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TitreSubmerged late Quaternary terrestrial deposits and paleoenvironment of northern Hecate Strait, British Columbia continental shelf, Canada
AuteurBarrie, J V; Conway, K W; Mathewes, R W; Josenhans, H W; Johns, M J
SourceQuaternary International vol. 20, 1994 p. 123-129,
Séries alt.Commission géologique du Canada, Contributions aux publications extérieures 36793
ÉditeurElsevier BV
Documentpublication en série
Mediapapier; en ligne; numérique
ProvinceRégion extracotière de l'ouest
SNRC103G/14; 103G/13; 103J/03; 103J/04; 103J/05; 103J/06; 103J/11; 103J/12
Lat/Long OENS-132.0000 -131.0000 54.7500 53.7500
Sujetspaléoenvironnement; sediments; paléoécologie; plate-forme continentale; Holocène; faciès; Pléistocène; Déglaciation Wisconsinienne; géologie des dépôts meubles/géomorphologie; stratigraphie; Quaternaire
Illustrationstables; cross-sections
Résumé(disponible en anglais seulement)
Stratigraphic and paleoenvironmental analyses of sediments recovered from cores on the western Canadian continental shelf indicate that areas of the north-central shelf were subaerial and supported terrestrial vegetation during the regional Late Wisconsinan deglaciation. Paleoecological analyses of now submerged shelf sediments reveal a Late Quaternary treeless environment locally covered by wet sedge tundra. Samples from a coeval onshore section on eastern Graham Island indicate that a dwarf shrub tundra with mosses and willows also occupied lowland areas on the Queen Charlotte Islands between 13 and 14 ka. Ice-free subaerial conditions persisted for a period of at least 3200 years on some parts of the emergent shelf, between 13.2 and 10 ka. During the same time period clay-rich glaciomarine sediment with ice-rafted debris was accumulating in the troughs of the shelf. Low relative sea levels during deglaciation on the continental shelf adjacent to the eastern Queen Charlotte Islands suggest that Late Wisconsinan ice was thin and limited in extent in this area. The presence of a habitable lowland environment during this time interval strengthens the view that a coastal migration of humans from Beringia was possible along portions of the exposed continental shelf.