Cretaceous porphyry magmatic-hydrothermal systems in the Tchaikazan River area, southwest B.C

The Hub, Charlie and Northwest Copper are spatially related mineral showings (Cu ± Mo) located in the Tchaikazan River area of southwest British Columbia. The Tchaikazan River area is located on the boundary between the Intermontane Belt and southeast Coast Belt (SECB). Evidence of magmatic-hydrothermal alteration is preserved throughout the study area. Multiple episodes of magmatic-hydrothermal activity are associated with these three centres of porphyry-style mineralization. The Hub diorite is the oldest dated pluton in the area, with a U-Pb zircon emplacement age of 81.19 ± 0.78 Ma. ZFT/AFT data suggests an emplacement depth of> 4km for the Hub diorite. The Hub diorite is crosscut by a biotite ± magnetite (± quartz) matrix/cemented hydrothermal breccia. A feldspar hornblende dyke crosscuts both the diorite and hydrothermal breccia and gives a U-Pb zircon age of 79.9 ± 1.5 Ma. Copper, molybdenite ± galena occurs in quartz veining and cement to the hydrothermal breccia. ZFT/U-Pb and Ar-Ar ages for the Hub diorite are within error of each other. AFT data suggests an average erosion rate of 40 m/myr for intrusive rocks in the Taseko Lakes area. Field relationships, geophysical anomalies, geochronology, and stable isotope data suggest that there are three centres for magmatic-hydrothermal activity in the Tchaikazan River area: The Hub, Northwest Copper pluton, and Ravioli Ridge. The area displays evidence for multiple, temporally-distinct intrusive, alteration and mineralizing events.Science, Faculty ofEarth, Ocean and Atmospheric Sciences, Department ofGraduat