UBC Theses and Dissertations
A geological evaluation of the Cinola (specogna) gold deposit, Queen Charlotte Islands, B.C. Champigny, Normand
Cinola (Specogna) gold deposit in the northern Queen Charlotte Islands, British Columbia, was first discovered in 1970. It is now at the feasibility stage, with proven reserves of 45.4 million short tons averaging 0.054 oz. Au/s.t. The deposit is in a clastic sequence consisting of a lower shale unit (Haida Formation, Late Cretaceous) and an overlying conglomerate-sandstone sequence (Skonun Formation, Middle Miocene). Both sedimentary units are cut by a stock and dykes of rhyolite-porphyry. Two K-Ar model ages indicate mineralization and probably rhyolite-porphyry intrusion at about 14 Ma (Middle Miocene). The model ages, together with plant microfos-sil and fauna examination, revealed a 17-15 Ma age for the fluviatile Skonun sequence, in which the Cinola deposit occurs. The deposit is the first Canadian Carlin-type deposit to be described in detail. Gold mineralization is widespread, and occurs as micron-size particles disseminated in the sedimentary host rocks and in quartz veins. Pyrite and marcasite are the main sulphides, and alteration type is dominantly argillic. The Cinola deposit resulted from the development of a large geothermal system, the energy for which derived from the rhyoii-tic intrusion. Ore fluids originated from pore water in the fluviatile host rock, as indicated by fluid inclusion studies. Two temperature regimes centred on 160°C and 270°C existed during circulation of the ore fluids. Depth of mineralization is estimated between 1.1 and 1.8 km. A geostatistical evaluation of geochemical data from Cinola shows that Au, Ag, Hg, As, Sb, and W have systematic distribution patterns in either primary or secondary environments, and could be useful pathfinders for exploration for similar types of gold deposits. A geostatistical study of assay data has shown the deposit to be particularly amenable to reserve estimation by kriging of selection units.
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