Glacial geomorphology and cosmogenic 10 Be and 26 Al exposure ages in the northern Dufek Massif, Weddell Sea embayment, Antarctica

Abstract We studied the glacial geomorphology and geochronology of two ice-free valleys in the Dufek Massif (Antarctic Specially Protected Area 119) providing new constraints on past ice sheet thickness in the Weddell Sea embayment. 10 Be and 26 Al cosmogenic surface exposure dating provided chronol...

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Bibliographic Details
Published in:Antarctic Science
Main Authors: Hodgson, Dominic A., Bentley, Michael J., Schnabel, Christoph, Cziferszky, Andreas, Fretwell, Peter, Convey, Peter, Xu, Sheng
Format: Article in Journal/Newspaper
Language:English
Published: Cambridge University Press (CUP) 2012
Subjects:
Geology
Ecology, Evolution, Behavior and Systematics
Oceanography
Antarctic
Weddell Sea
Weddell
Dufek Massif
Antarc*
Antarctic Science
Antarctica
Ice Sheet
Online Access:http://dx.doi.org/10.1017/s0954102012000016
https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102012000016
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Summary:Abstract We studied the glacial geomorphology and geochronology of two ice-free valleys in the Dufek Massif (Antarctic Specially Protected Area 119) providing new constraints on past ice sheet thickness in the Weddell Sea embayment. 10 Be and 26 Al cosmogenic surface exposure dating provided chronological control. Seven glacial stages are proposed. These include an alpine glaciation, with subsequent (mid-Miocene?) over-riding by a warm-based ice sheet. Subsequent advances are marked by a series of minor drift deposits at 760 m altitude at > 1 Ma, followed by at least two later ice sheet advances that are characterized by extensive drift sheet deposition. An advance of plateau ice field outlet glaciers from the south postdated these drift sheets. The most recent advance involved the cold-based expansion of the ice sheet from the north at the Last Glacial Maximum, or earlier, which deposited a series of bouldery moraines during its retreat. This suggests at most a relatively modest expansion of the ice sheet and outlet glaciers dominated by a lateral ice expansion of just 2–3 km and maintaining a thickness similar to that of the northern ice sheet front. These observations are consistent with other reports of modest ice sheet thickening around the Weddell Sea embayment during the Last Glacial Maximum.

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