{"id":1759,"date":"2016-05-23T18:32:56","date_gmt":"2016-05-23T18:32:56","guid":{"rendered":"https:\/\/courses.lumenlearning.com\/geologyxwaymakerxmaster\/?post_type=chapter&#038;p=1759"},"modified":"2019-09-03T19:29:38","modified_gmt":"2019-09-03T19:29:38","slug":"outcome-weathering-and-erosion","status":"publish","type":"chapter","link":"https:\/\/courses.lumenlearning.com\/colorado-wmopen-geology\/chapter\/outcome-weathering-and-erosion\/","title":{"raw":"Weathering and Erosion","rendered":"Weathering and Erosion"},"content":{"raw":"<h2>Weathering Versus Erosion<\/h2>\r\nWeathering and erosion sort of sound like the same thing, but geologists make a fairly simple distinction.\r\nWith weathering, we are merely speaking of the <em>in situ<\/em> breakdown of rock material <em>without<\/em> transport.\u00a0 In other words, weathering involves rocks breaking apart along fractures but not moving from the site of disaggregation.\u00a0 As you'll find below, we then categorize weathering as either mechanical or chemical (depending on whether or not the rock material changes chemical composition).\r\n\r\nIn the case of erosion, rock material is actually being <em>moved<\/em> from the site of weathering.\u00a0 It can be moved by gravity (fall, roll), or by moving water (probably the most common) or by air (wind).\r\n<div class=\"textbox learning-objectives\">\r\n<h3>What You\u2019ll Learn to Do<\/h3>\r\n<ul>\r\n \t<li>Identify the ways mechanical weathering alters materials on Earth.<\/li>\r\n \t<li>Identify the ways chemical weathering alters materials on Earth.<\/li>\r\n \t<li>Identify several influences on weathering.<\/li>\r\n<\/ul>\r\n<\/div>\r\n<h2>What Is Weathering?<\/h2>\r\nThe footprints that astronauts left on the Moon will be there forever.\r\nWell, unless a big space rock comes and whacks that part of the moon!\r\n<h2><a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/03192003\/untitled4.png\"><img class=\"alignnone size-full wp-image-3469\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/03192003\/untitled4.png\" alt=\"\" width=\"236\" height=\"213\" \/><\/a><\/h2>\r\nThe Moon has no atmosphere and no running water, and as a result, has virtually no weathering.\r\nWeathering on Earth is a primary factor in the modification and destruction of rocks-- and therefore in the generation of most landforms.\r\n<p id=\"x-ck12-MDA1MzZkYmUxOWYxY2JhZmE1ZGFhOGE5ZTE3ZDBjOGQ.-3km\">Weathering is the process that changes solid rock into sediments. With weathering, rocks break into smaller pieces.<\/p>\r\n<p id=\"x-ck12-MDYzY2NkNjE2ODc3Y2VjZWVlYTYwNTNkY2ZkMjE4ZDY.-ymr\">Erosion carries these sediments (smaller pieces) via four primary mechanisms-- water, wind, glaciers, and gravity.<\/p>\r\n\r\n<ul id=\"x-ck12-MzA1ZGU1MDZlZmNiYWMwYWIwYTBlNmUxZGQzNjYzMjc.-4kx\">\r\n \t<li>Water is responsible for most erosion. Water can move most sizes of sediments, depending on the strength of the force.<\/li>\r\n \t<li>Wind moves sand-sized and smaller pieces of rock through the air.<\/li>\r\n \t<li>Glaciers move all sizes of sediments, from extremely large boulders to the tiniest fragments.<\/li>\r\n \t<li>Gravity moves broken pieces of rock, large or small, downslope.<\/li>\r\n<\/ul>\r\n[caption id=\"attachment_413\" align=\"alignright\" width=\"350\"]<img class=\"wp-image-413\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/459\/2015\/05\/21061953\/Fig4_1_1.jpg\" alt=\"A pothole in a street\" width=\"350\" height=\"263\" \/> Figure 1. A once smooth road surface has cracks and fractures, plus a large pothole.[\/caption]\r\n<p id=\"x-ck12-OGE2NzdjOGQ1NTU5N2I3OGZjYjc2OWMxN2E5NWY2YzI.-0lm\">While the forces of plate tectonics can build huge mountains, weathering and erosion gradually tears landscapes away.<\/p>\r\nThe pothole pictured here ruined my tire!\r\nOK, just kidding...\r\nBut this is a case of a human-made rock (asphalt) undergoing weathering and erosion.\u00a0 The asphalt has disaggregated (chemically and perhaps due to freeze\/thaw) and then the material carried away by rain and water during storms.\r\n\r\n&nbsp;\r\n<h2>Mechanical Weathering<\/h2>\r\n<p id=\"x-ck12-ZTQyZGY2M2NjNzdkZDMzNmJiYzllNmVkOTI4ZDM2MWM.-xku\"><strong>Mechanical weathering<\/strong> (also termed physical weathering) breaks rock into smaller pieces. The rock has changed physically without changing its composition. The smaller pieces have the same minerals, in just the same proportions as the original rock.<\/p>\r\n<p id=\"x-ck12-YWFhODZhNDJlYzIwOWJlNmE0ZjQzYTMwOTU2NGE4NmY.-e8s\">Examples of mechanical weathering--<\/p>\r\n<strong>Ice wedging<\/strong> is the main form of mechanical weathering in any climate that regularly cycles above and below the freezing point (figure\u00a02). Ice wedging works quickly<span style=\"float: none;background-color: #ffffff;color: #373d3f;cursor: text;font-family: 'proxima-nova',sans-serif;font-size: 16px;font-style: normal;font-variant: normal;font-weight: 400;letter-spacing: normal;text-align: left;text-decoration: none;text-indent: 0px\"> in both polar regions and mid-latitudes, and of course also in mountainous locations.<\/span>\r\n\r\n[caption id=\"attachment_415\" align=\"aligncenter\" width=\"800\"]<img class=\"wp-image-415 size-full\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/459\/2015\/05\/21061955\/Fig4_1_2.jpg\" alt=\"Water seeps into cracks and fractures in rock. When the water freezes, it expands about 9% in volume, which wedges apart the rock. With repeated freeze\/thaw cycles, rock breaks into pieces.\" width=\"800\" height=\"250\" \/> Figure 2. Ice wedging.[\/caption]\r\n\r\n&nbsp;\r\n\r\n<a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/29222735\/p.jpg\"><img class=\"alignnone size-medium wp-image-3450\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/29222735\/p-300x211.jpg\" alt=\"\" width=\"300\" height=\"211\" \/><\/a>\r\n\r\n<a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/29222735\/p.jpg\">Above we see the north portion of Half Dome in Yosemite Valley, CA.\u00a0 This is where the cable-route allows a relatively simple ascent of the peak.\u00a0 From a distance, the rock formation looks a bit like a poorly-cut onion, with layers peeling off all over it!\u00a0 The onion skin peeling is termed \"exfoliation\"-- it is a form of mechanical weathering, largely caused by the release of pressure within the rock.\u00a0 This igneous rock formed deep under the earth, but over millions of years, uplift and erosion have removed the immense pressures associated with overlying rock.\u00a0 Half Dome expands a bit and generates exfoliation!<\/a>\r\n\r\n<strong>Abrasion<\/strong> is another form of mechanical weathering. In abrasion, particles (of any size) bump against each other.\r\n\r\n[caption id=\"attachment_416\" align=\"alignright\" width=\"350\"]<img class=\"wp-image-416\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/459\/2015\/05\/21061956\/Fig4_1_3.jpg\" alt=\"A beach covered with smooth pebbles\" width=\"350\" height=\"233\" \/> Figure 3. Rocks on a beach are worn down by abrasion as passing waves cause them to strike each other.[\/caption]\r\n<ul id=\"x-ck12-Nzg0NTRhMWY0ZGNkNTRmNWFlZThkYjE2NTZkMDhiODY.-gbh\">\r\n \t<li>Gravity causes abrasion as rock material moves down-hill.<\/li>\r\n \t<li>Moving water causes abrasion as particles in the water collide.<\/li>\r\n<\/ul>\r\n<p id=\"x-ck12-YzExNWQ0YzkxNmYyNjE5NTdlMGQ1MjNmNDk1YzM0ODg.-u1r\">Abrasion makes rocks with sharp or jagged edges smooth and round, e.g. beach glass or cobbles in a stream.<\/p>\r\n&nbsp;\r\n<p id=\"x-ck12-NjJjMjYwNGFhNjcyOTlhMDc3YjJkMzQyMjU5YjE4Mjk.-doi\">\u00a0Plants and animals can also generate\u00a0 mechanical weathering-- roots expanding into rock fissures or animals burrowing into soil and rock.<\/p>\r\nWe are about to consider CHEMICAL WEATHERING-- whereby rocks undergo modification and breakdown associated with chemical changes\/reactions.\u00a0 Interestingly, mechanical weathering increases the rate of chemical weathering. As rock breaks into smaller pieces, the surface area of the pieces increases figure 5. With more surfaces exposed, there are more surfaces on which chemical reactions can occur.\r\n\r\n[caption id=\"attachment_421\" align=\"aligncenter\" width=\"500\"]<img class=\"wp-image-421 size-full\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/459\/2015\/05\/21061959\/Fig4_1_5.jpg\" alt=\"A rock breaks into smaller pieces, overall surface increases, much like a single cube would gain surface area if it were split into several smaller cubes.\" width=\"500\" height=\"163\" \/> Figure 5. Mechanical weathering may increase the rate of chemical weathering.[\/caption]\r\n<h2>Chemical Weathering<\/h2>\r\n<strong>Chemical weathering<\/strong> is different from mechanical weathering because the rock actually changes chemical composition via reaction with things like water, acid rain, and air itself.\r\nMineral changes take place.\r\n\r\n[caption id=\"attachment_422\" align=\"alignright\" width=\"400\"]<img class=\"wp-image-422\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/459\/2015\/05\/21062000\/Fig4_1_6.jpg\" alt=\"A forest packed with trees next to a barren patch of soil\" width=\"400\" height=\"266\" \/> Figure 6. Deforestation in Brazil reveals the underlying clay-rich soil.[\/caption]\r\n\r\nSome minerals are particularly unstable under surface conditions-- those are typically minerals that initially form at high pressure or high temperatures deep in the earth. \u00a0 Examples include olivine and pyroxene.\r\n\r\nWhen these rocks reach the Earth\u2019s surface, they are now at very low temperatures and pressures. This is a very different environment from the one in which they formed and the minerals are no longer stable.\r\n\r\nChemical weathering changes minerals that were stable inside the earth to ones that are\u00a0 stable at Earth\u2019s surface. \u00a0 For example, clay minerals are stable at the surface and chemical weathering converts many minerals to clay (figure\u00a06).\r\n<h3>Chemical Weathering by Water<\/h3>\r\nA water molecule has a very simple chemical formula, H<sub>2<\/sub>O, two hydrogen atoms bonded to one oxygen atom. But water is pretty remarkable in terms of all the things it can do. Remember from the Earth's Minerals chapter that water is a polar molecule. The positive side of the molecule attracts negative ions and the negative side attracts positive ions. So water molecules separate the ions from their compounds and surround them. Water can completely dissolve some minerals, such as salt. Follow this link to check\u00a0out this <a href=\"http:\/\/www.northland.cc.mn.us\/biology\/Biology1111\/animations\/dissolve.html\" target=\"_blank\" rel=\"noopener\">animation of how water dissolves salt<\/a>.\r\n\r\n<strong>Hydrolysis<\/strong> is the name of the chemical reaction between a chemical compound and water. When this reaction takes place, water dissolves ions from the mineral and carries them away. These elements have undergone <strong>leaching<\/strong>. Through hydrolysis, a mineral such as potassium feldspar is leached of potassium and changed into a clay mineral. Clay minerals are more stable at the Earth\u2019s surface.\r\n\r\n<span style=\"background-color: #bfe6ff;color: #b00000\"><a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/03192609\/b3.jpg\"><img class=\"wp-image-3470 alignleft\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/03192609\/b3-219x300.jpg\" alt=\"\" width=\"191\" height=\"262\" \/><\/a><\/span>\r\n\r\nhttp:\/\/geologylearn.blogspot.com\/2015\/10\/types-of-weathering.html\r\n\r\nHighly altered granite, shown in this image=&gt; called \"grus\"\r\n\r\nIt's great example of chemical weathering-- feldspar and micaceous minerals (e.g. biotite) have altered to clay, and increased in volume, and therefore broken the rock apart!\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n<article id=\"article_1-0\" class=\"comp article chopped-article\" role=\"article\">\r\n<div id=\"list-sc_1-0\" class=\"comp article-content list article-content--text-link-test list-sc mntl-block\">\r\n<div id=\"list-sc-item_1-0-6\" class=\"comp mntl-sc-list-item list-sc-item mntl-block\">\r\n<figure id=\"mntl-sc-block_2-0-30\" class=\"comp mntl-sc-block mntl-sc-block-image figure-square figure-low-res\">\r\n<div class=\"figure-media\">\r\n<div class=\"img-placeholder\"><\/div>\r\n<\/div><\/figure>\r\n<\/div>\r\n<\/div>\r\n<\/article>\r\n\r\n[caption id=\"attachment_423\" align=\"alignright\" width=\"300\"]<img class=\"wp-image-423\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/459\/2015\/05\/21062001\/Fig4_1_7.jpg\" alt=\"A state with a deformed face\" width=\"300\" height=\"200\" \/> Figure 7. This statue has been damaged by acid rain.[\/caption]\r\n<h3><\/h3>\r\n<h3><\/h3>\r\n<h3>Chemical Weathering by Acid Rain<\/h3>\r\nCarbon dioxide (CO<sub>2<\/sub>) combines with water as raindrops fall through the atmosphere. This makes a weak acid, called carbonic acid. Carbonic acid is a very common in nature where it works to dissolve rock.\r\n\r\nPollutants, such as sulfur and nitrogen, from fossil fuel burning, create sulfuric and nitric acid. Sulfuric and nitric acids are the two main components of acid rain, which accelerate chemical weathering (figure\u00a07). Acid rain is discussed in the Human Actions and the Atmosphere chapter.\r\n\r\n<a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/29223657\/dd.jpg\"><img class=\"alignnone size-medium wp-image-3451\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/29223657\/dd-203x300.jpg\" alt=\"\" width=\"203\" height=\"300\" \/><\/a>\r\n\r\nThe climbers here (Joshua Tree National Park, CA) are in a sort of pocket, or cave region, on a granite face.\u00a0 The cave is characteristic of self-accentuating weathering and erosion.\u00a0 Once an overhang develops, more water tends to accumulate, and this water creates chemical weathering\r\n\r\n&nbsp;\r\n<h3>Chemical Weathering by Oxygen<\/h3>\r\n[caption id=\"attachment_424\" align=\"alignright\" width=\"300\"]<img class=\"wp-image-424\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/459\/2015\/05\/21062003\/Fig4_1_8.jpg\" alt=\"Rust\" width=\"300\" height=\"304\" \/> Figure 8. When iron rich minerals oxidize, they produce the familiar red color found in rust.[\/caption]\r\n\r\n<strong>Oxidation<\/strong> is a chemical reaction that takes place when oxygen reacts with another element. Oxygen is very strongly chemically reactive. The most familiar type of oxidation is when iron reacts with oxygen to create rust (figure\u00a08). Minerals that are rich in iron break down as the iron oxidizes and forms new compounds. Iron oxide produces the red color in soils.\r\n\r\n&nbsp;\r\n\r\n&nbsp;\r\n\r\n<a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2015\/04\/20143140\/Weathering_9039.jpg\"><img class=\"alignnone size-medium wp-image-3415\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2015\/04\/20143140\/Weathering_9039-300x200.jpg\" alt=\"\" width=\"300\" height=\"200\" \/><\/a>\r\n<h6>A freshly broken rock shows differential chemical weathering (probably mostly oxidation) progressing inward. This piece of sandstone was found in glacial drift near Angelica, New York<\/h6>\r\nSource: english wikipedia, original upload 17 July 2005 by <a class=\"extiw\" title=\"en:User:Pollinator\" href=\"https:\/\/en.wikipedia.org\/wiki\/User:Pollinator\">en:User:Pollinator<\/a>\r\n<h2>Influences on Weathering<\/h2>\r\n<p id=\"x-ck12-MDZhZmZlOGQ3ZWQwZmYwOGY0NmUzYTg2NzhkYjk0Zjc.-gbc\">Weathering rates depend on several factors. These include the composition of the rock and the minerals it contains as well as the climate of a region.<\/p>\r\n\r\n<h3 id=\"x-ck12-Um9jayBhbmQgTWluZXJhbCBUeXBl\">Rock and Mineral Type<\/h3>\r\n<p id=\"x-ck12-M2Q0ZDJiMjk3ZTRiNjE1NTZjZGNhOWI2MmNkMDg1MGI.-nat\">Different rock types weather at different rates. Certain types of rock are very resistant to weathering. Igneous rocks, especially intrusive igneous rocks such as granite, weather slowly because it is hard for water to penetrate them. Other types of rock, such as limestone, are easily weathered because they dissolve in weak acids.<\/p>\r\n&nbsp;\r\n\r\n<a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/26211410\/Picture1.jpg\"><img class=\"alignnone wp-image-3424\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/26211410\/Picture1-210x300.jpg\" alt=\"\" width=\"275\" height=\"393\" \/><\/a><a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/26211913\/Picture2.jpg\"><img class=\" wp-image-3425 alignright\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/26211913\/Picture2-236x300.jpg\" alt=\"\" width=\"289\" height=\"367\" \/><\/a>\r\n\r\n&nbsp;\r\n<p id=\"x-ck12-YmVhNDdkYjBiOGYzZGFjNzk5YjY4NmQzZDdkNGM1MmI.-es5\">Different minerals also weather at different rates. Some minerals in a rock might completely dissolve in water but the more resistant minerals remain. In this case, the rock\u2019s surface becomes pitted and rough. When a less resistant mineral dissolves, more resistant mineral grains are released from the rock.<\/p>\r\n\r\n<h3 id=\"x-ck12-Q2xpbWF0ZQ..\">Climate<\/h3>\r\n<p id=\"x-ck12-YjY1MzkyMjMyMDkxNWEyNzUwOTFmMzU4NGU5MzVlMDc.-uec\">A region\u2019s <strong>climate<\/strong> strongly influences weathering.<\/p>\r\nChemical weathering increases as:\r\n<ul id=\"x-ck12-YWM1M2E3YjAzNmMzNDk0MmI4N2Y0NDA4MWYzMTBjMTA.-fvv\">\r\n \t<li>Temperature increases: Chemical reactions proceed more rapidly at higher temperatures. For each 10<sup>o<\/sup>C increase in average temperature, the rate of chemical reactions doubles.<\/li>\r\n \t<li>Precipitation increases: More water allows more chemical reactions. Since water participates in both mechanical and chemical weathering, more water strongly increases weathering.<\/li>\r\n<\/ul>\r\n[caption id=\"attachment_429\" align=\"alignright\" width=\"350\"]<img class=\"wp-image-429\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/459\/2015\/05\/21062006\/Fig4_1_10.jpg\" alt=\"A mossy forest\" width=\"350\" height=\"234\" \/> Figure 10. Wet, warm tropical areas have the most weathering.[\/caption]\r\n<p id=\"x-ck12-YTcxNjBlOGU5OWU3ZmRlNGM1ZWU0NzU2YzdkNjkxNDc.-dow\">So how do different climates influence weathering? A cold, dry climate will produce the lowest rate of weathering. A warm, wet climate will produce the highest rate of weathering. Warm wet climates also enhance vegetation growth, which can in turn increase weathering rates.<\/p>\r\n<p id=\"x-ck12-ZGU5MmJlNDdiMTE3MzFlNzJjNmE1Njk4ODc2NWEyNDM.-5nb\">\u00a0In tropical climates, intense chemical weathering carries away all soluble minerals, leaving behind just the least soluble components. The aluminum oxide, bauxite, forms this way and is our main source of aluminum ore.<\/p>","rendered":"<h2>Weathering Versus Erosion<\/h2>\n<p>Weathering and erosion sort of sound like the same thing, but geologists make a fairly simple distinction.<br \/>\nWith weathering, we are merely speaking of the <em>in situ<\/em> breakdown of rock material <em>without<\/em> transport.\u00a0 In other words, weathering involves rocks breaking apart along fractures but not moving from the site of disaggregation.\u00a0 As you&#8217;ll find below, we then categorize weathering as either mechanical or chemical (depending on whether or not the rock material changes chemical composition).<\/p>\n<p>In the case of erosion, rock material is actually being <em>moved<\/em> from the site of weathering.\u00a0 It can be moved by gravity (fall, roll), or by moving water (probably the most common) or by air (wind).<\/p>\n<div class=\"textbox learning-objectives\">\n<h3>What You\u2019ll Learn to Do<\/h3>\n<ul>\n<li>Identify the ways mechanical weathering alters materials on Earth.<\/li>\n<li>Identify the ways chemical weathering alters materials on Earth.<\/li>\n<li>Identify several influences on weathering.<\/li>\n<\/ul>\n<\/div>\n<h2>What Is Weathering?<\/h2>\n<p>The footprints that astronauts left on the Moon will be there forever.<br \/>\nWell, unless a big space rock comes and whacks that part of the moon!<\/p>\n<h2><a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/03192003\/untitled4.png\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-full wp-image-3469\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/03192003\/untitled4.png\" alt=\"\" width=\"236\" height=\"213\" \/><\/a><\/h2>\n<p>The Moon has no atmosphere and no running water, and as a result, has virtually no weathering.<br \/>\nWeathering on Earth is a primary factor in the modification and destruction of rocks&#8211; and therefore in the generation of most landforms.<\/p>\n<p id=\"x-ck12-MDA1MzZkYmUxOWYxY2JhZmE1ZGFhOGE5ZTE3ZDBjOGQ.-3km\">Weathering is the process that changes solid rock into sediments. With weathering, rocks break into smaller pieces.<\/p>\n<p id=\"x-ck12-MDYzY2NkNjE2ODc3Y2VjZWVlYTYwNTNkY2ZkMjE4ZDY.-ymr\">Erosion carries these sediments (smaller pieces) via four primary mechanisms&#8211; water, wind, glaciers, and gravity.<\/p>\n<ul id=\"x-ck12-MzA1ZGU1MDZlZmNiYWMwYWIwYTBlNmUxZGQzNjYzMjc.-4kx\">\n<li>Water is responsible for most erosion. Water can move most sizes of sediments, depending on the strength of the force.<\/li>\n<li>Wind moves sand-sized and smaller pieces of rock through the air.<\/li>\n<li>Glaciers move all sizes of sediments, from extremely large boulders to the tiniest fragments.<\/li>\n<li>Gravity moves broken pieces of rock, large or small, downslope.<\/li>\n<\/ul>\n<div id=\"attachment_413\" style=\"width: 360px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-413\" class=\"wp-image-413\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/459\/2015\/05\/21061953\/Fig4_1_1.jpg\" alt=\"A pothole in a street\" width=\"350\" height=\"263\" \/><\/p>\n<p id=\"caption-attachment-413\" class=\"wp-caption-text\">Figure 1. A once smooth road surface has cracks and fractures, plus a large pothole.<\/p>\n<\/div>\n<p id=\"x-ck12-OGE2NzdjOGQ1NTU5N2I3OGZjYjc2OWMxN2E5NWY2YzI.-0lm\">While the forces of plate tectonics can build huge mountains, weathering and erosion gradually tears landscapes away.<\/p>\n<p>The pothole pictured here ruined my tire!<br \/>\nOK, just kidding&#8230;<br \/>\nBut this is a case of a human-made rock (asphalt) undergoing weathering and erosion.\u00a0 The asphalt has disaggregated (chemically and perhaps due to freeze\/thaw) and then the material carried away by rain and water during storms.<\/p>\n<p>&nbsp;<\/p>\n<h2>Mechanical Weathering<\/h2>\n<p id=\"x-ck12-ZTQyZGY2M2NjNzdkZDMzNmJiYzllNmVkOTI4ZDM2MWM.-xku\"><strong>Mechanical weathering<\/strong> (also termed physical weathering) breaks rock into smaller pieces. The rock has changed physically without changing its composition. The smaller pieces have the same minerals, in just the same proportions as the original rock.<\/p>\n<p id=\"x-ck12-YWFhODZhNDJlYzIwOWJlNmE0ZjQzYTMwOTU2NGE4NmY.-e8s\">Examples of mechanical weathering&#8211;<\/p>\n<p><strong>Ice wedging<\/strong> is the main form of mechanical weathering in any climate that regularly cycles above and below the freezing point (figure\u00a02). Ice wedging works quickly<span style=\"float: none;background-color: #ffffff;color: #373d3f;cursor: text;font-family: 'proxima-nova',sans-serif;font-size: 16px;font-style: normal;font-variant: normal;font-weight: 400;letter-spacing: normal;text-align: left;text-decoration: none;text-indent: 0px\"> in both polar regions and mid-latitudes, and of course also in mountainous locations.<\/span><\/p>\n<div id=\"attachment_415\" style=\"width: 810px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-415\" class=\"wp-image-415 size-full\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/459\/2015\/05\/21061955\/Fig4_1_2.jpg\" alt=\"Water seeps into cracks and fractures in rock. When the water freezes, it expands about 9% in volume, which wedges apart the rock. With repeated freeze\/thaw cycles, rock breaks into pieces.\" width=\"800\" height=\"250\" \/><\/p>\n<p id=\"caption-attachment-415\" class=\"wp-caption-text\">Figure 2. Ice wedging.<\/p>\n<\/div>\n<p>&nbsp;<\/p>\n<p><a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/29222735\/p.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-medium wp-image-3450\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/29222735\/p-300x211.jpg\" alt=\"\" width=\"300\" height=\"211\" \/><\/a><\/p>\n<p><a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/29222735\/p.jpg\">Above we see the north portion of Half Dome in Yosemite Valley, CA.\u00a0 This is where the cable-route allows a relatively simple ascent of the peak.\u00a0 From a distance, the rock formation looks a bit like a poorly-cut onion, with layers peeling off all over it!\u00a0 The onion skin peeling is termed &#8220;exfoliation&#8221;&#8211; it is a form of mechanical weathering, largely caused by the release of pressure within the rock.\u00a0 This igneous rock formed deep under the earth, but over millions of years, uplift and erosion have removed the immense pressures associated with overlying rock.\u00a0 Half Dome expands a bit and generates exfoliation!<\/a><\/p>\n<p><strong>Abrasion<\/strong> is another form of mechanical weathering. In abrasion, particles (of any size) bump against each other.<\/p>\n<div id=\"attachment_416\" style=\"width: 360px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-416\" class=\"wp-image-416\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/459\/2015\/05\/21061956\/Fig4_1_3.jpg\" alt=\"A beach covered with smooth pebbles\" width=\"350\" height=\"233\" \/><\/p>\n<p id=\"caption-attachment-416\" class=\"wp-caption-text\">Figure 3. Rocks on a beach are worn down by abrasion as passing waves cause them to strike each other.<\/p>\n<\/div>\n<ul id=\"x-ck12-Nzg0NTRhMWY0ZGNkNTRmNWFlZThkYjE2NTZkMDhiODY.-gbh\">\n<li>Gravity causes abrasion as rock material moves down-hill.<\/li>\n<li>Moving water causes abrasion as particles in the water collide.<\/li>\n<\/ul>\n<p id=\"x-ck12-YzExNWQ0YzkxNmYyNjE5NTdlMGQ1MjNmNDk1YzM0ODg.-u1r\">Abrasion makes rocks with sharp or jagged edges smooth and round, e.g. beach glass or cobbles in a stream.<\/p>\n<p>&nbsp;<\/p>\n<p id=\"x-ck12-NjJjMjYwNGFhNjcyOTlhMDc3YjJkMzQyMjU5YjE4Mjk.-doi\">\u00a0Plants and animals can also generate\u00a0 mechanical weathering&#8211; roots expanding into rock fissures or animals burrowing into soil and rock.<\/p>\n<p>We are about to consider CHEMICAL WEATHERING&#8211; whereby rocks undergo modification and breakdown associated with chemical changes\/reactions.\u00a0 Interestingly, mechanical weathering increases the rate of chemical weathering. As rock breaks into smaller pieces, the surface area of the pieces increases figure 5. With more surfaces exposed, there are more surfaces on which chemical reactions can occur.<\/p>\n<div id=\"attachment_421\" style=\"width: 510px\" class=\"wp-caption aligncenter\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-421\" class=\"wp-image-421 size-full\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/459\/2015\/05\/21061959\/Fig4_1_5.jpg\" alt=\"A rock breaks into smaller pieces, overall surface increases, much like a single cube would gain surface area if it were split into several smaller cubes.\" width=\"500\" height=\"163\" \/><\/p>\n<p id=\"caption-attachment-421\" class=\"wp-caption-text\">Figure 5. Mechanical weathering may increase the rate of chemical weathering.<\/p>\n<\/div>\n<h2>Chemical Weathering<\/h2>\n<p><strong>Chemical weathering<\/strong> is different from mechanical weathering because the rock actually changes chemical composition via reaction with things like water, acid rain, and air itself.<br \/>\nMineral changes take place.<\/p>\n<div id=\"attachment_422\" style=\"width: 410px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-422\" class=\"wp-image-422\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/459\/2015\/05\/21062000\/Fig4_1_6.jpg\" alt=\"A forest packed with trees next to a barren patch of soil\" width=\"400\" height=\"266\" \/><\/p>\n<p id=\"caption-attachment-422\" class=\"wp-caption-text\">Figure 6. Deforestation in Brazil reveals the underlying clay-rich soil.<\/p>\n<\/div>\n<p>Some minerals are particularly unstable under surface conditions&#8211; those are typically minerals that initially form at high pressure or high temperatures deep in the earth. \u00a0 Examples include olivine and pyroxene.<\/p>\n<p>When these rocks reach the Earth\u2019s surface, they are now at very low temperatures and pressures. This is a very different environment from the one in which they formed and the minerals are no longer stable.<\/p>\n<p>Chemical weathering changes minerals that were stable inside the earth to ones that are\u00a0 stable at Earth\u2019s surface. \u00a0 For example, clay minerals are stable at the surface and chemical weathering converts many minerals to clay (figure\u00a06).<\/p>\n<h3>Chemical Weathering by Water<\/h3>\n<p>A water molecule has a very simple chemical formula, H<sub>2<\/sub>O, two hydrogen atoms bonded to one oxygen atom. But water is pretty remarkable in terms of all the things it can do. Remember from the Earth&#8217;s Minerals chapter that water is a polar molecule. The positive side of the molecule attracts negative ions and the negative side attracts positive ions. So water molecules separate the ions from their compounds and surround them. Water can completely dissolve some minerals, such as salt. Follow this link to check\u00a0out this <a href=\"http:\/\/www.northland.cc.mn.us\/biology\/Biology1111\/animations\/dissolve.html\" target=\"_blank\" rel=\"noopener\">animation of how water dissolves salt<\/a>.<\/p>\n<p><strong>Hydrolysis<\/strong> is the name of the chemical reaction between a chemical compound and water. When this reaction takes place, water dissolves ions from the mineral and carries them away. These elements have undergone <strong>leaching<\/strong>. Through hydrolysis, a mineral such as potassium feldspar is leached of potassium and changed into a clay mineral. Clay minerals are more stable at the Earth\u2019s surface.<\/p>\n<p><span style=\"background-color: #bfe6ff;color: #b00000\"><a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/03192609\/b3.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-3470 alignleft\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/03192609\/b3-219x300.jpg\" alt=\"\" width=\"191\" height=\"262\" \/><\/a><\/span><\/p>\n<p>http:\/\/geologylearn.blogspot.com\/2015\/10\/types-of-weathering.html<\/p>\n<p>Highly altered granite, shown in this image=&gt; called &#8220;grus&#8221;<\/p>\n<p>It&#8217;s great example of chemical weathering&#8211; feldspar and micaceous minerals (e.g. biotite) have altered to clay, and increased in volume, and therefore broken the rock apart!<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<article id=\"article_1-0\" class=\"comp article chopped-article\" role=\"article\">\n<div id=\"list-sc_1-0\" class=\"comp article-content list article-content--text-link-test list-sc mntl-block\">\n<div id=\"list-sc-item_1-0-6\" class=\"comp mntl-sc-list-item list-sc-item mntl-block\">\n<figure id=\"mntl-sc-block_2-0-30\" class=\"comp mntl-sc-block mntl-sc-block-image figure-square figure-low-res\">\n<div class=\"figure-media\">\n<div class=\"img-placeholder\"><\/div>\n<\/div>\n<\/figure>\n<\/div>\n<\/div>\n<\/article>\n<div id=\"attachment_423\" style=\"width: 310px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-423\" class=\"wp-image-423\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/459\/2015\/05\/21062001\/Fig4_1_7.jpg\" alt=\"A state with a deformed face\" width=\"300\" height=\"200\" \/><\/p>\n<p id=\"caption-attachment-423\" class=\"wp-caption-text\">Figure 7. This statue has been damaged by acid rain.<\/p>\n<\/div>\n<h3><\/h3>\n<h3><\/h3>\n<h3>Chemical Weathering by Acid Rain<\/h3>\n<p>Carbon dioxide (CO<sub>2<\/sub>) combines with water as raindrops fall through the atmosphere. This makes a weak acid, called carbonic acid. Carbonic acid is a very common in nature where it works to dissolve rock.<\/p>\n<p>Pollutants, such as sulfur and nitrogen, from fossil fuel burning, create sulfuric and nitric acid. Sulfuric and nitric acids are the two main components of acid rain, which accelerate chemical weathering (figure\u00a07). Acid rain is discussed in the Human Actions and the Atmosphere chapter.<\/p>\n<p><a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/29223657\/dd.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-medium wp-image-3451\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/29223657\/dd-203x300.jpg\" alt=\"\" width=\"203\" height=\"300\" \/><\/a><\/p>\n<p>The climbers here (Joshua Tree National Park, CA) are in a sort of pocket, or cave region, on a granite face.\u00a0 The cave is characteristic of self-accentuating weathering and erosion.\u00a0 Once an overhang develops, more water tends to accumulate, and this water creates chemical weathering<\/p>\n<p>&nbsp;<\/p>\n<h3>Chemical Weathering by Oxygen<\/h3>\n<div id=\"attachment_424\" style=\"width: 310px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-424\" class=\"wp-image-424\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/459\/2015\/05\/21062003\/Fig4_1_8.jpg\" alt=\"Rust\" width=\"300\" height=\"304\" \/><\/p>\n<p id=\"caption-attachment-424\" class=\"wp-caption-text\">Figure 8. When iron rich minerals oxidize, they produce the familiar red color found in rust.<\/p>\n<\/div>\n<p><strong>Oxidation<\/strong> is a chemical reaction that takes place when oxygen reacts with another element. Oxygen is very strongly chemically reactive. The most familiar type of oxidation is when iron reacts with oxygen to create rust (figure\u00a08). Minerals that are rich in iron break down as the iron oxidizes and forms new compounds. Iron oxide produces the red color in soils.<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p><a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2015\/04\/20143140\/Weathering_9039.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone size-medium wp-image-3415\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2015\/04\/20143140\/Weathering_9039-300x200.jpg\" alt=\"\" width=\"300\" height=\"200\" \/><\/a><\/p>\n<h6>A freshly broken rock shows differential chemical weathering (probably mostly oxidation) progressing inward. This piece of sandstone was found in glacial drift near Angelica, New York<\/h6>\n<p>Source: english wikipedia, original upload 17 July 2005 by <a class=\"extiw\" title=\"en:User:Pollinator\" href=\"https:\/\/en.wikipedia.org\/wiki\/User:Pollinator\">en:User:Pollinator<\/a><\/p>\n<h2>Influences on Weathering<\/h2>\n<p id=\"x-ck12-MDZhZmZlOGQ3ZWQwZmYwOGY0NmUzYTg2NzhkYjk0Zjc.-gbc\">Weathering rates depend on several factors. These include the composition of the rock and the minerals it contains as well as the climate of a region.<\/p>\n<h3 id=\"x-ck12-Um9jayBhbmQgTWluZXJhbCBUeXBl\">Rock and Mineral Type<\/h3>\n<p id=\"x-ck12-M2Q0ZDJiMjk3ZTRiNjE1NTZjZGNhOWI2MmNkMDg1MGI.-nat\">Different rock types weather at different rates. Certain types of rock are very resistant to weathering. Igneous rocks, especially intrusive igneous rocks such as granite, weather slowly because it is hard for water to penetrate them. Other types of rock, such as limestone, are easily weathered because they dissolve in weak acids.<\/p>\n<p>&nbsp;<\/p>\n<p><a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/26211410\/Picture1.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"alignnone wp-image-3424\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/26211410\/Picture1-210x300.jpg\" alt=\"\" width=\"275\" height=\"393\" \/><\/a><a href=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/26211913\/Picture2.jpg\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-3425 alignright\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images\/wp-content\/uploads\/sites\/2666\/2016\/05\/26211913\/Picture2-236x300.jpg\" alt=\"\" width=\"289\" height=\"367\" \/><\/a><\/p>\n<p>&nbsp;<\/p>\n<p id=\"x-ck12-YmVhNDdkYjBiOGYzZGFjNzk5YjY4NmQzZDdkNGM1MmI.-es5\">Different minerals also weather at different rates. Some minerals in a rock might completely dissolve in water but the more resistant minerals remain. In this case, the rock\u2019s surface becomes pitted and rough. When a less resistant mineral dissolves, more resistant mineral grains are released from the rock.<\/p>\n<h3 id=\"x-ck12-Q2xpbWF0ZQ..\">Climate<\/h3>\n<p id=\"x-ck12-YjY1MzkyMjMyMDkxNWEyNzUwOTFmMzU4NGU5MzVlMDc.-uec\">A region\u2019s <strong>climate<\/strong> strongly influences weathering.<\/p>\n<p>Chemical weathering increases as:<\/p>\n<ul id=\"x-ck12-YWM1M2E3YjAzNmMzNDk0MmI4N2Y0NDA4MWYzMTBjMTA.-fvv\">\n<li>Temperature increases: Chemical reactions proceed more rapidly at higher temperatures. For each 10<sup>o<\/sup>C increase in average temperature, the rate of chemical reactions doubles.<\/li>\n<li>Precipitation increases: More water allows more chemical reactions. Since water participates in both mechanical and chemical weathering, more water strongly increases weathering.<\/li>\n<\/ul>\n<div id=\"attachment_429\" style=\"width: 360px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-429\" class=\"wp-image-429\" src=\"https:\/\/s3-us-west-2.amazonaws.com\/courses-images-archive-read-only\/wp-content\/uploads\/sites\/459\/2015\/05\/21062006\/Fig4_1_10.jpg\" alt=\"A mossy forest\" width=\"350\" height=\"234\" \/><\/p>\n<p id=\"caption-attachment-429\" class=\"wp-caption-text\">Figure 10. Wet, warm tropical areas have the most weathering.<\/p>\n<\/div>\n<p id=\"x-ck12-YTcxNjBlOGU5OWU3ZmRlNGM1ZWU0NzU2YzdkNjkxNDc.-dow\">So how do different climates influence weathering? A cold, dry climate will produce the lowest rate of weathering. A warm, wet climate will produce the highest rate of weathering. Warm wet climates also enhance vegetation growth, which can in turn increase weathering rates.<\/p>\n<p id=\"x-ck12-ZGU5MmJlNDdiMTE3MzFlNzJjNmE1Njk4ODc2NWEyNDM.-5nb\">\u00a0In tropical climates, intense chemical weathering carries away all soluble minerals, leaving behind just the least soluble components. The aluminum oxide, bauxite, forms this way and is our main source of aluminum ore.<\/p>\n\n\t\t\t <section class=\"citations-section\" role=\"contentinfo\">\n\t\t\t <h3>Candela Citations<\/h3>\n\t\t\t\t\t <div>\n\t\t\t\t\t\t <div id=\"citation-list-1759\">\n\t\t\t\t\t\t\t <div class=\"licensing\"><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Original<\/div><ul class=\"citation-list\"><li>Introduction to Weathering and Erosion. <strong>Authored by<\/strong>: Kimberly Schulte and Lumen Learning. <strong>Provided by<\/strong>: Lumen Learning. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by\/4.0\/\">CC BY: Attribution<\/a><\/em><\/li><\/ul><div class=\"license-attribution-dropdown-subheading\">CC licensed content, Shared previously<\/div><ul class=\"citation-list\"><li>9.1: Weathering. <strong>Provided by<\/strong>: CK-12. <strong>Located at<\/strong>: <a target=\"_blank\" href=\"http:\/\/www.ck12.org\/book\/CK-12-Earth-Science-For-High-School\/section\/9.1\/\">http:\/\/www.ck12.org\/book\/CK-12-Earth-Science-For-High-School\/section\/9.1\/<\/a>. <strong>License<\/strong>: <em><a target=\"_blank\" rel=\"license\" href=\"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0\/\">CC BY-NC: Attribution-NonCommercial<\/a><\/em><\/li><\/ul><\/div>\n\t\t\t\t\t\t <\/div>\n\t\t\t\t\t <\/div>\n\t\t\t <\/section>","protected":false},"author":17,"menu_order":2,"template":"","meta":{"_candela_citation":"[{\"type\":\"original\",\"description\":\"Introduction to Weathering and Erosion\",\"author\":\"Kimberly Schulte and Lumen Learning\",\"organization\":\"Lumen Learning\",\"url\":\"\",\"project\":\"\",\"license\":\"cc-by\",\"license_terms\":\"\"},{\"type\":\"cc\",\"description\":\"9.1: Weathering\",\"author\":\"\",\"organization\":\"CK-12\",\"url\":\"http:\/\/www.ck12.org\/book\/CK-12-Earth-Science-For-High-School\/section\/9.1\/\",\"project\":\"\",\"license\":\"cc-by-nc\",\"license_terms\":\"\"}]","CANDELA_OUTCOMES_GUID":"8ba6171b-85b4-4f71-bb49-fb10b786a110, 9febb2ee-3794-4074-974c-a988d5487f64, 20d6c766-28ba-46fb-a5f7-f75815b1a9a1, 05711b68-ac77-481a-8e79-01f0bccaa58d","pb_show_title":"on","pb_short_title":"","pb_subtitle":"","pb_authors":[],"pb_section_license":""},"chapter-type":[],"contributor":[],"license":[],"class_list":["post-1759","chapter","type-chapter","status-publish","hentry"],"part":25,"_links":{"self":[{"href":"https:\/\/courses.lumenlearning.com\/colorado-wmopen-geology\/wp-json\/pressbooks\/v2\/chapters\/1759","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/courses.lumenlearning.com\/colorado-wmopen-geology\/wp-json\/pressbooks\/v2\/chapters"}],"about":[{"href":"https:\/\/courses.lumenlearning.com\/colorado-wmopen-geology\/wp-json\/wp\/v2\/types\/chapter"}],"author":[{"embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/colorado-wmopen-geology\/wp-json\/wp\/v2\/users\/17"}],"version-history":[{"count":16,"href":"https:\/\/courses.lumenlearning.com\/colorado-wmopen-geology\/wp-json\/pressbooks\/v2\/chapters\/1759\/revisions"}],"predecessor-version":[{"id":3471,"href":"https:\/\/courses.lumenlearning.com\/colorado-wmopen-geology\/wp-json\/pressbooks\/v2\/chapters\/1759\/revisions\/3471"}],"part":[{"href":"https:\/\/courses.lumenlearning.com\/colorado-wmopen-geology\/wp-json\/pressbooks\/v2\/parts\/25"}],"metadata":[{"href":"https:\/\/courses.lumenlearning.com\/colorado-wmopen-geology\/wp-json\/pressbooks\/v2\/chapters\/1759\/metadata\/"}],"wp:attachment":[{"href":"https:\/\/courses.lumenlearning.com\/colorado-wmopen-geology\/wp-json\/wp\/v2\/media?parent=1759"}],"wp:term":[{"taxonomy":"chapter-type","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/colorado-wmopen-geology\/wp-json\/pressbooks\/v2\/chapter-type?post=1759"},{"taxonomy":"contributor","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/colorado-wmopen-geology\/wp-json\/wp\/v2\/contributor?post=1759"},{"taxonomy":"license","embeddable":true,"href":"https:\/\/courses.lumenlearning.com\/colorado-wmopen-geology\/wp-json\/wp\/v2\/license?post=1759"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}