Millennial-scale fluctuations of the European Ice Sheet at the end of the last glacial, and their potential impact on global climate

QUATERNARY SCIENCE REVIEWS

卷:123

Article

Toucanne, Samuel¹  Soulet, Guillaume²  Freslon, Nicolas¹  Jacinto, Ricardo Silva¹  Dennielou, Bernard¹  Zaragosi, Sebastien³  Eynaud, Frederique³  Bourillet, Jean-Francois¹  Bayon, Germain¹ 

[1] IFREMER, Unite Rech Geosci Marines, F-29280 Plouzane, France

[2] Woods Hole Oceanog Inst, Dept Geol & Geophys, Woods Hole, MA 02543 USA

[3] Univ Bordeaux, UMR CNRS EPOC 5805, F-33405 Talence, France

关键词: European ice-sheet;    Channel River;    Meltwater;    Deglaciation;    Neodymium;    Termination;   

DOI  :  10.1016/j.quascirev.2015.06.010

来源: Elsevier

【 摘 要 】

Reconstructing Northern Hemisphere ice-sheet oscillations and meltwater routing to the ocean is important to better understand the mechanisms behind abrupt climate changes. To date, research efforts have mainly focused on the North American (Laurentide) ice-sheets (LIS), leaving the potential role of the European Ice Sheet (EIS), and of the Scandinavian ice-sheet (SIS) in particular, largely unexplored. Using neodymium isotopes in detrital sediments deposited off the Channel River, we provide a continuous and well-dated record for the evolution of the EIS southern margin through the end of the last glacial period and during the deglaciation. Our results reveal that the evolution of EIS margins was accompanied with substantial ice recession (especially of the SIS) and simultaneous release of meltwater to the North Atlantic. These events occurred both in the course of the EIS to its LGM position (i.e., during Heinrich Stadial -HS- 3 and HS2; similar to 31-29 ka and similar to 26-23 ka, respectively) and during the deglaciation (i.e., at similar to 22 ka, similar to 20-19 ka and from 18.2 +/- 0.2 to 16.7 +/- 0.2 ka that corresponds to the first part of HS1). The deglaciation was discontinuous in character, and similar in timing to that of the southern LIS margin, with moderate ice-sheet retreat (from 22.5 +/- 0.2 ka in the Baltic lowlands) as soon as the northern summer insolation increase (from similar to 23 ka) and an acceleration of the margin retreat thereafter (from similar to 20 ka). Importantly, our results show that EIS retreat events and release of meltwater to the North Atlantic during the deglaciation coincide with AMOC destabilisation and interhemispheric climate changes. They thus suggest that the EIS, together with the LIS, could have played a critical role in the climatic reorganization that accompanied the last deglaciation. Finally, our data suggest that meltwater discharges to the North Atlantic produced by large-scale recession of continental parts of Northern Hemisphere ice sheets during HS, could have been a possible source for the oceanic perturbations (i.e., AMOC shutdown) responsible for the marine-based ice stream purge cycle, or so-called HE's, that punctuate the last glacial period. (C) 2015 Elsevier Ltd. All rights reserved.

【 授权许可】

Free