摘要
通过研究福建鹭峰山晶洞花岗岩的岩相学及锆石U-Pb同位素年代学特征,并与台湾东部地区同时代的岩浆岩进行简要对比,探讨闽台地区晚中生代岩浆活动特征及构造环境。鹭峰山岩体主要为中细粒晶洞碱长花岗岩,且具有特征性的晶洞构造,属A型花岗岩。鹭峰山晶洞花岗岩三个代表性岩石样品LA-ICP-MS锆石U-Pb年龄分别为84.5±1.0Ma、81.8±0.6Ma和84.9±0.5Ma,结合其他晶洞花岗岩体的年龄资料,认为长乐—南澳断裂带南东侧晶洞花岗岩的形成时代为93.8~81.8Ma,属晚白垩世。岩浆作用具向东迁移现象,可能受古太平洋板块的俯冲后撤作用控制。该次构造岩浆活动与台湾东部酸性岩浆作用属同一构造岩浆事件。
In comparison with the contemporary granite in eastern Taiwan,this paper analyzed the characteristics of tectonic and magmatic activities and tectonic environment of Fujian and Taiwan during late Mesozoic using petrography and zircon U-Pb isotope ages of Lufengshan miarolitic granite.Main rock type at Lufengshan is medium to fine-grained miarolitic alkali feldspar granite,which belongs to A-type granite with the characteristic miarolitic texture.LA-ICP-MS zircon U-Pb dating yielded three ages of 84.5±1.0 Ma,81.8±0.6 Ma and 84.9±0.5 Ma for the Lufengshan miarolitic granite.Combined with the ages of other miarolitic granites in the area,it can be concluded that the miarolitic granites in the southeastern part of the Changle-Nan ao fault zone formed at 93.8~81.8 Ma,belonging to late Cretaceous.The magmatic activity moved eastward,which might have been controlled by subduction retrogression of the paleo-Pacific Plate.Therefore,this tectonic-magmatic activity and felsic magmatism in eastern Taiwan should belong to the same tectonic-magmatic event.
作者
黄长煌
林慈銮
HUANG Chang-huang;LIN Ci-luan(Fujian Institute of Geological Survey,Fuzhou 350013,China)
出处
《华东地质》
2019年第3期170-178,共9页
East China Geology
基金
中国地质调查局“闽台中生代构造-岩浆岩区域地质专项调查(编号:12120114043301)”和“福建海域1∶5万平海、浮叶幅海洋区域地质调查(编号:GZH2014002011)”项目联合资助
关键词
福建鹭峰山
晶洞花岗岩
A型花岗岩
台湾东部
晚白垩世
Lufengshan,Fujian Province
miarolitic granite
A-type granite
eastern Taiwan
Late Cretaceous
