East Antarctica ice sheet in Schirmacher Oasis, Central Dronning Maud Land, during the past 158 ka

Abstract

Varied geomorphic landforms along the coast of eastern Antarctica suggest that the most recent phase of ice retreat was spatially heterogeneous. Ice retreat here comprised; a thinning of the East Antarctic Ice Sheet (EAIS) by up to 500 m and the recession of the ice wall in kilometre. This retreat deposited moraines over the Schirmacher Oasis (SO) in central Dronning Maud Land with minimal reworking. The present study used optical dating of the recessional moraines to determine the timing of their final emplacement. Three phases of moraine deposition, during 158–125 ka; 76–50 ka and 22 ka to present, were inferred. It is suggested that decreased sea surface temperatures and increased sea ice cover of the surrounding oceans limited the moisture supply and led to the retreat of ice. By ~ 35 ka the SO became ice-free and has remained so, ever since. The inference that the ice sheet in this region was moisture limited, implies that in a global warming context, this region may not contribute to an increase in sea-level. Instead, a warming-induced increase in moisture supply may even add to ice cover in the region.