Late Paleozoic Granitic Magmatism in the West Junggar Metallogenic Belt (Xinjiang), Central Asia, and Its Tectonic Implication

Xinjiang of China , is the Central Asian metallogenic domain (TU Guangzhi, 1999) of Western Balkhash metallogenic belt of the extension of the East, and is an important late Paleozoic tectonic magmatic metallogenic belt (Chen Xuanhua, 2011a; Shen et al., 2013). Central Asian metallogenic domain western Asia experienced a Paleozoic oceanic subduction multi-stage, lateral crustal accretion , growth of orogenic history(Hong et al., 2004; Windley et al, 2007; Xiao et al, 2010)and active continental margin tectonic magmatic metallogenic evolution (Heinhorst et al., 2000). Now in the western Junggar were found to have large very large Baogutu porphyry copper deposit, Hatu gold deposit (orogenic type gold), Yangzhuang beryllium deposit and Saertuohai large chromite deposit (with snake about greenstone), and Tooker Tooker, Hongyuan and Hongshan coppermolybdenum mine and quartzvein greisen Shuyunhe molybdenum deposit, is an important region of Central Asia mineralization mineralization prospects (Chen Xuanhua, 2011a). Granitoids are exploring the deep crust chemical geodynamics of the window, it is important to study the indication significance due to interaction between the crust and the mantle of continental crustal growth and evolution (Deng Jinfu et al., 2004; Mo Xuanxue et al., 2007). The late Paleozoic granitoids were widespread in the West Junggar area west of the Central Asian orogenic belt, they are generally having a positive εNd (t) and low (Sr/Sr) i value of features, it is closely related to the formation of the continental crust growth process, is an important area to late Paleozoic significant crustal growth and large-scale mineralization. Based on the previous study of granites, tectonic environment of Late Paleozoic in West Junggar area, and puts forward some different understanding, mainly have post-collision magmatism, after intra-oceanic island arc subduction, immature island arc, island arc accretion, arc basins , ridge subduction or slab windows and other point of view. In this study, we collected 33 samples from 11 granitoid plutons in the Hatu and Bieluagaxi areas in the West Junggar metallogenic belt (Xinjiang), CAOB. We further determine the tectonic environments of the West Junggar granitoids through chemical analyses and isotopic tracing, and correlate them to the granitoids in the Balkhash metallogenic belt, Kazakhstan. The Late Carboniferous granitoids in the Hatu area are mainly A-type ones formed in the postcollisional extensional tectonic setting. Meanwhile, adakites formed in the Bielu’agaxi area due to intra-ocean plate subduction. The results show the complicated tectonic setting in the West Junggar. HatuBieluagaxi area granite ε Nd (t) values were higher, with a depleted mantle component characteristics of Paleozoic juvenile crust, reflects the growth of the Central Asian orogenic belt in the West Junggar metallogenic belt of the early Palaeozoic new continental crust. In the late Paleozoic, Bieluagaxi area is still characterized by a Adakites I-type granite intrusion, indicating there might be subducted oceanic crust plate tectonic environment. Therefore, the late Paleozoic Late Carboniferous, West Junggar tectonic environment is more complex, that after the collision granitoids output environment, there exists not completely closed basin subducted oceanic environment. West Junggar speculated after the collision tectonic environment into the overall time frame for the Permian, may Balkhash metallogenic belt in the Permian collisional magmatism stage overall consistent. The west Junggar widely developed sinistral strike-slip faults, provides an important geodynamic background, the morphology and distribution of granitoid pluton has an important role in the constraints. The area granitoids εNd (t) value is higher, a common feature of the Central Asian orogenic granitoids, as the proliferation of newborn Paleozoic continental crust, the mantle source region and HUANG Penghui, CHEN Xuanhua, WANG Zhihong, YE Baoying, 2014. Late Paleozoic Granitic Magmatism in the West Junggar Metallogenic Belt (Xinjiang), Central Asia, and Its Tectonic Implication. Acta Geologica Sinica (English Edition), 88(supp. 2): 876-877.