Neoarchean

The Neoarchean period is crucial in Earth’s history for the first accumulation of free oxygen in the atmosphere, even though the levels were still relatively low. Cyanobacteria, which had developed the ability to perform oxygenic photosynthesis, played a significant role in this gradual increase in oxygen, although much of it was initially absorbed by iron and other chemicals in the ocean. The oxygen combined with dissolved iron in the oceans to form iron oxide deposits, resulting in the deposition of large amounts of Banded Iron Formations (BIFs), which are prevalent in the geological record. 

Tectonic activity during this time led to the assembly of one of Earth’s earliest supercontinents, known as Kenorland. Evidence of this supercontinent comes from cratons in modern-day North America, Baltica, and Australia. Volcanic activity remained high, and the Earth’s mantle was still hotter than today, affecting the dynamics of early tectonic plates.