西秦岭西段然果儿岗花岗闪长岩体锆石U-Pb定年及地质意义  

Zircon U-Pb Dating of Ranguoergang Granodiorite in Western Section of West Qinling, and its Geological Significance

作　　者：李小江[1] 李佐臣[1,2] 杨拴海[1] 杨高学[1,2] 景永康[1] 常亮[1] 魏立勇[1] 张哲[1] 李国英[1] 许东东[1] 赵常存 董俊超[1] 武海文[1] 刘江岭 

机构地区：[1]中国人民武装警察部队黄金第五支队,陕西西安710100 [2]长安大学地球科学与资源学院,陕西西安710054 [3]陕西中核资源有限公司,陕西西安710054

出　　处：《新疆地质》2015年第3期393-398,共6页Xinjiang Geology

基　　金：中国地质调查局区域地质矿产调查项目(1212011220660);中央高校基本科研业务费专项资金项目(2013G1271092)联合资助

摘　　要：对侵位于西秦岭造山带西段中下三叠统隆务河群中的然果儿岗花岗闪长岩进行年代学研究,探讨其形成环境。结果表明,花岗闪长岩中锆石Th/U比值较高,锆石内部发育振荡环带,具岩浆成因特点;花岗闪长岩的结晶年龄为(227±4)Ma(MSWD=2.0),表明其形成时代为晚三叠世卡尼期。然果儿岗花岗闪长岩形成于后碰撞环境,或者至少是由同碰撞到后碰撞的转折阶段。This paper studies the Ranguoergang granodiorite using zircon U-Pb geochronology methods in the Western Section of West Qinling,which emplaced in middle-upper Triassic of Longwuhe Group, discussions formation environment of the rock body. The results show that the granodiorite＇s zircons have higher Th/U ratios and the internal CL images of have oscillatory zoning indicated that the zircons of the samples were igneous in origin.The LA-ICP-MS zircon UPb isotope concordia diagram age is（227±4） Ma（MSWD=2.0）,indicated granodiorite rock body was formed in Late Triassic Carnian.The Ranguoergang granodiorite emplacement post-collision setting,or at least is from syn-collision to postcollision transition phase.

关 键 词：西秦岭造山带 花岗闪长岩 锆石U-PB定年 形成环境 

分 类 号：P597.3[天文地球—地球化学] P588.12[天文地球—地质学]