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Publications - Theses & Dissertations

The last glaciation of the Cumberland Sound region, Baffin Island, Canada, based on glacial geology, cosmogenic dating, and numerical modeling

PhD: University of Colorado Boulder, 1999.

The glacial history of the eastern Canadian Arctic, an important region because of former ice sheet-ocean interactions, has been controversial for at least two decades. This study uses terrestrial, modeling, and geochronological studies to examine the glacial history of southeastern Cumberland Peninsula and adjacent Cumberland Sound; the latter connected the interior of the Laurentide Ice Sheet to the Labrador Sea during the last glaciation.

During the last (Late Foxe) glaciation, local ice flowed off glacially-scoured lowlands (<300-400 m above present sea level) of southeastern Cumberland Peninsula into Cumberland Sound, where it was incorporated into a grounded Laurentide outlet glacier derived from the Foxe Dome. 10Be and 26Al surface exposure ages associated with the glacially-scoured lowlands lie between 19,000 and 9,000 years ago. Weathered upland plateaus (>300-400 m asl) on southeastern Cumberland Peninsula lack evidence of glacial erosion and contain weathered bedrock tors that produce 10Be and 26Al ages of >35,000 years ago, implying that these higher areas were not eroded by Late Foxe ice. The upper limit of glacial erosion constrains the maximum former ice surface elevations to <300 m asl, and translates into an ice surface slope of ∼0.5 m/km for the Laurentide outlet glacier in Cumberland Sound. Coastal southeastern Cumberland Peninsula deglaciated by 9.4 14C ka BP. Relatively slow ice margin retreat along outer Cumberland Sound, and when ice retreated onto land, caused restrained rebound.

The inferred former glacial configuration in the study area consists of dynamic low-gradient outlet glaciers occupying low-lying areas, including a Laurentide outlet glacier in Cumberland Sound, with coastal uplands either ice free or covered only by nonerosive snow or thin cold-based ice. This glacial scenario is simulated with a numerical model based on glaciological theory. Well-developed cirques along coastal southeastern Cumberland Peninsula indicate that the Laurentide Ice Sheet was not continuously present throughout Cumberland Sound during glacial cycles.

During the last glaciation, and by inference other cold, dry periods, basal conditions and low-gradient glacial systems on southern Baffin Island may have strongly influenced the dominant aspects of local and northeastern Laurentide ice dynamics.