Zircon U-Pb Dating and Ore-bearing Properties Evaluation of Yanshanian Shuitou Pluton in Southern Jiangxi Province

The Shuitou pluton is one of the composite plutons without accurate dating age in Southern Jiangxi province. Zircon samples taken from the Shuitou pluton were selected for U-Pb dating. The obtained age of (142.7±0.6) Ma confirmed that this granitic pluton belongs to the Yanshanian era and not the Caledonian era as a previous study has reported. Other old ages were also obtained for this pluton (such as Hercynian and Caledonian), which indicates that there were at least three periods of magmatic activity. This study indicates that Shuitou pluton is a composite pluton. Combining the petrological and geochemical study on this pluton, petrogenesis and ore-bearing properties are illustrated briefly in this paper. The Shuitou pluton mainly consists of biotite granites, which can be attributed to the peraluminous shoshonitic series with a middle fractionation of light rare earth element (LREE) and heavy rare earth element (HREE), and obvious Eu anomalies. These data indicate that the Shuitou pluton is a composite pluton formed by the result of in-situ-melting of granite. The geochemical data from this study show that this pluton has major mineralization conditions of mother rock for REE deposits.