A warm pool in the western European margin during the North Atlantic cold events of the MIS5a/4 transition
Abstract
Synchronous increases in eastern North Atlantic sea surface temperatures (SST) and temperate forest cover in western Europe have been reported from several European margin cores during periods of relatively stable ice volume, such as Marine Isotopic Stage (MIS) 3 and the interglacials of the last 400,000 years. Surprisingly, a zoom on climatic data from this region at the MIS 5a/4 transition (~80-70 ka), one of the four largest amplitude and speed ice growth transition of the last 250,000 years, shows a decoupling between marine (several SST proxies) and terrestrial (pollen-based vegetation reconstructions) responses to the millennial-scale climatic changes, i.e. Dansgaard-Oeshger (D-O) cycles 21 to 18' and C20 to C19, punctuating this transition. Our data show a long-term increase in the sea-land thermal gradient from MIS 5a to MIS 4 starting at the onset of C20. Superimposed to this long-term increase, three warmth phases in the eastern North Atlantic subtropical and mid-latitudes were synchronous with adjacent cold landmasses, suggesting three periods of strong sea-land thermal gradients in the western European margin. The occurrence of these strong thermal gradients could have favored the northward transport of moisture and the staggered northern hemisphere ice sheet growth over this period. This work points out that the systematic correlation of North Atlantic warming events with temperature increases in Greenland is not always obvious.
- Publication:
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AGU Spring Meeting Abstracts
- Pub Date:
- May 2013
- Bibcode:
- 2013AGUSMPP32A..02S
- Keywords:
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- 4952 PALEOCEANOGRAPHY / Palynology;
- 4954 PALEOCEANOGRAPHY / Sea surface temperature;
- 4901 PALEOCEANOGRAPHY / Abrupt/rapid climate change;
- 4962 PALEOCEANOGRAPHY / Thermohaline