Hidden under the ice: unravelling the tectonomorphic history of the Bellingshausen Sea Sector, West Antarctica

The Bellingshausen Sea sector is largely covered by the West Antarctic Ice Sheet, which impedes direct geological investigations. The rift-related structures of the West Antarctic Rift System presumably control the course of ice streams. In turn, the glacially eroded troughs provide pathways for warm oceanic deep water, which causes basal melting of the overlying ice.

During Polarstern cruise PS134 we collected rock samples from onshore nunataks and clastic sediments from glacial outlets. We apply petrographic analyses and radiometric dating on apatite and zircon to characterize the source area hidden beneath the ice and to investigate the thermotectonic evolution of the Bellingshausen sector.

Our data will provide insights into the geological units present under the ice as well as information on the timing of activity, mode, and kinematic relationships of the rift branches of the West Antarctic Rift System in the Bellingshausen Sea sector. These new data allow to refine palaeotopographic models of West Antarctica, which will provide boundary conditions for understanding and modelling the onset of the glaciation of West Antarctica. Combined with offshore seismic and sedimentological information, the new data will also allow to visualize onshore and offshore denudation and burial over time, which will contribute to understanding source-sink relationships, drainage patterns and the regional long-term landscape evolution.