{"id":349,"date":"2018-08-24T14:58:58","date_gmt":"2018-08-24T18:58:58","guid":{"rendered":"https:\/\/opentextbc.ca\/physicalgeologyh5p\/chapter\/10-1-controls-on-metamorphic-processes-2\/"},"modified":"2023-07-04T12:54:44","modified_gmt":"2023-07-04T16:54:44","slug":"controls-on-metamorphic-processes","status":"publish","type":"chapter","link":"https:\/\/opentextbc.ca\/physicalgeologyh5p\/chapter\/controls-on-metamorphic-processes\/","title":{"raw":"10.1 Controls on Metamorphic Processes","rendered":"10.1 Controls on Metamorphic Processes"},"content":{"raw":"The main factors that control metamorphic processes are:\r\n<ul>\r\n \t<li>The chemical composition of the parent rock<\/li>\r\n \t<li>The temperature at which metamorphism takes place<\/li>\r\n \t<li>The pressure applied, and whether the pressure is equal in all directions or not<\/li>\r\n \t<li>The amount and type of fluid (mostly water) that is present during metamorphism<\/li>\r\n \t<li>The amount of time over which metamorphic conditions are sustained<\/li>\r\n<\/ul>\r\n<h1>Mineral composition<\/h1>\r\nParent rocks can be from any of the three rock types: sedimentary, igneous, or metamorphic.\u00a0 The critical feature of the parent rock is its mineral composition.\u00a0 This is because the stability of minerals\u2014how they are influenced by changing conditions\u2014is what determines which minerals form as metamorphism takes place. When a rock is subjected to increased temperatures and pressures, some minerals will undergo chemical reactions and turn into new minerals, while others might just change their size and shape.\r\n<h1>Temperature<\/h1>\r\nTemperature is a key variable in determining which metamorphic reactions happen because minerals are stable over a specific range of temperatures (dependent on pressure and the presence of fluids). Quartz, for example, is stable from surface temperatures up to approximately 1800\u00b0C. Under higher pressures, that upper limit will also be higher. If water is present, the limit will be lower. Most other common minerals have upper limits between 150\u00b0C and 1000\u00b0C.\r\n\r\nSome minerals will change their crystal structure depending on the temperature and pressure. Quartz has different polymorphs that are stable between 0\u00b0C and 1800\u00b0C, but the differences in quartz polymorphs aren't nearly as stunning as with the minerals kyanite, andalusite, and sillimanite. They are polymorphs with the composition Al<sub>2<\/sub>SiO<sub>5<\/sub>. These polymorphs are especially useful for studying metamorphic rocks, because their presence can be used to figure out what pressures and temperatures a metamorphic rock experienced (Figure 10.3). If a rock has more than one of these polymorphs, the pressure and temperature range can be narrowed down even further to the boundaries of the stability fields.\r\n\r\n[caption id=\"attachment_347\" align=\"aligncenter\" width=\"600\"]<a href=\"https:\/\/opentextbc.ca\/physicalgeologyh5p\/chapter\/controls-on-metamorphic-processes\/al2sio5\/\"><img class=\"wp-image-347\" src=\"https:\/\/opentextbc.ca\/kzlab\/wp-content\/uploads\/sites\/360\/2018\/06\/Al2SiO5.png\" alt=\"\" width=\"600\" height=\"623\" \/><\/a> <strong>Figure 10.3<\/strong> The Al<sub>2<\/sub>SiO<sub>5<\/sub> polymorphs andalusite, kyanite, and sillimanite, and their stability fields. <em>Source:<\/em> Karla Panchuk (2018), CC BY-SA 4.0. Click for more attributions.[\/caption]\r\n<h1>Pressure<\/h1>\r\nPressure has implications for mineral stability, and therefore the mineral content of metamorphic rocks, but it also determines the texture of metamorphic rocks.\r\n\r\nWhen <strong>directed pressure<\/strong> (or <strong>directed stress<\/strong>) acts on a rock, it means the stress on the rock is greater in one direction than another. In an experiment with cylinders of modeling clay stacked in a block (Figure 10.4, top), pushing down on the clay from above resulted in higher directed pressure in the up-down direction (larger arrows; downward from pushing on the clay, and upward from the force of the table beneath the clay) than in the sideways direction, where only air pressure was acting (small arrows). The clay cylinders became elongated in the direction of least pressure.\r\n\r\n[caption id=\"attachment_348\" align=\"aligncenter\" width=\"600\"]<img class=\"wp-image-348\" src=\"https:\/\/opentextbc.ca\/kzlab\/wp-content\/uploads\/sites\/360\/2021\/08\/clay-experiment.png\" alt=\"\" width=\"600\" height=\"483\" \/> <strong>Figure 10.4<\/strong> Modelling clay experiments showing the effects of pressure on textures. Top: Directed pressure- clay was set on a flat surface and pushed down on from above (large arrows). Cylinders making up the clay block became elongated in the direction of least stress. Bottom: Shear stress applied to the top and bottom of a block of clay caused the interior to stretch. Note white dashed reference circles and elongated ellipses. Source: Karla Panchuk (2018), CC BY 4.0.[\/caption]\r\n\r\nRocks undergo <strong>shear stress<\/strong> when forces act parallel to surfaces. In another modelling-clay experiment, applying oppositely directed forces to the top and bottom of a block of clay (Figure 10.4, bottom) caused diagonal stretching within the block. Note the change in shape of the dashed white reference circles.\r\n\r\nIn both experiments, parts of the clay became elongated in a particular direction. When mineral grains within a rock become aligned like this, it produces a fabric called <strong>foliation<\/strong>. Foliation is described in more detail later in this chapter.\r\n<div class=\"textbox shaded\">\r\n\r\n<strong>Dance Break!<\/strong>\r\n\r\n<div class=\"offline\">\r\n\r\n<img class=\"aligncenter wp-image-1843\" src=\"https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2018\/08\/116-1.png\" alt=\"instructions for the moonwalk\" width=\"895\" height=\"270\" \/>\r\n<div class=\"textbox\"><strong>Image Description:<\/strong> Instructions for the moonwalk. Steps 2 and 4 involve brushing your foot backward on the floor. Steps 1 and 3 involve applying force straight up and down.<\/div>\r\n<strong>Fill in the dance-step numbers to complete these directions.<\/strong>\r\n\r\nThe moonwalk is a dance move that gets its awesome sauce from the contrast between the dancer appearing to be doing a forward walking motion, but actually sliding smoothly backward. Using these simple instructions, you too can moonwalk.\r\n\r\nJust be sure to apply only directed pressure to the floor during Step <span style=\"text-decoration: underline;\" aria-label=\"blank\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0<\/span> and Step <span style=\"text-decoration: underline;\" aria-label=\"blank\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0<\/span>.\r\n\r\nApply shear stress to the floor only during Step <span style=\"text-decoration: underline;\" aria-label=\"blank\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0<\/span> and Step <span style=\"text-decoration: underline;\" aria-label=\"blank\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0<\/span> as you drag your foot backward.\r\n<strong>\r\nTo check your answers, navigate to the below link to view the interactive version of this activity.<\/strong>\r\n\r\n<\/div>\r\n[h5p id=\"116\"]\r\n<\/div>\r\n<h1>Fluids<\/h1>\r\nWater is the main fluid present within rocks of the crust, and the only one considered here. The presence of water is important for two main reasons. First, water facilitates the transfer of ions between minerals and within minerals, and therefore can speed up metamorphic chemical reactions. Not only can metamorphism happen more rapidly, but processes can be completed that might not otherwise have time to occur.\r\n\r\nSecondly, water\u2014especially hot water\u2014can have elevated concentrations of dissolved substances, making it an important medium for moving ions from one place to another within the crust. Processes facilitated by hot water are called <strong>hydrothermal<\/strong> processes (<em>hydro<\/em> refers to water, and <em>thermal<\/em> refers to heat)<em>.\r\n<\/em>\r\n<h1>Time<\/h1>\r\nMost metamorphic reactions are slow. It's estimated that when new minerals grow in a rock during metamorphism, they add about 1 mm to the outside of the mineral crystal for every million years. Very slow reaction rates make it hard to study metamorphic processes in a lab.\r\n\r\nWhile the rate of metamorphism is slow, the tectonic processes that lead to metamorphism are also very slow, so there is a good chance that metamorphic reactions will be completed. For example, an important setting for metamorphism is many kilometres deep within the roots of mountain ranges. A mountain range takes tens of millions of years to form, and tens of millions of years more to be eroded to the extent that we can see the rocks that were metamorphosed deep beneath it.\r\n<div class=\"textbox shaded\">\r\n\r\n<strong>How Old Is This Rock?<\/strong>\r\n\r\n<div class=\"offline\">\r\n\r\nThe large reddish crystals in this metamorphic rock are garnet, and the surrounding light-coloured rock is dominated by muscovite mica. The largest of the garnets have diameters similar to that of the 23 mm Euro coin.\r\n\r\n<img class=\"wp-image-1834 aligncenter\" src=\"https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2018\/08\/117-1.jpeg\" alt=\"\" width=\"849\" height=\"637\" \/>\r\n\r\nAssume that the diameters of the garnets increased at a rate of 1 mm per million years. <strong>How old is this rock?<\/strong>\r\n<ul>\r\n \t<li>Much less than 23 million years old<\/li>\r\n \t<li>About 23 million years old<\/li>\r\n \t<li>A lot older than 23 million years<\/li>\r\n<\/ul>\r\n<strong>To check your answers, navigate to the below link to view the interactive version of this activity.<\/strong>\r\n\r\n<\/div>\r\n[h5p id=\"117\"]\r\n<\/div>","rendered":"<p>The main factors that control metamorphic processes are:<\/p>\n<ul>\n<li>The chemical composition of the parent rock<\/li>\n<li>The temperature at which metamorphism takes place<\/li>\n<li>The pressure applied, and whether the pressure is equal in all directions or not<\/li>\n<li>The amount and type of fluid (mostly water) that is present during metamorphism<\/li>\n<li>The amount of time over which metamorphic conditions are sustained<\/li>\n<\/ul>\n<h1>Mineral composition<\/h1>\n<p>Parent rocks can be from any of the three rock types: sedimentary, igneous, or metamorphic.\u00a0 The critical feature of the parent rock is its mineral composition.\u00a0 This is because the stability of minerals\u2014how they are influenced by changing conditions\u2014is what determines which minerals form as metamorphism takes place. When a rock is subjected to increased temperatures and pressures, some minerals will undergo chemical reactions and turn into new minerals, while others might just change their size and shape.<\/p>\n<h1>Temperature<\/h1>\n<p>Temperature is a key variable in determining which metamorphic reactions happen because minerals are stable over a specific range of temperatures (dependent on pressure and the presence of fluids). Quartz, for example, is stable from surface temperatures up to approximately 1800\u00b0C. Under higher pressures, that upper limit will also be higher. If water is present, the limit will be lower. Most other common minerals have upper limits between 150\u00b0C and 1000\u00b0C.<\/p>\n<p>Some minerals will change their crystal structure depending on the temperature and pressure. Quartz has different polymorphs that are stable between 0\u00b0C and 1800\u00b0C, but the differences in quartz polymorphs aren&#8217;t nearly as stunning as with the minerals kyanite, andalusite, and sillimanite. They are polymorphs with the composition Al<sub>2<\/sub>SiO<sub>5<\/sub>. These polymorphs are especially useful for studying metamorphic rocks, because their presence can be used to figure out what pressures and temperatures a metamorphic rock experienced (Figure 10.3). If a rock has more than one of these polymorphs, the pressure and temperature range can be narrowed down even further to the boundaries of the stability fields.<\/p>\n<figure id=\"attachment_347\" aria-describedby=\"caption-attachment-347\" style=\"width: 600px\" class=\"wp-caption aligncenter\"><a href=\"https:\/\/opentextbc.ca\/physicalgeologyh5p\/chapter\/controls-on-metamorphic-processes\/al2sio5\/\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-347\" src=\"https:\/\/opentextbc.ca\/kzlab\/wp-content\/uploads\/sites\/360\/2018\/06\/Al2SiO5.png\" alt=\"\" width=\"600\" height=\"623\" srcset=\"https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2018\/06\/Al2SiO5.png 648w, https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2018\/06\/Al2SiO5-289x300.png 289w, https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2018\/06\/Al2SiO5-65x68.png 65w, https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2018\/06\/Al2SiO5-225x234.png 225w, https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2018\/06\/Al2SiO5-350x364.png 350w\" sizes=\"auto, (max-width: 600px) 100vw, 600px\" \/><\/a><figcaption id=\"caption-attachment-347\" class=\"wp-caption-text\"><strong>Figure 10.3<\/strong> The Al<sub>2<\/sub>SiO<sub>5<\/sub> polymorphs andalusite, kyanite, and sillimanite, and their stability fields. <em>Source:<\/em> Karla Panchuk (2018), CC BY-SA 4.0. Click for more attributions.<\/figcaption><\/figure>\n<h1>Pressure<\/h1>\n<p>Pressure has implications for mineral stability, and therefore the mineral content of metamorphic rocks, but it also determines the texture of metamorphic rocks.<\/p>\n<p>When <strong>directed pressure<\/strong> (or <strong>directed stress<\/strong>) acts on a rock, it means the stress on the rock is greater in one direction than another. In an experiment with cylinders of modeling clay stacked in a block (Figure 10.4, top), pushing down on the clay from above resulted in higher directed pressure in the up-down direction (larger arrows; downward from pushing on the clay, and upward from the force of the table beneath the clay) than in the sideways direction, where only air pressure was acting (small arrows). The clay cylinders became elongated in the direction of least pressure.<\/p>\n<figure id=\"attachment_348\" aria-describedby=\"caption-attachment-348\" style=\"width: 600px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-348\" src=\"https:\/\/opentextbc.ca\/kzlab\/wp-content\/uploads\/sites\/360\/2021\/08\/clay-experiment.png\" alt=\"\" width=\"600\" height=\"483\" srcset=\"https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2021\/08\/clay-experiment.png 720w, https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2021\/08\/clay-experiment-300x242.png 300w, https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2021\/08\/clay-experiment-65x52.png 65w, https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2021\/08\/clay-experiment-225x181.png 225w, https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2021\/08\/clay-experiment-350x282.png 350w\" sizes=\"auto, (max-width: 600px) 100vw, 600px\" \/><figcaption id=\"caption-attachment-348\" class=\"wp-caption-text\"><strong>Figure 10.4<\/strong> Modelling clay experiments showing the effects of pressure on textures. Top: Directed pressure- clay was set on a flat surface and pushed down on from above (large arrows). Cylinders making up the clay block became elongated in the direction of least stress. Bottom: Shear stress applied to the top and bottom of a block of clay caused the interior to stretch. Note white dashed reference circles and elongated ellipses. Source: Karla Panchuk (2018), CC BY 4.0.<\/figcaption><\/figure>\n<p>Rocks undergo <strong>shear stress<\/strong> when forces act parallel to surfaces. In another modelling-clay experiment, applying oppositely directed forces to the top and bottom of a block of clay (Figure 10.4, bottom) caused diagonal stretching within the block. Note the change in shape of the dashed white reference circles.<\/p>\n<p>In both experiments, parts of the clay became elongated in a particular direction. When mineral grains within a rock become aligned like this, it produces a fabric called <strong>foliation<\/strong>. Foliation is described in more detail later in this chapter.<\/p>\n<div class=\"textbox shaded\">\n<p><strong>Dance Break!<\/strong><\/p>\n<div class=\"offline\">\n<p><img loading=\"lazy\" decoding=\"async\" class=\"aligncenter wp-image-1843\" src=\"https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2018\/08\/116-1.png\" alt=\"instructions for the moonwalk\" width=\"895\" height=\"270\" srcset=\"https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2018\/08\/116-1.png 966w, https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2018\/08\/116-1-300x90.png 300w, https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2018\/08\/116-1-768x231.png 768w, https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2018\/08\/116-1-65x20.png 65w, https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2018\/08\/116-1-225x68.png 225w, https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2018\/08\/116-1-350x105.png 350w\" sizes=\"auto, (max-width: 895px) 100vw, 895px\" \/><\/p>\n<div class=\"textbox\"><strong>Image Description:<\/strong> Instructions for the moonwalk. Steps 2 and 4 involve brushing your foot backward on the floor. Steps 1 and 3 involve applying force straight up and down.<\/div>\n<p><strong>Fill in the dance-step numbers to complete these directions.<\/strong><\/p>\n<p>The moonwalk is a dance move that gets its awesome sauce from the contrast between the dancer appearing to be doing a forward walking motion, but actually sliding smoothly backward. Using these simple instructions, you too can moonwalk.<\/p>\n<p>Just be sure to apply only directed pressure to the floor during Step <span style=\"text-decoration: underline;\" aria-label=\"blank\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0<\/span> and Step <span style=\"text-decoration: underline;\" aria-label=\"blank\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0<\/span>.<\/p>\n<p>Apply shear stress to the floor only during Step <span style=\"text-decoration: underline;\" aria-label=\"blank\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0<\/span> and Step <span style=\"text-decoration: underline;\" aria-label=\"blank\">\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a0<\/span> as you drag your foot backward.<br \/>\n<strong><br \/>\nTo check your answers, navigate to the below link to view the interactive version of this activity.<\/strong><\/p>\n<\/div>\n<div id=\"h5p-116\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-116\" class=\"h5p-iframe\" data-content-id=\"116\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Moonwalk example of directed and shear stress\"><\/iframe><\/div>\n<\/div>\n<\/div>\n<h1>Fluids<\/h1>\n<p>Water is the main fluid present within rocks of the crust, and the only one considered here. The presence of water is important for two main reasons. First, water facilitates the transfer of ions between minerals and within minerals, and therefore can speed up metamorphic chemical reactions. Not only can metamorphism happen more rapidly, but processes can be completed that might not otherwise have time to occur.<\/p>\n<p>Secondly, water\u2014especially hot water\u2014can have elevated concentrations of dissolved substances, making it an important medium for moving ions from one place to another within the crust. Processes facilitated by hot water are called <strong>hydrothermal<\/strong> processes (<em>hydro<\/em> refers to water, and <em>thermal<\/em> refers to heat)<em>.<br \/>\n<\/em><\/p>\n<h1>Time<\/h1>\n<p>Most metamorphic reactions are slow. It&#8217;s estimated that when new minerals grow in a rock during metamorphism, they add about 1 mm to the outside of the mineral crystal for every million years. Very slow reaction rates make it hard to study metamorphic processes in a lab.<\/p>\n<p>While the rate of metamorphism is slow, the tectonic processes that lead to metamorphism are also very slow, so there is a good chance that metamorphic reactions will be completed. For example, an important setting for metamorphism is many kilometres deep within the roots of mountain ranges. A mountain range takes tens of millions of years to form, and tens of millions of years more to be eroded to the extent that we can see the rocks that were metamorphosed deep beneath it.<\/p>\n<div class=\"textbox shaded\">\n<p><strong>How Old Is This Rock?<\/strong><\/p>\n<div class=\"offline\">\n<p>The large reddish crystals in this metamorphic rock are garnet, and the surrounding light-coloured rock is dominated by muscovite mica. The largest of the garnets have diameters similar to that of the 23 mm Euro coin.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-1834 aligncenter\" src=\"https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2018\/08\/117-1.jpeg\" alt=\"\" width=\"849\" height=\"637\" srcset=\"https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2018\/08\/117-1.jpeg 1024w, https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2018\/08\/117-1-300x225.jpeg 300w, https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2018\/08\/117-1-768x576.jpeg 768w, https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2018\/08\/117-1-65x49.jpeg 65w, https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2018\/08\/117-1-225x169.jpeg 225w, https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-content\/uploads\/sites\/360\/2018\/08\/117-1-350x263.jpeg 350w\" sizes=\"auto, (max-width: 849px) 100vw, 849px\" \/><\/p>\n<p>Assume that the diameters of the garnets increased at a rate of 1 mm per million years. <strong>How old is this rock?<\/strong><\/p>\n<ul>\n<li>Much less than 23 million years old<\/li>\n<li>About 23 million years old<\/li>\n<li>A lot older than 23 million years<\/li>\n<\/ul>\n<p><strong>To check your answers, navigate to the below link to view the interactive version of this activity.<\/strong><\/p>\n<\/div>\n<div id=\"h5p-117\">\n<div class=\"h5p-iframe-wrapper\"><iframe id=\"h5p-iframe-117\" class=\"h5p-iframe\" data-content-id=\"117\" style=\"height:1px\" src=\"about:blank\" frameBorder=\"0\" scrolling=\"no\" title=\"Crystal growth rate during metamorphism\"><\/iframe><\/div>\n<\/div>\n<\/div>\n","protected":false},"author":123,"menu_order":1,"template":"","meta":{"pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-349","chapter","type-chapter","status-publish","hentry"],"part":346,"_links":{"self":[{"href":"https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-json\/pressbooks\/v2\/chapters\/349","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-json\/wp\/v2\/users\/123"}],"version-history":[{"count":11,"href":"https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-json\/pressbooks\/v2\/chapters\/349\/revisions"}],"predecessor-version":[{"id":1919,"href":"https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-json\/pressbooks\/v2\/chapters\/349\/revisions\/1919"}],"part":[{"href":"https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-json\/pressbooks\/v2\/parts\/346"}],"metadata":[{"href":"https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-json\/pressbooks\/v2\/chapters\/349\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-json\/wp\/v2\/media?parent=349"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-json\/pressbooks\/v2\/chapter-type?post=349"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-json\/wp\/v2\/contributor?post=349"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/opentextbc.ca\/physicalgeologyh5p\/wp-json\/wp\/v2\/license?post=349"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}