The Jinman deposit is a low-temperature hydrothermal vein-type copper deposit, which occurs along faults and fractures within Middle Jurassic sandstone and mudstone units of the Lanping-Simao Mesozoic-Cenozoic basin o...The Jinman deposit is a low-temperature hydrothermal vein-type copper deposit, which occurs along faults and fractures within Middle Jurassic sandstone and mudstone units of the Lanping-Simao Mesozoic-Cenozoic basin of Yunnan Province. In this note, we report for the first time the Cu isotopic compositions of Cu-sulfides from the Jinman deposit. The data show large variations and low δ65Cu values of -3.70‰ to +0.30‰, which are in sharp con-trast to the δ65Cu values of high-temperature mag-matic-hydrothermal copper deposits (-0.62‰ to +0.40‰) and the modern ocean-floor massive sulfide deposits (-0.48‰ to +1.15‰). It is suggested that the Cu isotope fractionation at Jinman is affected mainly by the following factors, i.e. a low temperature of ore formation (150-286℃); a sedimen-tary source for ore materials; various stages of ore deposition; and involvement of organic matter in the ore-forming proc-esses.展开更多
基金This work was jointly supported by the Major State Basic Research Program of China (Grant No. G1999043208) the National Natural Science Foundation of China (Grant No. 49925306) a visiting research program of the Melbourne University.
文摘The Jinman deposit is a low-temperature hydrothermal vein-type copper deposit, which occurs along faults and fractures within Middle Jurassic sandstone and mudstone units of the Lanping-Simao Mesozoic-Cenozoic basin of Yunnan Province. In this note, we report for the first time the Cu isotopic compositions of Cu-sulfides from the Jinman deposit. The data show large variations and low δ65Cu values of -3.70‰ to +0.30‰, which are in sharp con-trast to the δ65Cu values of high-temperature mag-matic-hydrothermal copper deposits (-0.62‰ to +0.40‰) and the modern ocean-floor massive sulfide deposits (-0.48‰ to +1.15‰). It is suggested that the Cu isotope fractionation at Jinman is affected mainly by the following factors, i.e. a low temperature of ore formation (150-286℃); a sedimen-tary source for ore materials; various stages of ore deposition; and involvement of organic matter in the ore-forming proc-esses.
