Monday, 27 August 2007 - 1:50 PM
1.P1.A-2

Antarctic Ice Sheet dynamics through the Neogene from evidence in the ANDRILL–McMurdo Ice Shelf Project drillcore (AND-1B)

Ross D. Powell1, T. R. Naish2, L. A. Krissek3, G. H. Browne4, L. Carter2, E. A. Cowan5, G. B. Dunbar2, R. M. McKay2, T. I. Wilch6, and the Andrill - MIS Science Team7. (1) Department of Geology and Environmental Geosciences, Northern Illinois University, DeKalb, IL 60115, (2) Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand, (3) Department of Geosciences, The Ohio State University, Columbus, OH, (4) Geological and Nuclear Sciences, Lower Hutt, New Zealand, (5) Department of Geology, Appalachian State University, Boone, NC, (6) Department of Geological Sciences, Albion College, Albion, MI, (7) http://www.andrill.org/support/references/appendixc.html

ANDRILL completed its first season in 2006-07 drilling AND-1B through the McMurdo Ice Shelf (MIS) to a depth of 1,285m below the sea floor, a record for Antarctic margin drilling, with 99% recovery. The alternating glacial-interglacial sediment packages interbedded with volcanics provide a uniquely detailed record of Antarctic glacial and climatic change through the Neogene. This paper summarizes the initial characterization of lithofacies and syndepositional structures relevant to understanding the regime and dynamics of past Antarctic Ice Sheets based on the ANDRILL-MIS Initial Report. Results show the Antarctic Ice Sheet was massive under a cold polar glacial regime during the earlier Miocene and Pleistocene but under a more dynamic and warmer polythermal glacial regime in the later Miocene and Pliocene. More detailed research, including a modelling component, is planned in order to understand the dynamics under these different regimes.

[Manuscript]

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