That famous asteroid that killed all the dinosaurs millions of years ago, despite what prior theory indicates, likely did not lead to global firestorms that supposedly ravaged the Earth, according to a new study.
It is thought that about 66 million years ago, a massive impact in the Yucatán Peninsula in southeastern Mexico led to the dinosaurs' extinction (potentially with the help of volcanoes). Past researchers have contended that falling sand-sized droplets from this Earth-shattering collision heated up the atmosphere long enough to cause forests worldwide to spontaneously burst into flames.
But now, a new study published in the Journal of the Geological Society has debunked this theory - at least in part.
"We have reproduced in the laboratory the most intense impact-induced heat fluxes estimated to have reached different points on the Earth's surface using a fire propagation apparatus and investigated the ignition potential of forest fuels. The experiments indicate that dry litter can ignite, but live fuels typically do not, suggesting that any ignition caused by impact-induced thermal radiation would have been strongly regional dependent," the researchers wrote.
In short, that means the impact's subsequent heat pulse - which would have lasted for less than a minute - was too short to ignite live plant material close to the impact site - a 200-kilometer wide crater in Mexico.
However, the heat was intense enough and lasted long enough - about seven minutes - in areas as far away as New Zealand that wildfires could possibly develop and ignite live plant matter. So while global firestorms were probably not a worldwide phenomenon, it's still possible that they were felt in some regions around the globe.
"This has shown us that the heat was more likely to severely affect ecosystems a long distance away, such that forests in New Zealand would have had more chance of suffering major wildfires than forests in North America that were close to the impact," researcher Dr. Claire Belcher from the University of Exeter said in a statement. "This flips our understanding of the effects of the impact on its head and means that palaeontologists may need to look for new clues from fossils found a long way from the impact to better understand the mass extinction event."
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