Detailed seismic bathymetry beneath Ekstroem Ice Shelf, Antarctica: Implications for glacial history and ice-ocean interaction

The shape of ice-shelf cavities are a major source of uncertainty in understanding ice-ocean interaction and limit our assessment of the response of the Antarctic ice sheets to climate change. Here we use seismic reflection vibroseis data to map, with unprecedented detail, the bathymetry beneath the Ekstrom Ice Shelf, Dronning Maud Land. The new bathymetry reveals an inland-sloping trough, reaching depths of 1100 m near the current grounding line, which we attribute to a palaeo-ice stream. The trough does not cross-cut the continental shelf. Conductivity-Temperature-Depth profiles within the ice-shelf cavity reveal the presence of cold water at shallower depths with clear tidal mixing at the ice-shelf margins. It is unknown if warm water is present in the trough, although it has been observed in a similar trough under a neighbouring ice shelf. These similarities suggest this bathymetry is characteristic of Dronning Maud Land ice shelves.