辽东青城子矿集区双顶沟岩体年代学及地球化学研究  

Geochronology and Geochemistry Study of the Shuangdinggou Intrusion in the Qingchengzi Ore Concentration Area,Eastern Liaoning Province

作　　者：解洪晶[1] 王玉往[1] 李德东[1] 石煜[1] 周国超 龙灵利[1] XIE Hongjing;WANG Yuwang;LI Dedong;SHI Yu;ZHOU Guochao;LONG Lingli(Beijing Institute of Geology and Mineral Resources, Beijing, 100012;China University of Geosciences, Beijing, 100083)

机构地区：[1]北京矿产地质研究院,北京100012 [2]中国地质大学,北京100083

出　　处：《地质学报》2018年第6期1264-1279,共16页Acta Geologica Sinica

基　　金：中国地质调查局地质调查项目(编号:12120115034001;12120115034101)资助的成果

摘　　要：青城子矿集区印支期岩浆作用形成岩基状双顶沟岩体及岩脉状石英二长斑岩等,双顶沟岩体根据其岩相学特征可划分为主体相和中心相两个岩相带,主体相内含有大量暗色微粒包体,并常见矿物不平衡结构,显示岩浆混合的特征。在岩石地球化学方面,包体与寄主岩石的主要氧化物之间具有良好的线性关系,寄主岩石和包体的稀土元素配分曲线和微量元素蛛网图形态相似,指示寄主岩石与包体在岩石形成过程中发生过成分交换及均一化,也显示岩浆混合特征。双顶沟岩体主体相具有高Ba-Sr花岗岩特征,可能为加厚下地壳部分熔融形成的熔体与富集地幔岩浆混合作用的产物,中心相则为主体相经过长石、角闪石、黑云母等的分离结晶作用而形成。石英二长斑岩脉可能为双顶沟岩体演化的浅成相,两者具有相同的源区和成因,矿集区内铅锌、金银矿床的形成可能与岩浆混合作用演化形成的石英二长斑岩相关。The Indosinian magmatism in the Qingchengzi ore concentration area resulted in the formation of the Shuangdinggou batholith and quartz monzonitic porphyry veins.Based on the petrographic characteristics,the Shuangdinggou intrusion can be classified into two facies zones：the main lithofacies and the central lithofacies.The main lithofacies contain abundant mafic microgranular enclaves and show unbalanced textures,displaying the characteristic of magma mixing.Geochemically,the major oxide contents of the enclaves and their host rocks possess better linear relation in the plot.The REE and trace elements patterns of the enclaves and the host rocks are similar,suggesting that they display the exchanges and equilibrium of elements between the enclaves and the host rocks. The main lithofacies of the Shuangdinggou intrusion has similar geochemical characteristics as the high Ba-Sr granite,and likely originated from magma effect of melts from partial melting of thickened lower crust and magma of enriched mantle.The central lithofacies was formed by the fractional crystallization of feldspar,hornblende,bitite,etc.Quartz monzonitic porphyry might be the hypabyssal phase of Shuangdinggou intrusion and they both have the same source and genesis.The formation of the Pb-Zn or Au-Ag deposits in the Qingchengzi ore concentration area may be related to the quartz monzonitic porphyry which evolved from magma mixing.

关 键 词：青城子矿集区 双顶沟岩体 岩浆混合 暗色微粒包体 分异演化 

分 类 号：P618.2[天文地球—矿床学]