Abstract:The Tongde-Zeku polymetallic metallogenic belt in West Qinling is one of the most important mineral concentrated areas in Qinghai Province found at the westernmost end of the porphyry-skarn type Cu-Mo-Au metallogenic belt on the northern margin of West Qinling. Jiangligou deposit, which forms an important part of this area, is a typical porphyry-skarn type Cu-W-Mo deposit. In this paper, the ore-forming age of Jiangligou Cu-W-Mo deposit is measured using Re-Os isotopic dating before yielding the Re-Os isotopic pattern age of 219.5±3.1~222.2±4.0Ma and isochronic age of 224.3±7.3Ma for the five sample molybdenite ores. SHRIMP zircon U-Pb dating of the adamellite in the ore district suggests two stages of crystallization, 232±4Ma and 214±4Ma, implying that the granite in the area might be the product of two magmatism events. As porphyry type deposits are mineralized later than the ore-forming parent rock, we date the ore-forming of Jiangligou deposit back to Late Triassic. Its mineralization should have been closely associated the magmatic intrusion in the area at 232Ma, approximately 8Ma later than the rock-forming. The mineralization took place roughly at the same time as rock-forming. It is the product of the Indosinian tectono-magmatic activity in West Qinling. Our study has confined the approximate ore-forming time of deposits surrounding the Gangcha complex to 243.8~214Ma, which concurs with the Triassic tectono-magmatic process and ore-forming time of the West Qinling-East Kunlun region of the area, proving that the deposit is part of the porphyry-skarn type Cu-Mo-Au metellogenic system on the northern margin of West Qinling.