Cenozoic landscape evolution of the Lambert basin, East Antarctica: the relative role of rivers and ice sheets S.S.R. Jamieson a, * , N.R.J. Hulton a , D.E. Sugden a , A.J. Payne b,1 , J. Taylor b,1 a Institute of Geography, School of GeoSciences, University of Edinburgh, Drummond St., Edinburgh, EH8 9XP, UK b Bristol Glaciology Centre, School of Geographical Sciences, University Road, Bristol, BS8 1SS, UK Received 1 September 2003; accepted 28 September 2004 Abstract The inception of the Antarctic Ice Sheet at around 34 Ma followed a period of globally warm climatic conditions. The efficacy of glacial erosion since this time is modelled using BEDMAP Antarctic digital elevation data and seismically estimated offshore sediment volumes to derive a DEM of the preglacial topography. Using a GIS, sediment is dvirtually backstackedT on to the present-day topography under dynamic ice sheet conditions to produce a model of the preglacial landscape of the Lambert basin area in East Antarctica. Survival of a preglacial river valley system under the ice suggests that glacial modification of the Lambert region has been modest. The Lambert Graben has focussed erosion for the last 118 million years. Morphometric analysis of the modelled preglacial and present-day subglacial topographies shows parallels with present-day drainage systems in Africa and Australia. We calculate that average rates of glacial and fluvial erosion for the last 118 million years have been similar and are ca. 1–2 m Myr À1 and ca. 0.89–1.79 m Myr À1 respectively. D 2004 Elsevier B.V. All rights reserved. Keywords: Antarctic; Erosion; Evolution; Ice sheet; Landscape; Model 1. Aim We aim to understand what has controlled the evolution of the East Antarctic bedrock landscape since the breakup of Gondwana at 118 Ma. We investigate the influences initially of fluvial processes and subsequently of glacial erosion processes by backstacking the latter products onshore. The rock volumes involved are estimated from sedimentary strata known from seismic surveys and drilling offshore. Our investigation focuses on the Lambert region (Fig. 1) due to its well-defined topographic basin and because its erosion history is well constrained by studies of offshore sediment cores from continental shelf and fan environments in Prydz Bay. The importance of studying long-term landscape change 0921-8181/$ - see front matter D 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.gloplacha.2004.09.015 * Corresponding author. Tel.: +44 131 650 2565; fax: +44 131 650 2524. E-mail address: S.Jamieson@ed.ac.uk (S.S.R. Jamieson). 1 Fax: +44 117 928 7878. Global and Planetary Change 45 (2005) 35 – 49 www.elsevier.com/locate/gloplacha