A Post-Impact Deep Freeze for Dinosaurs

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https://eos.org/science-updates/a-post-impact-deep-freeze-for-dinosaurs

By Aubrey Zerkle, Eos/AGU. 

Excerpt: New research supports the hypothesis that dinosaurs were done in by climate change after an asteroid impact kicked up a massive plume of sulfur gases that circled the globe for several decades. ...the Cretaceous-Paleogene (K-Pg) asteroid impact, remains one of the highest-profile cosmic disasters in Earth history—it coincided with a planetwide extinction event that decimated nonavian dinosaurs and wiped out more than three quarters of life on Earth. The long-term biological consequences of this event are well established—the ecological reorganization that followed signified an end to the Mesozoic “Age of Reptiles” and ushered in the Cenozoic “Age of Mammals.” ...the impact caused a shock wave that wiped out everything in its immediate path, followed by devastating tsunamis and extensive wildfires. Seismic waves propagated up rivers and onto land, producing landslides that buried anything in their path, including intact fish with well-preserved ear bones that constrained their time of death to Northern Hemisphere spring [During et al., 2022]. ...Calculations confirm that dust and soot could have reduced sunlight almost entirely, but these heavier particles would have rained out of the atmosphere in months to years rather than decades [Tabor et al., 2020], limiting their effects to several chilling summers. The key to sustaining a long-term impact winter might lie in where the asteroid hit. ...data definitively showed that sulfur from the impact event was thrust into the stratosphere, where it would have prolonged global cooling and intensified the extinction. ...In 1991, the eruption of Mount Pinatubo released sulfate aerosols into the stratosphere. This event released about 100,000 times less sulfur than the Chicxulub impact, but it still caused global temperatures to decrease by 0.5°C for 2 years.… 

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