新疆阿舍勒铜矿英安-玄武-安山质火山岩的地球化学特征与构造背景  

Tectonic setting and geochemical characteristics of dacite andesite-basalt volcanic rocks in Ashele copper deposit,Xinjiang

作　　者：高珍权[1,2] 方维萱[1,2] 胡瑞忠[1] 李文铅[3] 

机构地区：[1]中国科学院地球化学研究所矿床地球化学开放研究实验室,贵州贵阳550002 [2]有色金属矿产地质调查中心,北京100814 [3]中国科学院广州地球化学研究所,广东广州510640

出　　处：《矿床地质》2010年第2期218-228,共11页Mineral Deposits

基　　金：科技部国家重点基础研究发展规划项目(200lCB4O9805);中国科学院地球化学研究所矿床地球化学重点实验室基金(200303)的联合资助

摘　　要：新疆阿舍勒铜矿床中泥盆统阿舍勒组的英安-安山-玄武质火山岩组合属亚碱性拉斑玄武系列,为铝过饱和、低钾、富镁系列的火山岩,相对富集MgO和轻稀土元素,亏损Ti、Nb、P和Ta,具有弱铕负异常(δEu值为0.84～0.94)和Th/Ta高比值(5.53～12.58)等特点。英安-安山-玄武质火山岩微量元素含量及比值特征、大离子半径及稀土元素配分模式、微量元素构造环境判别图的投点结果,显示它们具有同源区特点,均起源于富集地幔,属于玄武岩浆经岩浆结晶分异作用的产物,它们形成的大陆动力学背景为成熟岛弧环境。Volcanic rocks of Middle Devonian dacite-andesite-basalt association in the Ashele copper deposit of Xinjiang belong to the sub-alkaline volcanic rock series. Dacite, andesite and basalt are of peraluminous volcanic rock series with low potassium and high magnesium, characterized by the enrichment of MgO, LREE and the depletion of Ti, Nb, P and Ta, low native Eu anomalies （δEu 0.84～0.94） and high Th/Ta values （5.53～12.58）. Based on the features of the content and ratios of trace elements, the REE patterns, the spidergrams of trace elements, and the discrimination diagrams, it can be inferred that dacite-andesite-basalt volcanic rocks in Ashele were probably produced in the background of a mature island arc. Magmatic sources of acidic and basic volcanic rocks in the study area resulting from magmatic differentiation might have originated from the same magmatic source, i.e., the mantle.

关 键 词：地球化学 阿舍勒铜矿床 英安-安山-玄武质火山岩 成熟岛弧 活动大陆边缘 

分 类 号：P618.41[天文地球—矿床学]