HR: 13:40h
AN: PP53C-01    [Abstracts]
TI: Antarctic ice sheet collapse and growth in Pliocene times - an ice sheet modeling approach
AU: * Barrett, P J
EM: peter.barrett@vuw.ac.nz
AF: Antarctic Research Centre, Victoria University of Wellington P O Box 600, Wellington, 6005 New Zealand
AU: Payne, T J
EM: a.j.payne@bristol.ac.uk
AF: Bristol Glaciology Centre, School of Geographical Sciences University of Bristol University Road, Bristol, BS8 1SS United Kingdom
AB: Pliocene marine diatoms found in high level glacial deposits in the Transantarctic Mountains have been ascribed to inland seas and ice-free conditions in the Antarcic interior at that time followed by a major expansion of the ice sheet that over-rode the mountains. However, circumstantial evidence has led to an alternative view that the deposits are much older, and that the diatoms have become incorporated into the deposits through post-depositional atmospheric contamination. This study tests the feasibility of the East Antarctic interior as a possible source through ice sheet modeling. We address two questions. i) under what conditions could East Antarctic ice become thick enough and warm enough at the base to have deposited glacial debris in their present high locations in the Transantarctic Mountains, and ii) under these conditions is it likely that past ice sheets could have delivered diatomaceous marine sediments to the those locations from the Antarctic interior? We will model two situations i) Taking the present topography of East Antarctica, and varying regional temperature and likely related precipitation regimes. ii) Taking the present temperature (and representative past warmer temperatures) and lowering the Transantarctic Mountains barrier to a level where the basal glacial debris now found on benches up to 2500 m above sea level could have been deposited under temperate glacial conditions. We will focus on two regions in particular, the McMurdo Sound region, where both climate and uplift history are best known, and the Beardmore Glacier area, where the interpretation of the glacial deposits is most in contention.
DE: 9310 Antarctica
DE: 5416 Glaciation
DE: 3344 Paleoclimatology
DE: 3210 Modeling
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting