Moraine development at the high-arctic valley glacier Pedersenbreen, Svalbard

The formation of a moraine mound (hummocky moraine) complex at the Neoglacial limit of Pedersenbreen, Svalbard is discussed. The moraine mounds are composed for the most part of sheared basal diamicton with occasional units of fluvial gravel and laminated silts. In morphology the moraine mound complex resembles an imbricate stack of sediment units which dip towards the glacier margin. Observations of the debris structure within Pedersenbreen are used to explain the formation of the moraine mound complex. A model for the formation of such moraine mounds by englacial thrusting either as part of a glacier surge or due to flow compression at a polythermal ice margin is developed.