Origin of the Dongga Au deposit in the giant Xiongcun porphyry Cu-Au district, Tibet, China: Constraints from multiple isotopes (Re, Os, He, Ar, H, O, S, Pb) and fluid inclusions

被引:1
作者
Lang, Xinghai [1 ]
Deng, Yulin [2 ,3 ]
He, Qing [1 ,4 ]
Wang, Xuhui [1 ]
Harris, Chris [4 ]
Zhan, Hongyu [1 ]
Wu, Weizhe [1 ]
Wu, Changyi [1 ]
Jiang, Kai [5 ]
机构
[1] Chengdu Univ Technol, Coll Earth & Planetary Sci, Chengdu 610059, Peoples R China
[2] Chengdu Univ Technol, State Key Lab Oil & Gas Reservoir Geol & Exploitat, Chengdu 610059, Peoples R China
[3] Chengdu Univ Technol, Coll Energy, Chengdu 610059, Peoples R China
[4] Univ Cape Town, Dept Geol Sci, ZA-7700 Rondebosch, South Africa
[5] Tibet Tianyuan Mineral Explorat Co Ltd, Xigaze 857000, Peoples R China
基金
中国国家自然科学基金;
关键词
Subepithermal deposit; Fluid inclusion; Isotope; Dongga Au deposit; Tibet; SOUTHERN LHASA SUBTERRANE; COPPER-GOLD DISTRICT; VOLCANIC-ROCKS; U-PB; EPITHERMAL TRANSITION; NOBLE-GASES; ICP-MS; TERRANE; MINERALIZATION; GEOCHRONOLOGY;
D O I
10.1016/j.oregeorev.2024.106173
中图分类号
P5 [地质学];
学科分类号
0709 ; 081803 ;
摘要
The Dongga Au deposit (9.55 t Au; average grade = 6.9 g/t [up to 61.6 g/t]) is located in the Xiongcun giant porphyry Cu-Au district of the Gangdese porphyry Cu belt, Tibet. Its mineralization age, ore-forming processes, and relationship to adjacent porphyry mineralization remain unclear. To address this, we conducted a geological, pyrite Re-Os dating, He-Ar-H-O-S-Pb isotopic, and fluid inclusion study of the Dongga deposit. Pyrite samples from ore-bearing chlorite-sulfide veins yielded a weighted-mean Re-Os age of 178.4 +/- 2.6 Ma (MSWD=0.01), implying the deposit formed during the Early Jurassic. Fluid inclusion analyses yielded homogenization temperatures of 237-360 degrees C for quartz-sulfide veins and 125-201 degrees C for late quartz veins, with corresponding salinities of 2.7-43.8 and 0.9-9.9 wt% NaCleq, respectively. Fluid inclusion analyses of pyrite samples yielded 3He/4He and 40Ar/36Ar values of 0.50-1.08 Ra and 325.1-559.4, respectively, and delta D and delta 18Ofluid values of -86.2 %o to -72.1 %o and -5.6 %o to 3.9 %o, respectively. The He-Ar-H-O isotopic data suggest the mineralizing fluids were derived mainly from a crustal source with a small mantle contribution, and also contained a mixture of magmatic and meteoric waters. The S (delta 34S = -1.57 %o to -0.55 %o) and Pb (206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb are 18.17-18.41 %o, 15.55-15.63 %o and 38.15-38.37 %o, respectively) isotopic compositions of pyrite suggest the ore-forming metals were derived from a magma source in the mantle containing minor amounts of subducted sediment. Based on the geology, and isotopic and fluid inclusion data, we infer that mixing between magmatic and meteoric waters was the main trigger of Au precipitation. In addition, based on the geochronological, spatial, and genetic relationships with the adjacent No.2 deposit in the Xiongcun ore district, we propose that the Dongga Au deposit is a sub-epithermal deposit, which represents the transition between porphyry and epithermal deposits. The two deposits constitute a porphyry system and record the continuous evolution of hydrothermal fluids transported outwards in a porphyry system.
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页数:16
相关论文
共 134 条
[31]   U-Pb zircon age and geochemistry of the Cuocun gabbro in the southern Lhasa Terrane: Implications for Early Cretaceous rollback of theNeo-Tethyanoceanic slab [J].
He, Qing ;
Lang, Xinghai ;
Li, Liang ;
Chen, Cuihua ;
Wang, Xuhui ;
Deng, Yulin ;
Yin, Qing ;
Xie, Fuwei ;
Yang, Zongyao ;
Zhang, Zhong ;
Jiang, Kai .
GEOLOGICAL JOURNAL, 2021, 56 (03) :1424-1444
[32]  
Hedenquist J.W., 2000, EXPLORATION EPITHERM, V13, P245, DOI DOI 10.5382/REV.13.07
[33]   Evolution of an intrusion-centered hydrothermal system: Far Southeast-Lepanto porphyry and epithermal Cu-Au deposits, Philippines [J].
Hedenquist, JW ;
Arribas, A ;
Reynolds, TJ .
ECONOMIC GEOLOGY AND THE BULLETIN OF THE SOCIETY OF ECONOMIC GEOLOGISTS, 1998, 93 (04) :373-404
[34]  
Hoefs J., 2021, Stable Isotope Geochemistry, V201
[35]   Lithospheric Architecture of the Lhasa Terrane and Its Control on Ore Deposits in the Himalayan-Tibetan Orogen [J].
Hou, Zengqian ;
Duan, Lianfeng ;
Lu, Yongjun ;
Zheng, Yuanchuan ;
Zhu, Dicheng ;
Yang, Zhiming ;
Yang, Zhusen ;
Wang, Baodi ;
Pei, Yingru ;
Zhao, Zhidan ;
McCuaig, T. Campbell .
ECONOMIC GEOLOGY, 2015, 110 (06) :1541-1575
[36]   Himalayan Cu-Mo-Au mineralization in the eastern Indo-Asian collision zone: constraints from Re-Os dating of molybdenite [J].
Hou, ZQ ;
Zeng, PS ;
Gao, YF ;
Du, AD ;
Fu, DM .
MINERALIUM DEPOSITA, 2006, 41 (01) :33-45
[37]  
Huston D.L., 2023, Isotopes in Economic Geology, Metallogenesis and Exploration, P155
[38]  
Jiang X.J., 2024, Ore Geol. Rev.
[39]   A Smaller Greater India and a Middle-Early Eocene Collision With Asia [J].
Jin, Shuchen ;
Sun, Xinxin ;
Jing, Xianqing ;
Zhang, Zijian ;
Zhang, Xiang ;
Yang, Zhenyu .
GEOPHYSICAL RESEARCH LETTERS, 2023, 50 (03)
[40]  
Kendrick M.A., 2013, NOBLE GASES HALOGENS, P319, DOI [10.1007/978-3-642-28836-411, DOI 10.1007/978-3-642-28836-411]