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Department of Geography

Departmental Research Projects

Millennial-Scale History of the George VI Ice Shelf, Antarctic Peninsula

A research project of the Department of Geography.

Background

This project was a collaboration between Mike Bentley (Durham), David Sugden (Edinburgh), and Dom Hodgson (British Antarctic Survey). It was funded (AFI 2/69) by the UK Natural Environment Research Council (NERC) under its Antarctic Funding Initiative grants scheme.

Aims

The aim of this project was to determine the millennial-scale variability of George VI Ice Shelf. We used a multi-proxy approach to test the hypothesis that the ice shelf has waxed and waned in response to Holocene climate change. Distinctive lake-ice conveyor deposits and the lithology and biology of bottom sediments from epishelf lakes on the western margin of the ice shelf (such as Moutonnée Lake) indicate periods of former ice-shelf presence or absence throughout the Holocene.

Methods

We have used a variety of proxies for inferring ice shelf presence/absence, including clast lithology, size/mass, grain size distributions, magnetic susceptibility, total organic content, diatoms, foraminifera, isotopes (bulk sediment 13delC, carbonate 13delC and carbonate 18delO), macrofossils and several others.

Findings

We have achieved our overall aim of understanding the millennial-scale behaviour of George VI Ice Shelf, and have successfully tested the hypothesis that the ice shelf fluctuated in response to Holocene climate change. Our work has demonstrated that the George VI Ice Shelf was absent in the Early Holocene, from ca. 9595–7945 cal yr BP (Bentley et al., 2005). This is a key result because it is the first time that past collapse of a currently extant ice shelf has been demonstrated, and implies that one or both of Early Holocene atmospheric or oceanographic warmth were greater than seen in recent decades.

Published Results

Journal Article

  • Roberts, S.J., Hodgson, D.A., Bentley, M.J., Smith, J.A., Millar, I.L., Olive, V. & Sugden, D.E. The Holocene history of George VI Ice Shelf, Antarctic Peninsula from clast-provenance analysis of epishelf lake sediments. Palaeogeography, Palaeoclimatology, Palaeoecology. 2008;259:258-283.
  • Smith, J.A., Bentley, M.J., Hodgson, D.A. & Cook, A.J. George VI Ice Shelf: past history, present behaviour and potential mechanisms for future collapse. Antarctic Science. 2007;19:131-142.
  • Smith, J.A., Bentley, M.J., Hodgson, D.A., Roberts, S.J., Verleyen, E., Leng, M.J., Lloyd, J.M., Barrett, M.J. & Sugden, D.E. Oceanic and atmospheric forcing of early Holocene ice shelf retreat, George VI Ice Shelf, Antarctic Peninsula. Quaternary Science Reviews. 2007;26:500-516.
  • Hodgson, D.A., Bentley, M.J., Roberts, S.J., Smith, J.A., Sugden, D.E. & Domack, E.W. Examining Holocene stability of Antarctic Peninsula ice shelves. EOS, Transactions, American Geophysical Union. 2006;87:305-312.
  • Smith, J.A., Hodgson, D.A., Bentley, M.J., Verleyen, E., Leng, M.J. & Roberts, S.J. Limnology of two Antarctic epishelf lakes and their potential to record periods of ice shelf loss. Journal of Paleolimnology. 2006;35:373-394.
  • M. Bentley, D.A. Hodgson, D.E. Sugden, S.J. Roberts, J.A. Smith, M.J. Leng & C. Bryant Early Holocene retreat of the George VI Ice Shelf, Antarctic Peninsula. Geological Society of America. 2005;33:173-176.
  • Bentley, M.J., Hodgson, D.A., Smith, J.A. & Cox, N.J. Relative sea level curves for the South Shetland Islands and Marguerite Bay, Antarctic Peninsula. Quaternary Science Reviews. 2005;24:1203-1216.

Staff

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