The dinosaur-killing Chicxulub impact event created huge tsunamis, devastating firestorms, and ejected a thick cloud of soot up into the atmosphere that, according to conventional scientific wisdom, blanketed the entire planet. Without plants being able to photosynthesize, and with a darkened planet plunging in temperature, food chains collapsed and ecosystems changed so fast that the non-avian dinosaurs were given a dramatic coup de grâce.
A new study, published in Scientific Reports, is the first major piece of research in a long time to question this famous mass extinction mechanism. Although the authors are certain that an asteroid impact was responsible for the carnage at the end of the Cretaceous Period, they do not think that the entire world was uniformly suffocated by ejected soot.
“Soot has an important role as a kill mechanism of life,” lead author Kunio Kaiho, an associate professor of paleo-bioevents at Tohoku University, told IFLScience. “I do not know why no one has modeled the soot ejection in this way before.”
The team point out that despite the horrors that unfolded 66 million years ago, the avian dinosaurs, some mammals, and crocodilians survived. In particular, the fact that crocodilians survived has proved particularly baffling to researchers who note that their biology would have rendered them unlikely to have made it past this mass extinction event.
By digging around the geological layer formed during the Cretaceous-Paleogene boundary, this team reassessed the amount of soot that they presumed would have been almost entirely generated from a carbon-rich layer beneath the impact site. With the help of cutting-edge atmospheric circulation models run on a supercomputer, they have concluded that this ejected soot covered various parts of the planet differently.
This means that not all life experienced the impact event in the same way, and some managed to escape its wrath.
Don't breathe this. Kevin H Knuth/Shutterstock