Les minéralisations aurifères au sein de la tonalite de La Grande-Sud Baie-James Québec

Mercier-Langevin, P

doi:10.1522/11899414

Cited by 3 publications

(23 citation statements)

References 36 publications

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“…13J, K). Electron microprobe analyses of tennantite from Zone 32 indicate a very low component of tetrahedrite (<6.2 wt % Sb); however the presence of anomalous Hg in some Au-Cu mineralized samples (Mercier-Langevin, 2000) may also suggests that tennantite is enriched in Hg. Native Au is commonly found at sulfide grain boundaries (Fig.…”

Section: Styles Of Mineralizationmentioning

confidence: 98%

“…Three main sets of veins are developed in the La-Grande-Sud Tonalite (Mercier-Langevin, 2000). The first set is subvertical and trends N 070° (parallel to S2).…”

Section: Styles Of Mineralizationmentioning

confidence: 99%

“…= standard deviation, b.d. = analyses below detection limit; all analyses performed at the Centre de Recherches Minérales (CRM) in Quebec City, major elements determined by X-ray fluorescence and LECO, and trace elements determined by ICP-AES (multi-acid digestion), X-ray fluorescence and neutron activation; see Mercier-Langevin (2000) for the complete dataset 1 Analytical results of one representative sample for each alteration facies deformation episodes, respectively. The development of the planar fabrics are used as a proxy for the strain intensity, and interpolation of the index values shows that the deformation is mostly concentrated along the S and N margins of the intrusion (Fig.…”

Section: Deformationmentioning

confidence: 99%

“…The auriferous mineralization in the La-Grande-Sud Tonalite shares many similarities with different deposit types, from porphyry-style or intrusion-related to syntectonic. The La-Grande-Sud prospect has previously been classified as a remobilized, pre-to early-D1 intrusionrelated deposit (Mercier-Langevin, 2000), and as a syn-D1 or syn-D2 shear zone-hosted deposit (Gauthier, 2000;Goutier et al, 2001). As in many other Archean deformed supracrustal sequences (e.g., Goldfarb et al, 2005;Robert et al, 2005), mineralization in the James Bay area is likely to have been formed at different stages in the evolution of the belt, from synvolcanic to synmagmatic (syngenetic) to late orogenic (epigenetic).…”

Section: Introductionmentioning

confidence: 99%

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Geology of the Archean Intrusion-Hosted La-Grande-Sud Au-Cu Prospect, La Grande Subprovince, James Bay Region, Quebec(,

et al. 2012

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The Archean La Grande and Eastmain domains of the La Grande subprovince in the James Bay region of northwestern Québec are the focus of renewed and extensive exploration as a result of recent major discoveries made in this region (e.g., ~8 Moz Au Roberto deposit). A number of significant Neoarchean Au ± base metal occurrences are present in the La Grande domain, including the La-Grande-Sud Au-Cu prospect (Zone 32, inferred resource of 4.2 million metric tons (Mt) at 2.1 g/t Au and 0.2 wt % Cu).The La-Grande-Sud Au-Cu prospect is hosted in the 2734 ± 2 Ma synvolcanic La-Grande-Sud Tonalite in the 2751 to 2732 Ma Yasinski Group volcanic rocks. The La-Grande-Sud Tonalite is a synvolcanic calc-alkaline intrusion emplaced in an arc-like tectonomagmatic setting. Timing relationships in mineralized zones as well as associated hydrothermal alteration zones support a pre-to early-D1 origin for at least a part of the mineralization in the La-Grande-Sud Tonalite. Deformation events were responsible for the overprinting of the early mineralization by auriferous shear zone-related systems associated with D2.Evidence for a pre-D2 and pre-to early-D1 alteration and mineralization system includes: (1) a broadly concentric pattern defined by the hydrothermal alteration assemblages within the La-Grande-Sud Tonalite, which suggests that the hydrothermal alteration was, at least in part, controlled by the geometry of the intrusion rather than by the D2 deformation; (2) the development of a weak biotite-bearing potassic assemblage (biotite-epidote-plagioclase-muscovite-calcite ± pyrite) that is gradually replaced outward from the center of the intrusion by a chlorite-bearing propylitic assemblage (chlorite-epidote-muscovite-plagioclase-calcite-pyrite), and locally overprinted by a sericitic alteration assemblage (muscovite-quartz-albite-chlorite-pyrite-carbonate), which represents the most intense alteration in the La-Grande-Sud Tonalite; (3) the presence of mineralized hydrothermal breccias along the margins of the intrusion; (4) deformed disseminated and stockwork-style Au-Cu sulfide mineralization consisting of pyrite, chalcopyrite, tennantite, arsenopyrite, pyrrhotite, Bi sulfosalts, and native Au ± Bi in the sericite, chlorite, and biotite facies alteration zones; (5) S1-parallel elongated tonalite clasts and sulfide veinlets in D2-folded and transposed hydrothermal biotite breccias; and (6) pyrite porphyroblasts that are elongated parallel to the S1 fabric (syn-D1 metamorphic recrystallization) and that were folded during D2. D2 was associated with the development of conjugate auriferous extensional quartz-tourmaline veins (orogenicstyle veins) that were superimposed on the pre-to early-D1 intrusion-hosted mineralized system. Gold in these syn-to late-D2 veins could have been remobilized from preexisting mineralization (disseminated sulfides) or was related to a late (syn-D2) auriferous hydrothermal event.The intrusion-hosted Au mineralization of the La-Grande-Sud Au-Cu prospect illustrates that Archean synvolcanic intrusions, ...

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Section: Styles Of Mineralizationmentioning

confidence: 98%

“…Three main sets of veins are developed in the La-Grande-Sud Tonalite (Mercier-Langevin, 2000). The first set is subvertical and trends N 070° (parallel to S2).…”

Section: Styles Of Mineralizationmentioning

confidence: 99%

Section: Deformationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Geology of the Archean Intrusion-Hosted La-Grande-Sud Au-Cu Prospect, La Grande Subprovince, James Bay Region, Quebec(,

et al. 2012

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“…demeure spéculative. Toutefois, ailleurs dans la sous-province de La Grande, un premier épisode antérieur à la déformation penetrative est généralement reconnu et plus facilement identifiable (Goutier et al 1999(Goutier et al , 2001a(Goutier et al , 2001bMercier-Langevin 2000). Il est donc légitime de croire que le secteur de la propriété Aquilon présente une tectonique polyphasée similaire.…”

Section: Plissement Tardifunclassified

Caractérisation du système aurifère filonien d'Aquilon - Baie James, Québec /

Lapointe¹

2006

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Quantifying Hydrothermal Alteration: A Review of Methods

Mathieu

2018

Geosciences

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Hydrothermal alteration is proximal to many base and precious metal deposits, and its products can provide insights into the characteristics of hydrothermal systems. To be useful to exploration geologists and researchers, however, alteration needs to be typified and quantified. Alteration type informs on mineralising style (e.g., have we found a porphyry or a volcanogenic massive sulphide deposit?), while quantification of its intensity helps position a sample within the system (e.g., how close are we to the main economic deposit?). Numerous methods-all having their specific advantages and disadvantages-are dedicated to the characterisation of alteration. As alteration is a process that induces chemical and mineralogical changes in rocks, it can be studied using petrological (e.g., mineral recognition in thin sections, mineral chemistry), mineralogical (e.g., alteration indices that use normative minerals), and chemical (e.g., mass balance calculations) approaches. This short review provides an overview of the methods useful to researchers and that are also applicable in an exploration context.

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Les minéralisations aurifères au sein de la tonalite de La Grande-Sud Baie-James Québec

Cited by 3 publications

References 36 publications

Geology of the Archean Intrusion-Hosted La-Grande-Sud Au-Cu Prospect, La Grande Subprovince, James Bay Region, Quebec(,

Geology of the Archean Intrusion-Hosted La-Grande-Sud Au-Cu Prospect, La Grande Subprovince, James Bay Region, Quebec(,

Caractérisation du système aurifère filonien d'Aquilon - Baie James, Québec /

Quantifying Hydrothermal Alteration: A Review of Methods

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