{"id":121802,"date":"2024-08-26T16:15:08","date_gmt":"2024-08-26T16:15:08","guid":{"rendered":"https:\/\/news.talkwithrattan.com\/index.php\/2024\/08\/26\/mantle-waves-buoy-continents-upward-and-bedeck-them-with-diamonds\/"},"modified":"2024-08-26T16:15:08","modified_gmt":"2024-08-26T16:15:08","slug":"mantle-waves-buoy-continents-upward-and-bedeck-them-with-diamonds","status":"publish","type":"post","link":"https:\/\/news.talkwithrattan.com\/index.php\/2024\/08\/26\/mantle-waves-buoy-continents-upward-and-bedeck-them-with-diamonds\/","title":{"rendered":"Mantle waves buoy continents upward and bedeck them with diamonds"},"content":{"rendered":"<div style=\"text-align:center\"><img decoding=\"async\" src=\"https:\/\/i1.wp.com\/www.sciencenews.org\/081524_no_cratonwaves_inline1_mobile?ssl=1\" class=\"attachment-post-thumbnail size-post-thumbnail wp-post-image\" alt=\"Mantle waves buoy continents upward and bedeck them with diamonds\" title=\"Mantle waves buoy continents upward and bedeck them with diamonds\" \/><\/div> \r\n<br><div style=\"clear:both\">\n<style><![CDATA[\n.subscribe-cta {\n  color: black;\n  margin-top: 0px;\n  background-color: #EDD695;\n  background-size: cover;\n  padding: 20px;\n  border: 1px solid black;\n  border-top: 5px solid black;\n  clear: both;\n}\n\n.centered {\n  text-align:center;\n  margin:auto;\n}\n\n]]><\/style>\n<!-- \/wp:html -->\n\n<!-- wp:group {\"className\":\"subscribe-cta\"} -->\n<div id=\"subscribeConversion\" class=\"wp-block-group subscribe-cta\"><!-- wp:heading {\"textAlign\":\"center\",\"style\":{\"typography\":{\"fontSize\":\"2em\"}}} -->\n<h2 class=\"wp-block-heading has-text-align-center\" style=\"font-size:2em\">Extreme Climate Survey<\/h2>\n<!-- \/wp:heading -->\n\n<!-- wp:paragraph {\"align\":\"center\",\"style\":{\"typography\":{\"fontSize\":\"1.1em\"}}} -->\n<p class=\"has-text-align-center\" style=\"font-size:1.1em\"><strong><em>Science News <\/em>is collecting reader questions about how to navigate our planet&#8217;s changing climate.<\/strong><\/p>\n<p class=\"has-text-align-center\" style=\"font-size:1.1em\">What do you want to know about extreme heat and how it can lead to extreme weather events?<\/p>\n<!-- \/wp:paragraph -->\n\n<!-- wp:spacer {\"height\":\"20px\"} -->\n\n<!-- \/wp:spacer -->\n\n<!-- wp:buttons {\"className\":\"centered\",\"layout\":{\"type\":\"flex\",\"justifyContent\":\"center\"}} -->\n\n<!-- \/wp:buttons --><\/div>\n<!-- \/wp:group -->\n\n\n<p>At the center of this story lie the cratons, large blocks of mostly crystalline rock that typically occupy the interiors of continents. They are the oldest fragments of Earth\u2019s crust, with many having formed more than 2.5 billion years ago, during the Archean Eon. Much of the crust that once existed on Earth has been destroyed in subduction zones, where one tectonic plate plunges beneath another into the mantle. The cratons, however, evaded that fate.<\/p>\n\n\n\n<p>Cratons owe their longevity to their roots, or keels, Foster says. Cratons are much thicker than surrounding continental crust, with keels that can extend hundreds of kilometers down into the mantle. The keels are relatively buoyant, thereby helping to keep cratons afloat and intact while other parts of the crust get subducted.<\/p>\n\n\n\n<p>But something about the cratons had long puzzled geologists. Some, such as the Kaapvaal craton in southern Africa, are topped by vast plateaus that are rimmed by dramatic escarpments. But cratons are supposedly stable and often located far from the land-lifting tectonic activity that occurs at plate boundaries. So what raised these plateaus?<\/p>\n\n\n<figure class=\"wp-block-image \"><picture class=\"sn-responsive-image\"><source srcset=\"https:\/\/i0.wp.com\/www.sciencenews.org\/wp-content\/uploads\/2024\/08\/081524_no_cratonwaves_inline1_desktop.jpg?w=680&amp;ssl=1 680w, https:\/\/i0.wp.com\/www.sciencenews.org\/wp-content\/uploads\/2024\/08\/081524_no_cratonwaves_inline1_desktop.jpg?resize=330%2C162&amp;ssl=1 330w\" width=\"680\" height=\"334\" media=\"(min-width: 600px)\" sizes=\"(max-width: 1023px) 100vw, 680px\"><source srcset=\"https:\/\/i0.wp.com\/www.sciencenews.org\/wp-content\/uploads\/2024\/08\/081524_no_cratonwaves_inline1_mobile.jpg?w=680&amp;ssl=1 680w, https:\/\/i0.wp.com\/www.sciencenews.org\/wp-content\/uploads\/2024\/08\/081524_no_cratonwaves_inline1_mobile.jpg?resize=330%2C162&amp;ssl=1 330w\" width=\"680\" height=\"334\"><\/source><\/source><\/picture><figcaption><span class=\"caption mobile-caption wp-caption-3142520\">The Southern African Plateau (brown region top right) and its rim, the Great Escarpment (edge between green and brown regions), can be seen in this satellite image from May 2020. <\/span><span class=\"credit mobile-credit wp-credit-3142520\">T.M. Gernon\/Univ. of Southampton<\/span><span class=\"caption desktop-caption wp-caption-3142519\">The Southern African Plateau (brown region top right) and its rim, the Great Escarpment (edge between green and brown regions), can be seen in this satellite image from May 2020. <\/span><span class=\"credit desktop-credit wp-credit-3142519\">T.M. Gernon\/Univ. of Southampton<\/span><\/figcaption><\/figure>\n\n\n<p>Some studies have proposed that <a href=\"https:\/\/doi.org\/10.1002%2F2014JB010998\" target=\"_blank\" rel=\"noopener\">the landforms arose<\/a> as the craton passed over a large <a href=\"https:\/\/www.sciencenews.org\/article\/moon-planet-collision-earth-plate-tectonics\">plume of material upwelling<\/a> from deep in the mantle (<em>SN: 3\/15\/23<\/em>). But the geologic record doesn\u2019t appear to support that explanation, says earth scientist Thomas Gernon of the University of Southampton in England.<\/p>\n\n\n\n<p>So Gernon and colleagues harnessed computer simulations to track the evolution of a rift that opened in the middle of a continent. They found that pressure changes beneath the rift stirred up circulations in the mantle, inciting a wave that propagated laterally under a continent roughly 20 kilometers every million years.<\/p>\n\n\n\n<p>When the wave met a craton\u2019s keel in the simulation, it excoriated and swept material away into the mantle. This progressively unburdened the continent, causing the overlying surface to rise upward like a ship relieved of cargo. This uplift followed the mantle waves for hundreds of kilometers across the craton, raising a stable plateau roughly one to two kilometers high, Gernon says. And as these raised regions were eroded by wind and water, the surface buoyed up even more.<\/p>\n\n\n\n<div class=\"wp-block-sciencenews-content-sidebar\">\n<h3 class=\"wp-block-heading\">Catch the wave<\/h3>\n\n\n\n<p>Continental rifts can kick off waves in the underlying mantle that bumps up the crust and builds an extended plateau. Click through the slideshow below to see how this happens. In each illustration, the continent is divided into its upper crust, lower crust and continental lithosphere layers plus a relatively unstable thermal boundary layer. Beneath the continent is the asthenosphere, the ductile upper layer of Earth\u2019s mantle.<\/p>\n\n\n\n<p><strong>How mantle waves buoy Earth\u2019s surface to form broad plateaus<\/strong><\/p>\n\n\n\n<div class=\"slideshow__container___2inGd\" data-component=\"slideshow\">\n\t\n\n\t<ol class=\"slideshow__slides___BfLMo\">\n\t\t\n<li class=\"slideshow__wrapper___Aebb- item-1\" role=\"listitem\">\n\t<figure class=\"slideshow__figure___DHfIZ\">\n\t\t<img loading=\"lazy\" decoding=\"async\" width=\"579\" height=\"383\" class=\"attachment-medium size-medium\" alt=\"A diagram showing a 2D view of the crust splitting.\" data-attachment-id=\"3142522\" src=\"https:\/\/www.sciencenews.org\/081524_no_cratonwaves_slide1_mobile\" data-orig-file=\"https:\/\/i0.wp.com\/www.sciencenews.org\/wp-content\/uploads\/2024\/08\/081524_no_cratonwaves_slide1_mobile.jpg?fit=680%2C450&amp;ssl=1\" data-orig-size=\"680,450\" data-comments-opened=\"0\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"081524_no_cratonwaves_slide1_mobile\" data-image-description=\"\" data-image-caption=\"&lt;p&gt;As a rift zone (left) starts stretching apart a continent, it begins to influence the convection of material in the mantle (arrows at bottom left). Volcanic activity (denoted by the red vertical line over the rift) is largely clustered around the developing rift.&lt;\/p&gt;&#10;\" data-medium-file=\"https:\/\/i0.wp.com\/www.sciencenews.org\/wp-content\/uploads\/2024\/08\/081524_no_cratonwaves_slide1_mobile.jpg?fit=579%2C383&amp;ssl=1\" data-large-file=\"https:\/\/i0.wp.com\/www.sciencenews.org\/wp-content\/uploads\/2024\/08\/081524_no_cratonwaves_slide1_mobile.jpg?fit=680%2C450&amp;ssl=1\"\/>\n\t\t\n\t\t\t<figcaption class=\"slideshow__gallery-caption___jcoF1\">\n\t\t\t\t<span class=\"caption\">As a rift zone (left) starts stretching apart a continent, it begins to influence the convection of material in the mantle (arrows at bottom left). Volcanic activity (denoted by the red vertical line over the rift) is largely clustered around the developing rift.<\/span>\t\t\t\t<span class=\"credit\">T.M. Gernon <em>et al\/Nature<\/em> 2024<\/span>\t\t\t<\/figcaption>\n\n\t\t\t<\/figure>\n\n<\/li>\n<li class=\"slideshow__wrapper___Aebb- item-2\" role=\"listitem\">\n\t<figure class=\"slideshow__figure___DHfIZ\">\n\t\t<img loading=\"lazy\" decoding=\"async\" width=\"579\" height=\"383\" class=\"attachment-medium size-medium\" alt=\"A diagram showing a 2D view of the crust splitting and the bottom of a continent peeling off.\" data-attachment-id=\"3142524\" src=\"https:\/\/www.sciencenews.org\/081524_no_cratonwaves_slide2_mobile\" data-orig-file=\"https:\/\/i0.wp.com\/www.sciencenews.org\/wp-content\/uploads\/2024\/08\/081524_no_cratonwaves_slide2_mobile.jpg?fit=680%2C450&amp;ssl=1\" data-orig-size=\"680,450\" data-comments-opened=\"0\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"081524_no_cratonwaves_slide2_mobile\" data-image-description=\"\" data-image-caption=\"&lt;p&gt;As rifting progresses, material from the asthenosphere upwells to form oceanic lithosphere \u2014 the floor of a sea. In the mantle, a wave of convecting material (bottom center) propagates outward from the rift. This mantle wave scours material from the thermal boundary layer, a relatively weak part of the continental keel. This removal of material causes the overlying surface to buoy up, and also drives kimberlite eruptions (red lines), which carry diamonds to the surface and solidify as kimberlite pipes.&lt;\/p&gt;&#10;\" data-medium-file=\"https:\/\/i0.wp.com\/www.sciencenews.org\/wp-content\/uploads\/2024\/08\/081524_no_cratonwaves_slide2_mobile.jpg?fit=579%2C383&amp;ssl=1\" data-large-file=\"https:\/\/i0.wp.com\/www.sciencenews.org\/wp-content\/uploads\/2024\/08\/081524_no_cratonwaves_slide2_mobile.jpg?fit=680%2C450&amp;ssl=1\"\/>\n\t\t\n\t\t\t<figcaption class=\"slideshow__gallery-caption___jcoF1\">\n\t\t\t\t<span class=\"caption\">As rifting progresses, material from the asthenosphere upwells to form oceanic lithosphere \u2014 the floor of a sea. In the mantle, a wave of convecting material (bottom center) propagates outward from the rift. This mantle wave scours material from the thermal boundary layer, a relatively weak part of the continental keel. This removal of material causes the overlying surface to buoy up, and also drives kimberlite eruptions (red lines), which carry diamonds to the surface and solidify as kimberlite pipes.<\/span>\t\t\t\t<span class=\"credit\">T.M. Gernon <em>et al\/Nature<\/em> 2024<\/span>\t\t\t<\/figcaption>\n\n\t\t\t<\/figure>\n\n<\/li>\n<li class=\"slideshow__wrapper___Aebb- item-3\" role=\"listitem\">\n\t<figure class=\"slideshow__figure___DHfIZ\">\n\t\t<img loading=\"lazy\" decoding=\"async\" width=\"579\" height=\"383\" class=\"attachment-medium size-medium\" alt=\"A diagram showing a 2D view of the crust splitting and the bottom of a continent peeling off. The surface above has risen, forming a plateau.\" data-attachment-id=\"3142526\" src=\"https:\/\/www.sciencenews.org\/081524_no_cratonwaves_slide3_mobile\" data-orig-file=\"https:\/\/i0.wp.com\/www.sciencenews.org\/wp-content\/uploads\/2024\/08\/081524_no_cratonwaves_slide3_mobile.jpg?fit=680%2C450&amp;ssl=1\" data-orig-size=\"680,450\" data-comments-opened=\"0\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"081524_no_cratonwaves_slide3_mobile\" data-image-description=\"\" data-image-caption=\"&lt;p&gt;The mantle wave penetrates far beneath the continent, and the uplift and kimberlite volcanism migrate inland as well. A broad plateau has formed on the surface, and it is punctured with kimberlite pipes (red lines).&lt;\/p&gt;&#10;\" data-medium-file=\"https:\/\/i0.wp.com\/www.sciencenews.org\/wp-content\/uploads\/2024\/08\/081524_no_cratonwaves_slide3_mobile.jpg?fit=579%2C383&amp;ssl=1\" data-large-file=\"https:\/\/i0.wp.com\/www.sciencenews.org\/wp-content\/uploads\/2024\/08\/081524_no_cratonwaves_slide3_mobile.jpg?fit=680%2C450&amp;ssl=1\"\/>\n\t\t\n\t\t\t<figcaption class=\"slideshow__gallery-caption___jcoF1\">\n\t\t\t\t<span class=\"caption\">The mantle wave penetrates far beneath the continent, and the uplift and kimberlite volcanism migrate inland as well. A broad plateau has formed on the surface, and it is punctured with kimberlite pipes (red lines).<\/span>\t\t\t\t<span class=\"credit\">T.M. Gernon<em> et al\/Nature<\/em> 2024<\/span>\t\t\t<\/figcaption>\n\n\t\t\t<\/figure>\n\n<\/li>\t<\/ol>\n<\/div>\n<\/div>\n\n\n\n\n\n<p>The researchers also linked their simulations to the geologic record. From previously published research, they pulled geochemical data from rocks in the Southern Africa plateau, which recorded the plateau\u2019s thermal history. The data showed that the fastest rates of cooling \u2014 a proxy for when the rocks were being uplifted most rapidly \u2014 swept across the plateau at a pace that aligned with the migration of a mantle wave.<\/p>\n\n\n\n<p>The study links together many disparate hypotheses, says geophysicist Cynthia Ebinger of Tulane University in New Orleans. Scientists had previously linked <a href=\"https:\/\/www.sciencenews.org\/article\/pink-diamonds-build-destroy-supercontinent\">rifting to kimberlite volcanism<\/a> and shown that craton keels could be excoriated by material circulating in the mantle (<em>SN: 9\/19\/23<\/em>). But until now, no one had connected those pieces with the cratons\u2019 enigmatic topography.<\/p>\n\n\n\n<p>\u201cThese Archean fragments are still controlling aspects of plate tectonics,\u201d Ebinger says. \u201cThat early stage in Earth\u2019s history is still really important.\u201d<\/p>\n\n\n\n\t\t\t<\/div>\r\n<br>\r\n<br><a href=\"https:\/\/www.sciencenews.org\/article\/mantle-wave-continent-plateaus-diamonds\">Source link <\/a>","protected":false},"excerpt":{"rendered":"<p>Extreme Climate Survey Science News is collecting reader questions about how to navigate our planet&#8217;s changing climate. What do you want to know about extreme heat and how it can lead to extreme weather events? At the center of this story lie the cratons, large blocks of mostly crystalline rock that typically occupy the interiors [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":121803,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"tdm_status":"","tdm_grid_status":"","fifu_image_url":"https:\/\/www.sciencenews.org\/081524_no_cratonwaves_inline1_mobile","fifu_image_alt":"","footnotes":""},"categories":[606],"tags":[99005,99004,64465,33550,92532,38216,6897],"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/posts\/121802"}],"collection":[{"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/comments?post=121802"}],"version-history":[{"count":1,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/posts\/121802\/revisions"}],"predecessor-version":[{"id":121804,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/posts\/121802\/revisions\/121804"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/media\/121803"}],"wp:attachment":[{"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/media?parent=121802"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/categories?post=121802"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/news.talkwithrattan.com\/index.php\/wp-json\/wp\/v2\/tags?post=121802"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}