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TitreNew insights on the surficial geology of the Repulse Bay area, Nunavut: implications for mineral exploration
AuteurCampbell, J E; McMartin, I; Tremblay, T; Wityk, U; Dredge, L A
Source39th Annual Yellowknife Geoscience Forum, abstracts of talks and posters; par Fischer, B J; Watson, D M; Northwest Territories Geoscience Office, Yellowknife Geoscience Forum Abstracts Volume 2011, 2011 p. 24-25
LiensOnline - En ligne
Séries alt.Secteur des sciences de la Terre, Contribution externe 20110240
Documentpublication en série
SNRC46E; 46L; 46M; 56I
Lat/Long OENS-90.0000 -86.0000 68.0000 65.0000
Sujetsdépôts glaciaires; dépôts glaciaires; exploration de dépôts glaciaires; tills; échantillons de till; géochimie du till; géologie des dépôts meubles/géomorphologie; géologie économique; Cénozoïque; Quaternaire
ProgrammeGisements polymétalliques - Presqu'île Melville (Nunavut), GEM : La géocartographie de l'énergie et des minéraux
Résumé(disponible en anglais seulement)
The Geological survey of Canada has initiated a multi-year Quaternary mapping activity in the Repulse Bay-Wager Bay area, mainland Nunavut, as part of the Multiple Metals-Melville Peninsula Project under Canada's Geomapping for Energy and Minerals (GEM) Program. The area lies within one of the most active precious and base metal exploration areas of the Western Churchill Geological Province and is heavily drift covered, yet the surficial geology in this area has never been field mapped, and the glacial history, regional drift provenance and Quaternary framework necessary for the implementation of successful drift exploration programs are lacking. Both remote predictive mapping and field based investigations are being used to fill in these knowledge gaps.
Fieldwork during the past two summers has focused on the region west of Repulse Bay, stretching from Committee Bay in the north (NTS 46M-East), to west (NTS 46 L & 56I-East) and south (NTS 46E-North) of Repulse Bay. To date, 158 till samples (~ 7km spacing) have been collected for provenance, till geochemistry, various indicator mineral species and gold grains. Field observations indicate this region is key to the glacial history reconstruction of the northern part of Keewatin Ice Sector of the Laurentide Ice Sheet and for understanding the interplay between Keewatin Sector - Foxe Basin/Melville ice. Multiple striation directions, superimposed streamlined landforms, and convergent ice-flow directions into Repulse Bay were recorded. At least 4 main phases of ice flow have been identified. The late convergent flow into Repulse Bay, in part reverse and oblique to the dominant northward ice flow, resulted in a flow reversal over the southern part of the Rae Isthmus and has significant implications for mineral exploration, specifically for following up indicator mineral dispersal trains. A previously unknown, exotic carbonate-rich till was discovered south of Repulse Bay which extends the limit of carbonate dispersal over 30 km to the south of Rae Isthmus. This discovery changes the interpretation of source location for the carbonate till and the ice flow dynamics in the Repulse Bay ' Southampton Island ' southern Melville Peninsula area during deglaciation.
Diverse Quaternary sediments and depositional environments were observed and indicate a complex Quaternary geology and glacial history. Of particular interest are the east-flowing (46E and L) and north-flowing (56I) meltwater corridors with complex sediment-landform assemblages, the striking crag-and-tail landforms in 56I, and the major end moraines in 46M with divergent ice-flow directions on either side. These features have implications for understanding subglacial thermal conditions, glacial dynamics, and transport and depositional processes. Contrasting marine incursion limits north (240 m a.s.l.) and south of the end moraines (160-150 m a.s.l.), and further south of Repulse Bay (140 m a.s.l.), suggest the ice remained much longer over the Rae Isthmus and to the south. This confirms that paleo-Committee Bay must have been open and stable over a significant time period, likely related to the position of the Chantrey-Melville moraine system. This has implications for regional post-glacial uplift patterns and paleoglaciological reconstruction.