Zircon U-Pb age, geochemistry and geological significance of Shunzuo granite in Wuzhishan area, Hainan Island

Shunzuo granite is located in the Wuzhishan area of Hainan Island, on the east and west sides of the Cretaceous volcanic rocks. The LA-ICP-MS zircon U-Pb dating yielded an age of 254.4±2.4 Ma, suggesting Late Permian. Petrology and geochemistry show that it belongs to the sub-alkaline rock series, with SiO₂ content 69.88%~74.51%, 72.99% on average, implying an acidic rock. It has obvious negative anomalies of Ba, Ta-Nb, P and Ti and obvious positive anomalies of Rb, K, Pb and Nd. The initial strontium ratio is 0.70947~0.717388, which is lower than the average ratio of strontium to continental rock (0.719), suggesting moderate strontium granite. ε_Nd(t) is-9.25~-5.14, and T_2DM is 1444~1777Ma. It might have resulted from the action of crust thickening in the deep melts and NW-SE trending extrusion on slate, phyllite, plagiogneiss, granulite, plagioclase diopside and other rocks or deeper similar rocks, being a product of stress synergy. It is S-type granite, and the emplacement is a strong emplacement type in the syn-collision structure environment. It is of the hot air balloon expansive type underplating. It belongs to the shell source remelting granite, which was formed in the syn-collision environment.