The Proterozoic eon was a period of geologic history from 2.5 billion years ago to about 538.8 million years ago and was the interval between the Archean and the Phanerozoic eons. It corresponds to the Proterozoic eonothem in stratigraphy. The Proterozoic eon was divided into the Paleoproterozoic, Mesoproterozoic, and Neoproterozoic eras, and during this eon, important events such as the Oxygen Catastrophe, possible worldwide glaciation, and the evolution of soft-bodied multi-cellular organisms happened.
Definition[]
As of 2024, there is no GSSP definding the base of the Proterozoic, and its lower boundary defined chronometrically. However, is planned to designate a GSSP in the future.[1]