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  • 1
    In: Geofluids, Wiley, Vol. 2018 ( 2018), p. 1-21
    Abstract: Gold deposits are not uniformly distributed along major faults due to complex (and long-debated) interactions between seismicity, hydrothermalism, and structural heterogeneities. Here, we use static stress modelling (SSM) to quantitatively investigate these interactions, by exploring the role of Cadillac-Larder Lake Fault (CLLF) Archean seismicity in the genesis of the regional goldfields. Various rheological factors are evaluated for optimizing the models’ ability to reproduce known gold occurrences, regarded as the fossil primary markers of synkinematic hydrothermal systems. We propose that the marked structural heterogeneities of the CLLF induced persistent seismic segmentation and recurrent ruptures of the same fault windows that arrested on robust node points. These ruptures favour repeated occurrences of seismically triggered hydrothermalism along long-existing fluid pathways having an enhanced permeability and iterative ore formation into supracrustal discharge zones by means of episodic drops and build-ups of pressure. Two-dimensional SSM permits the predictive mapping of these high-potential zones. These modelled zones correlate positively with the actual observed gold distribution. We demonstrate that ( 1 ) the ruptures along the Joannes Segment arresting on the Davidson Fault and Lapa’s bend can explain the occurrence and location of the Rouyn and Malartic goldfields; ( 2 ) the models’ validity is improved by implementing regional geological constraints; and ( 3 ) the distant gold occurrences from the CLLF, including the Bourlamaque field, can be explained by doublet seismic events along the Rivière-Héva and Lapause subsidiary faults. Our results provide new perspectives from a fundamental standpoint and for exploration purposes.
    Type of Medium: Online Resource
    ISSN: 1468-8115 , 1468-8123
    Language: English
    Publisher: Wiley
    Publication Date: 2018
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    detail.hit.zdb_id: 2045012-6
    SSG: 13
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  • 2
    In: Ore Geology Reviews, Elsevier BV, Vol. 82 ( 2017-04), p. 49-69
    Type of Medium: Online Resource
    ISSN: 0169-1368
    Language: English
    Publisher: Elsevier BV
    Publication Date: 2017
    detail.hit.zdb_id: 55902-7
    SSG: 13
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  • 3
    Online Resource
    Online Resource
    Canadian Science Publishing ; 2018
    In:  Canadian Journal of Earth Sciences Vol. 55, No. 8 ( 2018-08), p. 905-922
    In: Canadian Journal of Earth Sciences, Canadian Science Publishing, Vol. 55, No. 8 ( 2018-08), p. 905-922
    Abstract: The Piché Structural Complex (PSC) extends over 150 km within the Cadillac – Larder Lake Fault Zone (CLLFZ), a gold-endowed, east-trending, and high-strain corridor located along the southern edge of the Archean Abitibi Subprovince. The PSC consists of discontinuous units of volcanic rocks ( 〈 1 km thick) that host multiple gold deposits. It is spatially associated with molasse-type Timiskaming sedimentary basins. This study describes and interprets the origin of structures and lithologies within the poorly understood PSC to unravel the tectonic evolution of the CLLFZ. Field mapping, chemical analyses, as well as interpretations of cross-sections from drill-hole data, were used to interpret the geometry and structure of the PSC. The PSC is subdivided into six homogeneous fault-bounded segments or slivers. These slivers consist mostly of ultramafic to intermediate volcanic rocks and include some felsic volcanic flows and intrusions. Volcanic facies, chemical compositions, and isotopic ages confirm that these slivers are derived from the early volcanic units of the southern Abitibi greenstone belt, which are located north of the CLLFZ. Cross-cutting relationships between volcanic rocks of the PSC and the Timiskaming-aged intrusions suggest that the slivers were inserted into the CLLFZ during the early stages of the accretion-related deformation ( 〈 2686 Ma) and prior to Timiskaming sedimentation and ductile deformation ( 〉 2676 Ma). The abundant ultramafic rocks located within the CLLFZ may have focused strain, thereby facilitating the nucleation of the fault as well as the displacements along this crustal-scale structure.
    Type of Medium: Online Resource
    ISSN: 0008-4077 , 1480-3313
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2018
    detail.hit.zdb_id: 417294-2
    detail.hit.zdb_id: 1491201-6
    SSG: 16,13
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  • 4
    Online Resource
    Online Resource
    American Chemical Society (ACS) ; 1995
    In:  The Journal of Physical Chemistry Vol. 99, No. 2 ( 1995-01), p. 790-797
    In: The Journal of Physical Chemistry, American Chemical Society (ACS), Vol. 99, No. 2 ( 1995-01), p. 790-797
    Type of Medium: Online Resource
    ISSN: 0022-3654 , 1541-5740
    RVK:
    Language: English
    Publisher: American Chemical Society (ACS)
    Publication Date: 1995
    detail.hit.zdb_id: 2006064-6
    detail.hit.zdb_id: 3003-X
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  • 5
    In: Tectonics, American Geophysical Union (AGU), Vol. 39, No. 7 ( 2020-07)
    Abstract: A seismic reflection survey of the Chibougamau area, Abitibi greenstone belt, is performed by the Metal Earth project The Metal Earth and Lithoprobe seismic surveys reveal that the northern part of the Abitibi greenstone belt has a consistent architecture The Chibougamau area is an Archean oceanic crust evolved through terrane imbrication and not through plume activity and subduction processes
    Type of Medium: Online Resource
    ISSN: 0278-7407 , 1944-9194
    Language: English
    Publisher: American Geophysical Union (AGU)
    Publication Date: 2020
    detail.hit.zdb_id: 2013221-9
    detail.hit.zdb_id: 780264-X
    SSG: 16,13
    SSG: 13
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  • 6
    Online Resource
    Online Resource
    Canadian Science Publishing ; 2021
    In:  Canadian Journal of Earth Sciences Vol. 58, No. 6 ( 2021-06), p. 519-541
    In: Canadian Journal of Earth Sciences, Canadian Science Publishing, Vol. 58, No. 6 ( 2021-06), p. 519-541
    Abstract: Unravelling the petrogenesis and stratigraphy of Archean mafic lava flows is essential to our comprehension of the early geodynamic evolution and economic potential of greenstone belts. This study focuses on one of the oldest and thickest sequences of lava flows observed in the Neoarchean Abitibi Subprovince (greenstone belt), that is, the Obatogamau Formation. The undated formation extends for more than 100 km in an E–W direction and consists mostly of aphyric and feldspar megacryst-bearing basaltic-andesite lava flows. These lava flows are tholeiitic, mostly Fe-rich, and have nearly homogeneous chemistry. Petrogenetic modelling carried out using MELTS software points to limited magmatic differentiation as most samples of mafic lava flows did not reach Fe-Ti-oxide saturation. Zircon U-Pb dating establishes a crystallization age of 2726.2 ± 1.6 Ma for a felsic unit located at an intermediate stratigraphic position in the sequence of lava flows. Constraints from stratigraphically overlying volcanic units suggest that the Obatogamau Formation was likely emplaced rapidly, possibly within a few million years and as a consequence of frequent replenishment of shallow magma accumulations. High eruption rates are consistent with short episodes of volcanic quiescence deduced from field observations, indicating non-optimal conditions for volcanogenic massive sulfide systems. The pressure and temperature of peak metamorphism deduced from amphibole chemistry, however, points to favorable conditions for the release of metamorphic fluids. The study area may thus be prospective for orogenic gold mineralization, provided that fluids had access to a source of gold and that structural conduits allowed for the channeling of hydrothermal fluids.
    Type of Medium: Online Resource
    ISSN: 0008-4077 , 1480-3313
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2021
    detail.hit.zdb_id: 417294-2
    detail.hit.zdb_id: 1491201-6
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  • 7
    Online Resource
    Online Resource
    Canadian Science Publishing ; 2022
    In:  Canadian Journal of Earth Sciences Vol. 59, No. 2 ( 2022-02), p. 87-110
    In: Canadian Journal of Earth Sciences, Canadian Science Publishing, Vol. 59, No. 2 ( 2022-02), p. 87-110
    Abstract: Magmatism during the maturation phase of Archean greenstone belts produced voluminous tonalite–trondhjemite–granodiorite (TTG) suites, as well as a lesser amount of tonalite–trondhjemite–diorite (TTD) suites. Such TTD suites have recently been recognized in the Archean Abitibi greenstone belt, on the southern flank of the Superior Craton, Canada, but their source(s), differentiation processes, and depths of emplacement remain poorly constrained. The Neoarchean Eau Jaune Complex lies in the northeastern corner of the Abitibi greenstone belt and represents one of the most voluminous tonalite-dominated and diorite-bearing intrusive suites of the Chibougamau region. This TTD suite comprises six intrusive phases with distinct petrology and chemistry. All units were emplaced as laccolith-like intrusions injected along discontinuities within the volcanic succession at ca. 2724 Ma (U–Pb zircon dating), during the synvolcanic interval (i.e., construction and maturation phase), at a depth of approximately 7–8 km. The most heavy rare-earth element (HREE)-depleted phases (granodiorite, tonalite, and trondhjemite) correspond to magmas that fractionated amphibole and were likely produced by partial melting of a garnet- and titanate-bearing amphibolite, akin to TTG magmas. The least HREE-depleted phases are dioritic in composition and correspond to mantle-derived magmas that may have interacted with TTG melts. This indicates interaction between coeval mantle-derived and crustal melts during the maturation phase of the Abitibi greenstone belt. Models formulated to address the geodynamic evolution of greenstone belts must account for the coeval production of basalt-derived (TTG suites) and mantle-derived (tholeiitic magmatism) melts occasionally interacting to form TTD suites.
    Type of Medium: Online Resource
    ISSN: 0008-4077 , 1480-3313
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2022
    detail.hit.zdb_id: 417294-2
    detail.hit.zdb_id: 1491201-6
    SSG: 16,13
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  • 8
    In: Canadian Journal of Earth Sciences, Canadian Science Publishing, Vol. 59, No. 10 ( 2022-10-01), p. 722-743
    Abstract: In orogenic gold systems, the source of the fluids and the processes leading to mobilization, transport, and deposition of gold remain debated. Most studies focus on endowed rather than on gold-poor orogenic systems to unravel the “key” parameters of gold mineralizing processes. Here, we present stable isotope (O, H) data from the Moly-Desgagné–Guercheville fault system (gold-free to low gold endowment) in the Chibougamau area, Abitibi greenstone belt, Canada. The gold-free Moly-Desgagné showing and nearby poorly endowed Hazeur showing and Monster Lake deposit share similar features typical of orogenic systems. The stable isotope compositions of tourmaline and quartz from the Moly-Desgagné–Guercheville fault system also display similar characteristics, such as (1) temperature of vein formation of 345 ± 86 °C (1σ); (2) fluid mixing between an upper crustal reservoir (low T – high δD – low δ 18 O) and a metamorphic water reservoir (high T – low δD – high δ 18 O); and (3) positive δD fluid values consistent with multiple boiling-condensation cycles related to fault-valve processes. These characteristics are similar to those from the gold-endowed Val-d’Or vein field. The difference in gold endowment between the Moly-Desgagné–Guercheville and Val-d’Or vein fields may be related to the nature of the fault system (i.e., terrane-bounding or “intragreenstone belt”) and the volume and (or) composition (i.e., gold, its ligands, CO 2 ) of the fluid source rocks.
    Type of Medium: Online Resource
    ISSN: 0008-4077 , 1480-3313
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2022
    detail.hit.zdb_id: 417294-2
    detail.hit.zdb_id: 1491201-6
    SSG: 16,13
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  • 9
    Online Resource
    Online Resource
    Canadian Science Publishing ; 2021
    In:  Canadian Journal of Earth Sciences Vol. 58, No. 6 ( 2021-06), p. 554-571
    In: Canadian Journal of Earth Sciences, Canadian Science Publishing, Vol. 58, No. 6 ( 2021-06), p. 554-571
    Abstract: Faults and deformation zones are important features of Archean terranes because of their significance for structural evolution and the formation of large gold districts. In the Chibougamau area, northeastern portion of the Abitibi Subprovince, an Apogee Metal Earth seismic reflection survey identified an association between an exceptional shallow-dipping subsurface reflector zone and the Barlow Fault Zone visible at the surface. This fault zone is located adjacent to the Opatica Subprovince and shares many characteristics with well-documented major gold-bearing faults in the more gold-endowed southern portion of the Abitibi Subprovince. This study aimed to reconstruct the kinematic evolution of the Barlow Fault Zone, determine its position within the structural setting of this section of the Abitibi Subprovince, and evaluate its importance for gold potential in the northern part of the Chibougamau area. The fault zone can be divided into three segments that differ markedly in dip. Structural reconstruction and field observations are compatible with a reverse south-over-north movement related to a ductile north–south shortening event, which culminated with amphibolite metamorphism. A late normal movement is deduced at the final stage. Geothermobarometers indicate peak metamorphism conditions of 550 ± 50 °C and 6 ± 1.2 kbar. Results from this study suggest that amphibolite facies metamorphism covers a much wider area within the Chibougamau region than previously documented. The Barlow Fault Zone shares similar geometric characteristics and evolutionary history with other gold-bearing structures in the Abitibi Subprovince, but ultimately it was unable to provide optimal conditions for channelling fluid and precipitating gold. High-grade metamorphism and the limited crustal extent of the fault likely prevented the tapping of deep metamorphic fluid and magma reservoirs. The Barlow Fault Zone is interpreted as a back-thrust fault that belongs to a more extensive south-dipping fault system encasing juxtaposed tectonic slivers. This system, with amphibolite facies metamorphism, is a defining feature of the northern portion of the Chibougamau area and developed during the accretion between the Opatica and Abitibi subprovinces.
    Type of Medium: Online Resource
    ISSN: 0008-4077 , 1480-3313
    Language: English
    Publisher: Canadian Science Publishing
    Publication Date: 2021
    detail.hit.zdb_id: 417294-2
    detail.hit.zdb_id: 1491201-6
    SSG: 16,13
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  • 10
    In: Solid Earth, Copernicus GmbH, Vol. 12, No. 5 ( 2021-05-19), p. 1143-1164
    Abstract: Abstract. Two high-resolution seismic reflection profiles acquired north and south of Chibougamau, located in the northeast of the Abitibi subprovince of Canada, help understand historic volcanically hosted massive sulfide (VMS) deposits and hydrothermal Cu–Au mineralization found there. Major faults crossed by the profiles include the Barlow fault in the north and the Doda fault and the Guercheville fault in the south, all targets of this study that seeks to determine spatial relationships with a known metal endowment in the area. Common-offset DMO corrections and common-offset pre-stack time migrations (PSTMs) were considered. Irregularities of the trace midpoint distribution resulting from the crooked geometry of both profiles and their relative contribution to the DMO and PSTM methods and seismic illumination were assessed in the context of the complex subsurface architecture of the area. To scrutinize this contribution, seismic images were generated for offset ranges of 0–9 km using increments of 3 km. Migration of out-of-plane reflections used cross-dip element analysis to accurately estimate the fault dip. The seismic imaging shows the thickening of the upper-crustal rocks near the fault zones along both profiles. In the northern seismic reflection section, the key geological structures identified include the Barlow fault and two diffraction sets imaged within the fault zone that represent potential targets for future exploration. The south seismic reflection section shows rather a complicated geometry of two fault systems. The Guercheville fault observed as a subhorizontal reflector connects to a steeply dipping reflector. The Doda fault dips subvertical in the shallow crust but as a steeply dipping reflection set at depth. Nearby gold showings suggest that these faults may help channel and concentrate mineralizing fluids.
    Type of Medium: Online Resource
    ISSN: 1869-9529
    Language: English
    Publisher: Copernicus GmbH
    Publication Date: 2021
    detail.hit.zdb_id: 2543230-8
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