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Geological Setting of the World-Class Musselwhite BIF- Hosted Gold Deposit, Ontario, Canada.

Oswald, William; Castonguay, Sébastien; Dubé, Benoît; McNicoll, Vicki; Biczok, John; Malo, Michel (2015). Geological Setting of the World-Class Musselwhite BIF- Hosted Gold Deposit, Ontario, Canada. In: 13th SGA Biennial Meeting on Mineral Resources in a Sustainable World - SGA 2015, 24-27 août 2015, Nancy, France.

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Résumé

The Musselwhite mine is a world-class gold deposit hosted in polydeformed amphibolite facies banded iron formation (BIF) of the Mesoarchean North Caribou greenstone belt (NCG), northwestern Superior Province. The deposit consists of narrow sub-vertical orebodies resulting from the intersection of second-order, Au-bearing structures with strongly reactive, silicate-rich BIF horizons. Geological mapping and geochronology work show that the mine sequence is overturned by a previously unrecognised F1 syncline, which influences the distribution of the highly prospective BIF sequence. Typical high grade ore is constituted by pyrrhotite replacement and silica-flooding of the iron formation, gangue minerals include almandine garnet, grunerite, ferrotschermakite, ankerite, and locally hedenbergite. The layered anisotropy of the BIF sequence in more competent mafic rocks, and the local presence of ultramafic dykes, induce a strong structural complexity and clearly influenced the rheological response to deformation. Crosscutting relationships show Au-mineralisation is syn-to late-D2 deformation and broadly synchronous to metamorphism. Recent monazite dating provides a preliminary age of 2666 Ma, interpreted as a minimum age for gold mineralisation event. These features, along with regional first-order structures and occurrences of polymictic conglomerates, are typically found in greenstone-hosted orogenic Au districts and provide useful guides for exploration targets in the NCG and other areas.

Type de document: Document issu d'une conférence ou d'un atelier
Mots-clés libres: Banded Iron Formation; gold deposits; structural controls; Superior Province
Centre: Centre Eau Terre Environnement
Date de dépôt: 09 déc. 2019 19:42
Dernière modification: 09 déc. 2019 19:42
URI: http://espace.inrs.ca/id/eprint/4327

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