Impact event Chicxulub Crater. This crater is centered on the Yucatán Peninsula of Mexico and was discovered by Tony Camargo and Glen Pentfield while working as geophysicists for the Mexican oil company PEMEX. What they reported as a circular feature later turned out to be a crater estimated to be in diameter. This convinced the vast majority of scientists that this extinction resulted from a point event that is most probably an extraterrestrial impact and not from increased volcanism and climate change (which would spread its main effect over a much longer time period). Although there is now general agreement that there
Manson crater Manson crater The Manson crater is an impact crater near the site of Manson, Iowa where an asteroid or comet nucleus struck the Earth during the Cretaceous Period, 74 Ma (million years ago). It was one of the largest known impact events to have happened in North America. Previously it was thought to have led to the extinction of the dinosaurs until isotopic ages proved that it was too old. No surface evidence exists due to comparatively recent coverage by glacial till, and the site where the crater lies buried is now a flat landscape. But, hidden about below the