Orosirian

The Orosirian Period (pronunciation: /ˌɒroʊˈsɪəriən/; Greek: oroseira - ὀροσειρά, meaning "mountain range") is the third geologic period in the Paleoproterozoic Era and lasted from 2050 Mya to 1800 Mya (million years ago). Instead of being based on stratigraphy, these dates are defined chronometrically. The later half of the period was an episode of intensive orogeny on virtually all continents.

Orosirian

The Orosirian Period (pronunciation: /ˌɒroʊˈsɪəriən/; Greek: oroseira - ὀροσειρά, meaning "mountain range") is the third geologic period in the Paleoproterozoic Era and lasted from 2050 Mya to 1800 Mya (million years ago). Instead of being based on stratigraphy, these dates are defined chronometrically. The later half of the period was an episode of intensive orogeny on virtually all continents.