张广才岭英城子金矿区早古生代花岗岩的元素地球化学特征、岩石成因及构造意义  

Element Geochemistry and Genesis of Early Paleozoic Granite in Yingchengzi Gold-Field,Eastern Zhangguangcai Mountain and Its Tectonic Significance

作　　者：陈行时[1,2] 张朋[3] 孙景贵[1] 唐臣[2] 崔培龙[1] 李怡欣[1] 

机构地区：[1]吉林大学地球科学学院,长春130061 [2]黑龙江省地质矿产局地质调查研究院.哈尔滨150036 [3]沈阳地质矿产研究所,沈阳110034

出　　处：《吉林大学学报（地球科学版）》2011年第2期440-447,共8页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(40472050,40772052);黑龙江省地球物理勘察院项目(3J106H424422);中国科学院地质与地球物理研究所矿产资源重点实验室基金项目(2007-2010)

摘　　要：系统研究了英城子金矿区内花岗岩的地质、岩相学和元素地球化学特征。研究结果显示:该类花岗岩为富硅(w(SiO2)=71.12%～75.66%)、高分异(DI=90.53～94.42)、钾质钙碱性岩(σ=2.37～3.94),富集大离子亲石元素(LREE/HREE=11.20～14.62,w(Rb)=(270.6～165.3)×10-6,Na2O/K2O=0.18～0.67,等),具负的铕异常,相对亏损Ba、Nb、Sr、P和Ti等元素。这种特征揭示该类花岗岩是准铝质、高分异I型花岗岩,它的母岩浆可能是I型花岗质岩浆,是母岩浆经以斜长石为主的矿物相分离结晶作用后产生的岩浆经结晶作用形成。结合锆石的年代学研究成果,进一步确立该花岗岩可能是在麻山期深变质作用过程中地壳深熔形成的岩浆经分离结晶作用形成,岩浆就位发生在麻山期陆内造山作用的挤压向伸展转换阶段,从发生到就位持续大约20Ma。Geology,petrography and element geochemistry for granites are studed from Yingchengzi gold-field,eastern Zhangguangcai Mountain.The granites are characterized by high SiO2（SiO2=71.12%-75.66%）,high fractionated index（DI=90.53-94.42）,and belong to Potassic calc-alkaline rock（σ=2.37-3.94）.They are enriched in LILE（LREE/HREE=11.20-14.62,w（Rb）=（270.6-165.3）×10-6,Na2O/K2O =0.18-0.67） and depleted in Ba,Nb,Sr,P and Ti,as well as negative Eu anomalys.These characteristics indicate that the granites belong to metaluminous and highly fractionated I-type granites,whose parent magma may be I-type granitic magma,and the magma for the granites is formed after fractional crystallization for parent magma dominated by plagioclase.Combined with zircon geochronology,it may be established that the magma was formed after the fractional crystallization for magma chamber during the Mashan period deep metamorphism,and the magma chamber was triggered by anatectic magmatism for the crust.The magma emplacement took place in intracontinental orogenic of the Mashan period,and the process may be lasted for about 20 Ma.

关 键 词：花岗岩 元素地球化学 岩石成因 英城子金矿区 张广才岭 

分 类 号：P618.51[天文地球—矿床学]