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TitreMarine evidence for a glacial ice stream in Amundsen Gulf, Canadian Arctic Archipelago
AuteurMacLean, 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; par CANQUA-CGRG; 2013 p. 159
Année2013
Séries alt.Secteur des sciences de la Terre, Contribution externe 20130217
ÉditeurAssociation canadienne pour l'étude du Quaternaire
Réunion CANQUA-CGRG 2013; Edmonton; CA; août 18-22, 2013
Documentlivre
Lang.anglais
Mediapapier
ProvinceRégion extracotière du nord
SNRC97; 87
Lat/Long OENS-128.0000 -112.0000 72.0000 69.0000
SujetsCalotte glaciaire Laurentide; géologie des dépôts meubles/géomorphologie; Quaternaire
ProgrammeRisques géo marines, Géoscience pour la sécurité publique
Résumé(disponible en anglais seulement)
Amundsen 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.
Résumé(Résumé en langage clair et simple, non publié)
Des études fondées sur l'imagerie radar multifaisceaux et des profils de sondeur de sédiments obtenus à 3,5 kHz par ArcticNet et l'Ocean Mapping Group de l'Université du Nouveau-Brunswick révèlent la présence de linéations de quille de glace sous forme de crêtes et de sillons sur le fond marin dans le golfe du Couronnement, le détroit de Dolphin et Union, et le golfe Amundsen. Ces entités permettent de préciser davantage l'histoire glaciaire de la marge nord-ouest de l'Inlandsis laurentidien.
GEOSCAN ID293036