U-Pb and Re-Os dating of the Jianlong Cu-W deposit in Xingguo County of southern Jiangxi Province: constraint on its petrogenic and metallogenetic ages

The Jianlong Cu-W deposit, as a newly discovered one in southern Jiangxi Province, is located at the convergent zone of the eastern Nanling EW-trending tectono-magmatic belt and Yushan depression of the western Wuyishan uplift belt. The ore bodies, including mineralized quartz vein and greisen, are hosted in the inner and outer contacts between Fozishan granite and Sinian epimetamorphic rocks. Based on the LA-ICP-MS zircon U-Pb and molybdenite Re-Os isochron dating, the ages of the granule biotite granite and the molybdenite in greisen were accurately determined. The weighted average age of single-grain LA-ICP-MS zircon U-Pb of granite is 154.2±1.7 Ma, and the Re-Os isochron ages of molybdenite is 155.9±1.2 Ma. The study results suggest that diagenesis and mineralization occur almost at the same time. The age of diagenesis and mineralization of the deposit is determined to be Late Jurassic, similar to the Huamei'ao, Zhangjiadi and Yanqian in this area. Combined with the previous research data, it is further confirmed that the tungsten polymetallic deposits in the eastern part of Nanling Mountains were mainly formed at 170-150 Ma. The rhenium content of molybdenite in the ore ranges from 6.484×10^-6 to 21.346×10^-6. Combined with sulfur isotope analysis, it is considered that the ore-forming materials of the deposit originate from crust-mantle mixing.