Abstract The Canadian Malartic low-grade bulk tonnage gold mine (total production and reserves of 303.3 t or 10.7 Moz at 0.97 g/t) is located in the Archean Abitibi greenstone belt, immediately south of the crustal-scale Larder Lake-Cadillac fault zone. The deposit is predominantly hosted in clastic metasedimentary rocks of the Pontiac Group and, to a lesser extent, in subalkaline porphyritic quartz monzodiorite and granodiorite. The quartz monzodiorite and granodiorite yielded syn-Timiskaming U-Pb ID-TIMS zircon ages of 2677.8 ± 1.5 and 2678.4 ± 1.7 Ma, respectively. The ore, which is characterized by a Au-Te-W-S-Bi-Ag ± Pb ± Mo metallic signature, mainly consists of quartz-carbonate vein stockworks and replacement zones with disseminated pyrite. The ore zones are dominantly oriented subparallel to a NW-striking S 2 foliation and to the E-striking and S-dipping Sladen fault, thus forming NW-SE and E-W mineralized trends. In both the sedimentary rocks and the quartz monzodiorite, the proximal and distal alteration zones are characterized by the presence of calcite and ferroan dolomite, respectively. In the sedimentary rocks, the ore zones show a wide distal biotite alteration halo with proximal assemblages made up of albite and/or microcline with pyrite. The quartz monzodiorite comprises a distal hematite-bearing alteration zone that is overprinted by proximal microcline + albite + quartz + pyrite replacement zones. The metallic signature of the ore, the presence of mineralized stockworks, the potassic alteration (biotite/microcline), and an association with ca. 2678 Ma porphyritic intrusions suggest the possibility of an early, syn-Timiskaming magmatic-hydrothermal auriferous event in the area. However, this study indicates that gold mineralization and its distribution at Canadian Malartic are largely controlled by D 2 deformation and related features such as faults, shears, and high-strain zones. Of particular importance are the S 2 cleavage developed in the hinge zone of F 2 folds, and the Sladen fault. Molybdenite from high-grade ore yielded a Re-Os age of 2664 ± 11 Ma that is compatible with a syn-D 2 timing for the bulk of the mineralization. The main characteristics of the Canadian Malartic deposit are thus best explained by a syndeformational event (D 2 ; ca. 2670–2660 Ma) potentially superimposed onto a gold-bearing magmatic/hydrothermal intrusion-related system associated with Timiskaming-age porphyritic intrusions emplaced along the crustal-scale Larder Lake-Cadillac fault zone.

Abstract Vein-stockwork deposits of tin and tungsten occur in a wide variety of structural styles that include individual veins, multiple vein systems, vein and fracture stockworks, breccias, and replacement zones in altered wall rocks adjacent to veins. The deposits generally occur in or near granitic intrusions which have been emplaced at relatively shallow levels (1 to 4 km) in the Earth’s crust. The associated intrusions are highly fractionated and typically enriched in lithophile elements such as Rb, Li, Be, Sn, W, Mo, Ta, Nb, U, Th, and REEs, and volatile elements such as F and B. Hydrothermal alteration of wall rocks associated with vein-stockwork tin and tungsten deposits is commonly greisen-type alteration that is characterized by Li-, F-, and/or B-bearing minerals such as topaz, fluorite, tourmaline, and various F- and/or Li-rich micas. Vein-stockwork deposits with extensively greisenized wall rocks that contain disseminated tin and/or tungsten minerals have been referred to as “greisen” deposits (Shcherba, 1970; Taylor, 1979; Reed, 1986). Such deposits are included in this review as vein-stockwork deposits; “greisen” is used primarily in reference to a type of alteration rather than as a type of deposit.