Cretaceous–Paleogene boundary had been that no documented crater matched the event. This was not a lethal blow to the theory; while the crater resulting from the impact would have been larger than in diameter, Earth's geological processes hide or destroy craters over time. 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
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