Abstract:This paper provided petrography, geochemical characteristics, LA-ICP-MA zircon U-Pb age, and zircon Lu/Hf isotopes of the Mesozoic granite in the Wugong Mountains area, Jiangxi, south China. The formation age, genesis, and tectonic significance of granites are discussed.Methods: Based on the field work, through the microscopic observation, the whole rock chemical analysis, the LA-ICP-MS zircon U-Pb isotopic chronology, and the LA-ICP-MS zircon Lu-Hf isotopes of granites.Results: The zircons of the Mesozoic granite in Wugong Mountains area were mostly long columns and developed oscillatory belts, showing the characteristics of magmatic origin. Zircon LA-ICPMS U-Pb isotopic chronology shows that the Mesozoic granites in the Wugong Mountains area were formed at 149.31~152.41 Ma. The rocks are riched in silicon (SiO2=72.96%~74.16%), alkali (Na2O+K2O=6.68%~8.42%), and poor in calcium (CaO=0.55~1.82%), magnesium (MgO=0.29%~0.70%). Aluminum saturation index (A/CNK=1.11~1.36). It is enriched in large ion lithophile elements such as Rb, U, Th and K, and relatively depleted in high field strength elements such as Sr and Ti. The ratio of light and heavy rare earth elements (La/Yb) N=1079~25.43, with a high degree of differentiation and moderate—weak negative Eu anomaly (δEu=0.17~0.28). The rare earth distribution curves are right leaning, indicating the characteristics of Stype granite. Zircon fLu/Hf values of the Wugong Mesozoic granite are all less than -0.9, and εHf(t) are all negative.Conclusions: Collectively, it is suggested that the granite belongs to strong peraluminous high potassium calc alkaline granite. It is Stype granite. The wugong granite was formed in Mesozoic, and the test results are relatively concentrated. The zircon Lu—Hf isotopic characteristics indicate that the magma source area is Neoproterozoic continental crust material. The Wugong granite was formed in an intracontinental subduction environment.
