What happened during this time?
Free oxygen present in the oceans, possibly formed from cyanobacteria around 3.2 billion years ago (Satkoski et al. 2015)
Evidence for chemical weathering of rocks leading to soil formation that occurred in the presence of O2 at least 3.02 billion years ago (Deane and Crowley 2014)
The oldest known glaciation event, Pongola, starts toward the end of this period (~2.9 Ga)
Extensive cratonization events, which have never been repeated in the history of the Earth.
The first supercontinent, Vaalbara, broke up during this time
The Supercontinent, Ur, may have originated during this time (~3.1 Ga)
Ur existed for a very long time, joining with other cratons to later form Rodinia, and even later, Pangaea.
Atmospheric oxygen levels remained very low, as the oxygen continued to be used up in oxidizing minerals on the earth's crust and in the sea
Oldest Banded Iron-Ore formations are from this time
Above: Living stromatolites at Shark's Bay, Australia