| Titre | Expanding the size of multi-parameter metasomatic footprints in gold exploration: utilization of mafic dykes in the Canadian Malartic district, Quebec, Canada |
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| Auteur | Perrouty, S ;
Linnen, R L; Lesher, C M; Olivo, G R; Piercey, S J; Gaillard, N; Clark, J R; Enkin, R J |
| Source | Mineralium Deposita vol. 54, 5, 2019 p. 761-786, https://doi.org/10.1007/s00126-018-0829-x |
| Liens | Erratum
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| Image |  |
| Année | 2019 |
| Séries alt. | Ressources naturelles Canada, Contribution externe 20200256 |
| Éditeur | Springer |
| Document | publication en série |
| Lang. | anglais |
| DOI | https://doi.org/10.1007/s00126-018-0829-x |
| Media | papier; en ligne; numérique |
| Formats | pdf |
| Province | Québec |
| Lat/Long OENS | -79.5000 -77.0000 49.0000 48.0000 |
| Sujets | or; sedimentation; analyses d'ensemble; filons mafiques; Ceinture d'Abitibi ; Subprovince de Pontiac ; Volcaniques de Malartic |
| Illustrations | cartes de localisation; tableaux; photomicrographies; diagrammes de distribution; graphiques; diagrammes ternaires |
| Diffusé | 2018 08 28 |
| Résumé | (disponible en anglais seulement)
Ore-forming hydrothermal fluids react differently with different country rocks, but few studies have applied this knowledge with the specific goal of expanding
the size of hydrothermal footprints in mineral exploration. To develop this concept, 122 metamorphosed mafic dykes from the world-class Canadian Malartic gold district (18.6 Moz Au) were sampled and analyzed for mineralogy, physical properties, and
lithogeochemistry (partial and total digestion). The mafic dykes intrude mainly metasedimentary rocks, post-date D-1 deformation, and cross-cut early-D-2 quartz monzodiorite intrusions, but they were deformed and altered during D-2 deformation,
mineralization, and metamorphism. They can be subdivided into three groups: Group 1 dykes are least-altered, characterized by amphibole-rich regional metamorphic assemblages and distributed throughout the Pontiac Subprovince. Group 2 and 3 dykes
underwent ore-related hydrothermal biotite-calcite-pyrite alteration and are associated with density- and volume-adjusted concentration gains of over 100% in Au-W-Te-C-S-Ag-Cs-Mo-Cu-K-Rb-Se-U-Pb-Ba-F-Bi-Sn. They define a metasomatic footprint up to
6km away from the deposit toward the SE and up to 2km away from the deposit toward the SW. Fifty-eight variables that define halos around the Canadian Malartic deposit have been identified and integrated using principal component analysis. PC1
explains 30% of the variance, separates least-mobile elements from ore-related elements, and is interpreted to reflect the ore-forming alteration process. PC2 and PC3 represent igneous processes. PC4 highlights the calcite-pyrite and biotite
alteration. Spatial variations of the modal abundances of amphibole, biotite, calcite, and pyrite are the simplest expression of the metasomatic footprint, and they can easily be documented during exploration at the camp scale. |
| GEOSCAN ID | 326668 |
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