Paleoproterozoic

 This period is part of the

 Hadean

 Archaean

 Paleoproterozoic

 Mesoproterozoic

 Neoproterozoic

The Paleoproterozoic is the first of the three sub-divisions of the Proterozoic occurring between 2500 to 1600 million years ago. This is when the continents first stabilized. This is also when the atmospheric oxygen increased. Cyanobacteria were responsible for the increase.