An isotopic and fluid inclusion study of the Rock Canyon Creek, fluorite-REE deposit, southeastern British Columbia

The Rock Canyon Creek fluorite-REE deposit is hosted by a Cambro-Ordovician to Devonian carbonate-dominated sedimentary sequence in southeastern British Columbia.; Five types of dolomite have been identified: (1) microdolomite; (2) replacement, non-ferroan dolomite; (3) saddle dolomite I, (4) coarse, ferroan dolomite, and (5) saddle dolomite II. Some Ordovician microdolomite falls in the isotopic range of typical Ordovician marine carbonates. Non-ferroan dolomite, which predates mineralization, is more depleted in 18O and 13C than microdolomite. The precipitation of saddle dolomite I, which predates mineralization, is related to veins and vugs. Geochemical and petrographic evidence suggest that saddle dolomite I and non-ferroan dolomite were precipitated from a hot, slightly saline fluid. Pervasive coarse ferroan dolomite occurs in most host rocks to the fluorite-REE mineralization. Saddle dolomite II occurs in open space associated with fluorite and quartz, has similar isotopic compositions to ferroan dolomite and is suggested to have precipitated from the same fluid as that which precipitated ferroan dolomite. (Abstract shortened by UMI.)...