The Proterozoic lasted about 2 billion years and accounts for 40% of the Earth's total geological history. The deep Archean oceans had become wide shallow seas with layers of marine sediments.

These Proterozoic carbonate platforms provided an ideal environment for primitive life forms such as anaerobic and aerobic prokaryotes to flourish and diversify. Fossils discovered within these carbonates record the evolution from simple single-celled organisms to first more advanced multicellular animals, some of which have relatives in modern times.

Continental masses, larger than those of Archean time accreted to become the first supercontinents. A major change in climate towards the end of the Proterozoic led to one of the most severe global ice ages on our planet.