新疆香山铜镍硫化物矿床Re-Os同位素测定  

Re Os isotopic dataing of the Xiangshan deposit,East Tianshan,NW China.

作　　者：李月臣[1] 赵国春[2] 屈文俊[3] 潘成泽[4] 毛启贵[5] 杜安道[3] 

机构地区：[1]中国科学院广州地球化学研究所,广州510640 [2]香港大学地球科学系 [3]国家地质实验测试中心,北京100037 [4]新疆资源环境中心,新疆乌鲁木齐830000 [5]中国科学院地质与地球物理研究所岩石圈演化国家重点实验室,北京100029

出　　处：《岩石学报》2006年第1期245-251,共7页Acta Petrologica Sinica

基　　金：国家重点基础研究发展规划项目(2001CB409801);国家自然科学基金项目(40172080;40572062);香港研究基金项目(HKU7040/04P;HKU7058/04P和HKU7055/05P)联合资助。

摘　　要：通过对香山铜镍硫化物矿石中的镍黄铁矿进行Re-Os同位素测年，获得等时线年龄数据为（298±7．1）Ma。该数据表明产于东天山黄山-镜儿泉一带的这些铜镍硫化物矿床形成于晚石炭世-早二叠世，与该区广泛发育的造山型金矿、矽卡岩型银铜矿床和火山岩型铁铜矿床为同一时期的产物。其等时线^187Os／^188Os初始比值为0．682±0．32，γOs平均为444，表明在成矿过程及岩浆侵位期间有地壳物质加入成矿系统中。The Xiangshan Cu-Ni deposit is located in the eastern part of the East Tianshan orogenic belt, northwestern China. Rhenium and osmium isotopic analyses of Ni-and Cu-bearing pentlandite from the deposit have been used to determine the timing of mineralization, the source of osmium, and, by inference, the source of ore metals. Pentlandite samples have osmium and rhenium concentrations varying in the ranges of 39.61 - 110. 60 ppb, and 0. 437 -3. 763 ppb, respectively. Analyses of these data yield a seven-point isochron with an age of 298 ± 7.1Ma. The age implies that the Cu-Ni sulfide deposit and other related magmatic deposits in the same area formed between the latest Carboniferous and Early Permian extension in the East Tianshan. An initial ^187Os/^188Os ratio of 0.682 ± 0.32 （ MSWD = 9.4） and the δ34 S of - 0.84‰ to ＋ 2.40‰ for the ores, suggests a magmatic source for the ores, with the melts being dominated by mantle contributions. The data also indicate that the Xiangshan Ni-Cu deposit, like many other silver, iron, copper, gold, and nickel deposits within East Tianshan, is related to a large-scale extensional process.

关 键 词：RE-OS同位素测年 铜镍硫化物矿床 香山 东天山 

分 类 号：P597.3[天文地球—地球化学]