Paleocene
Paleocene is the first epoch of the Paleogene Period in the Cenozoic Era, spanning roughly 66 to 56 million years ago. The name means “old recent,” marking its position after the Cretaceous and before the Eocene. The epoch begins at the Cretaceous–Paleogene boundary, which coincides with a mass extinction that ended most non-avian dinosaurs and cleared ecological space for mammals, birds, and other groups to diversify.
During much of the Paleocene the global climate was warm and largely ice-free, with high sea levels
Biota and ecosystems recovered and diversified after the K–Pg extinction. Mammals and birds expanded into new
Subdivisions and end: The Paleocene is divided into three ages—Danian, Selandian, and Thanetian—marking early, middle, and