Geology, hydrothermal alteration, and genesis of the world-class Canadian Malartic stockwork-disseminated Archaean gold deposit, Abitibi, Quebec.

The Canadian Malartic Mine consists of an Archaean low-grade bulk tonnage gold deposit (reserves of 10.7 Moz Au at 0.97 g/t) hosted by clastic metasedimentary rocks of the Pontiac Group and subalkaline porphyritic quartz monzodiorite and granodiorite located immediately south of the Larder Lake-Cadillac Fault Zone. Gold mineralisation is characterised by zones of quartz-carbonate vein stockwork and disseminated pyrite with a Au-Te-W-S-Bi-Ag±Pb±Mo metallic signature. Molybdenite from highgrade ore yielded a Re-Os age of ca. 2 664 Ma. A syn-Timiskaming magmatic-hydrothermal early phase of gold mineralisation can be inferred by the metallic signature or the ore, the presence of mineralised stockworks, the potassic alteration (biotite/microcline), and association with porphyritic intrusions. The main characteristics of the Canadian Malartic deposit is best explained by syn-D2 deformation gold (ca. 2 670-2 660 Ma) superimposed onto, or remobilised from, a gold-bearing magmatic/hydrothermal system related to Timiskaming-age porphyritic intrusions emplaced along a major fertile fault zone.
The Canadian Malartic Mine consists of an Archaean low-grade bulk tonnage gold deposit (reserves of 10.7 Moz Au at 0.97 g/t) hosted by clastic metasedimentary rocks of the Pontiac Group and subalkaline porphyritic quartz monzodiorite and granodiorite located immediately south of the Larder Lake-Cadillac Fault Zone. Gold mineralisation is characterised by zones of quartz-carbonate vein stockwork and disseminated pyrite with a Au-Te-W-S-Bi-Ag±Pb±Mo metallic signature. Molybdenite from highgrade ore yielded a Re-Os age of ca. 2 664 Ma. A syn-Timiskaming magmatic-hydrothermal early phase of gold mineralisation can be inferred by the metallic signature or the ore, the presence of mineralised stockworks, the potassic alteration (biotite/microcline), and association with porphyritic intrusions. The main characteristics of the Canadian Malartic deposit is best explained by syn-D2 deformation gold (ca. 2 670-2 660 Ma) superimposed onto, or remobilised from, a gold-bearing magmatic/hydrothermal system related to Timiskaming-age porphyritic intrusions emplaced along a major fertile fault zone.