岩矿测试2025，Vol.44Issue(1)：75-87,13.DOI:10.15898/j.ykcs.202403050032
独居石LA-ICP-MS U-Pb法测定北大别木子店片麻杂岩变质年龄
Monazite LA-ICP-MS U-Pb Dating to Constrain the Metamorphic Age of the Muzidian Gneiss Complex in the Northern Dabie Orogen
摘要
Abstract
The Muzidian gneiss complex(MGC)in the Northern Dabie Orogen is the oldest exposed rock formation in the South China block.However,there is still a lack of research on its metamorphic age and tectonic implications.LA-ICP-MS in situ U-Pb dating and trace element analysis of monazite were carried out on two gneiss samples from the MGC.The results show that most monazite grains exhibit homogeneous features with no zoning,evident depletion of HREEs and negative Eu anomalies,suggesting that they may be of metamorphic origin.The monazite U-Pb ages of the two gneiss samples are 129±1Ma and 130±1Ma,respectively,which represent the time of metamorphism of the MGC.These ages are broadly consistent with the emplacement age of the early Cretaceous granitoids in the Muzidian area,as well as the large amount of exposed migmatites in the Northern Dabie Orogen.Our study shows that the extensional collapse of the thickened continental crust and the delamination of the orogenic crustal root during the early Cretaceous of the Dabie Orogen caused contemporaneous metamorphism,migmatation,and magmatism,which constrained the tectonic regime switch time of the Northern Dabie Orogen from compression to extension to～130Ma.The BRIEF REPORT is available for this paper at http://www.ykcs.ac.cn/en/article/doi/10.15898/j.ykcs.202403050032.关键词
木子店片麻杂岩/变质作用/独居石/北大别构造带/英云闪长片麻岩/LA-ICP-MSKey words
Muzidian gneiss complex/metamorphism/monazite/Northern Dabie Orogen/tonalitic gneiss/LA-ICP-MS分类
地质学引用本文复制引用
邱啸飞,卢山松,谭娟娟,童喜润,吴年文,杨小莉,邵鑫,刘飞,杨小丽..独居石LA-ICP-MS U-Pb法测定北大别木子店片麻杂岩变质年龄[J].岩矿测试,2025,44(1):75-87,13.基金项目
国家自然科学基金项目(42272229,U2344210) （42272229,U2344210）
中国地质调查局花岗岩成岩成矿地质研究中心开放基金项目(PM202302) （PM202302）
中国地质调查局武汉地质调查中心"潜龙计划"青年拔尖人才项目(QL2022-02) （QL2022-02）
