The Poplar copper-molybdenum-gold porphyry deposit, central British Columbia

Special Volume, Vol. SV 46, No. 1995, 1995

The Poplar copper-molybdenum-gold porphyry deposit is hosted by a calc-alkaline intrusion belonging to the Bulkley Intrusive Suite of Late Cretaceous age. The deposit is located within the Intermontane Belt in west-central British Columbia and lies in the Interior Plateau physiographic region west of Prince George, British Columbia. The Poplar stock intrudes Jurassic Hazelton Group volcanic and volcaniclastic rocks which include a significant clastic sedimentary component. The stock appears to be the exposed part of a larger intrusive batholith, broken by post mineralization, northnorthwest trending normal faults downthrown to the west. The deposit Was' discovered by classical prospecting in the early 1970s and extensively explored by Utah Mines Ltd. during the period 1974 to 1981. Geological mapping, geophysical surveying and diamond drilling served to delineate a copper-molybdenum resource of 236 million tonnes grading 0.37% Cu equivalent. The Poplar deposit is hosted by a biotite feldspar monzonite porphyry. Copper and molybdenum mineralization is associated with signifiCtlflt potassic and propylitic alteration; sulphide minerals consist of pyrite, chalcopyrite and molybdenite. The chalcopyrite is commonly disseminated and associated with sericitized biotite, while molybdenite occurs predominantly in veins associated with gypsum and quartz. Diamond drilling on the Poplar stock in 1991 expanded reserves in the higher grade core of the deposit. In the northeast area of the claim block a soil geochemical survey has' delineated a strong copper anomaly which overlies a zone of propylitic alteration in a porphyritic biotite feldspar monzodiorite. This stock was- drill tested in the 1991 program, and returned significantly anomalous values in copper, molybdenum and gold.

Mots Clés: Poplar, Copper-molybdenum deposit, British Columbia, Jurassic Hazelton Group, Intrusive batholith, Classical prospecting