延边闹枝铜金矿区中生代火山岩锆石U-Pb年代学、 地球化学及其地质意义  

Zircon U-Pb chronology,geochemistry and geological implications of Mesozoic volcanic rocks from Naozhi copper-gold mining area,Yanbian

作　　者：李晓鹏 孙景贵[1] 刘阳[1] 王清海 任泽宁[1] 谷小丽 LI Xiao-peng;SUN Jing-gui;LIU Yang;WANG Qing-hai;REN Ze-ning;GU Xiao-li(College of Earth Sciences,Jilin University,Changchun 130061,China;International Center for Geoscience Research and Education in Northeast Asia,JilinUniversity,Changchun 130026,China;Changchun Automobile Industry Institute,Changchun 130011,China)

机构地区：[1]吉林大学地球科学学院,长春130061 [2]吉林大学东北亚国际地学研究与教学中心,长春130026 [3]长春汽车工业高等专科学校,长春130011

出　　处：《世界地质》2020年第3期528-543,共16页World Geology

基　　金：吉林省地质勘查基金项目(2016-16)。

摘　　要：为探究延边地区闹枝铜金矿区是否发育多期火山作用,笔者对矿区发育的火山岩开展详细的地质学、岩相学和锆石LA-ICP-MS U-Pb年代学研究。结果表明:矿区出露的安山岩与英安质晶屑岩屑凝灰岩之间存在明显的沉积间断,即安山岩的形成时间应早于英安质凝灰岩。其中,安山岩的岩浆结晶锆石U-Pb年龄为(125.8±2.5)Ma,含有(179.9±4.6)Ma的捕获锆石;英安质角砾凝灰岩的形成年龄为(107.6±2)Ma,英安质晶屑岩屑凝灰岩的形成年龄为(107.5±1.5)Ma。地球化学特征表明两类火山岩均形成于活动大陆边缘板块俯冲环境下,由壳幔混合而成,分别对应于早白垩世屯田营组与金沟岭组。屯田营期岩浆与地壳物质的混染作用、火山喷发与次火山热液活动可能是导致闹枝中硫化型铜金矿床成矿的主要因素,金沟岭组的火山喷发与浅成作用是导致富金斑岩铜矿-浅成热液金矿床成矿的前提。To explore multiple volcanisms in Naozhi copper-gold mining area,Yanbian region,detailed geological,petrographic and zircon LA-ICP-MS U-Pb chronological studies have been carried out on the volcanic rocks in the mining area.The results show that there exists an obvious hiatus between the andesites and the dacitic crystal lithic tuff,which shows the andesites should be older than dacitic tuff.The U--Pb age of the andesite is(125.8±2.5)Ma,with(179.9±4.6)Ma of captured zircons.The dacitic breccia tuff is aged(107.6±2)Ma,and the age of dacitic crystal lithic tuff is(107.5±1.5)Ma.The geochemical characteristics show that the two kinds volcanic rocks are formed in the subduction environment of active continental margin plate,derived from mixed crustal and mantle material.They can be correlated to the Early Cretaceous Tuntianying Formation and Jingouling Formation respectively.The mixing of the magma of Tuntianying Formation with crustal materials,volcanic eruptions and subvolcanic hydrothermal activities may be the main factors leading to the mineralization of Naozhi intermediate sulfidation copper-gold deposit.The volcanic eruption and hypabyssal process of Jingouling Formation are the premises for the metallogenesis of gold-rich porphyry copper-epithermal gold deposit.

关 键 词：锆石U-PB定年 地球化学 中生代火山岩 地质意义 闹枝铜金矿区 

分 类 号：P595[天文地球—地球化学] P597[天文地球—地质学]