Orosirian
From Wikipedia, the free encyclopedia
The Orosirian (IPA: /ˌɔːrəˈsɪriən/, Greek: orosira, meaning "mountain range") is the third geologic period in the Paleoproterozoic Era and lasted from 2050 Ma to 1800 Ma (million years ago). Instead of being based on stratigraphy, these dates are defined chronometrically.
Latter half of the period was an episode of intensive orogeny on virtually all continents.
Probably during this period Earth's atmosphere changed to oxygen-rich due to photosynthesis of cyanobacteria.
Two largest known impact events on Earth occurred during the Orosirian. At the very beginning of the period, 2023 Ma, a large asteroid collision created the Vredefort impact structure. The event that created the Sudbury Basin structure occurred near the end of the period, 1850 Ma.
[edit] References
- Orosirian Period. GeoWhen Database. Retrieved on January 5, 2006.
- James G. Ogg (2004). "Status on Divisions of the International Geologic Time Scale.". Lethaia 37: 183–199.
| Proterozoic eon | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Paleoproterozoic era | Mesoproterozoic era | Neoproterozoic era | |||||||
| Siderian | Rhyacian | Orosirian | Statherian | Calymmian | Ectasian | Stenian | Tonian | Cryogenian | Ediacaran |
br:Orosirieg de:Orosirium eu:Orosiriar fr:Orosirien it:Orosiriano nl:Orosirien pt:Orosiriano sh:Orosirij zh:造山纪
