小兴安岭东南伊春一带早中生代花岗岩与多金属成矿作用  

Early Mesozoic granites and polymetallic mineralization in southeastern Yichun area,Xiao Hinggan Mountains

作　　者：韩振哲[1,2,3] 赵海玲[1,2] 李娟娟 冷昌恩[1,2] 吕军[1,2,3] 李文龙 

机构地区：[1]中国地质大学地质过程与矿产资源国家重点实验室,北京100083 [2]中国地质大学岩石圈构造、深部过程及探测技术教育部重点实验室,北京100083 [3]黑龙江省地质调查研究总院齐齐哈尔分院,黑龙江齐齐哈尔161005

出　　处：《中国地质》2010年第1期74-87,共14页Geology in China

基　　金：中国地质调查局基础地质调查项目(200313000035)资助

摘　　要：小兴安岭东南伊春地区晚三叠世—早侏罗世二长花岗岩中普遍具有岩浆混合成因MME型暗色微细粒闪长质包体和同深成岩墙—中基性脉岩群等,反映出壳幔混合成因的特点,而正长-碱长花岗岩具铝质A2型花岗岩的特征,两者的岩相学、主微量及同位素特征显示,其形成均与古亚洲洋闭合之后大陆碰撞向碰撞后转变的伸展崩塌构造环境下的底侵作用有关。两者形成时代、成因及物质来源和成矿构造背景等特征上的相似性,也反映在矿床成矿系列的相似性上,二长花岗岩表现出Mo-Pb-Zn-Fe-Au-Ag矿床成矿系列,并以Mo、Pb成矿作用强烈为特征,而正长-碱长花岗岩矿床成矿系列表现为Zn-Pb-Cu-Mo-W-Fe,其成矿作用较弱且分散,同时也说明了成矿系列中存在一定差异,这可能与壳幔混合程度不同有关;早中生代花岗岩有关成矿特征、矿床类型、矿化强度、矿化类型等矿床成矿系列上的差异,说明该地区仍具有巨大的多金属找矿潜力。The Late Triassic-Early Jurassic monzonitic granite in southern Yichun area of the Xiao Hinggan Mountains extensively has migmatitic MME-type fine-grained dark dioritic enclaves and plutonic intermediatebasic mafic dikes,characterized by crust-mantle mixture.In contrast,the syenitic-alkali feldspar granite is characterized by aluminian A2 type granite.Their petrographic,major and minor element and isotopic features show that their formation was related to underplating in an extension-collapse environment of the transition period from continental collision to post-collision after the closure of the palaeo-Asia Ocean.The similarity of the two types of granites in genesis,material source and metallogenic background also finds expression in their similarity of metallogenic series.The monzonitic granite assumes the Mo-Pb-Zn-Fe-Au-Ag metallogenic series,with Mo and Pb ore-forming processes being most intense,whereas syenitic-alkali feldspar assumes the Zn-PbCu-Mo-W-Fe metallogenic series,characterized by weak and scattered mineralization.Their certain degrees of difference in metallogenic series might have to do with the somewhat different degrees of crust-mantle mixture.The difference of these Mesozoic granites in ore-forming features,ore deposit types,mineralization intensities and mineralization types indicates that this area still has great potential in search for polymetallic ore deposits.

关 键 词：矿床成矿系列 早中生代 碰撞后 底侵作用 伊春地区 

分 类 号：P588.121[天文地球—岩石学] P611[天文地球—地质学]