吉林安图海沟岩体岩石地球化学特征及其成岩构造环境  

Geochemical characteristics and tectonic setting of Haigou intrusion of Antu,Jilin

作　　者：范振华[1] 李绪俊[1] 梁本胜[1] 田素梅 范文亮[1] 任山峰 

机构地区：[1]吉林大学地球科学学院,长春130026 [2]云南省地质调查院,昆明650216 [3]吉林省海沟黄金矿业有限责任公司,吉林安图133617

出　　处：《世界地质》2012年第1期9-19,共11页World Geology

基　　金：中国地质调查局项目(资[2010]矿评01-20-05);吉林省科技发展计划项目(20090479)联合资助

摘　　要：海沟岩体是海沟金矿的赋矿岩体,由边缘相二长岩和中心相二长花岗岩组成,其岩石化学成分具有低硅,富铝,全碱含量较高等特点。海沟岩体富集高场强元素(HFSE)Th、U、Nb、Ta、Hf、Zr,亏损大离子亲石元素(LILE)。岩体稀土元素呈强分馏、无明显铕异常、轻稀土强烈富集模式。在构造环境判别图解上,样品均落入火山弧环境。综合分析认为海沟岩体与中太古宙色洛河群变质岩共同组成了一个小规模的变质核杂岩,结合海沟岩体锆石SHRIMP U-Pb精确定年结果 (322～326Ma),认为在海西早期中亚—蒙古洋尚未闭合、南北地体未发生碰撞前,大洋板块向南深俯冲于华北板块之后引起陆壳增生,部分融熔形成深熔含铀钾质花岗岩。海沟岩体可能为火山弧环境下形成敦化隆起这一陆壳增生过程的产物。Haigou intrusion,consisting mainly of marginal monzonite and central adamellite,is the direct host rocks of the Haigou gold deposit.The intrusion is characterized by low Si,high Al and high total alkali.The rocks are featured by the enrichment of HFSE（Th,U,Nb,Ta,Hf,Zr） and depletion of LILE.In the intrusion,REEs show strong fractionation and enrichment in LREE and unconspicuous anomaly of Eu.Discriminating diagrams of tectonic setting suggest that the samples locate in volcanic arc.The comprehensive analysis shows that Haigou intrusion probably make up a small-scale metamorphic core complexes with the surrounding metamorphic rocks of Seluohe group in Meso-Archean.Considering the zircon SHRIMP U——Pb dating of the Haigou intrusion（322~326 Ma）,the authors suggested that the oceanic plate subduction process to North China plate resulted in crust growth,and the partial melting formed U-bearing kaligranite before the closure of central Asian-Mongolia Ocean and the collision between northern and southern terranes in Early Hercynian.The Haigou intrusion was related to crust growth process of Dunhua uprise under volcanic arc tectonic setting.

关 键 词：岩石化学特征 U-PB测年 成岩构造环境 海沟岩体 安图 吉林 

分 类 号：P588.121[天文地球—岩石学] P595[天文地球—地质学]