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TitleVolcanology, geochemistry and petrogenesis of the Expo-Raglan magmatic system in the eastern Cape Smith Belt, Nunavik, northern Quebec
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AuthorMcKevitt, D J; Lesher, C M; Houlé, M G
SourceTargeted Geoscience Initiative: 2018 report of activities; by Rogers, N (ed.); Geological Survey of Canada, Open File 8549, 2019 p. 393-401, (Open Access)
PublisherNatural Resources Canada
Documentopen file
Mediaon-line; digital
RelatedThis publication is contained in Rogers, N; (2019). Targeted Geoscience Initiative: 2018 report of activities, Geological Survey of Canada, Open File 8549
File formatpdf
NTS35G/08; 35G/09; 35G/16; 35H/05; 35H/11; 35H/12; 35H/13; 35H/14
AreaNunavik; Lac Vaillant; Lac Rinfret; Lac Cross
Lat/Long WENS -74.5000 -73.0000 61.8000 61.4000
Subjectseconomic geology; tectonics; geochemistry; mineral deposits; mineral exploration; mineral potential; nickel; copper; sulphide deposits; ore mineral genesis; mineralization; ore controls; petrogenesis; tectonic setting; volcanology; volcanic-sedimentary belts; magmatism; intrusions; dykes; sills; volcanism; fluid dynamics; fluid flow; plate margins; bedrock geology; lithology; igneous rocks; intrusive rocks; volcanic rocks; mafic rocks; ultramafic rocks; petrographic analyses; thin section microscopy; geochemical analyses; field work; Cape Smith Belt; Southern Domain; Chukotat Group; Esker Lake Group; Povungnituk Group; Nuvilic Formation; Cécilia Formation; Beauparlant Formation; Nituk Formation; Kuuvvaluk Formation; Bélanger Gabbroic Suite; Expo Trend; Raglan Trend; Expo Dykes; Churchill Province; Paleoproterozoic; ore systems approach; platinum group elements (PGE); geological mapping; Precambrian; Proterozoic
Illustrationslocation maps; geoscientific sketch maps; geochemical plots; photographs; schematic models
ProgramKnowledge Management Coordination, Targeted Geoscience Initiative (TGI-5)
ProgramNickel-copper-PGE-chromium ore systems - deposit controls in cratonic areas, Targeted Geoscience Initiative (TGI-5)
Released2019 03 01
AbstractThe Paleoproterozoic volcano-sedimentary Cape Smith Belt in Nunavik (northern Quebec) contains a variety of mafic-ultramafic units classifiable by position in sequence, geometry, lithology, degree of differentiation and mineralization style. Non-differentiated to differentiated mafic flows/sills comprise the majority of the section as essentially non-mineralized massive-pillowed basalts, conformable gabbroic units and differentiated pyroxenite/gabbro/basalt flows. Differentiated mafic-ultramafic sills intrude sedimentary strata of the lower and upper Povungnituk Group and host reef-style PGE-(Cu)-(Ni) mineralization (e.g. Delta). Poorly differentiated ultramafic-mafic bladed dykes along the Expo Trend in the Povungnituk Group commonly host Cu-Ni-(PGE) sulphides along their margins (e.g. Expo-Ungava, Méquillon) and reach up to 35 weight % MgO in the most magnesian olivine pyroxenitic parts and up to 16 weight % MgO in their chilled melanogabbroic margins. Poorly differentiated ultramafic lava channels along the Raglan Trend at the base of the Chukotat Group host Ni-Cu-(PGE) mineralization at or near their lower contacts, and reach MgO contents of nearly 44 weight % in the most magnesian peridotitic parts and up to 20 weight % in their chilled pyroxenitic margins. Recent dating indicates a temporal overlap between the Expo and Raglan parts of the system; however, field and geochemical data suggest that the Expo dykes are derived from less magnesian magmas and formed mineralization with higher Cu/Ni ratios than the lava channels in in the Raglan Trend. The Expo dykes may have fed other parts of the system, but do not appear to represent direct feeders to the mineralized lava channels in the Raglan parts.