Muscovite 40Ar−39Ar age and its geological significance in Zhuxi W(Cu) deposit, northeastern Jiangxi

The Zhuxi W(Cu) skarn deposit, the world’s largest tungsten deposit is newly discovered in Jingdezhen city, northeastern Jiangxi province, China. It mainly occurs near the contact zone between the Yanshanian granites and the Late Paleozoic carbonate rocks. Three types of mineralization including skarn type, altered granite type and quartz vein-veinlet type orebodies have been observed. In this study, the 40 Ar −39 Ar age of hydrothermal muscovite coexisting with copper mineralization in the altered granite type orebody formed near the unconformity interface is determined by step-heating technology using CO 2 laser. The plateau age, isochron age, and inverse isochron age of muscovite are (147.39±0.94) Ma, (147.2±1.5) Ma, and (147.1±1.5) Ma, respectively. These ages are almost identical to the ages of ore-related granite and other mineralization types in the Zhuxi W(Cu) deposit, indicating that the Cu mineralizations occurred at the shallow depth and near the unconformity interface are contemporaneous during the Late Jurassic. This further suggested that the acompanied W and Cu mineralization in the Zhuxi W(Cu) deposit which may be controlled by the magma source is enriched in both W and Cu.