{"id":3044,"date":"2023-12-27T01:59:02","date_gmt":"2023-12-27T09:59:02","guid":{"rendered":"https:\/\/treehousewriters.com\/wp53\/?p=3044"},"modified":"2023-11-09T14:01:31","modified_gmt":"2023-11-09T22:01:31","slug":"new-evidence-on-how-the-dinosaurs-died","status":"publish","type":"post","link":"https:\/\/treehousewriters.com\/wp53\/2023\/12\/27\/new-evidence-on-how-the-dinosaurs-died\/","title":{"rendered":"New Evidence on How the Dinosaurs Died"},"content":{"rendered":"

Such a cool article from Universe Today, I think it merits a post all to itself!<\/p>\n

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Devastating Clouds of Dust Helped End the Reign of the Dinosaurs<\/a><\/span><\/h5>\n<\/header>\n
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When a giant meteor crashed into Earth 66 million years ago, the impact pulverized cubic kilometers of rock and blasted the dust and debris into the Earth\u2019s atmosphere. It was previously believed that sulfur from the impact and soot from the global fires that followed drove a global \u201cimpact winter\u201d that killed off 75% of species on Earth, including the dinosaurs.<\/span><\/p>\n

A new geology paper<\/a>\u00a0says that the die-off was additionally fueled by ultrafine dust created by the impact which filled the atmosphere and blocked sunlight for as long as 15 years. Plants were unable to photosynthesize and global temperatures were lowered by 15 degrees C (59 F).<\/span><\/p>\n

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Most scientists agree the disaster started with an asteroid impact, where an asteroid at least 10 kilometers wide struck the Chicxulub region in the present-day Yucat\u00e1n Peninsula in Mexico. The impact released 2 million times more energy than the most powerful nuclear bomb ever detonated.<\/span><\/p>\n

The devastation created layer of ash sandwiched between layers of rock, known as the Cretaceous-Paleogene (K\u2013Pg) boundary, formerly known as the Cretaceous\u2013Tertiary (K-T) boundary, which is found across the world in the geologic record. It includes a layer of iridium, an element common in asteroids but rare on Earth. It was this \u2018iridium anomaly\u2019 that first revealed the extinction event as an asteroid strike to geologists more than three decades ago.<\/span><\/p>\n

What has been debated is what created conditions for the post-impact winter. The leading candidates were sulphur from the asteroid\u2019s impact, or soot from global wildfires that ensued after the impact. Both would have blocked out sunlight and plunged the world into a long, dark winter, collapsing the food chain and creating a chain reaction of extinctions. \u00a0<\/span><\/p>\n

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Overview of the Cretaceous-Paleogene boundary in North Dakota (USA). The sediments indicate a river and swamp-like environment at the end of the age of the dinosaurs. The pink-brown layer yields ejecta debris derived from the Chicxulub impact event and the grain-size data from this interval were used as input parameters for the paleoclimate modeling study (photo: Pim Kaskes).<\/em><\/figcaption><\/figure>\n

But in this new research, scientists from the Royal Observatory of Belgium (ROB) studied new sediment samples taken from the Tanis fossil site in North Dakota in the US, which captures a 20-year period during the aftermath of the asteroid impact. Analysis of the samples revealed evidence of silicate dust particles, particles that were ejected into the atmosphere and eventually settled back down on the planet.<\/span><\/p>\n

\u201cWe specifically sampled the uppermost millimeter-thin interval of the Cretaceous-Paleogene boundary layer,\u201d\u00a0said Pim Kaskes<\/a>\u00a0\u00a0from the Archaeology, Environmental Changes & Geo-chemistry (AMGC) at the Vrije Universiteit Brussel (VUB) and the Vrije Universiteit Amsterdam (VUA), who was also involved in the study. \u201cThis interval revealed a very fine and uniform grain-size distribution, which we interpret to represent the final atmospheric fall-out of ultrafine dust related to the Chicxulub impact event. The new results show much finer grain-size values than previously used in climate models and this aspect had important consequences for our climate reconstructions.\u201d<\/p>\n

Based on their findings, the scientists also created a new paleoclimate computer model that evaluated the roles of sulfur, soot, and silicate dust on the post-impact climate.<\/span><\/p>\n

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Conceptual model of the Chicxulub impact plume showing different stages of (a) production, and (b) transport and deposition of the impact-generated ejecta (not to scale). (c) Paleoclimate model simulations showcasing the time evolution of the dust-induced photosynthetic active radiation flux across the planet following the Chicxulub impact 66 million years ago (modified from Senel et al., 2023; Nature Geoscience).<\/em><\/figcaption><\/figure>\n

\u201cThe new paleoclimate simulations show that such a plume of micrometric silicate dust could have remained in the atmosphere for up to 15 years after the event, contributing to global cooling of the Earth\u2019s surface by as much as 15 \u00b0C in the initial aftermath of the impact,\u201d said Cem Berk Senel from ROB, the lead author of the study.<\/span><\/p>\n

But while the dust was a contributor to the catastrophic conditions, the sulfur and soot were also a factor.<\/span><\/p>\n

\u201cWe suggest that, together with additional cooling contributions from soot and sulfur, this is consistent with the catastrophic collapse of primary productivity in the aftermath of the Chicxulub impact,\u201d the researchers\u00a0wrote.<\/span><\/p>\n

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The prolonged disruption in photosynthesis would pose severe challenges for both terrestrial and marine habitats and mass extinctions would occur in groups not adapted to survive the dark, cold, and food-deprived conditions for at least two years. The researchers said this matches the paleontological records, which show that any plants or animals that could enter a dormant phase (for example, through seeds, cysts, or hibernation in burrows) and were able to adapt to an omnivorous diet, or weren\u2019t dependent on one particular food source generally better survived the K-Pg event.<\/div>\n
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Related: \u00a0Previous research at the Tanis site suggests the Chicxulub impact happened in the springtime.<\/span><\/a><\/div>\n<\/div>\n<\/div>\n

<\/p>\n","protected":false},"excerpt":{"rendered":"

Such a cool article from Universe Today, I think it merits a post all to itself! Devastating Clouds of Dust Helped End the Reign of the Dinosaurs When a giant meteor crashed into Earth 66 million years ago, the impact pulverized cubic kilometers of rock and blasted the dust and debris into the Earth\u2019s atmosphere. […]<\/p>\n","protected":false},"author":6,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[586,181],"tags":[798,256,796,797],"class_list":["post-3044","post","type-post","status-publish","format-standard","hentry","category-astronomy","category-science","tag-asteroid-collision","tag-dinosaurs","tag-extinction","tag-paleoclimate"],"_links":{"self":[{"href":"https:\/\/treehousewriters.com\/wp53\/wp-json\/wp\/v2\/posts\/3044","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/treehousewriters.com\/wp53\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/treehousewriters.com\/wp53\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/treehousewriters.com\/wp53\/wp-json\/wp\/v2\/users\/6"}],"replies":[{"embeddable":true,"href":"https:\/\/treehousewriters.com\/wp53\/wp-json\/wp\/v2\/comments?post=3044"}],"version-history":[{"count":1,"href":"https:\/\/treehousewriters.com\/wp53\/wp-json\/wp\/v2\/posts\/3044\/revisions"}],"predecessor-version":[{"id":3045,"href":"https:\/\/treehousewriters.com\/wp53\/wp-json\/wp\/v2\/posts\/3044\/revisions\/3045"}],"wp:attachment":[{"href":"https:\/\/treehousewriters.com\/wp53\/wp-json\/wp\/v2\/media?parent=3044"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/treehousewriters.com\/wp53\/wp-json\/wp\/v2\/categories?post=3044"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/treehousewriters.com\/wp53\/wp-json\/wp\/v2\/tags?post=3044"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}