中文摘要：

报道了藏北羌塘中部果干加年山地区花岗闪长岩的锆石U-Pb定年结果和Hf同位素成分。花岗闪长岩的锆石U-Pb定年结果为（225.1±2.4） Ma，与该地区的高压变质带的形成时代一致。样品中锆石的εHf（t）值为-9.8--17.6，地壳Hf模式年龄为1874-2372 Ma，表明花岗闪长岩为古元古代地壳物质部分熔融的产物。结合区域地质资料，该花岗岩体可能形成于板块消减的火山弧构造环境，与羌塘地区古特提斯洋的晚三叠世俯冲消减有关。

英文摘要：

This paper reports new zircon U-Pb age and Hf-isotope data of granodiorites in Guoganjianian Mountain area, central Qiangtang, northern Tibet, China. Zircon LA-ICP-MS dating for granodiorites yields a weighted mean age of 225.1±2.4Ma. This age is consistent with that of the high pressure metamorphic rocks in this area. Moreover, the zircon εHf（t） values （from -9.8 to -17.6） and TDMC model ages （1874—2372 Ma） indicate that they were generated by the partial melting of the Paleo-proterozoic crust. According to regional geological data, the granodiorites of this study probably formed in a volcanic arc tectonic setting and was result of the subduction of Paleo-Tethys Ocean in the Late Triassic.