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Rhyacian Period
2300–2050 million years ago




The Rhyacian Period ( /rˈsiən/; Greek: ῥύαξ, romanizedrhýax, meaning "stream of lava") is the second geologic period in the Paleoproterozoic Era and lasted from 2300 Mya to 2050 Mya (million years ago).[1] Instead of being based on stratigraphy, these dates are defined chronometrically.[2]

The Bushveld Igneous Complex and other similar intrusions formed during this period.[2]

The Huronian (Makganyene) global glaciation began at the start of the Rhyacian and lasted 100 million years.[3]

For the time period from 2250 Ma to 2060 Ma, an alternative period based on stratigraphy rather than chronometry, named either the Jatulian or the Eukaryian, was suggested in the geological timescale review 2012 edited by Gradstein et al.,[4] but as of February 2017, this has not yet been officially adopted by the IUGS. The term Jatulian is, however, used in the regional stratigraphy of the Paleoproterozoic rocks of Fennoscandia.[5]

A reconstruction of the Earth as it appeared at the end of the Rhyacian period, 2050 million years ago

ReferencesEdit

  1. ^ "Rhyacian Period". GeoWhen Database. Archived from the original on August 19, 2006. Retrieved January 5, 2006.
  2. ^ a b James G. Ogg (2004). "Status on Divisions of the International Geologic Time Scale". Lethaia. 37 (2): 183–199. doi:10.1080/00241160410006492.
  3. ^ Kopp; Kirschvink, JL; Hilburn, IA; Nash, CZ; et al. (August 2005). "The Paleoproterozoic Snowball: A climate disaster triggered by the evolution of oxygenic photosynthesis" (PDF). PNAS. 102 (32): 11131–6. Bibcode:2005PNAS..10211131K. doi:10.1073/pnas.0504878102. PMC 1183582. PMID 16061801.
  4. ^ 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)
  5. ^ Bingen, B.; Solli, A.; Viola, G.; Torgersen, E.; Sandstad, J.S.; Whitehouse, M.J.; Røhr, T.S.; Ganerød, M.; Nasuti, A. (2015). "Geochronology of the Palaeoproterozoic Kautokeino Greenstone Belt, Finnmark, Norway: Tectonic implications in a Fennoscandia context" (PDF). Norwegian Journal of Geology. 95: 365–396. doi:10.17850/njg95-3-09.