Crescentic Scours on Palaeo-ice Stream Beds

Subglacial landforms include a range of depositional and erosional features formed by the interaction of ice or meltwater with a soft sedimentary or bedrock substrate. The genesis of many such landforms has received considerable scrutiny, but sets of half-moon- (crescent-) shaped scoured depressions that are known from a number of relict ice-sheet beds have received little attention. New data reveal that these enigmatic features, here termed crescentic scours , are more widespread than previously reported and may be important in understanding broader subglacial processes.