The Gold Dollar talc deposits lie near the British Columbia- Alberta border, in Kootenay National Park, and are situated on a spur 1 kilometre south of Talc Lake. Access to the deposit is 20 kilometres west of Banff, Alberta, where a secondary road leads off Highway 1 following Redearth Creek; from the mouth of Pharoah Creek a trail heads south into Redearth Pass and Talc Lake.
A series of talc bodies are exposed 300 to 1000 metres to the southeast of Talc Lake (Red Mountain, 082O 002 and Gold Dollar respectively), and also 1 kilometre northwest of Talc Lake (Saddle, 082O 003). They may represent erosional remnants of a once continuous and extensive zone. The bodies are in the hangingwall and close to and southwest of the northwest trending informally named Haiduk normal fault (Fieldwork 1992, page 365). The fault cuts through saddles along the spurs, two of which mark the contact between the Lower Cambrian Gog Group and Takakkaw tongue (slope facies of the Middle Cambrian Cathedral Formation). The talc bodies are just southeast and north of the northeast corner of an embayment in the Cathedral escarpment. There is a facies change at the Cathedral escarpment between the platformal Cathedral and Mount Whyte formations in the east, to the basinal Takakkaw tongue and Middle Cambrian Naiset Formation to the west. The Red Mountain and Gold Dollar occurrences are at the base of the Takakkaw tongue (or Naiset Formation), whereas the Saddle occurrences are at the base of the Cathedral Formation.
At the Gold Dollar (North) occurrence, black talc is poorly exposed in several sloughed handcuts on the north side of the spur, 300 metres southeast of the Red Mountain occurrence. The talc body is at the top of an extensive talus apron below a cliff. Fifty metres east of the talc, the Haiduk fault is inferred to cut through the broad saddle between quartz arenites of the Gog Group to the east, and cliff-forming dolomites of the Takakkaw tongue to the west. This near-black, very rubbly weathering talc is at least 3 metres thick. The talc is weakly to strongly sheared and cut by a well developed slaty cleavage. It is very fine grained and moderately to very soft. A thin section reveals relic polygonal grains outlined by carbonaceous material, suggesting a protolith of brecciated carbonaceous dolomite. Analysis (XRF) indicates that the black colour of the talc probably results from extremely fine-grained chlorite as well as a carbonaceous mineral (Fieldwork 1992, pages 369, 370).
The talc grades upward into several metres of black argillite cut by a few per cent white talc veinlets. The argillite grades upward to a few metres of dolomitic argillite with intervals of black argillite and dolomite, into slaty argillaceous dolomite with 0.5 per cent fine to medium grained disseminated pyrite. All are thin to very thin bedded and laminated.
The Gold Dollar (South) occurrence is the second largest body of talc in the Talc Lake area and is exposed in a bluff that is 30 metres wide and 100 metres south and on the opposite side of the spur from the Gold Dollar (North) occurrence. A cut was made several metres into the talc at the base of the bluff. The contacts of the talc body are covered. The sheared body appears to occupy the hangingwall of the Haiduk fault and occurs between the top of the Gog Group to the east, and the Takakkaw tongue to the west. The talc weathers rusty orangish brown and has a very irregular, rough- weathered surface.
The eastern 7 metres of the talc body is medium to light grey with streaks and lenses of black on fresh surfaces. Partly talc-altered, very thin bedded and laminated dolomite interbedded with carbonaceous(?) argillaceous dolomite is locally apparent. The central 19 metres of talc is light grey and white with variable proportions of medium to dark grey and few per cent near-black carbonaceous lenses and patches. The interval is variably pyritic. The pyrite is very fine to medium grained and tends to cluster in irregular patches. The western 5 metres of talc is carbonaceous and near black with a few per cent white spots and a few, thin, sheared lenses of white talc.
