Book Description
The Central Manitoba mine trend is one of the most important lode gold camps in the Rice Lake greenstone-granitoid belt of the western Uchi Subprovince within the western Superior Province, Manitoba, Canada. Neoarchean host rocks consist of a south-facing volcano-sedimentary succession (2.75-2.73 Ga) intruded by voluminous gabbroic sills and tonalitic-granodioritic plutons (2.73-2.72 Ga), as well as late aplite dikes (2.73-2.72 Ga) and quartz-feldspar porphyry dikes (2.73-2.71 Ga). Five generations of deformation structures have been recognized through detailed geological mapping. The entire succession was folded during early deformation prior to rare late aplite dike emplacement. All fault-fill veins and extension veins cut all lithologic units, and are structurally governed by late conjugate shear zones. Main gold mineralization occurs within fault-fill veins hosted by west-trending steeply-dipping dextral brittle-ductile and ductile shear zones, which occur along or across contacts of metabasalt, metagreywacke and metagabbro or entirely within metagabbro. Microstructural and paragenetic analyses on main gold-bearing veins have revealed that gold is intimately associated with quartz, pyrrhotite and tellurobismuthite. Main gold introduction is interpreted to have taken place contemporaneously with pyrrhotite and tellurobismuthite deposition early during dextral shearing. The Ogama-Rockland gold deposit consists of shear zone-associated quartz veins hosted by the Ross River pluton, a ca. 2728-2724 Ma tonalitic-granodioritic intrusion in supracrustal rocks (