Part of the Mesoarchean Era
Vaalbaran Period - Pongolan Period - Methanian Period
The Pongolan Period is the second, and final, period of the Mesoarchean Era and the fourth of the Archean Eon. The Pongolan begins at the time from which the earliest terrestrial basins are known and ends at the time from which the earliest continental flood basalts are known. The oldest known impact crater, at Miitsoq, Greenland, is known from this period and has been dated at around 2975 MYA. Oxygenic photosynthesis first evolved during the Pongolan, and would lead to Oxygen Catastrophe that was to occur later in the Oxygenian Period. The Pongola glaciation occurred during this period, at around 2900 MYA, and is currently the oldest known glaciation in the planet's geologic history.
The Pongolan is not further subdivided into epochs.
Pongolan Timescale:
Pongolan Period - 3020-2780 MYA