A large tectonic-controlled subglacial lake with ocean drainage in Princess Elizabeth Land, East Antarctica

Abstract

<p>The Princess Elizabeth Land (PEL) sector of the East Antarctic Ice Sheet, one of the largest grounded ice reservoirs in Antarctica, is adjacent to regions that experienced significant change during the last glacial maximum. The identification of subglacial water in PEL (to date only inferred from satellite image data) would provide important constraints on our estimation of the basal thermal condition in this region. Also, the existence of a large subglacial hydrology system in PEL comes with potential impacts on the basal melting rate and stability of downstream ice shelves, such as the West Ice Shelf. Here we present geophysical evidences confirming the existence of a large subglacial lake in PEL, hereby referred as Lake Snow Eagle (LSE), for the first time, using recently acquired aerogeophyscial data by international collaborations. We estimate LSE to be about 42 km in length and 370 km<sup>2</sup> in area, making it one of the largest subglacial lakes in Antarctica. LSE is shown to lie in a subglacial canyon system that is linked to the coastal ice shelves, which makes LSE the first known major Antarctic interior water body that has a potential direct hydrological pathway into the ocean. We then systematically investigate its geological characteristics and bathymetry by 2-D geophysics modellings. We estimate the water volume of LSE to be about 21 km<sup>3</sup>, while the sediment volume to be about 20 km<sup>3</sup>. Our geophysical modelling results also suggest that LSE is located along a compressional geologic boundary, indicating possible tectonic controls over LSE.</p>