What Happened the Day a Giant, Dinosaur-Killing Asteroid Hit the Earth
The immense Chicxulub crater is a remnant of one of the most consequential days in the history of life on Earth. The asteroid strike triggered the Cretaceous-Paleogene, or K-Pg, mass extinction. The catastrophe not only decimated the dinosaurs, leaving only birds to carry their legacy, but also annihilated various forms of life from flying reptiles called pterosaurs to coil-shelled nautilus relatives called ammonites. Lizards, snakes, mammals and more suffered their own setbacks. The best clues to what happened now lie buried in rock layers stacked 12 miles deep.
Using a core sample collected in 2016, University of Texas at Austin geologist Sean Gulick and a team of dozens of other researchers have further pieced together the story of the Cretaceous-Paleogene extinction. “We interpret this section to represent the first day post impact, which by the definition of the geologic time scale, makes it the first day of the Cenozoic since the Cretaceous ended the moment the asteroid struck,” Gulick says. The team’s study, “The first day of the Cenozoic,” was published today in the Proceedings of the National Academy of Sciences.
The drill site was selected to investigate the series of events that followed the impact. When an asteroid the size of the Chicxulub impactor, estimated to be more than six miles wide, strikes a planet, material is ripped up from below the surface and tossed into the air, collapsing in circular mountain range within the crater. Such devastating upheaval triggers a cascading sequence of natural disasters, sending tsunamis rolling across the oceans and ejecting an immense amount of debris into the atmosphere.