Active Thermokarst Processes, Eastern Banks Island, Western Canadian Arctic

Abstract

Active thermokarst processes occur on the hummocky and rolling terrain of eastern Banks Island, in the western Canadian Arctic. The underlying sediments are ice-rich glacial silts, sands, and gravels. Ground ice slumps, triggered by a variety of local conditions, are particularly numerous in the area to the west of Johnson Point. Maximum rates of headwall retreat of between 6.0–8.0 m/y−1 appear typical but many slumps are short-lived and become stabilised within 30–50 summers of their initiation. Rapid thermal erosion along ice wedges gives rise to badland topography in certain areas where ice-rich silts enclose large ice wedges.