Large areas of the Antarctic continent lack terrestrial or airborne magnetic and gravity survey coverage due to the harsh climate and extended distances involved. Satellite data are often the only source of information for the study of this remote region. New, high resolution Gravity Recovery and Climate Experiment (GRACE) gravity data greatly improve upon the previous EGM96 (Earth Gravity Model) data for the region by filling in the missing data with satellite gravity measurements.
The new information from GRACE is of sufficient resolution to perform regional gravity studies of the Antarctic continent in areas previously lacking good gravity data, such as East Antarctica. Comparative analyses between GRACE gravity and topographic data from land, airborne, and marine surveys can provide new insights on the tectonic properties of the Antarctic continent.
These data are analyzed for improved estimates of the crustal thickness variations for the region south of 60° South including West and East Antarctica and the surrounding marine area. These thickness variations provide important constraints on the heat flow, seismicity, and neotectonism in the region. These results, in combination with the GRACE gravity observations, provide evidence of an impact crater located deep under the continental ice sheet in Wilkes Land, East Antarctica. The inferred impact crater includes a circular area of thinned crust with a ringed basin in the subglacial BEDMAP topography that is overlain by a positive relative gravity anomaly. This combination of data signatures is observed over giant impact basins
on the Moon, Mars, and other planets where it is related to impact-generated crustal mascons. Several lines of evidence are explored concerning the possible effects of the inferred impact crater on the crustal evolution of East Antarctica and its possible relation to the great Permian-Triassic extinction.