Vredefort crater is believed to have formed in this period.
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). 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 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., but as of February 2017[update],
this has not yet been officially adopted by the IUGS.
The supercontinent Columbia formed at the end of this period.
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.
^ David Huddart; Tim Stott (16 April 2013). Earth Environments: Past,
Present and Future. John Wiley & Sons. pp. 1599–.
^ 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
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