Abstract:In the Garry Lake area, the northern margin of the 1.72 Ga Thelon Basin overlies the lower Proterozoic Amer Group, and Archean gneisses and plutonic rocks. Northeast- to north-northeast- and northwest...In the Garry Lake area, the northern margin of the 1.72 Ga Thelon Basin overlies the lower Proterozoic Amer Group, and Archean gneisses and plutonic rocks. Northeast- to north-northeast- and northwest-striking faults record post-Thelon Formation displacement. A uraniferous boulder train was located near the erosional edge of the Thelon Basin. Polymetallic calcite-bearing veins containing native silver-altaite-clausthalite-pitchblende, are hosted by lower greenschist grade arkosic wacke belonging to the upper Amer Group clastic sedimentary sequence. Based on the polymetallic elemental signature in the veins, thin argillic alteration envelopes mantling crack-and-fill veins, and calcite as the principal gangue mineral in veins, this occurrence resembles the clay-bounded subtype of unconformity-related uranium deposits. Recognition of this subdeposit type in the northern Thelon Basin extends its known areal distribution and signals this segment of the basin to be prospective for unconformity-related uranium deposits.Read More