U-Pb zircon age of the foliated garnet-bearing granites in western Dabie Mountains,Central China  

作　　者：ZHANG Hongfei ZHONG Zengqiu GAO Shan ZHANG Benren LI Huiming 

机构地区：[1]Faculty of Earth Sciences,China University of Geosciences,Wuhan 430074,China [2]Department of Geology,Northwest University,Xi’an 710069,China [3]Tianjin Institute of Geology and Mineral Resource,Tianjin 300170,China

出　　处：《Chinese Science Bulletin》2001年第19期1657-1660,共4页

基　　金：This work was supported by the National Natural Science Foundation of China (Grant Nos. 49794043 and 40073005) ;and the Ministry of Science and Technology of China (Grant No. G1999075506).

摘　　要：U-Pb zircon dating on two foliated garnet-bearing granite samples in the western Dabie ultra-high-pressure (UHP) metamorphic unit yields concordant ages of (234±4) Ma and (227±5) Ma, respectively. These ages, following the UHP peak metamorphism, represent the magma emplacement ages for the foliated garnet-bearing granites. This, for the first time, shows that there are the Triassic granites in the Dabie Mountains. The foliated garnet-bearing granites resemble A-type granite in geochemical characteristics, indicating that they were formed in exten-sional geodynamic setting. The magma formation reflects a reheating event in the Dabie orogenic belt and it enhances the transfer of tectonic regime from collision into extension and promotes the rapid exhumation into lower crust for the UHP metamorphic rocks.U-Pb zircon dating on two foliated garnet-bearing granite samples in the western Dabie ultra-high-pressure (UHP) metamorphic unit yields concordant ages of (234±4) Ma and (227±5) Ma, respectively. These ages, following the UHP peak metamorphism, represent the magma emplacement ages for the foliated garnet-bearing granites. This, for the first time, shows that there are the Triassic granites in the Dabie Mountains. The foliated garnet-bearing granites resemble A-type granite in geochemical characteristics, indicating that they were formed in extensional geodynamic setting. The magma formation reflects a reheating event in the Dabie orogenic belt and it enhances the transfer of tectonic regime from collision into extension and promotes the rapid exhumation into lower crust for the UHP metamorphic rocks.

关 键 词：DABIE orogenic belt foliated garnet-bearing GRANITE U-Pb zircon age POST-COLLISIONAL granite. 

分 类 号：P597[天文地球—地球化学]