Stenian

The third and final period of the Mesoproterozoic era, spanning 1.2 billion to 1 billion years ago and closing the era. It is distinguished from the preceding two periods by the formation of orogenic, or mountain building, belts, as the supercontinent Rodinia began assembling from the fragments of Columbia. This description is adapted from Wikipedia contributors under CC BY-SA 4.0; changes were made. https://creativecommons.org/licenses/by-sa/4.0/