{"id":241798,"date":"2025-09-20T16:11:11","date_gmt":"2025-09-20T16:11:11","guid":{"rendered":"https:\/\/www.europesays.com\/us\/241798\/"},"modified":"2025-09-20T16:11:11","modified_gmt":"2025-09-20T16:11:11","slug":"when-non-avian-dinosaurs-went-extinct-the-earth-changed-literally-scientists-think-they-finally-know-why","status":"publish","type":"post","link":"https:\/\/www.europesays.com\/us\/241798\/","title":{"rendered":"When Non-Avian Dinosaurs Went Extinct, the Earth Changed\u2014Literally. Scientists Think They Finally Know Why"},"content":{"rendered":"

Rocks formed immediately before and after non-avian dinosaurs went extinct are strikingly different, and now, tens of millions of years later, scientists think they\u2019ve identified the culprit\u2014and it wasn\u2019t the Chicxulub asteroid<\/a> impact.<\/p>\n

In a study<\/a> published Monday in the journal Communications Earth & Environment, researchers argue that dinosaurs physically influenced their surroundings so dramatically that their disappearance led to stark changes to the Earth\u2019s landscape, and, in turn, the geologic record.<\/p>\n

Specifically, their mass extinction\u2014an event known as the Cretaceous-Paleogene (or K-Pg) mass extinction\u2014enabled dense forests to grow, stabilizing sediments, and shaping rivers with broad meanders, or curves.<\/p>\n

\u201cVery often when we\u2019re thinking about how life has changed through time and how environments change through time, it\u2019s usually that the climate changes and, therefore, it has a specific effect on life, or this mountain has grown and, therefore, it has a specific effect on life,\u201d Luke Weaver, a paleontologist at the University of Michigan, said in a statement<\/a>.<\/p>\n

\u201cIt\u2019s rarely thought that life itself could actually alter the climate and the landscape. The arrow doesn\u2019t just go in one direction.\u201d<\/p>\n

\"EcosystemAn artistic rendering of how a landscape may have changed after most dinosaurs went extinct. \u00a9 Julius Csotonyi River deposits, not pond deposits <\/p>\n

Weaver and his colleagues concentrated their studies on the Williston Basin, which spreads throughout parts of Montana, North Dakota, and South Dakota; and the Bighorn Basin, in north-central Wyoming. Williston Basin\u2019s Fort Union Formation dates to after non-avian dinosaurs went extinct, and features colorful rock layers that Weaver described as resembling pajama stripes. Beneath the Fort Union Formation are water-rich soils similar to a floodplain\u2019s outer edges.<\/p>\n

Past research has posited that the colorful layers are evidence of pond deposits from rising sea levels. But the team\u2019s new investigation, however, revealed that \u201cthe pajama stripes actually weren\u2019t pond deposits at all. They\u2019re point bar deposits, or deposits that form the inside of a big meander in a river,\u201d Weaver said.<\/p>\n

\u201cSo instead of looking at a stillwater, quiet setting, what we\u2019re actually looking at is a very active inside of a meander,\u201d he explained.<\/p>\n

Above and below these river deposits were layers of a kind of coal created by plant matter, which the team thinks formed thanks to the stabilizing effect of thick forests, which can prevent rivers from frequent flooding. Stable rivers don\u2019t distribute clay, silt, and sand across a floodplain, so the organic remains mostly pile up instead.<\/p>\n

The iridium anomaly <\/p>\n

The researchers then turned to what is called the iridium anomaly\u2014a layer of rock rich in the element iridium\u2014which deposited over parts of our planet when the Chicxulub asteroid struck Earth. As such, the iridium anomaly represents the K-Pg boundary.<\/p>\n

At Bighorn Basin, Weaver analyzed samples from a thin line of red clay between the dinosaur-era formation and the subsequent mammal-era formation. \u201cLo and behold, the iridium anomaly was right at the contact between those two formations, right where the geology changes,\u201d Weaver said.<\/p>\n

\u201cThat discovery convinced us that this isn\u2019t just a phenomenon in the Williston Basin. It\u2019s probably true everywhere throughout the Western Interior of North America.\u201d<\/p>\n

\"IridiumWeaver pointing out the iridium anomaly in layers of rock. \u00a9 Luke Weaver\/University of Michigan <\/p>\n

Still, the researchers were puzzled as to why. They suspected that dinosaurs had somehow shaped their environment such that it influenced the geology, but it was only after weaver stumbled across a series of talks about how living animals like elephants shape their ecosystems that the team finally had its \u201clightbulb moment.\u201d These ancient reptiles must have been the \u201cecosystem engineers\u201d of their time.<\/p>\n

\u201cDinosaurs are huge. They must have had some sort of impact on this vegetation,\u201d Weaver said.<\/p>\n

He and his colleagues argue that when non-avian dinosaurs were alive, they flattened vegetation and, as a result of their sheer size, affected the tree cover, likely shaping sparse, weedy landscapes with scattered trees. This would have meant that rivers without wide meanders may have flooded frequently. In the wake of their mass extinction, however, forests thrived, stabilized sediments, built point bars, and structured rivers.<\/p>\n

\u201cTo me, the most exciting part of our work is evidence that dinosaurs may have had a direct impact on their ecosystems,\u201d said Courtney Sprain, a co-author on the study.<\/p>\n

\u201cSpecifically, the impact of their extinction may not just be observable by the disappearance of their fossils in the rock record, but also by changes in the sediments themselves.\u201d<\/p>\n

Earth clearly felt the loss of the dinosaurs in more ways than one. I, however, am glad that Tyrannosaurus Rex doesn\u2019t exist anymore (and don\u2019t even get me started on the Meraxes Gigas<\/a>).<\/p>\n","protected":false},"excerpt":{"rendered":"Rocks formed immediately before and after non-avian dinosaurs went extinct are strikingly different, and now, tens of millions…\n","protected":false},"author":3,"featured_media":241799,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[129093,25052,20774,159,67,132,68],"class_list":{"0":"post-241798","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-science","8":"tag-chicxulub","9":"tag-dinosaurs","10":"tag-geology","11":"tag-science","12":"tag-united-states","13":"tag-unitedstates","14":"tag-us"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@us\/115237505808126655","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/241798","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=241798"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/241798\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media\/241799"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media?parent=241798"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/categories?post=241798"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/tags?post=241798"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}