{"id":566958,"date":"2026-02-05T01:32:16","date_gmt":"2026-02-05T01:32:16","guid":{"rendered":"https:\/\/www.europesays.com\/us\/566958\/"},"modified":"2026-02-05T01:32:16","modified_gmt":"2026-02-05T01:32:16","slug":"how-did-this-river-flow-uphill-geologists-may-finally-have-an-answer-sciencealert","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/us\/566958\/","title":{"rendered":"How Did This River &#8216;Flow Uphill&#8217;? Geologists May Finally Have an Answer : ScienceAlert"},"content":{"rendered":"<p>For more than a century, the Green River&#8217;s course through the Uinta Mountains in Utah&#8217;s northeast has been a geological mystery, seemingly defying physics.<\/p>\n<p>Rivers carve their paths by flowing downhill across many years, which means they usually follow the slopes and furrows of any mountain ranges they encounter.<\/p>\n<p>And yet the Green River, which has been following this course for just 8 million years, cuts right across the 50-million-year-old mountains to meet with the Colorado River, etching out the 700-meter (roughly 2,300-foot) deep Canyon of Lodor that runs perpendicular to the range (and all logic).<\/p>\n<p>Geologist Adam Smith from the University of Glasgow in Scotland led a team to interrogate this long-held mystery. It turns out, the Green River did not have to flow uphill at all: instead, the mountain range was conveniently lowered, in a phenomenon known as <a href=\"https:\/\/en.wikipedia.org\/wiki\/Lithospheric_drip\" rel=\"nofollow noopener\" target=\"_blank\">lithospheric drip<\/a>.<\/p>\n<p><img decoding=\"async\" src=\"https:\/\/www.europesays.com\/us\/wp-content\/uploads\/2026\/02\/Media_1243463_smxx-642x676.jpg\" alt=\"a diagram showing the densified crust below the uinta mountains, falling into the mantle as a drip while the mountains above subside, and then the drip detaching and the mountains rebounding. \" width=\"642\" height=\"676\" class=\"size-medium wp-image-191015\"   loading=\"lazy\"\/>A combination of seismic imaging and sophisticated data modeling helped the team reach their conclusion. (Smith et al., J. of Geo., 2026)<\/p>\n<p>&#8220;Other rivers in the Uinta Mountains provide evidence that the height of the Uinta Mountains changed in the last few million years,&#8221; Smith and team <a href=\"https:\/\/doi.org\/10.1029\/2025JF008733Digital\" rel=\"nofollow noopener\" target=\"_blank\">write<\/a>.<\/p>\n<p>Their data suggests the root of the Uinta Mountains, a dense mineral chunk at the base of the lithosphere, became so heavy that it &#8216;dripped&#8217; into Earth&#8217;s liquid mantle. This would have temporarily pulled the mountain range down, allowing the Green River to chart its unlikely course.<\/p>\n<p>Later, the Uinta mountains grew by 400 meters up around the river, forming the canyon we have today.<\/p>\n<p><a href=\"https:\/\/www.sciencealert.com\/newsletter?utm_source=promo_octopus_yellow\" rel=\"nofollow noopener\" target=\"_blank\"><img decoding=\"async\" src=\"https:\/\/www.europesays.com\/us\/wp-content\/uploads\/2026\/02\/Octopus-yellow-final-642x272.jpg\" alt=\"Subscribe to ScienceAlert's free fact-checked newsletter\" width=\"642\" height=\"272\" class=\"alignnone wp-image-190927 size-medium\"   loading=\"lazy\"\/><\/a>Seismic imaging involves reading the scatter of earthquake vibrations as they pass through Earth to create a picture of what&#8217;s going on down there. At the Uinta Mountains, seismic images revealed a cold, round chunk about 200 kilometers below the surface: probably the drip in question.<\/p>\n<p>What&#8217;s more, the crust below these mountains is much thinner than you&#8217;d usually expect: more evidence that the drip had torn away the lower layers.<\/p>\n<p><strong>Related: <a href=\"https:\/\/www.sciencealert.com\/earths-crust-is-dripping-under-midwest-us-scientists-discover\" rel=\"nofollow noopener\" target=\"_blank\">Earth&#8217;s Crust Is Dripping Under Midwest US, Scientists Discover<\/a><\/strong><\/p>\n<p>Once this drip broke free from the lithosphere about 2-5 million years ago, the mountain range was able to rebound. By then, the Green River had settled in for good: The Canyon of Lodor was there to stay, and the Green River became a tributary of the Colorado River.<\/p>\n<p>&#8220;The merging of the Green and Colorado Rivers millions of years ago altered the continental divide of North America,&#8221; Smith <a href=\"https:\/\/www.gla.ac.uk\/news\/headline_1243462_en.html\" rel=\"nofollow noopener\" target=\"_blank\">explains<\/a>.<\/p>\n<p>&#8220;It created the line that separates the rivers that flow into the Pacific from those that flow into the Atlantic, and created new habitat boundaries for wildlife that influenced their evolution.&#8221;<\/p>\n<p>The research is published in the <a href=\"https:\/\/doi.org\/10.1029\/2025JF008733\" rel=\"nofollow noopener\" target=\"_blank\">Journal of Geophysical Research: Earth Surface<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"For more than a century, the Green River&#8217;s course through the Uinta Mountains in Utah&#8217;s northeast has been&hellip;\n","protected":false},"author":3,"featured_media":566959,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[352,159,67,132,68],"class_list":{"0":"post-566958","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-science","8":"tag-msft-content","9":"tag-science","10":"tag-united-states","11":"tag-unitedstates","12":"tag-us"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@us\/116015447823548773","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/566958","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/comments?post=566958"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/566958\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media\/566959"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media?parent=566958"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/categories?post=566958"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/tags?post=566958"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}