The area is underlain by rocks of the Lower Jurassic Unuk River Formation, Hazelton Group. These rocks consist of sandstone, wackes and shale overlain by lapilli-tuff of andesitic composition. The Brucejack fault and associated splay faults cut the country rock in a north-south to northwest direction. North of Brucejack Lake the fault system is bounded on the east by rocks of the Lower Jurassic Betty Creek Formation, Hazelton Group. A variety of Jurassic hornblende syenites and alkali feldspar syenites occur in the area.

Several lead-zinc showings were mapped on the Red River claims by Granduc Mines in 1976 (Assessment Report 6255). (These showings have all been further examined and/or grouped with the Goldwedge (104B 105) and Brucejack Flat (104B 295) occurrences.) Minor amounts of sphalerite and galena are reported to occur in sheared and hornfelsed arenaceous rock (Exploration in B.C., 1976).

The Red River showing occurs about 1.25 kilometres to the northwest of Brucejack Lake (0.75 kilometres south of the Goldwedge occurrence) (Open File 1988-4).