辽宁青城子地区印支期岩浆作用与找矿预测  

Indosinian magmatism and ore prospecting prediction in Qingchengzi area,Liaoning Province

作　　者：李德东[1] 王玉往[1] 杨云鹏 邱金柱 解洪晶[1] 张志超 LI DeDong;WANG YuWang;YANG YunPeng;QIU JinZhu;XIE HongJing;ZHANG ZhiChao(Beijing Institute of Geology for Mineral Resources Co.,Ltd.,Beijing 100012,China;Team No.103 of Liaoning Non-Ferrous Geological Co.,Ltd.,Dandong 118008,Liaoning,China)

机构地区：[1]北京矿产地质研究院有限责任公司,北京100012 [2]辽宁省有色地质一〇三队有限责任公司,辽宁丹东118008

出　　处：《矿床地质》2023年第4期713-728,共16页Mineral Deposits

基　　金：国家重点研发计划项目(编号:2018YFC0603804);紫金集团综合找矿预测专项(编号:KCDZKCY-2022-048)共同资助。

摘　　要：大量研究表明辽宁青城子地区主要成矿作用与印支期岩浆活动有密切关系,为了进一步研究印支期岩浆活动与成矿关系,文章在详细野外工作的基础上,对印支期侵入岩体进行了岩石地球化学测试分析。结果表明,青城子地区印支期花岗岩的w(SiO_(2))介于61.67%~77.69%,w(K_(2)O)介于3.96%~6.67%,w(Na_(2)O)为0.04%~4.42%,里特曼指数为0.57~5.19,多数小于3.3,主要为高钾钙碱性和钾玄岩系列;在以w(SiO_(2))为横坐标、其他氧化物为纵坐标的哈克图解中,除了w(Na_(2)O)、w(K_(2)O)与w(SiO_(2))的线性关系不明显外,其他氧化物均与w(SiO_(2))呈线性关系,说明它们具有明显的岩浆演化关系;微量元素均富集大离子亲石元素,亏损高场强元素,原始地幔标准化配分曲线呈右倾模式,稀土元素球粒陨石标准化配分模式呈轻稀土元素富集、重稀土元素亏损的右倾模式;构造判别图指示了青城子地区印支期岩浆活动产于同碰撞大地构造环境;根据地球化学特征及各岩体之间的演化关系,判别它们侵位的先后顺序为双顶沟岩体主体相→花岗斑岩脉→双顶沟岩体中心相。文章通过蚀变花岗斑岩与未蚀变花岗斑岩成分对比分析,认为花岗斑岩可作为铅锌、金-银矿床的找矿标志。经统计,大量钻孔中花岗斑岩脉的数量分布密度在水平面投影上与矿床分布具有高度吻合性,文章预测桃源东北部花岗斑岩分布区具有较大的成矿潜力。A large number of studies have shown that the main mineralization in Qingchengzi area is closely related to the Indosinian magmatism.In order to further study the relationship between magmatic activity and mineralization in Indosinian period,the lithogeochemical analysis of Indosinina intrusive rocks were carried out on the basis of detailed field work.The results show that the SiO_(2) content,K_(2)O content and Na_(2)O content of Indosinian granites in Qingchengzi area are 61.67%~77.69%,3.96%~6.67%and 0.04%~4.42%,respectively.The Reitman composite index is 0.57~5.19,mostly less than 3.3,which is mainly high potassium calc-alkaline and shoshonite series.In the Harker diagrams with SiO_(2) as the abscissa and other oxides as the ordinate,except Na_(2)O and K_(2)O have no obvious linear relationships with SiO_(2),other oxides have linear relationship with SiO_(2),indicating that they have obvious magmatic evolution relationship.The trace elements are enriched in large ion lithophile elements,depleted in high field strength elements,and the curve of the primitive mantle-normalized shows a right-leaning mode.The pattern of rare earth elements chondrite-normalized shows a right-leaning mode of enrichment of light rare earth elements and depletion of heavy rare earth elements.The tectonic discrimination plots of trace element indicate that the magmatic activity in Qingchengzi area belongs to the syn-collision tectonic environment.According to the geochemical characteristics and the evolution relationship between various rocks,it is determined that their emplacement sequence is the main facies of Shuangdinggou intrusive body→granite porphyry dikes→central facies of Shuangdinggou intrusive body.Through the comparative analysis between the compositions of altered granite porphyry and unaltered granite porphyries,it is considered that granite porphyry can be used as a prospecting indicator for lead-zinc and gold-silver deposits.The quantitative distribution density of granite porphyry dikes from a large number of boreh

关 键 词：地质学 印支期 岩浆作用 花岗斑岩 找矿预测 青城子地区 辽宁 

分 类 号：P618.42[天文地球—矿床学]