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TitreGlacial and postglacial landforms and processes adjacent to King William Island, Nunavut, Canadian Arctic Archipelago
TéléchargerTéléchargement (publication entière)
LicenceVeuillez noter que la Licence du gouvernement ouvert - Canada remplace toutes les licences antérieures.
AuteurShaw, J; Todd, B J
SourceProgram and abstracts: 2017 GeoHab Conference, Dartmouth, Nova Scotia, Canada; par Todd, B J; Brown, C J; Lacharité, M; Gazzola, V; McCormack, E; Commission géologique du Canada, Dossier public 8295, 2017 p. 109, (Accès ouvert)
LiensGeoHab 2017
ÉditeurRessources naturelles Canada
Réunion2017 GeoHab: Marine Geological and Biological Habitat Mapping; Dartmouth, NS; CA; mai 1-4, 2017
Documentdossier public
Mediaen ligne; numérique
Référence reliéeCette publication est contenue dans Todd, B J; Brown, C J; Lacharité, M; Gazzola, V; McCormack, E; (2017). Program and abstracts: 2017 GeoHab Conference, Dartmouth, Nova Scotia, Canada, Commission géologique du Canada, Dossier public 8295
ProvinceRégion extracotière du nord; Nunavut
SNRC57B; 57C; 67A; 67D; 67E
Lat/Long OENS-100.0000 -94.5000 70.5000 68.2500
Sujetstechniques de cartographie; océanographie; milieux marins; études côtières; conservation; organismes marins; écologie marine; gestion des ressources; peuplements biologiques; etudes de l'environnement; écosystèmes; levés géophysiques; levés acoustiques marins; levés au sonar; sonar latéral; dépôts postglaciaires; sédiments marins; dépôts glaciaires; dépôts glaciomarins; topographie glaciaire; elements glaciaires; dorsales sous-marines; drumlins; écoulement glaciaire; directions des mouvements de la glace; eskers; gougeage de la glace; paléocourants; directions des paléocourants; antecedents glaciaires; glaciation; retrait de la glace; changements du niveau de la mer; niveaux paléomers; Wisconsinien; topographie du fond océanique; caractéristiques sous-marines; chenaux; configurations lit; trous; marques d'affouillement; dégagements gazeux; récifs; Calotte glaciaire Laurentide; Éponges; biologie; géologie marine; géologie des dépôts meubles/géomorphologie; géologie de l'environnement; géophysique; Phanérozoïque; Cénozoïque; Quaternaire
ProgrammeGéoscience en mer, Géoscience de la gestion des océans
Diffusé2017 09 26
Résumé(disponible en anglais seulement)
The subaerial morphology of coastal King William Island and the bathymetry of adjacent offshore channels of the Canadian Arctic Archipelago have been explored with terrestrial/marine LiDAR and multibeam sonar surveys. During the Late Wisconsinan, the Laurentide Ice Sheet extended northward across most of the Canadian Arctic and imprinted the buried landscape. Analysis of the survey data elucidates both glacial and postglacial processes that have shaped the seafloor in channels of the south-central Canadian Arctic Archipelago.
Glacial landforms include multiple, parallel, elongated, ridges many kilometres in length (mega-scale glacial lineations), and fields of drumlins; both of these features are indicative of ice flow direction, generally to the north. During ice sheet retreat, eskers and tunnel valleys formed beneath the ice and swarms of icebergs were released at the calving front. The keels of numerous icebergs incised the seabed with a pattern of furrows flanked by berms; these iceberg ploughmarks provide insight into paleocurrent directions in the archipelago during glacial retreat. Iceberg ploughmarks subaerially exposed on King William Island indicate a formerly higher sea level than at present.
Postglacial landforms include raised beaches on King William Island, formed during the lowering of sea level to its present elevation. Extensive fields of small seabed pockmarks, 2 to 3 m in diameter, were likely formed by the release of gas within the sea floor sediment. A biogenic or petrogenic source for the gas has yet to be determined. Enigmatic, flat-bottomed pits, about 30 m in diameter, may be strudel scour or may be also related to gas release.
Work is continuing to determine if Hexactinellid sponge reefs populate Victoria Strait west of King William Island. The seabed morphology in Victoria Strait strongly resembles that of sponge reefs mapped in the Pacific Ocean off British Columbia, where these reefs preferentially grow on ridges of coarse-grained glacial deposits exposed on the seabed.