CGRG Bibliography of Canadian Geomorphology
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Author : England, J.
Date : 1987.
Title : In situ shells of full glacial age beneath former ice shelves /
Publication : Abstracts of the 16th Arctic Workshop : research on the roof of the world, Boreal Institute for Northern Studies, University of Alberta, Edmonton, Alberta, T6G 2E9, April 30 - May 2, 1987. Edmonton, Alta. : Boreal Institute for Northern Studies, University of Alberta, 1987
Issue :
Page(s) : 20-22.
Abstract
Today, outlet glaciers from the western margin of the Agassiz ice cap occupy the heads of Antoinette Bay and d'Iberville Fiord, north-central Ellesmere Island. During the last glaciation, these glaciers advanced ca. 10 km forming small ice shelves in the full glacial sea that occupied most of Greely Fiord. The uppermost shoreline of the full glacial sea is marked by intermittent washing limits, beaches and deltas that have emerged differentially to 120 to 145 m asl. Isobases drawn on this shoreline parallel the orientation of Greely Fiord (WSW-ENE) and converge with similar values reported further east on Ellesmere Island and Northwest Greenland. Inside the last ice limit, marine limits descend abruptly to 104-123 m asl, indicating that at least 20-40 m of emergence occurred prior to the breakup of the local ice shelves. Individual shells associated with the limit of the full glacial sea were dated by accelerator mass spectrometry (AMS) andshow a wide range of ages. On the north-central shore of Greely Fiord in situ bivalves of Portlandia arctica underlie a marine limit delta at 123 m asl and date 8750 ± 180 BP (TO-141). On the adjacent south side of the fiord the marine limit rises to 140 m asl where surface shells of Hiatella arctica were collected at 134 and 137 m asl (the highest elevations to which shells were observed). Individual valves from these elevations yield AMS dates of 8540 ± 100 (T0-142) and 8000 ± 70 BP (TO-143), respectively. Finally, along the outer north shore of d'Iberville Fiord, shells were collected from pebbly silt and sand at 124 m asl immediately below the limit of the full glacial sea, locally at 135 m asl.
Bibliography of Canadian Geomorphology