Talus slope evolution under the influence of glaciers with the example of slopes near the Hans Glacier, SW Spitsbergen, Norway

Abstract

On Spitsbergen, which is 60% glaciated, talus slopes have frequently developed in interaction with glaciers, which had an influence on the evolution of the internal structure of slopes. This paper presents the results of geophysical surveys (electrical resistivity tomography – ERT and ground-penetrating radar – GPR) of the talus slopes near the Hans Glacier (SW Spitsbergen). The aim of investigations was to compare the talus slopes under the influence of glaciers in two different parts of the area in order to reveal differences in their internal structure. We assumed that different locations of talus slopes can have an influence on the slope structure, showing different stages of evolution of the talus slopes. The maximum thickness of studied slopes ranges from 20m in a marginal zone of the glacier, to up to 35m without contact with the glacier. Permafrost begins at a depth of 2–3m and can develop until bedrock is reached. The internal structure of these talus slopes contains glacial ice, which is covered by a layer of slope material with a thickness from a few to up to 10m. The buried glacial ice is slowly melting simultaneously with the deglaciation of the area but can remain in the structure of the talus slopes for much longer. Morphogenetic processes, such as avalanches, rockfalls, and debris flows are most visible until the glacial ice is completely melted within the internal structure of the slope. Based on the geophysical and geomorphological data, general models were proposed for the early stages of evolution of talus slopes in valleys under deglaciation.