The Statherian is the fourth and final geologic period in the Paleoproterozoic Era, lasting from 1800 to 1600 million years ago (Ma) and spanning 200 million years. It follows the Orosirian Period and precedes the Calymmian Period, with the latter belonging to the Mesoproterozoic Era. Instead of being based on stratigraphy, these dates are defined chronometrically.