The Info List - Orosirian

The Vredefort crater
Vredefort crater
is believed to have formed in this period.

The Orosirian
Period ( /ˌɒroʊˈsɪəriən/; Greek: ὀροσειρά, translit. oroseirá, meaning "mountain range") is the third geologic period in the Paleoproterozoic Era and lasted from 2050 Mya to 1800 Mya (million years ago).[1] 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. Two of the largest known impact events on Earth occurred during the Orosirian. At the very beginning of the period, 2023 Mya, a large asteroid collision created the Vredefort impact structure. The event that created the Sudbury Basin
Sudbury Basin
structure occurred near the end of the period, 1850 Mya. For the time period from about 2060 Ma to 1780 Ma, an alternative period based on stratigraphy rather than chronometry, named the Columbian, was suggested in the geological timescale review 2012 edited by Gradstein et al.,[2] but as of February 2017[update], this has not yet been officially adopted by the IUGS. Paleogeography[edit] The supercontinent Columbia formed at the end of this period. References[edit]

" Orosirian
Period". GeoWhen Database. Retrieved July 8, 2011.  James G. Ogg (2004). "Status on Divisions of the International Geologic
Time Scale". Lethaia. 37 (2): 183–199. doi:10.1080/00241160410006492. 

^ David Huddart; Tim Stott (16 April 2013). Earth Environments: Past, Present and Future. John Wiley & Sons. pp. 1599–. ISBN 978-1-118-68812-0.  ^ Gradstein, F.M. et al. (editors) (2012). The Geologic
Time Scale 2012. 1. Elsevier. pp. 361–365. ISBN 978-0-44-459390-0. CS1 maint: Extra text: authors list (link)

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Paleoproterozoic Era Mesoproterozoic Era Neoproterozoic Era

Siderian Rhyacian Orosirian Statherian

Calymmian Ectasian Stenian

Tonian Cryogenian Ediacaran

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