Study on Zircon LA-ICP-MS U-Pb Dating and Sr-Nd Isotope of the Guposhan Granite in Guangxi

Zircon U-Pb dating with the LA-ICP-MS method was applied to determining the ages of different units of the Guposhan granite, among which the east Guposhan unit is 160. 8 plus/minus 1. 6 Ma, the west Guposhan unit is 165. 0+/-1. 9 Ma, and the Lisong unit is 163. 0+1. 3 Ma in age. It is worth noticing that the ages of the three units are very similar to each other within the analytical error. It thus proves that the whole Guposhan granite was formed in the same age. They are products of large-scale magmatism of crust-remelting granitoids in the first stage of the middle Yanshanian Period in South China. Though forming in the same age, the three units have differences in petrological and geochemical characteristics. Besides the differences in major, trace and rare earth elements, they are distinct in their Rb-Sr and Sm-Nd isotopic compositions. The east unit, Lisong unit and its enclaves have a similar ('Sr/'Sr); value of 0. 70643 and average eNd (t) (-3. 03) , indicating that more mantle materials participated