滇西澜沧江断裂两侧成矿流体性质对比

处在印度-亚洲大陆主碰撞带南东侧的“三江”地区是世界上著名的成矿带之一,其中澜沧江断裂为一深切入地幔的超岩石圈断裂,不少学者认为其两侧为截然不同的地质单元,成矿地质背景不同,成矿流体性质亦有差别,具有不同的成矿模式。笔者着眼于滇西地区,以澜沧江断裂为界,其东西两侧各选取了位于兰坪盆地的白秧坪铜银多金属矿及保山地块的核桃坪铅锌矿等典型矿床,通过研究发现,两侧流体均为中低温（80～331℃）中等密度（0.48～1.11g/cm3）流体,其形成压力差别不大,成矿作用均发生在较浅成的环境。流体包裹体数据显示,两侧成矿流体主要由大气降水演化而来且均具有地幔流体混入的特点,性质上存在着极大的相似性,故认为两侧矿床是在印度-亚洲板块闭合之后才逐渐形成。     

A reconnaissance of Cu isotopic compositions of hydrothermal vein-type copper deposit Jinman,Yunnan, China

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 contrast to the δ⁶⁵Cu values of high-temperature magmatic-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 sedimentary source for ore materials; various stages of ore deposition; and involvement of organic matter in the ore-forming processes.     

A reconnaissance of the Cu isotopic compositions of hydrothermal vein-type cop-per deposit, Jinman, Yunnan,China

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 65Cu values of 3.70‰ to +0.30‰, which are in sharp contrast to the 65Cu values of high-temperature magmatic-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 sedimentary source for ore materials; various stages of ore deposition; and involvement of organic matter in the ore-forming processes.