| Titre | Dispersal trains produced by ice streams: an example from Strange Lake, Labrador, Canada |
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| Auteur | Paulen, R C ;
Stokes, C R; Fortin, R; Rice, J M; Dube-Loubert, H; McClenaghan, M B |
| Source | Exploration 17, conference proceedings; 2017 p. 871-875 
Accès ouvert |
| Liens | Online - En ligne
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| Image |  |
| Année | 2017 |
| Séries alt. | Secteur des sciences de la Terre, Contribution externe 20160419 |
| Éditeur | Decennial Mineral Exploration Conferences |
| Réunion | Exploration '17 - Sixth DMEC Decennial Exploration Conference; 2017 |
| Document | livre |
| Lang. | anglais |
| Media | en ligne; numérique |
| Formats | pdf |
| Programme | GEM2 : La géocartographie de l'énergie et des minéraux Nord-est du Québec-Labrador, géologie des dépôts meubles de la région
d'Hudson/Ungava |
| Diffusé | 2017 01 01 |
| Résumé | (disponible en anglais seulement)
Large tracts of northern Canada were impacted by a large number of land-terminating and marine-terminating palaeo-ice streams during deglaciation of the
Laurentide Ice Sheet. In soft-bedded areas, subglacial landforms can be used to map the spatial extent of ice stream tracks (e.g., mega-scale glacial lineations, ice stream shear margin moraines). Over hard-bedded areas, the geomorphic imprint of ice
streams is less obvious. However, sediment dispersal trains, coupled with erosive corridors of streamlined terrain, provide a potentially powerful means of identifying 'hard-bedded' ice streams. The Strange Lake dispersal train, in northern Quebec
and Labrador, has a remarkably linear, ribbon-like dispersal pattern trending more than 40 km down ice from a mineralized rare earth element (REE) peralkaline intrusion. The train was originally attributed to a consistent regional ice flow regime of
the Laurentide Ice Sheet. Recent mapping of Laurentide Ice Sheet streams places the Strange Lake train directly within the Kogaluk River ice stream, one of a number of ice streams that operated near the centre of the Labrador dome and drained into
the Atlantic Ocean. There are numerous mega-scale glacial lineations (up to 5 km long, with length: width ratios exceeding 12) within the mapped dispersal train. The dispersal train shows a remarkably linear consistency with REE element
concentrations in till tens of kilometres down-ice from the mineral source, a phenomenon similarly observed with carbonate dispersal trains formed by ice streams in Nunavut. Thus, while drift prospecting methods have traditionally considered long
term steady-state ice flow as the primary method for transporting glacial debris from a mineralized source, we argue that changes in glacial erosion, transport distances and diffusion rates are factors that should be considered when mapping and
interpreting glacial dispersal trains in palaeo-ice stream corridors. Identification of ice-stream corridors in northern Canada may provide additional insight into many indicator mineral anomalies, which have no identified source. |
| Sommaire | (Résumé en langage clair et simple, non publié)
Application de la nouvelle recherche glaciaire mondiale et des progrès de la science glaciaire, en particulier des glaces et des flux glaciaires
rapides, à l'exploration minérale dans les régions prospectives du Canada qui étaient jadis touchées par les glaciers glaciaires. Cette recherche pourrait amener l'industrie de l'exploration à réexaminer les anomalies des minéraux indicateurs dans le
nord du Canada qui n'ont aucune source connue dans la roche en place. Cette recherche est une production de l'activité geologie de surface de la zone noyau dans GEM2-Hudson-Ungava. |
| GEOSCAN ID | 299851 |
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