ISSN 1006-3021 CN11-3474/P
Published bimonthly started in 1979
南秦岭佛坪地区早中生代变质-深熔-变形作用的锆石U-Pb年代学制约
  
关键词:metamorphism-anataxis-deformation  U-Pb dating  gneiss dome  strike-slip shear zone  South Qinling belt
基金项目:国家重点基础研究发展规划项目(编号: 2015CB856104);国家自然科学基金项目(编号: 41872059; 41472064)
作者单位E-mail
刘志慧 中国地质科学院地质力学研究所
北京大学地球与空间科学学院 
liuzhihui@pku.edu.cn 
陈龙耀 中国地质科学院地质力学研究所  
曲玮 中国地质科学院地质力学研究所  
胡娟 中国地质科学院地质力学研究所  
刘晓春 中国地质科学院地质力学研究所 liuxchqw@cags.ac.cn 
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摘要:
Early Mesozoic Metamorphism, Anataxis and Deformation of Foping Area in South Qinling Belt: Constrains from U-Pb Zircon Dating
      In this study, Based on an analysis of geometry and kinematics, the authors outlined a framework of Longcaoping migmatitic gneiss dome, Foping County gneiss dome and Yangtianba-Shilipu strike-slip shear zone. This paper also presents a combined petrologic and geochronologic study of migmatites, granulites and deformed granitoids from Foping area in South Qinling belt. Zircons from migmatite show distinct core-rim structure. The mesosome of migmatite yielded a weighted mean age of (211.8±9) Ma, while the leucosome contains Late Triassic zircon rims with U-Pb age of (203.7±1.6) Ma and detrital zircon cores with age spectrum analogous to that of the Devonian metasedimentary rocks from Foping area. Zircons from granulite also show distinct core-rim structure, with U-Pb age of (201.5±7.0) Ma for the core and (188.1±1.5) Ma for the rim. The pegmatite and granite dikes recorded similar ages at (200.4±2.0) Ma and (201.1±1.5) Ma, while two gneisses yielded slightly younger ages at (198.1±2.2) Ma and (196.1±2.1) Ma. The deformed granite yielded a weighted mean age of (205.5±3.0) Ma. Combining the tectonic analysis with the study of metamorphism, anataxis and magmatism, the authors constructed an Early Mesozoic tectonic evolution sequence and put forward the opinion that the activation of the Yangtianba–Shilipu strike-slip shear zone facilitated the emplacement of gneiss domes. It is also held that the South Qinling belt was under a subduction setting prior to 217~212 Ma, collision setting in 211~201 Ma and post-collision setting during 200~190 Ma.
LIU Zhi-hui,CHEN Long-yao,QU Wei,HU Juan,LIU Xiao-chun.2019.Early Mesozoic Metamorphism, Anataxis and Deformation of Foping Area in South Qinling Belt: Constrains from U-Pb Zircon Dating[J].Acta Geoscientica Sinica,40(4):545-562.
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