Full bibliography

The East Antarctic Ice Sheet (EAIS) is generally assumed to have been relatively insensitive to Quaternary climate change. However, recent studies have shown potential instabilities in coastal, marine sectors of the EAIS. In addition, long-term climate reconstructions and modelling experiments indicate the potential for significant changes in ice volume and ice sheet configuration since the Pliocene. Hence, more empirical evidence for ice surface and ice volume changes is required to discriminate between contrasting inferences. MAGIC-DML is an ongoing Swedish-US-Norwegian-German-UK collaboration focused on improving ice sheet models by filling critical data gaps that exist in our knowledge of the timing and pattern of ice surface changes along the western Dronning Maud Land (DML) margin and combining this with advances in numerical techniques. Here, we report cosmogenic multi-nuclide data from bedrock and erratics at 72 sample locations on nunatak ranges from Heimefrontfjella to along Penck-Jutulstraumen ice stream throughs in western Dronning Maud Land. The sample locations span elevations between 741-2437 m above sea level, and record apparent exposure ages between <2 ka and >5 Ma. The highest bedrock samples, from high on the inland nunatak ranges, indicate continuous exposure since >5 Ma, with a very low erosion rate of 15±3 cm Ma-1. These results indicate that the ice sheet has not extensively buried and eroded these mountain ranges since at least the Pliocene Moreover, and in contrast to current studies in eastern Dronning Maud Land, we record clear indications of a thicker-than-present ice sheet along the Penck-Jutulstraumen throughs within the last glacial cycle, with a thinning of ~35-120 m towards the present ice surface on several nunataks during the Holocene (~2-11 ka). These results thus indicate ice-surface fluctuations of several hundred meters between the current grounding line and the edge of the polar plateau for the last glacial cycle.