Gaskiers glaciation

The Gaskiers glaciation is a period of widespread glacial deposits (e.g. diamictites) that lasted under 340 thousand years, between 579.63 ± 0.15 and 579.88 ± 0.44 million years ago[1] – i.e. late in the Ediacaran Period – making it the last major glacial event of the Precambrian.[2]

Deposits attributed to the Gaskiers - assuming that they were all deposited at the same time - have been found on eight separate palaeocontinents, in some cases occurring close to the equator (at a latitude of 10-30°). The 300 m-thick name-bearing section at Gaskiers, NL is packed full of striated dropstones.[1] Its δ13C values are really low (pushing 8‰), consistent with a period of environmental abnormality.[1] The bed lies just below some of the oldest fossils of the Ediacaran biota, leading to early suggestions that the passing of the glaciation may have paved the way for the evolution of these odd organisms. More accurate dating methods have shown that there is in fact a 9 million year gap between the diamictites and the 570 Ma macrofossils.[1]

References

  1. 1 2 3 4 Pu, Judy P.; Bowring, Samuel A.; Ramezani, Jahandar; Myrow, Paul; Raub, Timothy D.; Landing, Ed; Mills, Andrea; Hodgin, Eben; MacDonald, Francis A. (2016). "Dodging snowballs: Geochronology of the Gaskiers glaciation and the first appearance of the Ediacaran biota". Geology. 44 (11): 955. doi:10.1130/G38284.1.
  2. ↑ F. M. Gradstein, Gabi Ogg, Mark Schmitz, The Geologic Time Scale, Elsevier, 2012, p. 428.


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