滇西腾冲—梁河地区花岗岩锆石稀土元素组成和U-Pb同位素年龄  

Rare Earth Element Geochemistry and U-Pb Age of Zircons from Granites in Tengchong-Lianghe Area,Western Yunnan

作　　者：丛峰[1] 林仕良[1] 谢韬[1] 李再会[1] 邹光富[1] 梁婷[2] 

机构地区：[1]中国地质调查局成都地质调查中心,成都610081 [2]中国地质大学地质过程与矿产资源国家重点实验室,武汉430074

出　　处：《吉林大学学报（地球科学版）》2010年第3期573-580,共8页Journal of Jilin University：Earth Science Edition

基　　金：中国地质调查局项目(1212010784007)

摘　　要：在详细的区域地质调查基础上,对滇西腾冲—梁河地区花岗岩的锆石进行了阴极发光观察,并通过LA-ICP-MS分析了其稀土元素组成和U-Pb同位素年龄。花岗岩中大部分锆石具有振荡环带,锆石稀土元素表现为亏损轻稀土、阶梯式富集重稀土、强烈正Ce异常及强烈负Eu异常,表明锆石为典型的岩浆锆石。花岗岩(D0053)锆石的206Pb/238U加权平均年龄为(127.9±1.0)Ma(MSWD=2.9,27个点),花岗岩(D4310)锆石的206Pb/238U加权平均年龄为(58.3±0.5)Ma(MSWD=1.8,21个点),表明腾冲—梁河地区存在大量早白垩世和早第三纪花岗岩浆活动,它们是特提斯演化过程的岩浆响应。Based on detailed regional geological survey,the internal textures,rare earth element composition and U-Pb age of zircons from granites in Tengchong-Lianghe area,western Yunnan,were studied by cathodoluminescence （CL） and LA-ICP-MS,respectively.Both the oscillatory zoning and chondrite-normalized REE pattern characterized by a steeply-rising slope from the LREE to the HREE with the obviously positive Ce anomaly and negative Eu anomaly,indicate the magmatic genesis of these zircons from the granites.The zircons in the granite （D0053） yield a weighted mean 206 Pb/238 U age of （127.9±1.0） Ma （MSWD=2.9,n=27）.Those in granite （D4310） yield a weighted mean 206 Pb /238 U age of （58.3±0.5） Ma （MSWD=1.8,n=21）.The results indicate that there happened widely the Early Cretaceous and Early Tertiary granitic magmatisms in Tengchong-Lianghe area,western Yunnan,as the magmatic response to the tethys evolution.

关 键 词：滇西 花岗岩 锆石 稀土元素 U-PB同位素年龄 

分 类 号：P581[天文地球—岩石学]