Department of Geography

Glacial Geomorphology

Glaciation leaves behind a variety of bedforms on the Earth surface. Part of my research explores how they form, with an aim to reconstruct the conditions of past ice flow using them and to learn something about the processes that operate at the glacier bed. The following images show two examples which I have studied.

Centimetre-scale: Pins of calcite precipitate protruding from the leeside of a limestone bed specimen (collected by Bernard Hallet from Castleguard Glacier, Canada)

Kilometre-scale: Drumlins of the Puget Sound, Washington State, USA. This LIDAR image is about 6 km wide. Image courtesy: Ralph Haugerud.

When sediment-laden ice sublimates, a debris layer (an ablation till) forms on the surface and it can become thick enough to obscure the ice. This situation is found in central Beacon Valley, Antarctica. Together with collaborators at the University of Washington, I have studied the cosmogenic ³He systematics of the debris accretion process and applied our model to understand how the till layer in Beacon Valley developed while it also became spectacularly patterned by contraction-crack polygons

Beacon Valley (photo by Ron Sletten)

Polygonal pattern on the sublimation till that covers relict ice (not visible) in Beacon Valley. The polygon diameter is about 10m.