Geology and structure of a sulfide-rich gold deposit; an example from the Mouska gold mine, Bousquet District, Canada

Belkabir, Abdelhay; Hubert, Claude

doi:10.2113/gsecongeo.90.5.1064

Cited by 9 publications

(7 citation statements)

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“…Gold mineralization at Mouska occurred during several stages of deposition, ranging from a predeformation sulfide-dominant stage to a multistage quartz-dominant syndeformation stage. Textural relationships among ore minerals (see above), combined with results of prior structural analyses (Belkabir & Hubert 1995), indicate that progressive shearing occurred after the formation of a first generation of ore minerals, including pyrite I, chalcopyrite, pyrrhotite, magnetite and gold, all of which are confined to an early stage of gold-sulfide mineralization. Among these minerals, only the preexisting pyrrhotite -chalcopyrite -gold assemblage in pyrite I belongs to the early-stage mineralization.…”

Section: Paragenesismentioning

confidence: 93%

“…1). The mine geology and ore mineralization were described in detail by Belkabir & Hubert (1995), and only a summary of these features is given here. The geology of the area is dominated by Archean bimodal mafic and felsic rocks of the Blake River Group.…”

Section: Background Informationmentioning

confidence: 99%

“…Textural relationships indicate destabilization [e.g., increase f(S 2 )] and transformation (replacement) of the more iron-rich sulfides (pyrrhotitechalcopyrite matrix) to form pyrite I. During the multistage quartz mineralization, a part, if not all, of the sulfide may have resulted from short-range remobilization and recrystallization of earlier sulfides (Belkabir & Hubert 1995). In Figure 6, we summarize the above-mentioned paragenetic successions at Mouska.…”

Section: Paragenesismentioning

confidence: 99%

“…Lithological units are sche- matically represented, as they vary notably in width and vertical extent. Although Belkabir & Hubert (1995) clearly demonstrated that sulfide mineralization took place prior to dynamic metamorphism, the timing of the hydrothermal alteration accompanying emplacement of the sulfides is not easily identified, because this alteration has been obliterated to variable degrees by later deformation and metamorphic events. In the 08 and 07 ore zones, altered fragments of breccia lacking foliation within a dominantly biotite -quartz -epidote assemblage and enclosed by deformed sulfide veins suggest a predynamic metamorphic alteration (Fig.…”

Section: Petrography and Distribution Of Altered Metabasic Rocksmentioning

confidence: 99%

“…In an earlier paper (Belkabir & Hubert 1995), we examined the geometrical and structural aspects of the sulfide-rich Archean Mouska gold deposit, in the Abitibi Province of Quebec, with emphasis on interactions between host rocks, sulfide bodies, shear zones and quartz veins. The sulfide bodies were overprinted by ductile deformation, metamorphism and quartz veining.…”

Section: Introductionmentioning

confidence: 99%

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Gold Emplacement and Hydrothermal Alteration in Metabasic Rocks at the Mouska Mine, Bousquet District, Abitibi, Quebec, Canada

Belkabir

Hubert

Hoy

2004

The Canadian Mineralogist

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The Mouska mine, in the Bousquet region of the Abitibi greenstone belt, Quebec, exploits a sulfide-rich quartz-vein-type gold deposit hosted by a metavolcanic sequence of basalt and andesite. The ore zones constitute three main structural and lithologic systems, named 07, 08 and 22, comprising both lenses of massive and disseminated sulfides and quartz veins. Gold, varying from microscopic to visible, is hosted by both sulfide and quartz veins. The ore minerals consist of pyrrhotite and chalcopyrite, together with minor amounts of pyrite. Pyrite in particular, consists of two generations. Pyrite I is fine-grained (100 to 200 m), and encloses micro-inclusions of gold (10 to 12 m), chalcopyrite and pyrrhotite. Pyrite II is late, coarse-grained and cataclastic, and lacks micro-inclusions of gold. Pyrite I is rare, and partially to completely replaced by chalcopyrite and pyrrhotite. It may well represent a remnant of the first paragenetic assemblage (with chalcopyrite and pyrrhotite inclusions) in the deposit. Gold in the Mouska deposit exhibits a wide range of occurrences and habits. The gold micro-inclusions in pyrite I contain 4 to 6% Ag; gold in any other habit contains up to 25% Ag. Compared to the common Archean auriferous quartz-vein deposits, the Mouska deposit has a higher sulfide content of the veins, and the variably altered and deformed metabasic rocks show both distal and proximal halos of alteration. Such halos result from a complex and progressive interaction between hydrothermal-predeformational (sulfide event) and tectonometamorphic (quartz event) imprints. Mineralogical, geochemical and isotopic studies show that alteration assemblages surrounding the ore zones not only vary with lithology (basalt to andesite), but indicate a complex hydrothermal history, where the mafic protoliths have undergone several transformations during the Au-sulfide and Au-quartz depositions. In the proximal alteration, the mass-balance calculations display a clear addition of K, which may account for the observed enrichment in biotite and white mica toward the ore zones. However, these calculations show substantial addition of SiO 2 only in the altered basalts, which can be explained by the massive destruction of ferromagnesian minerals.

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Section: Paragenesismentioning

confidence: 93%

Section: Background Informationmentioning

confidence: 99%

Section: Paragenesismentioning

confidence: 99%

Section: Petrography and Distribution Of Altered Metabasic Rocksmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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