Penultimate Glacial Period

Diagram of glacial cycles, with the Penultimate Glacial Period labelled as MIS 6.

The Penultimate Glacial Period (PGP) is the glacial period that occurred before the Last Glacial Period. The penultimate glacial period is officially unnamed just like the Last Glacial Period. The PGP lasted from ~194,000 years ago, to ~135,000 years ago, and was succeed by the Last Interglacial.[1] The PGP also occurred during Marine Isotope Stage 6 (MIS6).[2] At the glacial ages’ height, it is known to be the most extensive expansion of glaciers in the last 400,000 years over Eurasia, and could be the second or third coolest glacial period over the last 1,000,000 years, as shown by ice cores.[3] Due to this, the global sea level dropped to between 92 and 150 metres below modern-day global mean sea level.[1] The penultimate glacial period expanded ice sheets and shifted temperature zones worldwide, which had a variety of effects on the world's environment, and the organisms that lived in it.[4] At its height, the penultimate glacial period was a more severe glaciation than the Last Glacial Maximum.[2] The PGP covers the last period of the Saalian glaciation in Europe, called the Wolstonian Stage in Britain, and is equivalent to the Illinoian in North America.

  1. ^ a b Colleoni, Florence; Wekerle, Claudia; Näslund, Jens-Ove; Brandefelt, Jenny; Masina, Simona (1 April 2016). "Constraint on the penultimate glacial maximum Northern Hemisphere ice topography (≈140 kyrs BP)". Quaternary Science Reviews. 137: 97–112. Bibcode:2016QSRv..137...97C. doi:10.1016/j.quascirev.2016.01.024.
  2. ^ a b Sjödin, Per; E. Sjöstrand, Agnès; Jakobsson, Mattias; Blum, Michael G.B. (1 July 2012). "Resequencing Data Provide No Evidence for a Human Bottleneck in Africa during the Penultimate Glacial Period". Molecular Biology and Evolution. 29 (7): 1851–1860. doi:10.1093/molbev/mss061. PMID 22319141.
  3. ^ Jouzel, J.; Barkov, N. I.; Barnola, J. M.; Bender, M.; Chappellaz, J.; Genthon, C.; Kotlyakov, V. M.; Lipenkov, V.; Lorius, C.; Petit, J. R.; Raynaud, D.; Raisbeck, G.; Ritz, C.; Sowers, T.; Stievenard, M.; Yiou, F.; Yiou, P. (July 1993). "Extending the Vostok ice-core record of palaeoclimate to the penultimate glacial period". Nature. 364 (6436): 407–412. Bibcode:1993Natur.364..407J. doi:10.1038/364407a0. S2CID 4329245.
  4. ^ Cite error: The named reference Manabe was invoked but never defined (see the help page).

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