Geology, fluid inclusion and age constraints on the genesis of the Sarekuobu gold deposit in Altay, NW China

Abstract

The Sarekuobu gold deposit was discovered in the 1990s and is located in the Kelan Basin on the southern margin of the Chinese Altay Orogen. Orebodies are hosted in the Early Devonian metamorphosed volcanic-sedimentary sequence and controlled by the NW-trending Abagong Fault. Mineralization can be divided into early, middle and late stages, characterized by quartz-pyrite, polymetallic quartz-sulphides and carbonate-quartz, respectively. Four types of fluid inclusions were identified in quartz veins, i.e. pure CO 2 (PC-type), CO 2 -H 2 O (C-type), aqueous (W-type) and daughter mineral-bearing inclusions (S-type). Hydrothermal fluids related to the mineralization are composed of CO 2 -H 2 O-NaCl ± CH 4 ± N 2 fluids with T h values of 236-374°C and salinities of 4.8-15.0 wt.% NaCl eqv. (in general 8.0-15.0 wt.% NaCl eqv.), combined with trapping pressures of 90-330 MPa, suggesting that the mineralization resulted from a metamorphic fluid system. One biotite sample from the polymetallic quartz lodes yields a 40 Ar/ 39 Ar isotopic plateau age of 213.5 ± 2.3 Ma, marking the time of mineralization as Triassic. This mineralization age is broadly comparable with the mineralization age reported from the Tiemurt Pb-Zn deposit and Wulasigou Cu deposit located near the Sarekuobu gold deposit, indicating that the deposit was possibly related to the Permian-Triassic continental collision at the southern margin of the Altay Orogen. Our results show that the Sarekuobu gold deposit is not syngenetic, but an epigenetic orogenic gold deposit.

Geology, fluid inclusions and sulphur isotopes of the Zhifang Mo deposit in Qinling Orogen, central China: a case study of orogenic‐type Mo deposits

“…The salient features of orogenic‐type mineral systems (Kerrich et al ., ; Chen, ) include the following: (1) the ores were formed at convergent plate margins in accretionary and collisional orogens; (2) the locations of the ore bodies are controlled by shear zones or faults; (3) the ore fluids are generally of low salinity and CO 2 ‐rich with variable CH 4 ; (4) the mineralization temperature and depth shows a wide range from 220 to 500 °C and from 5 to 18 km, respectively; (5) the mineralization is coeval with a major orogeny. Many orogenic‐type mineral systems have been identified based on these characters, such as the Tieluping Ag deposit (Chen et al ., ), Weishancheng Ag–Au belt (Zhang et al ., ), Lengshuibeigou Pb–Zn deposit (Qi et al ., ), Wangpingxigou Pb–Zn deposit (Yao et al ., ), Yindonggou Ag–Au–Pb–Zn deposit (Yue et al ., ) and Dahu Au–Mo deposit (Li et al ., ; Ni et al ., , ) in the Qinling Orogen; the Bainaimiao Cu–Au deposit (Li et al ., ) and Huogeqi Cu–Pb–Zn–Fe deposit (Zhong et al ., ) in the eastern part of the Central Asian Orogenic Belt; the Sarekuobu Au deposit (Zhang et al ., ), Tiemurt Pb–Zn deposit (Zhang et al ., ), Wulasigou Cu deposit (Zheng et al ., ), Qiaxia Cu deposit (Zheng et al ., ) and Mengku Fe deposit (Wan et al ., ) in the Altay Orogen in NW China; and the W–Mo deposit in the Caledon Orogen in Norway (Larsen and Stein, ).…”

Petrogenesis and tectonic setting of the Middle Permian A‐type granites in Altay, northwestern China: Evidences from geochronological, geochemical, and Hf isotopic studies

“…The Chinese Altay orogenic belt is situated between the southern margin of the Siberian Block and the northern margin of the Kazakhstan–Junggar Block, bounded to the northwest by the Rudny Altay of Kazakhstan and the Gorny Altay of Russia, to the southeast by Gobi Altay of Mongolia, and separated from the Junggar Basin by the Erqis Fault (Li, Yang, Li, Santosh, Chen, & Xiao, ; Xiao & Santosh, ; Zhang, Chen, Zheng, Qin, & Li, ; Zheng et al, ). Northwest (NW)‐trending faults are widely developed in the Chinese Altay orogen, such as the Hongshanzui Fault, Abagong Fault, Tesibahan Fault, and Erqis Fault.…”

“…These results can be used to constrain their possible emplacement ages, source, and petrogenesis and thus provide important insights into understanding the postcollisional extensional environment of the Chinese Altay orogeny. 2 | REGIONAL GEOLOGY The Chinese Altay orogenic belt is situated between the southern margin of the Siberian Block and the northern margin of the Kazakhstan-Junggar Block, bounded to the northwest by the Rudny Altay of Kazakhstan and the Gorny Altay of Russia, to the southeast by Gobi Altay of Mongolia, and separated from the Junggar Basin by the Erqis Fault (Li, Yang, Li, Santosh, Chen, & Xiao, 2014b;Xiao & Santosh, 2014;Zhang, Chen, Zheng, Qin, & Li, 2014b;Zheng et al, 2014).…”

Geology, isotope geochemistry, and ore genesis of the Yindonggou Ag–Au(–Pb–Zn) deposit, Hubei Province, China

“…Orogenic deposits identified in the Central Asian Orogen (CAO) to the north of the NCC include the Sawayaerdun Au deposit (Chen et al ., , b), Sarekuobu Au deposit (L. Zhang et al ., ), Tiemurt Pb–Zn deposit (Zhang et al ., ; Zheng et al ., ), Wulasigou Cu deposit (Zheng et al ., ), and the Qiaxia Cu deposit (Zheng et al ., ). However, orogenic Ag–polymetal deposits have only been reported in the Qinling Orogen, and especially in the Xiong'er Terrane and Tongbai region (Chen et al ., ; Zhang et al ., ).…”