Architecture et origine du système de minéralisation polymétallique du secteur lac Line, région de Chibougamau, Québec /

Côté-Mantha, O

doi:10.1522/030109183

Cited by 6 publications

(17 citation statements)

References 69 publications

(117 reference statements)

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“…3), suggesting a possible genetic link between magmatism (e.g., the porphyritic phase) and mineralization in this area. Moreover, textural and geochemical similarities between the Line Lake stock and the biotite-tonalite porphyry phase of the Chibougamau Pluton (Racicot et al, 1984;Côté-Mantha, 2009), which is associated with the Chibougamau-type Cu-Au deposits, support the notion that the stock may have contributed to the hydrothermal system of the Line Lake area.…”

Section: ±mentioning

confidence: 89%

“…A poorly to well-developed penetrative schistosity commonly occurs in the stock along this structure. Numerous meterscale E-W, plus some NW-SE and N-S dikes related to the Line Lake stock are found up to 500 m S of the intrusion (Pilote, 1986;Côté-Mantha, 2009 …”

Section: Line Lake Stockmentioning

confidence: 99%

“…The lowermost part of the younger volcanic cycle consists of mafic flows and sills that are overlain by an assemblage of intermediate to felsic flows, sills, and volcaniclastic deposits that are considered as remnants of variably preserved volcanic edifices (Couture, 1986;Pilote, 1986;Côté-Mantha, 2009). The volcanic rocks of the youngest cycle are genetically related to the Chibougamau Pluton (Racicot, 1980(Racicot, , 1981Racicot et al, 1984;, which is a polyphase, tonalitic-dioritic, calcalkaline intrusion emplaced into the Doré Lake Complex at around 2718 Ma (Krogh, 1982;Pilote et al, 1996;Joanisse, 1998).…”

Section: Regional Settingmentioning

confidence: 99%

“…Sample processing, U-Pb isotope analysis, and data reduction followed standard procedures described in Davis and Lin (2003). Detailed location, analytical techniques, interpretation, and discussion concerning the dating are provided in Côté-Mantha (2009 .0 Ma in Mortensen (1993), and at 2713 ± 7, 2711 ± 6, and 2704 ± 2 Ma in Joanisse (1998). The Line Lake stock age is older than the oldest syntectonic pluton (2701 Ma; Mortensen, 1993).…”

Section: ±mentioning

confidence: 99%

“…Alteration and mineralization also occur in this unit, although less well developed than in the underlying massive volcanic rocks. These tuffs are interpreted as reworked volcaniclastic deposits (Archer, 1983(Archer, , 1984Lefebvre, 1991;Côté-Mantha, 2009). The uppermost part of the Brosman prospect host-rock succession consists of variably textured, medium-grained gabbroic sills that are in intrusive to locally faulted contact with the underlying unit.…”

Section: Host-rock Unitsmentioning

confidence: 99%

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Geology, Alteration, and Origin of Archean Au-Ag-Cu Mineralization Associated with the Synvolcanic Chibougamau Pluton: The Brosman Prospect, Abitibi Greenstone Belt, Canada

Côté-Mantha¹,

Gaboury²,

Chartrand³

et al. 2012

Economic Geology

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The Au-Ag-Cu Brosman prospect is located in the Line Lake area on the northern limb of the Chibougamau anticline, in the northeast part of the Archean Abitibi greenstone belt. This prospect comprises a broad N-S, subvertical mineralized envelope formed in a synvolcanic fault-related environment. This envelope is at least 300 m long, up to 30 m wide, and is known to a depth of 950 m, where it remains open. It exhibits two contrasting mineralized zones that are representative of the varying styles of mineralization in the area. The Auriferous zone consists of both ubiquitous pyrite disseminations and Au-bearing silicate-sulfide veins in strongly fractured intrusive, effusive, and volcaniclastic rocks showing propylitic and chloritic alteration assemblages. The Polymetallic zone, on the other hand, is characterized by discrete, Cu-Ag-Au−rich magnetite-sulfide veins and lesser pyrite disseminations within distal propylitic and proximal potassic to sodic alteration zones. The Polymetallic zone is hosted by a chaotic assemblage of gabbro and tuff bodies interpreted as a talus megabreccia.Several lines of evidence, including the spatial distribution pattern and nature of the alteration and mineralization assemblages, metal associations, mass-balance calculations, pyrite composition, and crosscutting relationships are indicative of a preregional deformation, synvolcanic origin for the hydrothermal activity. Crosscutting relationships, alteration characteristics as well as whole-rock and LA-ICP-MS pyrite analyses reveal two stages of hydrothermal alteration and mineralization. Stage I consists of both ubiquitous disseminated pyrite, found in the Polymetallic and Auriferous zones, and contemporaneous magnetite-sulfide veins, restricted to the Polymetallic zone. Stage II is restricted to the Auriferous zone and corresponds to Au-bearing silicate-sulfide veins with characteristic vein-halo chloritic alteration overprinting Stage I alteration and mineralization.This hydrothermal activity is interpreted to have occurred concurrently with the development of the fertile, deeper magmatic-hydrothermal system related to the Chibougamau Pluton. Stage I hydrothermal activity, related to the early build-up of the volcanic sequence, formed a continuum of mineralization from discrete massive magnetite-sulfide veins to ubiquitous pyrite disseminations in a submarine talus megabreccia generated along synvolcanic faults. Afterward, a late Au-rich contribution to the hydrothermal fluids, possibly related to intermediate to felsic magmatism (the 2707.6 ± 1.4 Ma Line Lake stock), produced Stage II silicate-sulfide veins overprinting mineralization and alteration in favorably oriented and sustainably permeable fracture zones of the Auriferous zone.Overall, this study suggests that the Brosman prospect is a rare example of Archean polymetallic mineralization produced by a shallow subaqueous epithermal-style subsystem developed in a broader, fertile magmatichydrothermal arc setting.

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Section: ±mentioning

confidence: 89%

Section: Line Lake Stockmentioning

confidence: 99%

Section: Regional Settingmentioning

confidence: 99%

Section: ±mentioning

confidence: 99%

Section: Host-rock Unitsmentioning

confidence: 99%

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Geology, Alteration, and Origin of Archean Au-Ag-Cu Mineralization Associated with the Synvolcanic Chibougamau Pluton: The Brosman Prospect, Abitibi Greenstone Belt, Canada

Côté-Mantha¹,

Gaboury²,

Chartrand³

et al. 2012

Economic Geology

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Deep Into the Chibougamau Area, Abitibi Greenstone Belt: Structure of a Neoarchean Crust Revealed by Seismic Reflection Profiling

et al. 2020

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Copper‐gold magmatic‐hydrothermal systems dominate in the Chibougamau area of the Neoarchean Abitibi subprovince (greenstone belt) of the Superior Province (craton), whereas orogenic gold mineralization is more common in the rest of the Abitibi. Understanding differences in metal endowment within the Abitibi greenstone belt requires insights into the geodynamic evolution of the Chibougamau area. This was addressed by imaging the crust using seismic reflection profiling acquired as part of the Metal Earth project. Seismic reflection sections display shallowly south‐dipping reflectors located within the upper crust (e.g., a possible deep continuation of the Barlow fault) and a northward‐dipping midcrust imbricated with older crust (Opatica subprovince) to the north. Multiple reflectors characterize the upper part of the midcrust, interpreted as faults superimposed on a major lithological boundary. These structures likely formed during terrane accretion prior to craton stabilization. Combining the new seismic data with known stratigraphic, structural, and magmatic records, we propose that the study area was initially a normal (i.e., thick) Archean oceanic crust that formed at or before 2.80 Ga and that evolved through terrane imbrication at 2.73–2.70 Ga. Shortening caused rapid burial, devolatilization, and partial melting of hydrated mafic rocks to produce tonalite magmas that may have mixed with mantle‐derived melts to produce the diorite‐tonalite suite associated with observed Cu‐Au magmatic‐hydrothermal mineralization.

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genetic role of dykes on the mineralization of the Monsabrais sector, Blake River Group, Abitibi greenstone belt /

Koth¹

2013

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The Monsabrais area is a volcano-plutonic center located at the Northwest of the Blake River Group. It is situated between the inner and outer ring faults of the interpreted Misema Caldera based on the mega caldera complex model for the Blake River. The presence of a volcanic sequence intruded by a swarm of radial and concentric dykes within the plutonic suite of Monsabrais is the key features of the sector, and commonly very favourable for volcanogenic mineralization. The project had for main objective the establishment of the genetic role of the dykes on the mineralization. A series of techniques were used: mapping and sampling, pétrographie study of fresh and altered and mineralized samples, lithogeochemistry of dykes and host rocks and sulfide studies based on trace element signature yields by LA-ICP-MS.As result of the application of those techniques, it is possible to determine the co-magmatic character of this predominant intermediate, transitional magmaticvolcanic system. The intrusive lithologies are: major dykes, equigranular dykes, porphyritic dykes, Monsabrais plutonic suite and aplitic dykes. The major gabbroic dykes are interpreted as feeder conduits for the volcanic sequence. The gabbro to granodiorite plutonic suite crosscuts the precedent units. The granodiorite to granite aplitic dykes are a late and felsic phase from the pluton. The equigranular and porphyritic dykes have the same plutonic composition but a finer granulometry and occur crosscutting the other lithologies.The hydrothermal alteration has a random distribution interpreted as resulting from the analogous overprinting of semi-conformable alteration zones. The alteration zones are represented by the pervasive alteration of the following minerals: quartz, epidote, chlorite and carbonate. The quartz-carbonate veins are considered as related to the alteration zone genesis. Those alterations are the consequence of the distal leaching of elements from the rocks by hydrothermal fluids and the following precipitation of those elements in a proximal, hotter zone. The fluid source is interpreted as heated sea water and possibly later magmaticfluids from the plutonic suite.The mineralization is manifested by the occurrence of pyrite, pyrrhotite and chalcopyrite that occur on the area in three forms: disseminated in the whole rock, filling amygdules and less recurrent in quartz-carbonate veins. The pyrite defines texturally two families that share similar elemental signatures. The pyrrhotite has similar elemental signature to the pyrite families, evidencing that sulfides result from the same event. These are chemically and texturally comparable to other known volcanogenic deposits.Evolution model defines the Monsabrais complex as a two stage magmatic event. A first extrusive event is responsible for the formation of the volcanic sequence, fed by the major dykes. The second magmatic event is responsible for the plutonic suite emplacement. The other dykes are emplaced continuously during and between both events. Those features support the...

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Architecture et origine du système de minéralisation polymétallique du secteur lac Line, région de Chibougamau, Québec /

Cited by 6 publications

References 69 publications

Geology, Alteration, and Origin of Archean Au-Ag-Cu Mineralization Associated with the Synvolcanic Chibougamau Pluton: The Brosman Prospect, Abitibi Greenstone Belt, Canada

Geology, Alteration, and Origin of Archean Au-Ag-Cu Mineralization Associated with the Synvolcanic Chibougamau Pluton: The Brosman Prospect, Abitibi Greenstone Belt, Canada

Deep Into the Chibougamau Area, Abitibi Greenstone Belt: Structure of a Neoarchean Crust Revealed by Seismic Reflection Profiling

genetic role of dykes on the mineralization of the Monsabrais sector, Blake River Group, Abitibi greenstone belt /

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