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Millennial-Scale History of the George VI Ice Shelf, Antarctic Peninsula
A research project of the Department of Geography.
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.
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.
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.
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.
- Roberts, S.J., Hodgson, D.A., Bentley, M.J., Smith, J.A., Millar, I.L., Olive, V. & Sugden, D.E. (2008). The Holocene history of George VI Ice Shelf, Antarctic Peninsula from clast-provenance analysis of epishelf lake sediments. Palaeogeography, Palaeoclimatology, Palaeoecology 259: 258-283.
- Smith, J.A., Bentley, M.J., Hodgson, D.A. & Cook, A.J. (2007). George VI Ice Shelf: past history, present behaviour and potential mechanisms for future collapse. Antarctic Science 19(1): 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. (2007). Oceanic and atmospheric forcing of early Holocene ice shelf retreat, George VI Ice Shelf, Antarctic Peninsula. Quaternary Science Reviews 26: 500-516.
- Hodgson, D.A., Bentley, M.J., Roberts, S.J., Smith, J.A., Sugden, D.E. & Domack, E.W. (2006). Examining Holocene stability of Antarctic Peninsula ice shelves. EOS, Transactions, American Geophysical Union 87(31): 305-312.
- Smith, J.A., Hodgson, D.A., Bentley, M.J., Verleyen, E., Leng, M.J. & Roberts, S.J. (2006). Limnology of two Antarctic epishelf lakes and their potential to record periods of ice shelf loss. Journal of Paleolimnology 35: 373-394.
- M. Bentley, D.A. Hodgson, D.E. Sugden, S.J. Roberts, J.A. Smith, M.J. Leng & C. Bryant (2005). Early Holocene retreat of the George VI Ice Shelf, Antarctic Peninsula. Geological Society of America 33(3): 173-176.
- Bentley, M.J., Hodgson, D.A., Smith, J.A. & Cox, N.J. (2005). Relative sea level curves for the South Shetland Islands and Marguerite Bay, Antarctic Peninsula. Quaternary Science Reviews 24(10-11): 1203-1216.