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Fluid inclusion and isotope characteristics of the X ishanwanyangchang silver polymetallic deposit, I nner M ongolia, C hina
Author(s) -
Kang Ming,
Yuan Ye,
Yue Changcheng,
Gao Chao
Publication year - 2018
Publication title -
geological journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.721
H-Index - 54
eISSN - 1099-1034
pISSN - 0072-1050
DOI - 10.1002/gj.3189
Subject(s) - fluid inclusions , geology , hydrothermal circulation , mineralization (soil science) , sphalerite , galena , quartz , mineralogy , pyrite , salinity , halite , magmatic water , geochemistry , chemistry , gypsum , paleontology , oceanography , seismology , soil science , soil water
The Xishanwanyangchang silver polymetallic deposit is located in Inner Mongolia. The upper part is a silver orebody, and the lower part is a lead–zinc orebody. The Xishanwanyangchang deposit is related to Mesozoic volcanic hydrothermal activity, and the hydrothermal ore‐forming process of the deposit includes 3 stages, that is, the early, middle, and late stages. The early lead–zinc mineralization stage is marked by quartz–pyrite–galena–sphalerite, with salinities of 0.88 to 13.94 wt% NaCl equivalent and homogenization temperatures of greater than 330°C. Fluid inclusions are mainly composed of gas–liquid two‐phase aqueous solutions, characterized by high‐temperature and low‐salinity fluid. The middle mineralization stage is marked by quartz‐polymetallic sulphide minerals, with salinities of 0.35 to 31.90 wt% NaCl equivalent and homogenization temperatures of 250°C to 330°C. Inclusions are characterized by coexistence of low‐salinity aqueous inclusions and high‐salinity multiphase inclusions containing daughter minerals. The late mineralization stage is marked by quartz–carbonate, with salinities of 0.71 to 32.66 wt% NaCl equivalent and homogenization temperatures of 169°C to 250°C. Inclusions are characterized by coexistence of low‐salinity aqueous solution inclusions and high‐salinity inclusions, containing halite daughter minerals. The δ 34 S values of sulphides range from 4.0‰ to 6.1‰, and the 206 Pb/ 204 Pb, 207 Pb/ 204 Pb, and 208 Pb/ 204 ratios range from 16.641 to 16.798, 15.366 to 15.590, and 36.972 to 37.696, respectively, showing that ore‐forming materials were mainly from deep‐source magmas, and fluid mixing may be the main ore‐forming mechanism. The deposit formed through mixing of metal‐bearing high‐salinity fluid and cold groundwater at the ore precipitation site, followed by precipitation and enrichment of metals.