Detailed seismic bathymetry beneath Ekström Ice Shelf, Antarctica:
Implications for glacial history and ice-ocean interaction
Abstract
The shape of ice-shelf cavities are a major source of uncertainty in
understanding ice-ocean interactions. This limits assessments of the
response of the Antarctic ice sheets to climate change. Here we use
vibroseis seismic reflection surveys to map the bathymetry beneath the
Ekström Ice Shelf, Dronning Maud Land. The new bathymetry reveals an
inland-sloping trough, reaching depths of 1100 m below sea level, near
the current grounding line, which we attribute to erosion by palaeo-ice
streams. The trough does not cross-cut the outer parts of the
continental shelf. Conductivity-temperature-depth profiles within the
ice-shelf cavity reveal the presence of cold water at shallower depths
and tidal mixing at the ice-shelf margins. It is unknown if warm water
can access the trough. The new bathymetry is thought to be
representative of many ice shelves in Dronning Maud Land, which together
regulate the ice loss from a substantial area of East Antarctica.