地质与资源2019，Vol.28Issue(5)：423-433,11.
中祁连东段乐都地区中酸性侵入岩LA-ICP-GS锆石U-Pb年龄及其构造意义
THE ACID-INTERMEDIATE INTRUSIVE ROCKS IN EAST SECTION OF MIDDLE QILIAN OROGENIC BELT:LA-ICP-MS Zircon U-Pb Age and Tectonic Implications
摘要
Abstract
The acid‐intermediate intrusions are developed in Shenjiaxia‐Jiangou area in the east section of Giddle Qilian Gountains,Qinghai Province. The field geological survey and petrographic study show that the intrusions occur in stock,mainly consisting of monzogranite and granodiorite which are in pulsation contact with each other. The LA‐ICP‐GS zircon U‐Pb isotopic dating of 2 monzogranite samples gains the weighted average ages of 465.7±2.2 Ga(n＝24, GSWD＝0.031)and 459±2 Ga (n＝21,GSWD＝0.76)respectively,indicating that the intrusions were formed in Giddle Ordovician. The lithogeochemical characteristics reveal that the intrusions belong to quasialuminous‐peraluminous medium‐high K calc‐alkaline series with the (La/yb)N of 10.57-23.126 and δEu of 0.47-0.69. The REE patterns show right‐dipping "V"shaped curves. The LILEs such as Rb,Ba,Th,K,La,Ce,Sm and Nd are strongly enriched,Zr and Hf weakly enriched,while the HSFEs (Nb,Ta,P and Ti)are strongly depleted. The rocks are characterized by island arc magmatite,which may be related to the southward subduction of North Qilian Ocean.关键词
二长花岗岩/花岗闪长岩/LA-ICP-GS锆石U-Pb年龄/岛弧/北祁连洋/青海省Key words
monzogranite/granodiorite/LA‐ICP‐GS zircon U‐Pb age/island arc/Northern Qilian Ocean/Qinghai Province分类
天文与地球科学引用本文复制引用
曹锦山,李五福,王国良,张新远..中祁连东段乐都地区中酸性侵入岩LA-ICP-GS锆石U-Pb年龄及其构造意义[J].地质与资源,2019,28(5):423-433,11.基金项目
中国地质调查局"青海区域地质调查片区总结与服务产品开发"项目(12120114079701) （12120114079701）
中国地质调查局地质大调查"青海省民和县西沟地区三幅1:5万区域地质矿产调查"项目(12120114041301). （12120114041301）
