Sturtian glaciation

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The Sturtian glaciation was a worldwide glaciation during the Cryogenian Period when the Earth experienced repeated large-scale glaciations.[2][4] As of January 2023, the Sturtian glaciation is thought to have lasted from c. 717 Ma to c. 660 Ma, a time span of approximately 57 million years.[2] It is hypothesised to have been be a Snowball Earth event, or contrastingly multiple regional glaciations, and is the longest and most severe known glacial event preserved in the geologic record.

Etymology of name[edit]

The Sturtian glaciation is an informal, but commonly used name for the older of two (the other is known as the Marinoan/Elatina glaciation) worldwide glacial events preserved in Cryogenian rocks.[5] The term Sturtian was originally defined[6] as chronostratigraphic unit (Series) and later proposed as an international chronostratigraphic division;[7] however, this has been superseded by international nomenclature. Ultimately, current usage of the term is in reference to the globally significant Sturt Formation (originally Sturtian Tillite)[8] within the Adelaide Superbasin. The suggestion of the glacial nature of the Sturt Formation in the early 20th century led to international discussion about Neoproterozoic (thought to be Cambrian at the time) glaciations and spurred the research that eventually led to the snowball Earth hypothesis.[5][9] The Sturt Formation itself is named after Sturt Gorge, South Australia.[5][10]

Geology[edit]

Rocks preserving evidence for the Sturtian Glaciation are found on every continent. Notable sections are found in Australia, Canada, China, Ethiopia, Namibia, Siberia, and Svalbaard.

According to Eyles and Young, "Glaciogenic rocks figure prominently in the Neoproterozoic stratigraphy of southeastern Australia and the northern Canadian Cordillera. The Sturtian glaciogenic succession (c. 740 Ma) unconformably overlies rocks of the Burra Group." The Sturtian succession includes two major diamictite-mudstone sequences which represent glacial advance and retreat cycles. It is stratigraphically correlated with the Rapitan Group of North America.[11]

Reusch's Moraine in northern Norway may have been deposited during this period.[12]

See also[edit]

References[edit]

  1. ^ a b Arnaud, Emmanuelle; Halverson, Galen P.; Shields-Zhou, Graham Anthony (30 November 2011). "Chapter 1 The geological record of Neoproterozoic ice ages". Memoirs. Geological Society of London. 36 (1): 1–16. doi:10.1144/M36.1.
  2. ^ a b c d Hoffman, Paul F.; Abbot, Dorian S.; Ashkenazy, Yosef; Benn, Douglas I.; Brocks, Jochen J.; Cohen, Phoebe A.; Cox, Grant M.; Creveling, Jessica R.; Donnadieu, Yannick; Erwin, Douglas H.; Fairchild, Ian J.; Ferreira, David; Goodman, Jason C.; Halverson, Galen P.; Jansen, Malte F. (2017-11-03). "Snowball Earth climate dynamics and Cryogenian geology-geobiology". Science Advances. 3 (11): e1600983. doi:10.1126/sciadv.1600983. ISSN 2375-2548. PMC 5677351. PMID 29134193.
  3. ^ Brocks, Jochen J. (2018-09-28). Lyons, Timothy W.; Droser, Mary L.; Lau, Kimberly V.; Porter, Susannah M. (eds.). "The transition from a cyanobacterial to algal world and the emergence of animals". Emerging Topics in Life Sciences. 2 (2): 181–190. doi:10.1042/ETLS20180039. ISSN 2397-8554.
  4. ^ Arnaud, Emmanuelle; Halverson, Galen P.; Shields-Zhou, Graham Anthony (30 November 2011). "Chapter 1 The geological record of Neoproterozoic ice ages". Memoirs. 36 (1): 1–16. doi:10.1144/M36.1.
  5. ^ a b c Lloyd, Jarred Cain; Preiss, Wolfgang V.; Collins, Alan S.; Virgo, Georgina M.; Blades, Morgan L.; Gilbert, Sarah E.; Subarkah, Darwinaji; Krapf, Carmen B. E.; Amos, Kathryn J. (2022-03-24). "Geochronology and formal stratigraphy of the Sturtian Glaciation in the Adelaide Superbasin". doi:10.31223/x50g9n – via EarthArXiv. {{cite journal}}: Cite journal requires |journal= (help)
  6. ^ Mawson, Douglas; Sprigg, Reginald (1950). "Subdivision of the Adelaide System". Australian Journal of Science. 13 (3): 69–72.
  7. ^ Dunn, P. R.; Thomson, B. P.; Rankama, Kalervo (1971). "Late Pre-Cambrian Glaciation in Australia as a Stratigraphic Boundary". Nature. 231 (5304): 498–502. doi:10.1038/231498a0. ISSN 1476-4687.
  8. ^ Howchin, Walter (1920). "Past Glacial Action in Australia". Year Book. Vol. 13. Australia: Australian Bureau of Statistics. pp. 1133–1146.
  9. ^ Cooper, Barry (2010-12-01). "'Snowball Earth': The Early Contribution from South Australia". Earth Sciences History. 29 (1): 121–145. doi:10.17704/eshi.29.1.j8874825610u68w5. ISSN 0736-623X.
  10. ^ "Australian Stratigraphic Units Database, Geoscience Australia". asud.ga.gov.au. Retrieved 2023-01-04.
  11. ^ Eyles, Nicholas; Young, Grant (1994). "Geodynamic controls on glaciation in Earth history". In Deynoux, M.; Miller, J. M. G.; Domack, E. W.; Eyles, N.; Fairchild, I. J.; Young, G. M. (eds.). Earth's Glacial Record. Cambridge: Cambridge University Press. pp. 5–10. ISBN 978-0521548038.
  12. ^ Arnaud, Emmanuelle; Eyles, Carolyn H. (2002). "Glacial influence on Neoproterozoic sedimentation: the Smalfjord Formation, northern Norway". Sedimentology. 49 (4): 765–788. Bibcode:2002Sedim..49..765A. doi:10.1046/j.1365-3091.2002.00466.x. S2CID 128719279.