A Detailed Postglacial Retreat Chronology for the Lambert Glacier, East Antarctica

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This award is for support for one year of funding to produce a dated record of the late Pleistocene highstand and subsequent retreat of the Lambert Glacier and its tributaries in East Antarctica. These glaciers comprise one of the largest outflow systems in the East Antarctic ice sheet, draining ~ 10% of its area. Cosmogenic isotopes will be used to date boulders from glacial maximum moraines and younger retreat moraines at two sites; on the Lambert Glacier at the Mawson Escarpment, and on the Fisher Glacier, at Mt Menzies. These sites were mapped and sampled in 1997/98. The goal of this study is to produce an ice-surface reconstruction of the Lambert Basin from the last glacial maximum to present. In particular, dating the moraine sequence in the Mawson Escarpment will constrain the surface lowering history of the Lambert Glacier itself, indicating whether this giant outlet glacier withdrew rapidly or gradually from its glacial maximum position. This work will complement evidence from marine studies in Prydz Bay and will allow comparisons to be made with the deglaciation of the Ross Sea region. The reconstruction will also help to define the ice loading history of the Lambert Basin for isostatic rebound modeling and geodetic studies.