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TitleMarine evidence for a glacial ice stream in Amundsen Gulf, Canadian Arctic Archipelago
AuthorMacLean, B; Blasco, S; Bennett, R; Lakeman, T; Hughes-Clarke, J; Kuus, P; Patton, E
SourceCANQUA-CGRG 2013. Canadian Quaternary Association and Canadian Geomorphology Research Group Conference, Program and Abstracts; by CANQUA-CGRG; 2013 p. 159
Alt SeriesEarth Sciences Sector, Contribution Series 20130217
PublisherCanadian Quaternary Association
Meeting CANQUA-CGRG 2013; Edmonton; CA; August 18-22, 2013
ProvinceNorthern offshore region
NTS97; 87
AreaAmundsen Gulf
Lat/Long WENS-128.0000 -112.0000 72.0000 69.0000
Subjectssurficial geology/geomorphology; glacial features; glaciation; Laurentide Ice Sheet; Quaternary
ProgramMarine Geohazards, Public Safety Geoscience
AbstractAmundsen Gulf lies at the southwestern end of the Northwest Passage adjacent to the Beaufort Sea. Extensive high resolution multibeam sonar imagery and sub-bottom profiles of the seabed have been acquired by ArcticNet and Ocean Mapping Group, University of New Brunswick. These data reveal a variety of seabed features including mega-scale glacial ridge and groove lineations, drumlins, moraines, ice-contact sediments, iceberg scours, bedrock outcrops, and discontinuous sediment deposits of variable thickness. The lineations and drumlins resemble bedforms found by researchers in Antarctica, Svalbard, Greenlarid, and other Canadian Arctic regions where they have been interpreted to have been emplaced by fast flowing glacial ice streams.

The pattern of glacial sole marks on the seabed in Amundsen Gulf and regional data from the adjacent mainland and islands confirm that a glacial ice stream from the northwest Laurentide Ice Sheet occupied Amundsen Gulf and adjoining waterways. Part of the northwestward flowing ice stream was deflected around the ColevilIe Mountains on Victoria Island and rejoined the main ice stream in Amundsen Gulf by way of Prince Albert Sound. The grounded ice stream extended northwestward to a depth of 450 m in the Beaufort Sea. It is inferred to have reached its maximum extent coincident with the Late Glacial Maximum. Multi-sequence ice-contact sediment deposits indicate that successive advances and retreats of the ice stream occurred in the northwestern part of the gulf'. Final retreat from the maximum position began prior to 13,000 cal yr BP and terrestrial radiocarbon ages indicate that the calving margin had reached southeastern Amundsen Gulf and southwestern Victoria Island by 12,500 cal yr BP. A subsequent phase of east-to-west ice- flow on southern Victoria Island extended across Dolphin and Union Strait onto the mainland. These findings further delineate the extent, thickness, and dynamical history of the northwest Laurentide Ice Sheet, and complement ongoing research into the sedimentary history of the adjacent Arctic Ocean basin.
Summary(Plain Language Summary, not published)
Studies of multibeam imagery and 3.5kHz sub-bottom profiles obtained by ArcticNet and the Ocean Mapping Group, University of New Brunswick reveal the presence of ice keel ridge and groove lieantions on the seafloor in Coronation Gulf, Dolphin and Union Strait and Amundsen Gulf. These features further delineate the glacial history of the northwest margin of the Laurentide ice sheet.