西昆仑塔什库尔干地区赞坎铁矿床磁铁矿元素地球化学特征及其对成矿的制约  

Geochemical characteristics of magnetite from Zankan iron deposit in Tashen-kuergan orefield and its constraint on mineralization

作　　者：陈登辉 隋清霖[1,2,3] 赵晓健 李旭拓[1,2,3] 高永宝 王志华[1,2,3] CHEN DengHu;SUI QingLin;ZHAO XiaoJian;LI XuTuo;GAO YongBao;WANG ZhiHua(Key Laboratory for the Study of Focused Magmatism and Giant Ore Deposits, MNR, Xi'an 710054, Shaanxi, China;ResearchCenter for Orogenic Geology, China Geological Survey, Xi'an 710054, Shaanxi, China;Xi'an Center of Geological Survey,China Geological Survey, Xi'an 710054, Shaanxi, China)

机构地区：[1]自然资源部岩浆作用成矿与找矿重点实验室,陕西西安710054 [2]中国地质调查局造山带地质研究中心,陕西西安710054 [3]中国地质调查局西安地质调查中心,陕西西安710054

出　　处：《矿床地质》2019年第2期426-438,共13页Mineral Deposits

基　　金：国家自然科学基金项目(编号:41503046;41402079);陕西省自然科学基金(编号:2017JM4024);中国地质调查局地质调查项目(编号:12120115019501)联合资助

摘　　要：赞坎铁矿床是塔什库尔干地区一个典型的沉积变质型铁矿,具有多阶段成矿的特征,是塔什库尔干地区铁矿成矿作用演化的典型代表。文章将赞坎铁矿床主要矿石矿物磁铁矿的形成划分为3个世代,分别为条带状磁铁矿、浸染状磁铁矿和粗晶脉状或块状磁铁矿,分别代表3个成矿阶段的产物。电子探针和LAICP-MS原位分析表明,赞坎铁矿从条带状磁铁矿到粗晶块状磁铁矿随着磁铁矿的成矿演化主量元素中Al元素有减少的趋势,而Ti、Mn、Mg、V元素均具有增加的趋势;微量元素中Co、Nb、Hf、Ta等具有减少的趋势,Sc、Ga、Zr、Sn等元素具有增加的趋势。根据以上各成矿阶段中磁铁矿成分变化,并结合前人的研究成果发现,赞坎铁矿早期条带状磁铁矿与火山沉积作用有关,成矿后期特别是在粗晶块状和脉状磁铁矿阶段受岩浆热液影响明显,富铁矿有岩浆热液的参与。Zankan iron deposit is a typical sedimentary metamorphic iron deposit, with a multi-stage ore-forming process.It is a representative of the iron mineralization evolution in the Tashenkuergan orefield. The magnetite formation is divided into three stages: banded magnetite, disseminated magnetite, and coarse-grained vein or massive magnetite. In situ electron microprobe and LA-ICP-MS analyses of magnetite from Zankan iron deposit show that, accompanying the evolution of mineralization, the major elements has trends of Al decreasing, Ti, Mn, Mg and V increasing whereas the trace elements had trends of Co, Nb, Hf and Ta decreasing and Sc, Ga, Zr and Sn increasing.Combined with previous studies, the varying compositions of magnetite in various stages indicate that the early stage of banded magnetite was related to the submarine volcanic sedimentation, the final stage of coarse-grained vein or massive magnetite was obviously affected by magmatic hydrothermal activity, and the magmatic hydrothermal fluid took part in the formation of high-grad iron ore deposit.

关 键 词：地球化学 赞坎铁矿 磁铁矿 LA-ICP-MS 电子探针 西昆仑 

分 类 号：P618.31[天文地球—矿床学]