Part of the Archean Eon
Zirconian Era - Paleoarchean Era - Mesoarchean Era
The Paleoarchean is the first era of the Archean Eon. The Paleoarchean begins at the time from which the planet's oldest rocks - Acasta Gneiss - are known, and ends at the time from which the the oldest macroscopic fossils - stromatolites - are known. The Late Heavy Bombardment that began in the Hadean and likely destroyed all Hadean life - believed to have evolved by the Jacobian Period - and vaporized the early oceans raged on well into the Paleoarchean. However, the young Earth would recover from the bombardment, and by the end of the era, life had rose again and the oceans had reformed. The supercontinent of Vaalbara - the first such land mass in the planet's history - would form during this era.
The Paleoarchean is subdivided into two period: the Acastan and the Isuan.
Paleoarchean Timescale:
Paleoarchean Era - 4030-3490 MYA
-Acastan Period - 4030-3810 MYA
-Isuan Period - 3810-3490 MYA