Zircon U-Pb dating of granite porphyry and Re-Os isotopic dating of molybdenite from Wangwu porphyry Mo-Cu deposit, Jiangxi Province, and their geological significance

The Wangwu Mo-Cu deposit, located in the northern part of the Qin-Hang tectonic magmatic metallogenic Belt (QHB), is a middle tonnage porphyry type deposit. The orebodies of the deposit are mainly composed of quartz-molybdenite-chalcopyrite veins, with minor disseminated mineralization. Yanshanian granite porphyry and quartz diorite porphyrite dykes are cryptoplasmic in the area. In this paper, we present LA-ICP-MS U-Pb zircon age data for the granite porphyry and Re-Os isotope age data for molybdenite from the quartz-molybdenite veins. The U-Pb age of zircons from the granite porphyry is 136. 7 +/- 2. 2Ma, and Re-Os dating of molybdenite yields an isochron age of 134. 8 +/- 2. 1Ma. Re-Os isotopic model ages of molybdenite range from 132.6 +/- 1. 8Ma to 134.5 +/- 2. 0Ma, with a weighted average age of 133. 7 +/- 0.94Ma. The results show that the ages of granite porphyry and molybdenite mineralization are the same within errors. Furthermore, geological and geochronological evidence indicate that the granite porphyry and molybdenite mineralization have very close genetic relationships. The integrating results of this study with published data and regional tectonic setting suggest that the Wangwu molybdenum-copper deposit was formed in an extensional tectonic setting at Early Cretaceous. The regional diagenetic and metallogenic age data show that the Cu-Mo-Pb-Zn-Ag mineralization of North Wuyi area were mainly occured in Yanshanian and can be grouped into two stages of 150 similar to 165Ma and 140 similar to 125Ma, respectively.