Chicxulub crater may predate...

the K-T boundary by 300,000 years according to new research published in the Journal of the Geological Society, casting doubt on the popular notion that this impact was responsible for the demise of the dinosaurs 65 million years ago. Key evidence:

"At one site at El Penon, the researchers found 52 species present in sediments below the impact spherule layer, and counted all 52 still present in layers above the spherules. We found that not a single species went extinct as a result of the Chicxulub impact, says Keller."

Instead, prolific volcanic eruptions at the Deccan Traps in India seems the likely candidate.