Evidence of the evolution of the East Antarctic Ice Sheet on the continental slope and rise sedimentary record: Insights from the Sabrina Coast, East Antarctica

Abstract

Deciphering how the Antarctic Ice Sheet has responded to past climate warming is critical to understanding its sensitivity and role in current and future climate change. In this context, knowledge of the evolution of the Antarctic Ice Sheet in catchments with large potential sea-level contributions plays a key role. The Sabrina Coast of East Antarctica lies seaward of the second largest, but least known, subglacial basin on Earth, the Aurora Subglacial Basin. It is part of the East Antarctic Ice Sheet and drains to the Sabrina Coast via the Totten Glacier, the third largest drainage system in East Antarctica. Our refined, comprehensive seismic stratigraphic analysis of a large multichannel seismic data set collected in this sector of the Antarctic margin shows that sediments deposited on the continental slope and rise of the Sabrina Coast retain a well-preserved record of variations in glacial and oceanographic dynamics. Isobath and isopach maps evidence a complex, asymmetric evolution of the Sabrina slope and rise, with the western sector being the main sediment depocenter since the emplacement of the East Antarctic Ice Sheet, as indicated by the up to 4-km-thick glacial-related sequences and inferred sedimentation rates of up to 300 m/m.y. However, significant sediment accumulation also occurs in the eastern area, particularly in the western levees of the canyons. Our findings highlight the potential of this region for deep ocean drilling that will provide an unprecedented history of the dynamics of the marine-based ice sheet in the Aurora Subglacial Basin and its sensitivity to climate change under different background climate conditions.