Kaigas

Events of the Cryogenian Period

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-760 —

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-740 —

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-720 —

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-700 —

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-680 —

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-660 —

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-640 —

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-620 —

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Cryogenian

Ediacaran

Tonian

 

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Marinoan^[1]

Sturtian^[1]

←

First sponge-like animal?^[2]

←

Kaigas glaciation?^[3]

←

First demosponges.^[4]

 Major Glacial period

The Kaigas glaciation was a hypothesized snowball earth event in the Neoproterozoic Era, preceding the Sturtian glaciation. Its occurrence was inferred based on the interpretation of Kaigas formation conglomerates in the stratigraphy overlying the Kalahari Craton as correlative with pre-Sturtian Numees formation glacial diamictites. However, the Kaigas formation was later determined to be non-glacial, and a Sturtian age was assigned to the Numees diamictites. Thus, there is no longer any evidence for a Neoproterozoic glaciation prior to the Sturtian snowball earth event.^[5]

References

1. 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. Brain, C. K., Prave, A. R., Hoffmann, K. H., Fallik, A. E., Herd D. A., Sturrock, C., Young, I., Condon, D. J., Allison, S. G. (2012). "The first animals: ca. 760-million-year-old sponge-like fossils from Namibia". S. Afr. J. Sci. 108 (8): 1–8. doi:10.4102/sajs.v108i1/2.658.
3. Macdonald, F. A.; Schmitz, M. D.; Crowley, J. L.; Roots, C. F.; Jones, D. S.; Maloof, A. C.; Strauss, J. V.; Cohen, P. A.; Johnston, D. T.; Schrag, D. P. (4 March 2010). "Calibrating the Cryogenian". Science 327 (5970): 1241–1243. doi:10.1126/science.1183325. PMID 20203045. (Duration and magnitude are enigmatic)
4. "Discovery of possible earliest animal life pushes back fossil record". phys.org. Retrieved 7 December 2012.
5. Rooney, A. D.; Strauss, J. V.; Brandon, A. D.; MacDonald, F. A. (2015). "A Cryogenian chronology: Two long-lasting synchronous Neoproterozoic glaciations". Geology 43 (5): 459. Bibcode:2015Geo....43..459R. doi:10.1130/G36511.1.