At the turn of the Mesozoic Era some 66 million years ago, two of prehistory’s greatest catastrophes struck almost in unison. We’ve all grown familiar with the cosmic collision that dispatched the non-avian dinosaurs, ending their 135-million-year run as the world's overlords. But over the past four decades, while the asteroid narrative settled into the collective conscience, a vigorous debate raged as scientists continued to amplify another character in the story: volcanism.
Despite being the most studied of the “Big Five” mass extinctions, the Cretaceous-Paleogene — which, in addition to the dinos, wiped out three-quarters of all species — still holds its secrets. The case is muddled, with two suspects confirmed at the scene of the crime. “I don’t want to be too morbid,” says University of Edinburgh paleontologist Stephen Brusatte, “but a body disappears, and you know that both John Wayne Gacy and Jeffrey Dahmer were in the neighborhood the day before.” Which killer is to blame? Did they act in concert?
