Zircon LA-ICP-MS U-Pb dating of granitic gneisses from Wuzhishan area, Hainan, and geological significances

Better understanding on the formation and evolution of the convergence of the South China with Indochina Blocks had been restricted by the lack of precise geochronological data.Syntectonic granitic gneisses with NW-trending gneissic foliations are widely distributed in Wuzhishan area,Hainan Island.LA-ICP-MS zircon U-Pb dating of four samples yielded crystallization ages of 263–269 Ma,representing a key thermal-tectonic event in the Middle Permian.Combined with previous work,our dating results for the Wuzhishan orthogneiss suggest the Wuzihshan syntectonic granitic gneisses were derived from the convergence of the South China with Indochina Blocks.This age(263–269 Ma) might represent the initial time of the collision between the South China and Indochina Blocks.