Observations of geomorphic features dated with cosmogenic nuclides are used to determine the configuration of glaciation in Cumberland Sound, Baffin Island, during the last glacial maximum. Cumberland Sound, which was a major drainage of the Laurentide Ice Sheet at its northeastern (Arctic Canada) margin, contained low-gradient ice with a surface slope of ∼0.03° and a driving stress between 2 and 7 kPa. These values are similar to those observed for the ice streams that dominate the dynamics of the West Antarctic ice sheet today. The presence of low-gradient ice in Cumberland Sound and other major outlets may similarly have influenced Laurentide ice sheet behavior and would account for the iceberg discharge episodes that produced the Heinrich-event debris layers observed in North Atlantic ocean sediments.

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