The Anjing Hitam Pb-Zn deposit in northern Sumatra(Indonesia) is one of the largest Pb-Zn deposits in the region. The stratiform orebodies are mainly hosted in the middle member of the Carboniferous–Permian Kluet For...The Anjing Hitam Pb-Zn deposit in northern Sumatra(Indonesia) is one of the largest Pb-Zn deposits in the region. The stratiform orebodies are mainly hosted in the middle member of the Carboniferous–Permian Kluet Formation of the Tapanuli Group. Mineral paragenesis and crosscutting relationships suggest a two-stage Pb-Zn mineralization:(I) sedimentary and(Ⅱ) hydrothermal mineralization. Ore-related calcite from both stages Ⅰ and Ⅱ contains mainly liquid-and gas-liquid two-phase-type fluid inclusions(FI). For stage I ore-forming fluids, FI homogenization temperatures(T_h) are 105 to 199 oC, and the salinities are 9.6 wt.% to 16.6 wt.% NaCleqiv, reflecting low temperature and medium-low salinity; whereas in stage Ⅱ, the T_h(206 to 267 oC) and salinity(19.0 wt.% to 22.5 wt.% NaCleqiv) are considerably higher. Fluid inclusion and C-O isotope characteristics suggest that the stage I ore-forming fluids were mainly derived from a mixture of seawater and magmatic fluids(probably from deep-lying plutons), whereas the stage Ⅱ ore-forming fluids were likely magmatic-derived with wall rock input. We propose that the Anjing Hitam deposit was a Carboniferous exhalative sedimentary(SEDEX) deposit overprinted by the Pleistocene vein-style magmatic-hydrothermal mineralization.展开更多
基金financially supported by the National Basic Research Program of China (No. 2014CB440901)
文摘The Anjing Hitam Pb-Zn deposit in northern Sumatra(Indonesia) is one of the largest Pb-Zn deposits in the region. The stratiform orebodies are mainly hosted in the middle member of the Carboniferous–Permian Kluet Formation of the Tapanuli Group. Mineral paragenesis and crosscutting relationships suggest a two-stage Pb-Zn mineralization:(I) sedimentary and(Ⅱ) hydrothermal mineralization. Ore-related calcite from both stages Ⅰ and Ⅱ contains mainly liquid-and gas-liquid two-phase-type fluid inclusions(FI). For stage I ore-forming fluids, FI homogenization temperatures(T_h) are 105 to 199 oC, and the salinities are 9.6 wt.% to 16.6 wt.% NaCleqiv, reflecting low temperature and medium-low salinity; whereas in stage Ⅱ, the T_h(206 to 267 oC) and salinity(19.0 wt.% to 22.5 wt.% NaCleqiv) are considerably higher. Fluid inclusion and C-O isotope characteristics suggest that the stage I ore-forming fluids were mainly derived from a mixture of seawater and magmatic fluids(probably from deep-lying plutons), whereas the stage Ⅱ ore-forming fluids were likely magmatic-derived with wall rock input. We propose that the Anjing Hitam deposit was a Carboniferous exhalative sedimentary(SEDEX) deposit overprinted by the Pleistocene vein-style magmatic-hydrothermal mineralization.
