Basal debris entrainment and transport in glaciers of southwestern Bylot Island, Canadian Arctic

• Main Authors: Zdanowicz, Christian, Michel, F. A., Shilts, W. W.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Carleton University, Ottawa, Canada 1996
• Subjects: Glaciers; sedimentology; mineralogy; geochemistry; till; Physical Geography; Naturgeografi; Earth and Related Environmental Sciences; Geovetenskap och miljövetenskap; Arctic; Bylot Island; Annals of Glaciology
• Online Access: http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-300891; https://doi.org/10.3198/1996AoG22-1-107-113

ABSTRACT. Glaciers on southwestern Bylot Island in the Canadian Arctic flow from an alpine setting in high-grade crystalline Archean terrane, on to coastal lowlands underlain by clastic sedimentary strata of Cretaceous to Tertiary age. We have used the contrasting mineralogy of the substrate as a tool to study subglacialentrainment and transport of debris in two large piedmont glaciers on Bylot Island. High chlorite/ and mica-illite/smectite ratios indicate that most basal debris is derived from crystalline rocks underlying the upper reaches of the glaciers. The subglacial accretion of Cretaceous-Tertiary sediments appears restricted to the lowermost part ofthe basal zone and is most noticeable near the glaciers' termini. lce associated with discrete silty-sandy debris layers is characterized by an isotopic signature indicative of refreezing of meltwater at the glacier sole. The compositional, textural and isotopic characteristics of basal sediment and ice lead us to conclude that subglacial entrainment through basal ice accretion occurs in both the upper and marginal parts of the glaciers