Princeton University paleontologist Gerta Keller believes a single meteor didn't have the capacity to wipe out all dinosaurs:
Multiple meteorite impacts, massive volcanic activity coupled with irreversible climate change were the main causes for the extinction of dinosaurs, Keller told at the annual meeting of the Geological Society of America in Philadelphia.
The Chicxulub meteorite impact is thought to have wiped out the dinosaurs altogether, but Keller believes that this impact, though powerful, was not enough. "The Chicxulub impact alone could not have caused the mass extinction because this impact predates the mass extinction," said Keller.
Science has accepted that the so-called K-T extinction event, which occurred 65 million years ago, accounted for all non-avian dinosaurs. But Keller and colleagues argue that the Chicxulub impact, which left a 100-mile crater in Mexico occurred 300,000 years before dinosaurs became extinct.