云南个旧卡房铜多金属矿床流体包裹体特征及其地质意义 |
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关键词:ore-forming fluid fluid inclusion C-H-O isotopic composition Kafang deposit Gejiu mining area |
基金项目:云南省科技计划项目企业基础研究应用基础研究联合专项(编号: 202101BC070001);云南省科技计划项目(编号: 202202AG050006);云南省科技计划项目高层次科技人才及创新团队选拔专项(编号: 202305AT350004) |
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Fluid Inclusion Features and Applications of the Kafang Cu-polymetallic Deposit in Gejiu District, Yunnan Province |
The Kafang deposit, located in the Gejiu polymetallic district in Yunnan Province, is a typical Cu-polymetallic deposit. Systematical research on the nature of ore forming fluids and origin of the metal is constrained, limiting our understanding of the ore formation in this deposit. In this study, detailed field petrography, mineralogy, C-H-O isotopes, and in-situ composition analysis of fluid inclusions were carried out for the layered Cu-polymetallic ore bodies (the main metallogenic type) which produced in basalt. The results show that the fluid inclusions had mainly gas-liquid biphasic characteristics. The homogenization temperature of quartz fluid inclusions varied from 264.5–330.5 ℃, the salinaty w(NaCleq) varied from 16.24% to 18.20% and the density varied from 0.853 to 0.924 g/cm3. The homogenization temperature of fluorite fluid inclusions varied from 199.8 to 339.1℃, the salinaty w(NaCleq) varied from 8.81% to 18.88% and the density varied from 0.822 to 0.955 g/cm3. The homogenization temperature of calcite fluid inclusions varied from 112.1 to 199.4℃, the salinaty w(NaCleq) varied from 4.96% to 10.86% and the density varied from 0.910 to 1.011 g/cm3. These parameters collectivelly indicate that the ore-forming fluid of the Kafang Cu-polymetallic deposit was characteries by medium-low temperature, medium-low salinity and low density. Thers is a notable decrease in metallogenic temperature and fluid salinity from the early to the late stages of ore formation. The δDV-SMOW and δ18OH2O values of quartz associated with Cu ore are –83.9‰ – –78.9‰ and 4.63‰–12.14‰, respectively. The δ13CV-PDB values of calcite associated with Cu ore are –7.11‰–0.64‰. Cuncurrently, in-situ analyses of single fluid inclusions within quartz indicate an enrichment in large ion lithophile elements, such as Na, K, Rb, Cs, Sr. These features suggest that the fluid may be derived from hydrothermal fluids related to granitic magma. Additionally, there is evidence of an intense water-rock reaction between hydrothermal fluids and the surrounding strata of carbonatite strata during ascent, protentially facilitating the extraction of Cu from the basalt and consequently contributing to enrichment and mineralization of Cu. |
LI Fen,AN Peng,XIAO Shugang,KONG Zhigang,YU Bo,YAN Kuo,LIU Yudong.2024.Fluid Inclusion Features and Applications of the Kafang Cu-polymetallic Deposit in Gejiu District, Yunnan Province[J].Acta Geoscientica Sinica,45(4):561-574. |
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