Rhombohedral crevasse-fill ridges at the marine margin of a surging Svalbard ice cap

Abstract

The ice cap of Ausftonna in eastern Svalbard is the largest in the Eurasian Arctic at 8,000 km2 and has about 200 km of marine-terminating ice cliffs (Dowdeswell et al. 2008). Several of its drainage basins are of surge-type (Meier & Post 1969) and between 1936 and 1938 one of these basins, Bråsvellbreen (1,100 km2), increased its velocity rapidly and underwent an advance of about 20 km along a 30 km-wide front (Schytt 1969). Since that time the ice-cap terminus has stagnated and retreated, losing mass by a combination of surface melting, thinning and iceberg production. Retreat has revealed several distinctive and well-preserved submarine landforms (Fig. 1) linked to this recent surge activity (Solheim & Pfirman 1985; Solheim 1991).