新疆巴伦台钾长花岗岩的地球化学及年代学

The geochemical characteristics and chronology of the K-feldspar granite in Baluntai area,Xinjiang

目的探究新疆中天山巴伦台地区钾长花岗岩的地球化学特征、成岩年龄及其地质意义。方法在详细的地质调查基础上,分析其主量、微量元素含量等地球化学特征,并利用锆石LA-ICP-MS U-Pb定年方法确定其成岩年龄。结果钾长花岗岩具有火山弧花岗岩特征,形成年龄为369.6 Ma±2.6 Ma。结论古生代南天山洋洋壳向伊犁—中天山微板块下的俯冲至少延续到晚泥盆世。

Aim To study the geochemistry characteristics,zircon U-Pb chronology and the geological significance of the K-feldspar granite in northern Baluntai area.Methods Based on the geological investigation,geochemistry analysis and LA-ICP-MS zircon U-Pb dating about the K-feldspar granite,the geological significance of the K-feldspar granite has been studied.Results The K-feldspar granite has the characteristics of island-arc granites,and formed at 369.5 Ma±2.6 Ma.Conclusion The paleo-southern Tianshan ocean lithosphere had been subducting beneath the Yili-middle Tianshan block from Silurian to late Devonian.