What happened during this time?
Period of intense volcanism on Earth
Mineral-rich igneous rock deposited (Bushveld Complex in South Africa)
Source of rich mines, contains much of the world's andalusite, chromium, fluorspar, platinum and vanadium.
Contains the richest deposits of platinum in the world.
The volcanism of this period produced large quantities of carbon dioxide and other greenhouse gases
Ended the Huronian glaciation (~2.1 Ga), which was started by Great Oxygenation Event
At the end of the Huronian glaciations, considerable rise in marine arsenic concentrations (Fru et al. 2015).
There is a concurrent rapid decrease of atmospheric oxygen, which resulted from due to widespread ocean toxicity, which resulted from the release of toxic elements into the oceans when the ice melted.
Above: oldest evidence of a mobile organism from 2.1 Ga in Gabon
Above: Reconstruction of Diskagma
Prokarotic cyanobacteria dominate along coastlines and in marine waters
Possible evidence for life on land (~2.2 Ga)
Diskagma buttonii: Fossils the size of match heads and connected into bunches by threads in the surface of an ancient soil from South Africa (Retallack et al. 2013)
Most probably the oldest known eukaryote.
Its exact biological affinities are unknown. Its size and hollow shape are similar to the living fungus Geosiphon
Steranes, chemical signatures of eukaryotes, found in Rhyacian rocks
Molecular clock evidence indicates green algae possibly present
Evidence of a mobile organism in an oxygenated shallow-marine environment (Albani et al. 2019)