Wednesday, 29 August 2007 - 9:00 AM
3.PL-2

Landscape evolution of Antarctica

David Sugden, Stewart Jamieson, and Nick Hulton. School of GeoSciences, University of Edinburgh, Drummond Street, Edinburgh, United Kingdom

We build a synthesis of landscape evolution based on the geomorphology of passive continental margins and former mid-latitude Pleistocene ice sheets. In common with other continental fragments of Gondwana, there is a fluvial signature to the landscape in the form of the coastal erosion surfaces and escarpments, incised river valleys and a continent-wide network of river basins. A selective glacial signature reflects the presence or absence of ice at the pressure melting point.  Early phases of local, often warm-based glaciation centred on mountain massifs began around 34 Ma.  The ice sheet expanded to its maximum at ~14 Ma and eroded a radial array of troughs through the coastal mountains and deepened the continental shelf, before retreating to its present dimensions.  Subsequent changes in ice extent are forced mainly by sea-level change.  Weathering rates of exposed bedrock have been remarkably slow under the hyper-arid polar climate of the last ~13.5 Ma.

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