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
Ammonius (crater) by the IAU in 1976. Before it was called Ammonius, the crater was planned to be called Lyot proposed by Hugh Percy Wilkins and Patrick Moore, instead, Lyot would be named in the Moon's southeastern limb. Ammonius (crater) Ammonius is a bowl-shaped lunar impact crater with a slightly raised rim and is named after It is located on the floor of the walled plain Ptolemaeus, about 30 kilometers northeast of the crater midpoint. Just to the north on the lava-flooded floor of Ptolemaeus is a relatively prominent "ghost" crater: the discernible buried rim of a pre-existing crater. The diameter of