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Ore‐forming Fluid and Mineral Source of the Hongshi Copper Deposit in the Kalatage Area, East Tianshan, Xinjiang, NW China
Author(s) -
YU Mingjie,
WANG Jingbin,
MAO Qigui,
FANG Tonghui,
ZHANG Rui
Publication year - 2018
Publication title -
acta geologica sinica ‐ english edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.444
H-Index - 61
eISSN - 1755-6724
pISSN - 1000-9515
DOI - 10.1111/1755-6724.13676
Subject(s) - meteoric water , fluid inclusions , geology , chalcopyrite , geochemistry , magmatic water , quartz , pyrite , gangue , mineralization (soil science) , ore genesis , copper , metamorphic rock , mineralogy , mantle (geology) , metallurgy , groundwater , materials science , paleontology , soil science , soil water , geotechnical engineering
The Hongshi copper deposit is located in the middle of the Kalatage ore district in the northern segment of the Dananhu‐Tousuquan island‐arc belt in East Tianshan, Xinjiang, NW China. This study analyses the fluid inclusions and H, O, and S stable isotopic compositions of the deposit. The fluid‐inclusion data indicate that aqueous fluid inclusions were trapped in chalcopyrite‐bearing quartz veins in the gangue minerals. The homogenization temperatures range from 108°C to 299°C, and the salinities range from 0.5% to 11.8%, indicating medium to low temperatures and salinities. The trapping pressures range from 34.5 MPa to 56.8 MPa. The δ 18 O H2O values and δ D values of the fluid range from –6.94‰ to –5.33‰ and from –95.31‰ to –48.20‰, respectively. The H and O isotopic data indicate that the ore‐forming fluid derived from a mix of magmatic water and meteoric water and that meteoric water played a significant role. The S isotopic composition of pyrite ranges from 1.9‰ to 5.2‰, with an average value of 3.1‰, and the S isotopic composition of chalcopyrite ranges from –0.9‰ to 4‰, with an average value of 1.36‰, implying that the S in the ore‐forming materials was derived from the mantle. The introduction of meteoric water decreased the temperature, volatile content, and pressure, resulting in immiscibility. These factors may have been the major causes of the mineralization of the Hongshi copper deposit. Based on all the geologic and fluid characteristics, we conclude that the Hongshi copper deposit is an epithermal deposit.