene<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_980\">crystal habit<\/a> that may be used to identify <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">minerals<\/a> including <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_968\">plagioclase<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_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_138_1765\">minerals<\/a> have a strong cleavage, some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_967\">quartz<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1789\">olivine<\/a> rarely show cleavage and typically break into <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_987\">conchoidal<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1781\">bonds<\/a> within the layer and very weak <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">Mineral<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_987\">conchoidal<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_986\">fracture<\/a>. Uneven <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_228\">volcanic<\/a> glass, called <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_999\">obsidian<\/a>, breaks with this characteristic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_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_138_1765\">minerals<\/a> characteristic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_968\">plagioclase<\/a> below. Cleavage planes arise from the tendency of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_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_138_1765\">minerals<\/a> are: one perfect cleavage (as in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_966\">mica<\/a>), two cleavage planes (as in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_968\">feldspar<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1790\">pyroxene<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1791\">amphibole<\/a>), and three cleavage planes (as in halite, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_970\">calcite<\/a>, and galena). One perfect cleavage (as in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_966\">mica<\/a>) develops on the top and bottom of the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_1765\">minerals<\/a><\/strong><\/p>\n<ul>\n<li><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_967\">Quartz<\/a>\u2014none (<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_987\">conchoidal<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_986\">fracture<\/a>)<\/li>\n<li><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1789\">Olivine<\/a>\u2014none (<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_987\">conchoidal<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_986\">fracture<\/a>)<\/li>\n<li><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_966\">Mica<\/a>\u20141 perfect<\/li>\n<li><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_968\">Feldspar<\/a>\u20142 perfect at 90\u00b0<\/li>\n<li><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1790\">Pyroxene<\/a>\u20142 imperfect at 90\u00b0<\/li>\n<li><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1765\">minerals<\/a> or that allow some <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">minerals<\/a> is a property related to density called <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_989\">specific gravity<\/a><\/strong>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_989\">Specific gravity<\/a> measures the weight of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">mineral<\/a> and water weights. To measure <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_989\">specific gravity<\/a>, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_989\">specific gravity<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_976\">native<\/a> gold. The high density of these <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> gives rise to a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1725\">qualitative<\/a> property called \u201cheft.\u201d Experienced geologists can roughly assess <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_989\">specific gravity<\/a> by heft, a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_1765\">mineral<\/a>, the specimen is dolomite. The difference between these two <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_970\">calcite<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_971\">oxide<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_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_138_968\">plagioclase<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_968\">feldspar<\/a> from potassium <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_968\">feldspar<\/a> (<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_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_138_968\">feldspar<\/a> (albite) separating from the dominant potassium <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_968\">feldspar<\/a> (<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_968\">K-spar<\/a>) within the crystal structure. The two different <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">mineral<\/a> properties is <strong>fluorescence<\/strong>. Certain <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a>, or \u00a0trace <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_1765\">Mineral<\/a> properties are determined by their atomic <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1781\">bonds<\/a>. Most <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1750\">magma<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1785\">precipitate<\/a> as ions and molecules out of a <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1784\">saturated<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1783\">solution<\/a>. The <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1787\">silicates<\/a> are largest group of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1658\">crust<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1664\">mantle<\/a>. Based on the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1788\">silicon-oxygen tetrahedra<\/a>, the crystal structure of <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1778\">elements<\/a>. Non-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1787\">silicate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">Minerals<\/a> are identified by their unique physical properties, including <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_977\">luster<\/a>, color, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_978\">streak<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_979\">hardness<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_980\">crystal habit<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_1977\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_2174\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_2174\"><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_138_244\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_235\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1005\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1001\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_488\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_488\"><div tabindex=\"-1\"><p>By Krishnavedala (Own work) [<a href=\"http:\/\/creativecommons.org\/publicdomain\/zero\/1.0\/deed.en\">CC0<\/a>], <a href=\"https:\/\/commons.wikimedia.org\/wiki\/File%3AHalf_times.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_138_1687\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1687\"><div tabindex=\"-1\"><p>Term for a rock made definitively of glacial till.<\/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_138_220\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_2167\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_2167\"><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_138_2181\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_2181\"><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_138_2158\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_2446\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_973\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_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_138_1740\">renewable<\/a>\u00a0resource is different from a\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_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_138_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_138_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_138_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_138_1740\">renewable<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1739\">nonrenewable<\/a>. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_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_138_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_138_228\">volcanic<\/a> zones or regions with a thinner <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1740\">renewable<\/a> resources provide energy that powers society. Other <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1739\">nonrenewable<\/a> resources come from planetary, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1739\">nonrenewable<\/a> resources include specific concentrated <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_1778\">elements<\/a>. However, it is rare that\u00a0these <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1765\">minerals<\/a>, but it can be applied to valuable <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">mineral<\/a> deposit. The term <strong><a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_246\">landslides<\/a> do occur, such as the very large <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">minerals<\/a>\u00a0by introducing chemical agents, which dissolve\u00a0the target\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">mineral<\/a>.\u00a0Then, they bring the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1783\">solution<\/a> to the surface where\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1765\">minerals<\/a>\u00a0from\u00a0ore bearing\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1778\">element<\/a>\u00a0from a host\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_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_138_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_138_1745\">atmosphere<\/a> as CO<sub>2<\/sub>, causing <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_504\">anticline<\/a> or domal structure, an impermeable salt <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_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_138_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_138_1778\">elements<\/a>. As plant material is incorporated into\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_1765\">Mineral<\/a>\u00a0resources, while principally\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_1765\">mineral<\/a>\u00a0mining\u00a0is the source of many of these\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">minerals<\/a>\u00a0and their associated\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">minerals<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1009\">ultramafic<\/a> to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_1684\">volatiles<\/a>\u00a0that are not incorporated into\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">mineral<\/a>\u00a0crystals when a\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1750\">magma<\/a>\u00a0crystallizes can become\u00a0concentrated\u00a0around the crystallizing\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_996\">pegmatites<\/a><\/strong>. They form from <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1750\">magma<\/a> fluids that are expelled from the solidifying <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1750\">magma<\/a> when nearly the entire <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1750\">magma<\/a> body has crystallized. In addition to <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> that are predominant in the main <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1753\">igneous<\/a> mass, such as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_967\">quartz<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_968\">feldspar<\/a>, and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_966\">mica<\/a>, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_996\">pegmatite<\/a> bodies may also contain very large crystals of unusual <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> that contain rare <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_976\">native<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1778\">elements<\/a> like gold. Such <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_228\">volcanic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_233\">conduit<\/a> that transports <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1009\">ultramafic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1750\">magma<\/a> from within the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1257\">Archean<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_222\">geothermal gradient<\/a>\u00a0cause many geochemical reactions that form various <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_1270\">Precambrian<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_994\">porphyritic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1753\">igneous<\/a> texture, although the name is derived from the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_994\">porphyritic<\/a> texture that is nearly always present in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">minerals<\/a> closely associated with <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1007\">intermediate<\/a> and <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1006\">felsic<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1778\">elements<\/a> including copper, gold, molybdenum, and silver. Underground <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_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_138_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_138_971\">oxides<\/a>,\u00a0such as hematite or goethite. The copper <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">minerals<\/a> are converted\u00a0into secondary higher-copper content\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1750\">magma<\/a>-derived, highly saline metalliferous fluids react with\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_969\">carbonate<\/a>\u00a0rocks to create calcium-magnesium-<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1787\">silicate<\/a>\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a>\u00a0like\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1790\">pyroxene<\/a>,\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_973\">sulfide<\/a>\u00a0or\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_971\">oxide<\/a>\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_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_138_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_138_1742\">system<\/a>. Places where oxygen is plentiful, as in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_1785\">precipitation<\/a> of the\u00a0iron\u00a0beds. Because BIFs are generally\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_508\">basin<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_250\">Soils<\/a>\u00a0and\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_250\">soils<\/a> formed in wet tropical environments. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_250\">Soils<\/a> containing aluminum concentrate <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a>, such as <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_968\">feldspar<\/a>, and ferromagnesian <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> in <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1009\">Ultramafic<\/a> rocks that undergo <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1754\">weathering<\/a> form nickel-rich <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1754\">weathering<\/a>, it forms goethite, a friable <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_976\">Native<\/a>\u00a0gold,\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_976\">native<\/a>\u00a0platinum,\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_973\">sulfide<\/a>\u00a0<a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1754\">weathering<\/a>. In oxygenated water, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_969\">carbonate<\/a> <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">minerals<\/a> like <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_973\">sulfides<\/a> from dissolving and subsequently percolating the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">mineral<\/a> resources, also known as industrial <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_1765\">minerals<\/a>. The most basic is building stone. Limestone, travertine, <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1765\">mineral<\/a> resources are not <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">mineral<\/a> specific; nearly any rock or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_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_138_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_138_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_138_1778\">element<\/a> that occurs in the <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_1765\">mineral<\/a> apatite, which is found in trace amounts in common <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_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_138_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_138_1740\">renewable<\/a> or <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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_138_1739\">nonrenewable<\/a> fossil fuels. <a class=\"glossary-term\" aria-haspopup=\"dialog\" aria-describedby=\"definition\" href=\"#term_138_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_138_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. 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). Annual Reviews 4139 El Camino Way, PO Box 10139, Palo Alto, CA 94303-0139, USA: 17\u201345.<\/li>\n<li style=\"text-align: left\">Delaney, M. L. 1998. \u201cPhosphorus Accumulation in Marine Sediments and the Oceanic Phosphorus Cycle.\u201d <em>Global Biogeochemical Cycles<\/em> 12 (4). Wiley Online Library: 563\u201372.<\/li>\n<li style=\"text-align: left\">Demaison, G. J., and G. T. Moore. 1980. \u201cAnoxic Environments and Oil Source Bed Genesis.\u201d Organic Geochemistry 2 (1). Elsevier: 9\u201331.<\/li>\n<li style=\"text-align: left\">Dott, Robert H., and Merrill J. Reynolds. 1969. \u201cSourcebook for Petroleum Geology.\u201d American Association of Petroleum Geologists Tulsa, Okla. http:\/\/archives.datapages.com\/data\/specpubs\/methodo1\/data\/a072\/a072\/0001\/0000\/vi.htm.<\/li>\n<li style=\"text-align: left\">Duffield, Wendell A. 2005. \u201cVolcanoes, Geothermal Energy, and the Environment.\u201d <em>Volcanoes and the Environment<\/em>. 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. Anthony. 1975. \u201cDistribution by Latitude of Phanerozoic Evaporite Deposits.\u201d <em>The Journal of Geology<\/em> 83 (6). journals.uchicago.edu: 671\u201384.<\/li>\n<li style=\"text-align: left\">Haber, Fritz. 2002. \u201cThe Synthesis of Ammonia from Its Elements Nobel Lecture, June 2, 1920.\u201d <em>Resonance<\/em> 7 (9). Springer India: 86\u201394.<\/li>\n<li style=\"text-align: left\">Hawley, Charles Caldwell. 2014. <em>A Kennecott Story: Three Mines, Four Men, and One Hundred Years, 1887-1997<\/em>. University of Utah Press.<\/li>\n<li style=\"text-align: left\">Hirsch, Robert L., Roger Bezdek, and Robert Wendling. 2006. \u201cPeaking of World Oil Production and Its Mitigation.\u201d <em>AIChE Journal. American Institute of Chemical Engineers<\/em> 52 (1). Wiley Subscription Services, Inc., A Wiley Company: 2\u20138.<\/li>\n<li style=\"text-align: left\">Hitzman, M., R. Kirkham, D. Broughton, J. Thorson, and D. Selley. 2005. \u201cThe Sediment-Hosted Stratiform Copper Ore System.\u201d <em>Economic Geology and the Bulletin of the Society of Economic Geologists<\/em> 100th . eprints.utas.edu.au. http:\/\/eprints.utas.edu.au\/705\/.<\/li>\n<li style=\"text-align: left\">Hofstra, Albert H., and Jean S. Cline. 2000. \u201cCharacteristics and Models for Carlin-Type Gold Deposits.\u201d <em>Reviews in Economic Geology<\/em> 13. Society of Economic Geologists: 163\u2013220.<\/li>\n<li style=\"text-align: left\">James, L. P. 1979. <em>Geology, Ore Deposits, and History of the Big Cottonwood Mining District, Salt Lake County, Utah<\/em>. Bulletin (Utah Geological and Mineral Survey). Utah Geological and Mineral Survey, Utah Department of Natural Resources.<\/li>\n<li style=\"text-align: left\">Kim, Won-Young. 2013. \u201cInduced Seismicity Associated with Fluid Injection into a Deep Well in Youngstown, Ohio.\u201d <em>Journal of Geophysical Research, [Solid Earth]<\/em> 118 (7). Wiley Online Library: 3506\u201318.<\/li>\n<li style=\"text-align: left\">Klein, Cornelis. 2005. \u201cSome Precambrian Banded Iron-Formations (BIFs) from around the World: Their Age, Geologic Setting, Mineralogy, Metamorphism, Geochemistry, and Origins.\u201d <em>The American Mineralogist<\/em> 90 (10). Mineralogical Society of America: 1473\u201399.<\/li>\n<li style=\"text-align: left\">Laylin, James K. 1993. <em>Nobel Laureates in Chemistry, 1901-1992<\/em>. Chemical Heritage Foundation.<\/li>\n<li style=\"text-align: left\">Leach, D. L., and D. F. Sangster. 1993. \u201cMississippi Valley-Type Lead-Zinc Deposits.\u201d <em>Mineral Deposit Modeling: Geological<\/em>. researchgate.net. https:\/\/www.researchgate.net\/profile\/Elisabeth_Rowan\/publication\/252527999_Genetic_link_between_Ouachita_foldbelt_tectonism_and_the_Mississippi_Valley-type_Lead-zinc_deposits_of_the_Ozarks\/links\/00b7d53c97ac2d6fe7000000.pdf.<\/li>\n<li style=\"text-align: left\">Lehmann, Bernd. 2008. \u201cUranium Ore Deposits.\u201d <em>Rev. Econ. Geol. AMS Online 2008<\/em>. kenanaonline.com: 16\u201326.<\/li>\n<li style=\"text-align: left\">London, David, and Daniel J. Kontak. 2012. \u201cGranitic Pegmatites: Scientific Wonders and Economic Bonanzas.\u201d <em>Elements<\/em> 8 (4). GeoScienceWorld: 257\u201361.<\/li>\n<li style=\"text-align: left\">Mancuso, Joseph J., and Ronald E. Seavoy. 1981. \u201cPrecambrian Coal or Anthraxolite; a Source for Graphite in High-Grade Schists and Gneisses.\u201d <em>Economic Geology and the Bulletin of the Society of Economic Geologists<\/em> 76 (4). economicgeology.org: 951\u201354.<\/li>\n<li style=\"text-align: left\">McKenzie, Hermione, and Barrington Moore. 1970. \u201cSocial Origins of Dictatorship and Democracy.\u201d JSTOR. http:\/\/www.jstor.org\/stable\/27856441.<\/li>\n<li style=\"text-align: left\">Needham, Joseph, Ling Wang, and Gwei Djen Lu. 1963. <em>Science and Civilisation in China<\/em>. Vol. 5. Cambridge University Press Cambridge.<\/li>\n<li style=\"text-align: left\">Nuss, Philip, and Matthew J. Eckelman. 2014. \u201cLife Cycle Assessment of Metals: A Scientific Synthesis.\u201d <em>PloS One<\/em> 9 (7). journals.plos.org: e101298.<\/li>\n<li style=\"text-align: left\">Orton, E. 1889. <em>The Trenton Limestone as a Source of Petroleum and Inflammable Gas in Ohio and Indiana<\/em>. U.S. Government Printing Office.<\/li>\n<li style=\"text-align: left\">Palmer, M. A., E. S. Bernhardt, W. H. Schlesinger, K. N. Eshleman, E. Foufoula-Georgiou, M. S. Hendryx, A. D. Lemly, et al. 2010. \u201cScience and Regulation. Mountaintop<\/li>\n<li style=\"text-align: left\">Mining Consequences.\u201d <em>Science<\/em> 327 (5962). science.sciencemag.org: 148\u201349.<\/li>\n<li style=\"text-align: left\">Pratt, Wallace Everette. 1942. <em>Oil in the Earth<\/em>. University of Kansas Press.<\/li>\n<li style=\"text-align: left\">Qu\u00e9r\u00e9, C. Le, Robert Joseph Andres, T. Boden, T. Conway, R. A. Houghton, Joanna I. House, Gregg Marland, et al. 2013. \u201cThe Global Carbon Budget 1959--2011.\u201d <em>Earth System Science Data<\/em> 5 (1). Copernicus GmbH: 165\u201385.<\/li>\n<li style=\"text-align: left\">Richards, J. P. 2003. \u201cTectono-Magmatic Precursors for Porphyry Cu-(Mo-Au) Deposit Formation.\u201d <em>Economic Geology and the Bulletin of the Society of Economic Geologists<\/em> 98 (8). economicgeology.org: 1515\u201333.<\/li>\n<li style=\"text-align: left\">Rui-Zhong, Hu, Su Wen-Chao, Bi Xian-Wu, Tu Guang-Zhi, and Albert H. Hofstra. 2002. \u201cGeology and Geochemistry of Carlin-Type Gold Deposits in China.\u201d <em>Mineralium Deposita<\/em> 37 (3-4). Springer-Verlag: 378\u201392.<\/li>\n<li style=\"text-align: left\">Schr\u00f6der, K-P, and Robert Connon Smith. 2008. \u201cDistant Future of the Sun and Earth Revisited.\u201d <em>Monthly Notices of the Royal Astronomical Society<\/em> 386 (1). mnras.oxfordjournals.org: 155\u201363.<\/li>\n<li style=\"text-align: left\">Semaw, Sileshi, Michael J. Rogers, Jay Quade, Paul R. Renne, Robert F. Butler, Manuel Dominguez-Rodrigo, Dietrich Stout, William S. Hart, Travis Pickering, and Scott W. 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_138_1961\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1961\"><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_138_1920\"><div class=\"glossary__definition\" role=\"dialog\" data-id=\"term_138_1920\"><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":2,"template":"","meta":{"pb_show_title":"","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[49],"contributor":[],"license":[],"class_list":["post-138","chapter","type-chapter","status-publish","hentry","chapter-type-numberless"],"part":19,"_links":{"self":[{"href":"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/wp-json\/pressbooks\/v2\/chapters\/138","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\/138\/revisions"}],"predecessor-version":[{"id":1791,"href":"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/wp-json\/pressbooks\/v2\/chapters\/138\/revisions\/1791"}],"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\/138\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/wp-json\/wp\/v2\/media?parent=138"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/wp-json\/pressbooks\/v2\/chapter-type?post=138"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/wp-json\/wp\/v2\/contributor?post=138"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/integrations.pressbooks.network\/testcloneglossaryterms\/wp-json\/wp\/v2\/license?post=138"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}