Preliminary report of geological and geophysical surveys off Amery Ice Shelf, East Antarctica

Geological and geophysical surveys off the Amery Ice Shelf, East Antarctica, were carried out during the 1984-1985 Antarctic summer season. The surveyed area involves the continental shelf, slope, rise, the abyssal plain and part of the Kerguelen Plateau. Thickness of the sedimentary layer beneath the continental shelf is estimated to be more than 3.5km from a sonobuoy result. A series of upper strata progrades seaward and is eroded at the sea bottom. In the continental slope, rise and the abyssal plain, the presence of sediments whose thickness exceeds 6km is confirmed. The sediments seem to become thicker toward the continent, particularly the center of Prydz Bay to which the Lambert graben is thought to extend from the inland of Antarctica. In the southwestern margin of the Kerguelen Plateau, the acoustic basement rises toward the Plateau, and is thinly covered by an acoustic transparent layer whose age is relatively old. Dipping strata suggest that the acoustic basement consists of highly consolidated sedimentary layers which have been subjected to a complex tectonic movement related to the origin of the Plateau