Evidence for regional cooling, frontal advances, and East Greenland Ice Sheet changes during the demise of the last interglacial

QUATERNARY SCIENCE REVIEWS

卷:150

Article

Irvali, Nil^1,2  Ninnemann, Ulysses S.^1,2  Kleiven, Helga (Kikki) F.^1,2  Galaasen, Eirik V.^1,2  Morley, Audrey³  Rosenthal, Yair^4,5 

[1] Univ Bergen, Dept Earth Sci, Allegaten 41, N-5007 Bergen, Norway

[2] Bjerknes Ctr Climate Res, Bergen, Norway

[3] Natl Univ Ireland, Discipline Geog, Univ Rd, Galway, Ireland

[4] Rutgers State Univ, Inst Marine & Coastal Sci, 71 Dudley Rd, New Brunswick, NJ 08901 USA

[5] Rutgers State Univ, Dept Geol, 71 Dudley Rd, New Brunswick, NJ 08901 USA

关键词: Eirik drift;    Greenland Ice Sheet;    North Atlantic;    Last interglacial;    Glacial inception;    Multi-proxy;   

DOI  :  10.1016/j.quascirev.2016.08.029

来源: Elsevier

【 摘 要 】

High-resolution lithic and sea surface climate records are used to portray the progression of North Atlantic climate, hydrography, and Greenland Ice Sheet (GIS) activity through the peak of Marine Isotope Stage (MIS) 5e into the last glacial inception. We use Eirik Drift sediment core MD03-2664 (57 degrees 26.34'N, 48 degrees 36.35'W), recovered south of Greenland, strategically located to monitor fluctuations in GIS extent and iceberg calving events. Our results show that a significant amount of ice-rafted debris (IRD) was present during the early MIS 5e, until gradually tapering off by 122 kyr BP due to a diminishing GIS. Sea surface temperatures (SSTs) in the northern subpolar gyre reached peak values early in MIS 5e coinciding with peak insolation. Regional cooling leading to the demise of the last interglacial started prior to the end of the MIS 5e benthic delta O-18 plateau, at approximately 119 kyr BP, as summer insolation waned. This gradual cooling trend is interrupted by an abrupt and brief cooling episode at similar to 117 kyr BP. Increased IRD abundance during the 117 kyr BP cooling event suggests that regional ice sheet growth occurred prior to the end of the MIS 5e benthic delta O-18 plateau, and the major glacial inception. SSTs south of Greenland followed a two-step cooling during the glacial inception similar to the pattern observed across much of the North Atlantic and Europe. Benthic delta O-18 increases in parallel, suggesting that this two-step cooling is linked to a two-phased intensification of Northern Hemisphere glaciation. (C) 2016 The Authors. Published by Elsevier Ltd.

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