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The Cryosphere An interactive open-access journal of the European Geosciences Union
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Volume 12, issue 7 | Copyright
The Cryosphere, 12, 2383-2399, 2018
https://doi.org/10.5194/tc-12-2383-2018
© Author(s) 2018. This work is distributed under
the Creative Commons Attribution 4.0 License.

Research article 20 Jul 2018

Research article | 20 Jul 2018

Deglaciation and future stability of the Coats Land ice margin, Antarctica

Dominic A. Hodgson1,2, Kelly Hogan1, James M. Smith1, James A. Smith1, Claus-Dieter Hillenbrand1, Alastair G. C. Graham3, Peter Fretwell1, Claire Allen1, Vicky Peck1, Jan-Erik Arndt4, Boris Dorschel4, Christian Hübscher5, Andrew M. Smith1, and Robert Larter1 Dominic A. Hodgson et al.
  • 1British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, UK
  • 2Department of Geography, University of Durham, Durham, DH1 3LE, UK
  • 3Department of Geography, University of Exeter, Exeter, EX4 4RJ, UK
  • 4Alfred Wegener Institute Van-Ronzelen-Str. 2, 27568 Bremerhaven, Germany
  • 5Institute of Geophysics, University of Hamburg, Bundesstr. 55 20146 Hamburg, Germany

Abstract. The East Antarctic Ice Sheet discharges into the Weddell Sea via the Coats Land ice margin. We have used geophysical data to determine the changing ice-sheet configuration in this region through its last glacial advance and Holocene retreat and to identify constraints on its future stability. Methods included high-resolution multibeam bathymetry, sub-bottom profiles, seismic-reflection profiles, sediment core analysis and satellite altimetry. These provide evidence that Coats Land glaciers and ice streams merged with the palaeo-Filchner Ice Stream during the last glacial advance. Retreat of this ice stream from 12848 to 8351cal.yrBP resulted in its progressive southwards decoupling from Coats Land outlet glaciers. Moraines and grounding-zone wedges document the subsequent retreat and thinning of these glaciers, their loss of contact with the bed and the formation of ice shelves, which re-advanced to pinning points on topographic highs at the distal end of the troughs. Once fully detached from the bed, these ice shelves were predisposed to rapid retreat back to coastal grounding lines. This was due to reverse-bed slopes, the consequent absence of further pinning points in the troughs and potentially to the loss of structural integrity resulting from weaknesses inherited at the grounding line. These processes explain why there are no large ice shelves in the eastern Weddell Sea between 75.5 and 77°S.

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We studied the Coats Land ice margin, Antarctica, providing a multi-disciplinary geophysical assessment of the ice sheet configuration through its last advance and retreat; a description of the physical constraints on the stability of the past and present ice and future margin based on its submarine geomorphology and ice-sheet geometry; and evidence that once detached from the bed, the ice shelves in this region were predisposed to rapid retreat back to coastal grounding lines.
We studied the Coats Land ice margin, Antarctica, providing a multi-disciplinary geophysical...
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