Geologic setting of the Jolu gold mine, Saskatchewan; U-Pb age constraints on plutonism, deformation, mineralization, and metamorphism

Abstract

Structurally hosted lode gold deposits in the Early Proterozoic Reindeer zone, Saskatchewan, have many attributes in common with Archcan counterparts worldwide. The detailed field relationships at the Jolu mine indicate that the development of shear zones and mineralization in the Star Lake pluton clearly postdates eraplacement of the host footwall granodiorite at 1846 + or - Ma and predates the time of regional metamorphism in the Star Lake area estimated at 1783 Ma using a U-Pb titanitc age obtained from the Star Lake pluton. The best estimate for the timing of gold mineralization is 1807 Ma based on U-Pb dating of hydrothermal titanitc found in a mafic dike sample that exhibits a close spatial and temporal relationship to quartz vein mineralization. This age of mineralization is identical to high-grade metamorphism at deeper crustal levels in the Trans-Hudson orogen (e.g., in the Kisseynew domain) and, as has been shown for some Archcan lode gold deposits, provides a temporal link between gold mineralization at high crustal levels and high-grade metamorphism and devolatilization at depth.