The asteroid moved 24 times faster than a rifle bullet as it struck Earth some 66 million years ago. Its supersonic shock wave flattened trees across North and South America, and its heat wave sparked incomprehensibly large forest fires.The event lofted so much debris into the atmosphere that photosynthesis
The asteroid moved 24 times faster than a rifle bullet as it struck Earth some 66 million years ago. Its supersonic shock wave flattened trees across North and South America, and its heat wave sparked incomprehensibly large forest fires.
In 2016, scientists drilled into the heart of the so-called Chicxulub crater and excavated a 2,750-foot-long core of sediments, allowing scientists all over the world, such as Bettina Schaefer of Curtin University in Australia, to parse the rocks for their own research. So when Schaefer’s team saw those preserved fats in the core near the time of the impact, they knew cyanobacteria must have been present. Crucially, the fats were deposited atop a layer of fossilized plants that were washed into the crater by the tsunami that followed, but below another layer of iridium that was deposited once the debris in the atmosphere rained back down on Earth after a few years.
Chris Lowery, a paleoceanographer at the University of Texas at Austin and an author of the recent study, suspects that the crater was only partially dead, in part because the team also saw evidence for fossils of plankton that rely on oxygen. Perhaps the crater’s oxygen-depleted waters existed within only certain layers of its water column. Or, like the dead zone in the modern gulf, maybe those waters were only seasonal.
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