矿床地球化学国家重点实验室知识库

The Xiongcun district is located in the western segment of the Gangdese porphyry copper belt (GPCB). The No.2 deposit in the Xiongcun district hosts a measured and indicated resource of 1.34 Mt copper, 76.34 t gold, and 193.78 t silver. The copper-gold mineralization of the No.2 deposit is mainly hosted in the Early Jurassic quartz diorite porphyry which intruded volcano-sedimentary rocks of the Early Jurassic Xiongcun Formation. S and Pb isotopic compositions of the ore sulfides and Re contents of molybdenite suggest a mantle source with minor contamination of subducted sediments for the ore-forming materials. Hydrogen and oxygen isotopic compositions of quartz from the quartz-sulfide veins suggest that the ore-forming fluid was a mixture of magmatic and meteoric water. Geochemical and Sr-Nd-Hf isotopic compositions of the Early Jurassic quartz diorite porphyry suggest that the mineralization of the No.2 deposit formed in an intra-oceanic island arc setting. The magmas of the Early Jurassic quartz diorite porphyry were likely sourced from partial melting of mantle with limited contamination by subducted sediments (ca. 5%). The formation of the porphyry and the No.2 deposit were related to the northward intra-oceanic subduction of the Neo-Tethys oceanic slab during the Early Jurassic.