Genesis of the Jianbeigou Gold Deposit on the Southern Margin of the North China Craton: Insights from Fluid Inclusions, H-O-S Isotopes, and Pyrite in situ Trace Element Analyses  

作　　者：LI Fengchun ZENG Qingdong ZHU Rixiang CHU Shaoxiong XIE Wei YU Bing WU Jinjian LI Xinghui 

机构地区：[1]Key Laboratory of Mineral Resources,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China [2]Innovation Academy for Earth Science,Chinese Academy of Sciences,Beijing 100029,China [3]College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China [4]State Key Laboratory of Lithospheric Evolution,Institute of Geology and Geophysics,Chinese Academy of Sciences,Beijing 100029,China [5]School of Earth Science and Engineering,Hebei University of Engineering,Handan,Hebei 056038,China

出　　处：《Acta Geologica Sinica(English Edition)》2024年第4期969-991,共23页地质学报（英文版）

基　　金：jointed supported by National Key Research and Development Program of China (Grant No. 2021YFC2901704);the National Natural Science Foundation of China (Grant No. 41930430);the State Key Laboratory of Lithospheric Evolution, IGGCAS (Grant No. SKL-Z201905)。

摘　　要：The Jianbeigou gold deposit is a typical lode gold deposit in the Qinling metallogenic belt, located on the southern margin of the North China Craton. Three stages of the hydrothermal process can be distinguished, including the quartz ± pyrite, quartz-polymetallic sulfide, and quartz-carbonate ± pyrite stages. From the early to late stages, the homogenization temperatures of primary fluid inclusions are 281–362°C, 227–331°C, and 149–261°C, respectively. The corresponding salinities estimated for these fluids are 3.9–9.9 wt%, 0.4–9.4 wt%, and 0.7–7.2 wt% Na Cl equiv. Combined with laser Raman spectroscopy data, the ore-forming fluid belongs to a H_(2)O-CO_(2)-Na Cl ± CH_4 system with medium–low temperature and salinity. The δ~(18)Ofluid and δD values for the quartz veins are-1.0‰ to 6.0‰ and-105‰ to-84‰, respectively, which indicates that the ore-forming fluid is of mixed source, mainly derived from magma, with a contribution from meteoric water. Pyrite has been identified into three generations based on mineral paragenetic sequencing, including Py1, Py2, and Py3. The pyrites have δ~(34)S sulfur isotopic compositions from three stages between 3.7‰ and 8.4‰, indicating that sulfur mainly originated from magma. Te, Bi, Sb, and Cu contents in pyrite were all high and showed a strong correlation with Au concentrations. Native gold and the Au-Ag-Bi telluride minerals were formed concurrently, and the As concentration was low and decoupled from the Au content. Therefore, Te, Bi, Sb and other low-melting point chalcophile elements play an important role for gold mineralization in arsenic-deficient ore-forming fluid. Combined with the geological setting, evolution of pyrite, and ore-fluids geochemistry, we propose that the Jianbeigou deposit can be classified as a magmatic–hydrothermal lode gold deposit. Gold mineralization on the southern margin of the North China Craton is related to Early Cretaceous magmatism and formed in an extensional setting.

关 键 词：ore genesis H-O-S isotopes fluid inclusions in-situ trace element Jianbeigou gold deposit 

分 类 号：P618.51[天文地球—矿床学]