Palaeogene

The Palaeogene is the first period of the Cenozoic era, spanning from approximately 66 million years ago to 23 million years ago. It is divided into three epochs: the Paleocene, Eocene, and Oligocene. The Palaeogene period is notable for significant geological and biological changes, including the extinction of the non-avian dinosaurs and the rise of mammals. The Paleocene epoch saw the recovery of life after the Cretaceous-Paleogene extinction event, which marked the end of the Mesozoic era. The Eocene epoch is characterized by the diversification of mammals and the development of the Antarctic ice sheet. The Oligocene epoch is marked by the cooling of the climate and the beginning of the formation of the modern continental ice sheets. The Palaeogene period also saw the development of the Atlantic Ocean and the opening of the Central American Seaway, which facilitated the exchange of species between North and South America. The period is also significant for the evolution of hominids, with the earliest known hominid fossils dating back to the Oligocene epoch. The Palaeogene period is a critical time in Earth's history, providing insights into the recovery of life after a major extinction event and the evolution of modern ecosystems.