北祁连塞浦路斯型铜矿床地质地球化学特征对比研究  

A Contrastive Study on the Geological and Geochemical Characteristics of Cyprus-type Copper Deposits in North Qilian Mountain,China

作　　者：郭周平[1] 李文渊[1] 贾群子[1] 宋忠宝[1] 高永宝[1] 

机构地区：[1]中国地质调查局西安地质调查中心,陕西西安710054

出　　处：《地质与勘探》2010年第1期76-84,共9页Geology and Exploration

基　　金："十一五"国家科技支撑计划"中西部大型矿产基地综合勘查技术与示范"项目专题"秦祁昆成矿域成矿规律及矿产预测示范"(2006BAB01-01-07)资助;中国地质调查局<祁连成矿带重大找矿疑难问题研究>项目(200420190002)资助

摘　　要：北祁连奥陶纪典型的塞浦路斯型铜矿床均产出于北祁连山弧后盆地的蛇绿岩中,西段石居里矿床赋存的蛇绿岩带生成环境为近弧的弧后盆地扩张脊环境,东段猪嘴哑吧矿床赋存的蛇绿岩生成环境为近陆的弧后盆地扩张脊环境。东西段构造环境差异导致北祁连山东西段塞浦路斯型铜矿在矿体形态和成矿元素富集程度上存在差异。西段以柱状、似透镜状为主,东段以透镜状为主;成矿元素上东段相比西段更富锌和硫。硫同位素分析,两段均为海水中硫酸盐和玄武岩中硫酸盐混合沉淀结果,东段比西段海水混入程度低。Pb同位素研究显示,Pb主要来自幔源。流体包裹体成分显示西段石居里以海水成因为主,而东段猪嘴哑吧则为火山热液流体成因,成矿温度均为中低温。Shijuli its and Zhuzuiyaba copper deposits, as the key Cyprus type deposits, lie in the ophiolite of north Qilian Mountain. Shijuli copper deposits lie in the ophiolite, near to the arc of the back-arc basin expand system while the Zhuzuiyaba deposit lies in the ophiolite, near to the land of the back-arc basin expand system. The difference of ore body and metal element concentration between east and west Cyprus type deposits in North Qilian mountain is caused by the tectonic discrepancy. The ore bodies of west deposits take a colunm and lens look, but the most of east ore bodies look like lens. After contrasting isotopes, east deposits have more zinc and sulfur. 834S of chalcopyrite and pyrite in Shijuli copper deposits is 6, 69%0 in average, and in Zhuzuiyaba is 3.63%e , which indicates that sulfur are from seawater and basalt, although the east deposits sulfur blended degree lower than the west deposits. The ratio values of 208spb/204pb to 36. 993% - 38. 092%, of 207pb/204apb eqval to 15. 383% - 15. 573% and 206pb/204apb to 17. 355% - 18. 068% indicate that Pb comes from earth＇s mantle. The temperature of mineralization varies from 230℃ to 389℃, a low-middle temperature. The composition analysis of fluid inclusion indicate that the fluid of Shijuli copper deposits comes from seawater and that of Zhuzuiyaba copper deposits come from volcanic .

关 键 词：塞浦路斯型铜矿床 弧后盆地 矿床地质地球化学 北祁连 

分 类 号：P618.41[天文地球—矿床学]