New Insights into Past East Antarctic Margin Ice Sheet Behavior from Combined Geophysical and Geological Data Collected During RV Polarstern Expeditions PS140 and PS141 (EASI-2 and -3)

Compared to its inherently unstable West Antarctic companion, the East Antarctic Ice Sheet (EAIS) as the largest ice mass on Earth, was long considered to react relatively robustly to external oceanic and/or atmospheric forcing. Many studies from recent years, however, revealed that ice masses in its marine-based portions such as the Wilkes and Aurora Subglacial Basins, which hold a potential sea-level equivalent of about 20 metres, may react just as sensitively. Currently, many outlet glaciers that connect into these deep hinterland basins are subject to significant ice flow acceleration and grounding-line retreat, hence may hint at potentially substantial ice losses in coming decades and centuries. Since those observations only cover a relatively short time period of several decades, it remains largely uncertain how the modern rapid changes in those sectors compare to ice sheet dynamics since the ice sheet’s last maximum extent some 20,000 years ago. Here, we report first results from newly acquired multibeam bathymetry, sediment echography and in-situ sediment core data from the Davis and Mawson Sea continental shelves, revealing major palaeo-ice stream troughs, grounding-line stabilization features, and extensive meltwater drainage systems. These new combined data will allow for establishing crucial spatiotemporal benchmarks for characterizing past ice sheet dynamics for these vulnerable EAIS portions, and with that deliver a needed framework for testing and validating palaeo-ice sheet models that ultimately aim at predicting their future response more reliably.

Presented at the 29th International Polar Conference 'Dynamic Poles and High Mountain Environments'