Dust Doomed the Dinos, Scientists Say

We all know how the story goes: a large asteroid falls to Earth from space, slamming into the Yucatán Peninsula with 100 million megatons of force. The impact spawned WatchThe M3 MacBook Pro: Made Dark for Halloween CCShare SubtitlesOffEnglishDifferent ideas about what exactly killed the dinosaurs—and plenty of other organisms 66 million years ago—have been suggested over the years. But something blocking out the Sun, whether it be volcanic activity or fallout from an asteroid impact, is frequently in the cards. In 2020, a different team of researchers AdvertisementThe researchers ran simulations which “support a dust-induced photosynthetic shut-down for almost 2 [years] post-impact,” the team stated in the paper. “We 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.”AdvertisementWithout most plant life doing photosynthesis—the process by which they convert sunlight into chemical energy—plants would have died wholesale, causing a domino effect up the food chain. For about 620 days (1.7 years) after the impact, the planet would have been plunged into a cool, dark wasteland, according to the new research. Flora and fauna that could enter a dormant stage and weren’t picky about their food sources were more likely to get through the period alive.Paleoclimate models showing the distribution of dust immediately after and 5 days after the impact.Illustration: Simulations by Cem Berk SenelAdvertisementThe Chicxulub impact was so intense it left “We specifically sampled the uppermost millimeter-thin interval of the Cretaceous-Paleogene boundary layer,” said Pim Kaskes, a geochemist at Vrije University Brussel in Belgium and co-author of the study, in a Royal Observatory of Belgium release. “This 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.”AdvertisementThe researchers stated that more studies of the K-Pg boundary—the geological layer that includes the fallout of the Chicxulub impact—would help clarify exactly how life rebounded in the months and years after the event.More:

Based on reporting by gizmodo.com.