Part of the Paleoarchean Era
Procrustean Period - Acastan Period - Isuan Period
The Acastan Period is the first period of the Paleoarchean Era and of the Archean Eon. The Acastan begins at the time from which the oldest known rocks - the Acasta Gneiss of Canada's Northwest Territories - are known, and ends at the time from which the oldest known supracrustal rocks - the Isua greenstone belt - are known. The Late Heavy Bombardment would rage through this period, sending many meteorites on collision paths with Earth and vaporizing the oceans. The bombardment would not end until the very end of the Acastan or very early in the Isuan Period. Life is likely to have existed throughout the Acastan, assuming it had not been destroyed by the bombardment.
The Acastan is not further subdivided into epochs.
Acastan Timescale:
Acastan Period - 4030-3810 MYA