Australia: The Land Where Time Began

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Decoupling of Air-Sea Temperature in Western Europe During the Interglacial-Glacial Transition

A decrease in summer insolation is said by the authors1 to have controlled a period of continental ice growth, the Marine Isotope Stage (MIS) 5a/4 transition, between about 80,000-70,000 BP, that was among the 4 largest expansions of ice to have occurred in the past 250,000 years (Ruddimann & McIntyre, 1981). It has been proposed that the warm subpolar and northern subtropical Atlantic Ocean are the sources of the moisture for this expansion of ice (Ruddiman & McIntyre, 1981; Ruddiman & McIntyre, 1979). It is unclear what the mechanism was that allowed the continuous growth of the ice sheets through 3 subtropical cooling events, associated with the discharge of icebergs in the North Atlantic (McManus et al., 1994; Chapman & Shackleton, 1999), and cooling over Greenland (Dansgaard et al., 1984; Anderson et al., 2006), that occurred during this period. In this paper the authors1 reconstruct parallel records of sea surface temperatures from the marine microfossil record and air temperatures from pollen data, from 2 sediment cores collected within the northern subtropical gyre. Throughout the MIS5a/4 transition the thermal gradient between the cold air and the warmer sea increased, being marked by 3 intervals during which there were thermal gradients that were even more pronounced that were associated with the C20, C19 and C18' cold events. The authors1 argue that along the western European margin the warm ocean surface provided a source of moisture that was transported by northward-tracking storms to feed the ice sheets in colder Greenland, northern Europe and the Arctic.

Sources & Further reading

  1. Sanchez Goni, Maria Fernanda, Edouard Bard, Amaelle Landais, Linda Rossignol, and Francesco d/'Errico. "Air-Sea Temperature Decoupling in Western Europe During the Last Interglacial-Glacial Transition." Nature Geosci 6, no. 10 (10//print 2013): 837-41.
Author: M. H. Monroe
Email:  admin@austhrutime.com
Last updated  10/10/2013
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                                                                                           Author: M.H.Monroe  Email: admin@austhrutime.com     Sources & Further reading