%A GU Xuexiang, ZHANG Yongmei, GE Zhanlin, CHEN Weizhi, XU Jingchi, HUANG Gang, TAO Wei %T The orogenic Au mineralization system and regional tectonic evolution in the Kalamaili area, East Junggar, Xinjiang %0 Journal Article %D 2020 %J Earth Science Frontiers %R 10.13745/j.esf.sf.2020.3.21 %P 254-275 %V 27 %N 2 %U {https://www.earthsciencefrontiers.net.cn/CN/abstract/article_5894.shtml} %8 2020-03-25 %X

Au deposits, including the Jinshuiquan, Shuangquan, Nanmingshui, and East Sujiquan Au deposits in the Kalamaili area of eastern Junggar, Xinjiang, constitute a mineralization system related to the late Paleozoic collisional orogeny. The deposits are sandwiched between the regional Kalamaili and Qingshui-Sujiquan faults. Au mineralization is controlled by the subsidiary brittle-ductile faults in slightly metamorphosed, late Paleozoic volcanic sedimentary rocks, and typically occurs as medium-to-steep dipping auriferous quartz veins and surrounding altered rocks. Fluid inclusions, H-O-S-Pb isotopes, and hydrothermal zircon U-Pb dating indicate that the ore-forming fluids are characterized by medium-to-high temperature (mostly 240-330 ℃), low salinity (<6 wt% NaCleq), and CO2-rich metamorphic water. The ore-forming material was sourced from host volcanic sedimentary rocks. Fluid immiscibility (phase separation) and fluid-rock interaction (wall-rock sulfidation) are the principal mechanisms of Au deposition. The timing of mineralization was approximately 314 Ma, and mineralization depths ranged from 7 to 15 km. From the Late Carboniferous to Early Permian, the transition of the tectonic system from compression to strike-slip or strike-slip extension in the study area resulted in the migration of deep metamorphic auriferous CO2-H2O-NaCl±CH4 fluids to shallower depths along NW- to EW-trending strike-slip faults. Au precipitation in the subsidiary faults of the brittle-ductile transition zone or brittle deformation zone led to the formation of auriferous quartz veins and related altered rock ores.