Chicxulub crater Chicxulub crater The Chicxulub crater (; ) is an impact crater buried underneath the Yucatán Peninsula in Mexico. Its center is located near the town of Chicxulub, after which the crater is named. It was formed by a large asteroid or comet about in diameter, the Chicxulub impactor, striking the Earth. The date of the impact coincides precisely with the Cretaceous–Paleogene boundary (K–Pg boundary), slightly less than 66 million years ago, and a widely accepted theory is that worldwide climate disruption from the event was the cause of the Cretaceous–Paleogene extinction event, a mass extinction in which 75% of plant
Stefan (crater) a small ray system, which is indicative of a relatively young impact. The interior floor of Stefan is a generally level surface that is marked by several impacts. The most notable is a ring-shaped crater rim projecting up through the southern half of the floor. Near the midpoint is a low hill, possibly the buried remnant of a central peak. Stefan lies at the approximate margin of the Coulomb-Sarton Basin, a 530 km wide impact crater of Pre-Nectarian age. By convention these features are identified on lunar maps by placing the letter on the side of the crater midpoint that