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
Liverpool crater event to form the rim. Flat-lying and non-deformed sandstone that must have been deposited after the impact event is exposed within the crater's center. Because the crater is quite well preserved, it can be argued that it was buried by younger sedimentary rock soon after the impact event; this younger rock has now been mostly eroded away except in the crater center. The crater-filling sandstone was originally thought to be of Cretaceous age, leading to the Cretaceous age listed for the crater in older literature sources. But more recent studies suggest that the infilling rock is more likely to be