Reconstruction of changes in the Weddell Sea sector of the Antarctic Ice Sheet since the Last Glacial Maximum

QUATERNARY SCIENCE REVIEWS

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Article

Hillenbrand, Claus-Dieter¹  Bentley, Michael J.²  Stolldorf, Travis D.³  Hein, Andrew S.⁴  Kuhn, Gerhard⁵  Graham, Alastair G. C.⁶  Fogwill, Christopher J.⁷  Kristoffersen, Yngve⁸  Smith, James A.¹  Anderson, John B.³  Larter, Robert D.¹  Melles, Martin⁹  Hodgson, Dominic A.¹  Mulvaney, Robert¹  Sugden, David E.⁴ 

[1] British Antarctic Survey, Cambridge CB3 0ET, England

[2] Univ Durham, Dept Geog, Durham DH1 3LE, England

[3] Rice Univ, Dept Earth Sci, Houston, TX 77005 USA

[4] Univ Edinburgh, Sch Geosci, Edinburgh EH8 9XP, Midlothian, Scotland

[5] Hemholtz Zentrum Polar & Meeresforsch, Alfred Wegener Inst, D-27568 Bremerhaven, Germany

[6] Univ Exeter, Coll Life & Environm Sci, Exeter EX4 4RJ, Devon, England

[7] Univ New S Wales, Climate Change Res Ctr, Sydney, NSW, Australia

[8] Univ Bergen, Dept Earth Sci, N-5014 Bergen, Norway

[9] Univ Cologne, Inst Geol & Mineral, D-50674 Cologne, Germany

关键词: Antarctica;    Cosmogenic nuclide surface exposure age dating;    Deglaciation;    Geomorphology;    Glacial history;    Ice sheet;    Ice Shelf;    Last Glacial Maximum;    Radiocarbon dating;    Sea level;    Weddell Sea;   

DOI  :  10.1016/j.quascirev.2013.07.020

来源: Elsevier

【 摘 要 】

The Weddell Sea sector is one of the main formation sites for Antarctic Bottom Water and an outlet for about one fifth of Antarctica's continental ice volume. Over the last few decades, studies on glacial geological records in this sector have provided conflicting reconstructions of changes in ice-sheet extent and ice-sheet thickness since the Last Glacial Maximum (LGM at ca 23-19 calibrated kiloyears before present, cal ka BP). Terrestrial geomorphological records and exposure ages obtained from rocks in the hinterland of the Weddell Sea, ice-sheet thickness constraints from ice cores and some radiocarbon dates on offshore sediments were interpreted to indicate no significant ice thickening and locally restricted grounding-line advance at the LGM. Other marine geological and geophysical studies concluded that subglacial bedforms mapped on the Weddell Sea continental shelf, subglacial deposits and sediments over-compacted by overriding ice recovered in cores, and the few available radiocarbon ages from marine sediments are consistent with major ice-sheet advance at the LGM. Reflecting the geological interpretations, different ice-sheet models have reconstructed conflicting LGM ice-sheet configurations for the Weddell Sea sector. Consequently, the estimated contributions of ice-sheet build-up in the Weddell Sea sector to the LGM sea-level low-stand of similar to 130 m vary considerably. In this paper, we summarise and review the geological records of past ice-sheet margins and past ice-sheet elevations in the Weddell Sea sector. We compile marine and terrestrial chronological data constraining former ice-sheet size, thereby highlighting different levels of certainty, and present two alternative scenarios of the LGM ice-sheet configuration, including time-slice reconstructions for post-LGM grounding-line retreat. Moreover, we discuss consistencies and possible reasons for inconsistencies between the various reconstructions and propose objectives for future research. The aim of our study is to provide two alternative interpretations of glacial-geological datasets on Antarctic Ice-Sheet History for the Weddell Sea sector, which can be utilised to test and improve numerical ice-sheet models. (C) 2014 The Authors. Published by Elsevier Ltd. All rights reserved.

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