Abstract

Marine-limit elevations and radiocarbon dates from Melville Peninsula suggest rapid deglaciation of Committee Bay about 9100 years ago when sea level was 235 m higher than present. During deglaciation, an extensive prominent moraine with both terrestrial and glaciomarine segments developed along the western margin of the Foxe Ice Dome. It developed between 8500 and 6500 years ago as glaciologic response to the opening of the bay. By the time ice had receded from the moraine, sea level had dropped to about 140 m. Garry Bay was not deglaciated until ice lay east of the Melville Moraine. Lithologic evidence and the persistence of ice in this lowland area suggest that the outer part of Garry Bay was the calving terminus of a major ice stream flowing westwards across the peninsula. Four well-controlled emergence curves, based on 37 radiocarbon dates, are presented. The Baker Bay and Brevoort curves depict disjunct emergence patterns in which the disjunction corresponds in time and elevation to the formation of the moraine; the other two cover only the last 7000 years and depict a normal exponential style of emergence. Differences in timing and amount of emergence in the curve from Fury and Hecla Strait are attributed to a late ice flow southwards from Baffin Island. The Melville Moraine is younger than the age initially proposed for the Cockburn moraine system, of which it forms a part. It formed as a glaciodynamic response to a shift from marine-based to terrestrially grounded ice margin, rather than to climatic factors.

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