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Sediment infill of subglacial meltwater channels on the West Antarctic continental shelf

Smith, James A.; Hillenbrand, Claus-Dieter; Larter, Robert D.; Graham, Alastair G.C.; Kuhn, Gerhard. 2009 Sediment infill of subglacial meltwater channels on the West Antarctic continental shelf. Quaternary Research, 71 (2). 190-200. 10.1016/j.yqres.2008.11.005

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Abstract/Summary

Subglacial meltwater plays a significant yet poorly understood role in the dynamics of the Antarctic ice sheets. Here we present new swath bathymetry from the western Amundsen Sea Embayment, West Antarctica, showing rneltwater channels eroded into acoustic basement. Their morphological characteristics and size are consistent with incision by subglacial meltwater. To understand how and when these channels formed we have investigated the infill of three channels. Diamictons deposited beneath or proximal to an expanded grounded West Antarctic Ice Sheet are present in two of the channels and these are overlain by glaciomarine sediments deposited after deglaciation. The sediment core from the third channel recovered a turbidite sequence also deposited after the last deglaciation. The presence of deformation till at one core site and the absence of typical meltwater deposits (e.g., sorted sands and gravels) in all three cores suggest that channel incision pre-dates overriding by fast flowing grounded ice during the last glacial period. Given the overall scale of the channels and their incision into bedrock, it is likely that the channels formed over multiple glaciations, possibly since the Miocene, and have been reoccupied on several occasions. This also implies that the channels have survived numerous advances and retreats of grounded ice. (c) 2008 University of Washington. All rights reserved.

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1016/j.yqres.2008.11.005
Programmes: BAS Programmes > Global Science in the Antarctic Context (2005-2009) > Glacial Retreat in Antarctica and Deglaciation of the Earth System
ISSN: 0033-5894
Additional Keywords: Subglacial meltwater; Tunnel valleys; Sediment infill; Subglacial lakes; Antarctica
NORA Subject Terms: Glaciology
Hydrology
Earth Sciences
Date made live: 12 Nov 2010 11:29
URI: http://nora.nerc.ac.uk/id/eprint/11284

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