地质学报2017，Vol.91Issue(10)：2212-2230,19.
福建上杭地区燕山期花岗岩锆石U-Pb年代学及Hf同位素组成
LA-ICP-MS Zircon U-Pb Geochronology and Hf Isotopic Compositions of Yanshanian Granites in the Shanghang Area, Fujian Province
摘要
Abstract
Medium-coarse grained granite of the Zijinshan pluton,fine grained monzogranite in west of Shibizhai,and porphyritic biotite monzogranite in east of Shibizhai were selected to conduct U-Pb,Lu-Hf and trace elements analysis.LA-ICP-MS dating of zircons from three rock bodies yielded three magma crystallization ages of 156.5±2.7Ma (late Jurassic),166.2±8.1Ma (middle Jurassic) and 154.1±1.4Ma (late Jurassic)for three rock bodies,respectively.Zircon Lu-Hf isotope analysis results show that zircon Hf isotope twostage model ages (tDM2) are 1.6～2.2Ga,1.7～2.0Ga and 1.7～1.9Ga.Zircon Hf isotope initial values (εHf(t)) are negative:-14.88～-8.40,-11.9～-7.8 and-10.9～-7.4.The zircon εHf(t) and Hf isotope crustal model ages vary in a small range,implying that magma source was of much uniform zircon Hf isotope composition.During the Middle Jurassic (166.2 ± 8.1Ma),paleo-Pacific plate collided with Eurasian plate,resulting in that oceanic crust subducted beneath the continental crust and partial melting of small-scale continental crust formed the pluton in the west of Shibizhai during the time.Upon completion of the collision in the Late Jurassic (145 ～ 156Ma),tectonic environment converted from extrusion to extension,triggering lithospheric extension and thinning,extensive melting of crust-derived substance,and finally giving rise to the formation of the Zijinshan pluton and the Shibizhaidong pluton.The result of this study will provide new data evidence for studying granite source and regional tectonic evolution in southwestern Fujian Province.关键词
花岗岩类/锆石U-Pb年代学/Lu-Hf同位素/燕山期/石壁寨/紫金山矿田/福建省Key words
Granitoids/Zircon U-Pb chronology/Lu-Hf isotope system/Yanshanian/Shibizhai/Zijinshan ore field/Fujian Province引用本文复制引用
谢其锋,蔡元峰,董云鹏,黎敦朋,林荣锋..福建上杭地区燕山期花岗岩锆石U-Pb年代学及Hf同位素组成[J].地质学报,2017,91(10):2212-2230,19.基金项目
本文为南京大学内生金属矿床成矿机制研究国家重点实验室项目(20-15-05),福州大学2017年国家级大学生创新训练计划项目(201710386031)资助成果. （20-15-05）
