Jason Peninsula (66°10'S, 61°00'W) is a prominent feature extending some 80 km into the Larsen Ice Shelf from the eastern coast of the Antarctic Peninsula, and consists of widely spaced rock exposures and several ice-domes with elevations up to some 600 m (Fig. 1). The feature was first seen from seaward on 1 December 1893 by Captain C.A. Larsen, who named one of the high summits “Mount Jason” after his ship. Leading the 1902–1904 Swedish Antarctic Expedition, Dr Otto Nordenskjöld observed the area from Borchgrevink Nunatak (66°03'S; 62°30'W) and reported that the summits seen by Larsen were separated from the Antarctic Peninsula. The name “Jason Island” was subsequently adopted for this feature, but in the 1950s researchers belonging to the currently named British Antarctic Survey (BAS) determined Larsen's discovery to be a large peninsula, underlain mainly by calc-alkaline volcanic rocks.