The Stenian is the last geological period in the Mesoproterozoic. It began 1.2 billion years ago, and ended at 1 billion years ago. Before it was the Ectasian. It is followed by the Tonian.

The supercontinent Rodinia began forming in this period.Fossils of the first known sexually-reproducing eukaryotes are found at the end of the previous period in the Hunting Formation on Somerset Island, Nunavut, Canada.

This period includes the Keweenawan Age at about 1100 mya. view more...