Zircon U-Pb Age, Geochemistry and Geological Implications of Granitoids in Tuerkubantao, Xinjiang  

作　　者：石煜 王玉往 王京彬 王莉娟 丁汝福 陈言飞 

机构地区：[1]School of Gemmology,China University of Geosciences [2]Beijing Institute of Geology for Mineral Resources

出　　处：《Journal of Earth Science》2013年第4期606-618,共13页地球科学学刊（英文版）

基　　金：supported by the Major State BasicResearch Program of China(No.2007CB411304);the Crisis Mine Project of China National Geological Survey(No.200699105)

摘　　要：Three types of granitoids were recognized in Tuerkubantao （土尔库班套） district, located on the northwestern margin of the Junggar Block. The zircon U-Pb age of the three types of granitoids suggests that they formed in different orogenic stage in response to the convergence and collision be- tween Siberian and Kazakhstan plates. Biotite granite is similar to the volcanic arc granites in composi- tion, with zircon U-Pb age of 382.8±2.5 and 355.6±2.4 Ma. The former is crystallizing age of the volcan- ic arc granite, while the later record the time of hydrothermal alteration induced by a later magmatism. The granite is severe altered and its zircon grain get a lower intercept age of 324.4±7.3 Ma, which is possibly coursed by magmatism in syn-collision. The rhyolite with composition similar to A-type gra- nites in adjacent area, crystallized at 295.9±1.4 Ma, is possibly the extrusive phase of A-type granite formed in the post-orogenic tectonic setting. The granitoids in Tuerkubantao area record the evolution of the northwestern Junggar orogen. The area has been in convergence setting from Middle to Late Devonian, and stepped into syn-collisional tectonic setting in Early Carboniferous, finally evolved into the post-orogenic tectonic stage since Early Permian.Three types of granitoids were recognized in Tuerkubantao （土尔库班套） district, located on the northwestern margin of the Junggar Block. The zircon U-Pb age of the three types of granitoids suggests that they formed in different orogenic stage in response to the convergence and collision be- tween Siberian and Kazakhstan plates. Biotite granite is similar to the volcanic arc granites in composi- tion, with zircon U-Pb age of 382.8±2.5 and 355.6±2.4 Ma. The former is crystallizing age of the volcan- ic arc granite, while the later record the time of hydrothermal alteration induced by a later magmatism. The granite is severe altered and its zircon grain get a lower intercept age of 324.4±7.3 Ma, which is possibly coursed by magmatism in syn-collision. The rhyolite with composition similar to A-type gra- nites in adjacent area, crystallized at 295.9±1.4 Ma, is possibly the extrusive phase of A-type granite formed in the post-orogenic tectonic setting. The granitoids in Tuerkubantao area record the evolution of the northwestern Junggar orogen. The area has been in convergence setting from Middle to Late Devonian, and stepped into syn-collisional tectonic setting in Early Carboniferous, finally evolved into the post-orogenic tectonic stage since Early Permian.

关 键 词：zircon U-Pb age GRANITOID orogen evolution Tuerkubantao. 

分 类 号：P597.3[天文地球—地球化学]