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TitleThe Strange Lake dispersal train: a product of a hard-bedded ice stream
AuthorPaulen, R CORCID logo; Stokes, C R; Fortin, RORCID logo; McCLenaghan, M BORCID logo; Rice, J MORCID logo; Dubé-Loubert, H
SourceGAC-MAC 2017 Kingston, Ontario: abstracts/GAC-MAC 2017 Kingston, Ontario: résumés; Geological Association of Canada-Mineralogical Association of Canada, Joint Annual Meeting, Programs with Abstracts vol. 40, 2017 p. 303 Open Access logo Open Access
LinksOnline - En ligne (complete volume - volume complet, PDF, 3.09 MB)
Alt SeriesNatural Resources Canada, Contribution Series 20190410
PublisherGeological Association of Canada
MeetingGAC-MAC 2017; Kingston, ON; CA; May 14-18, 2017
Mediaon-line; digital
File formatpdf
ProvinceQuebec; Newfoundland and Labrador
AreaStrange Lake; Labrador
Subjectssurficial geology/geomorphology; geochemistry; geophysics; Science and Technology; Nature and Environment; dispersal trains
ProgramGEM2: Geo-mapping for Energy and Minerals Hudson/Ungava, Northeastern Quebec-Labrador, surficial geology
Released2017 05 01
AbstractThe Strange Lake glacial dispersal train, in northern Quebec and Labrador, is a remarkably linear, ribbon-like geochemical dispersal pattern trending >40 km down ice (northeast) from a mineralized rare earth element (REE) peralkaline intrusion. Recent mapping of Laurentide Ice Sheet streams by Margold and others in 2015, places the Strange Lake train directly within the trunk of the Kogaluk River ice stream (IS #187), one of a number of ice streams that operated near the center of the Labrador dome and drained into the Atlantic Ocean. In soft-bedded areas, subglacial landforms can be used to map the spatial extent of ice stream tracks (e.g., megascale glacial lineations, ice stream shear margin moraines). Over hard-bedded, higher relief areas, the geomorphic imprint of ice streams tends to be less obvious, and sometimes features, such as shear margin moraines, can be completely absent. Despite the relatively thin till cover in the Strange Lake area, fast-flowing ice formed spectacular crag-and-tail landforms down ice of bedrock outcrops (up to 5 km long, with length:width ratios exceeding 12 and higher) within the dispersal train.
Airborne gamma-ray spectrometry surveys conducted in the Lac Brisson region in the 1980s show a subdued signal over part of the Strange Lake deposit and a long equivalent thorium (eTh) ribbon that extends more than 60 km to the northeast, well beyond the till geochemistry train. Deposition of REE-sediment was also controlled, in part, by the local rugged bedrock topography. Sediment dispersal trains, coupled with erosive corridors of streamlined terrain, provide a potentially powerful means of identifying hard-bedded ice streams elsewhere in northern Canada.

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