A Surge Affected, Tidewater Glacier Environment

Austfonna ice cap on the island Nordaustlandet in the Svalbard archipelago (Fig.1) terminates in the open Barents Sea along a nearly 200 km long tidewater glacier front. 28% of the 8,120 km2 ice cap is grounded below sea level. The ice cap comprises 19 drainage basins [Dowdeswell, 1986], of which Bråsvellbreen (1,109 km2) is the second largest. Bråsvellbreen had a major surge between 1936 and 1938, during which the terminus advanced up to 15 km over sea floor with depths varying between 30 m and 100 m. The glacier has experienced a post-surge retreat of up to 5 km, exposing a large area of sea floor that was recently covered by grounded, surged ice. Detailed investigations in this area include single channel 3 kJ sparker seismic, 3.5 kHz echo sounding and 50 kHz side scan sonar profiling [Solheim, 1991]