CGRG Bibliography of Canadian Geomorphology
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Author : Clark, C.D.; Knight, J.K.; and Gray, J.T.
Date : 2000.
Title : Geomorphological reconstruction of the Labrador Sector of the Laurentide Ice Sheet.
Publication : Quaternary Science Reviews
Issue : 19(13):
Page(s) : 1343-1366.
Abstract
The Labrador sector formed one of three major domes of the Laurentide Ice Sheet during the last (Wisconsinan) glaciation. Reconstruction of its evolution is important because it modulated atmospheric and oceanic circulation over 1--100 ka time scales. This paper reports new geomorphological evidence of ice flow, which is used to reconstruct glimpses of the behaviour of the Labrador Sector during its evolution. Flow evidence indicates a southern position (51°N) of the Labrador ice divide, presumed to be the usual location when the ice sheet was close to its maximum extent. A previously inferred dramatic surge of Labrador ice across Hudson Strait and onto Baffin Island (at 9.9--9.4 ka) is verified. Seemingly contradictory evidence regarding deglaciation in northern Quebec has been analysed and a reconstruction developed that solves this problem. Deglacial retreat of the Labrador Ice Sheet was highly asymmetric with rapid retreat of the southern margin, northwards migration of the centre of mass by 500 km, and slow retreat along the northern margin. As it shrank its thermal regime changed from cold-centred to entirely cold-based and it finally fragmented into many residual ice caps and glaciers. This dynamic and asymmetric behaviour may be due to destabilisation of the Labrador Ice Sheet triggered by Heinrich-event ice streaming through Hudson Strait.
Bibliography of Canadian Geomorphology