福建金刚山晶洞花岗岩年代学及其构造意义  

Chronology and its Tectonic Significance of Jinggangshan Geode Granite in Fujian Province

作　　者：陈鸿炜 Chen Hongwei(East China University of Technology,Nanchang,330013;Fujian Institute of Geological Survey,Fuzhou,350013)

机构地区：[1]东华理工大学,南昌330013 [2]福建省地质调查研究院,福州350013

出　　处：《福建地质》2021年第1期1-12,共12页Geology of Fujian

基　　金：福建省公益性基础性地质调查项目“福建1∶5万长桥、漳浦县幅区域地质调查”。

摘　　要：通过1∶5万长桥、漳浦县区域地质调查,获得金刚山晶洞碱长花岗岩的LA-ICP-MS锆石U-Pb同位素年龄为(95±2.8)Ma;主量元素具有高硅富碱,贫钙、镁、铁特征;微量元素总体表现为大离子亲石元素Rb、K、U、Th相对富集,而Ba、Sr、P、Ti明显亏损;轻稀土相对重稀土富集,具显著的Eu负异常,δEu值小于0.30,显示过铝质A型花岗岩的特征。研究认为该岩体形成于后造山阶段,产于大陆边缘弧塌陷构造环境。Through the 1∶50000 regional geological survey in Changqiao and Zhangpu counties,the isotopic age of LA-ICP-MS zircon U-Pb obtained was(95±2.8)Ma in Jingangshan geode alkali feldspar granite.The main elements have the characteristics of high silicon and alkali-rich,the poor calcium-poor,magnesium and iron.Rb、K、U、Th are relatively enriched that they showed the large ionic lithophiles in the trace elements,but Ba、Sr、P、Ti obvious loss.The light rare earth is enriched relative to the heavy rare earth,which has significant negative Eu anomaly andδEu values is less than 0.30.It shows the characteristics of aluminous A-type granite.It is considered that the rock mass was formed in the post-orogenic stage and occurred in the continental margin arc collapse tectonic environment.

关 键 词：晶洞碱长花岗岩 锆石U-PB年代学 后造山 大陆边缘弧 福建金刚山 

分 类 号：P588.121[天文地球—岩石学]