SHRIMP zircon U-Pb dating for subduction-related gran-itic rocks in the northern part of east Junggar, Xinjiang  

作　　者：ZHANG Zhaochong YAN Shenghao CHEN Bailin ZHOU Gang HE Yongkang CHAI Fengmei HE Lixin WAN Yusheng 

机构地区：[1]State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China [2]Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China [3]Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China [4]Institute of Geomechanics, Chinese Academy of Geological Sciences, Beijing 100037, China [5]No. 4 Geological Party, Xinjiang Bureau of Geology and Mineral Resources, Altay 836500, China

出　　处：《Chinese Science Bulletin》2006年第8期952-962,共11页

基　　金：supported by the National Natural Science Foundation of China(Grant No.40072061);National 305 Project(Grant No.2001BA609A-07-02);Program for New Century Excellent Talents in University(Grant No.NCET-04-0728);"973"Project(Grant No.2001 CB409807).

摘　　要：SHRIMP U-Pb zircon dating on the Xileketehalasu granodiorite porphyry and Kalasayi monodiorite porphyry that intrude middle Devonian Beitashan Formation at the north part of east Junggar region shows that they were formed at 381±6 Ma and 376±10 Ma respectively. They are interpreted as subduction-related granitic rocks, which is the first report that the isotopic ages for the granitic rocks range from 350 to 390 Ma. Another determined age for the Kalasayi monodiorite porphyry is 408±9 Ma, representing the age of underlain Lower Devonian volcanic rocks. Thus, the U-Pb dates suggest that the northeastward subduction of Junggar ocean from southwest occurred at 408 to 376 Ma (the real inter- val may be larger). Because the ore-bearing porphyry intruded following the formation of the volcanic rocks of middle Devonian Beitashan Formation, their tec- tonic setting is similar to the Andes Mountains that hosts world-class porphyry copper deposits, and the researched area could be regarded as a potential area for prospecting large porphyry copper deposits.SHRIMP U-Pb zircon dating on the Xileketehalasu granodiorite porphyry and Kalasayi monodiorite porphyry that intrude middle Devonian Beitashan Formation at the north part of east Junggar region shows that they were formed at 381±6 Ma and 376±10 Ma respectively. They are interpreted as subduction-related granitic rocks, which is the first report that the isotopic ages for the granitic rocks range from 350 to 390 Ma. Another determined age for the Kalasayi monodiorite porphyry is 408±9 Ma, representing the age of underlain Lower Devonian volcanic rocks. Thus, the U-Pb dates suggest that the northeastward subduction of Junggar ocean from southwest occurred at 408 to 376 Ma （the real interval may be larger）. Because the ore-bearing porphyry intruded following the formation of the volcanic rocks of middle Devonian Beitashan Formation, their tectonic setting is similar to the Andes Mountains that hosts world-class porphyry copper deposits, and the researched area could be regarded as a potential area for prospecting large porphyry copper deposits.

关 键 词：花岗岩 斑岩 新疆 年代测定 

分 类 号：P585[天文地球—岩石学]