| Extension of the Louzidian Metamorphic Core Complex and Development of Supradetachment Basins in Southern Chifeng, Inner Mongolia, China |
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| 作者姓名： | WANG Xinshe ZHENG Yadong and JIA Wen |
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| 作者单位： | WANG Xinshe，ZHENG Yadong and JIA Wen Department of Earth and Space Science，Peking University，Beijing 100871;Institute of Geology，Chinese Academy of Geological Science，Beijing 100037 No. 10 Institute of Geological and Resource Exploration of Inner Mongolia，Chifeng 024005 |
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| 摘 要： | The Louzidian metamorphic core complex (LMCC) in southern Chifeng is located on the northern margin of the North China craton. Structural analyses of the LMCC and its extensional detachment system indicate that the LMCC experienced two-stage extension. The ductile regime experienced top-to-northeast shearing extension and the brittle detachment fault underwent top-down-outwards slipping. Between these two stages, a semi-ductile regime recorded the transition from ductile to brittle. The hanging wall of the detachment fault is similar to those classic supradetachment basins in western North America. Analyses of provenance and paleocurrent directions in the basins show that there were two filling stages. In the early stage, materials came from the southwest margin of the basin and the hanging wall of the detachment system and were transported from southwest to northeast; while in the late stage, deposits were derived from the footwall of the detachment fault and transported outwards to the two sides of the
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| 关 键 词： | 核联体变质作用 扩张状态 糜棱岩 花岗岩 盆地上部 |
Extension of the Louzidian Metamorphic Core Complex and Development of Supradetachment Basins in Southern Chifeng, Inner Mongolia, China |
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| Authors: | WANG Xinshe ZHENG Yadong and JIA Wen |
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| Institution: | WANG Xinshe,ZHENG Yadong and JIA Wen Department of Earth and Space Science,Peking University,Beijing,Institute of Geology,Chinese Academy of Geological Science,Beijing No. Institute of Geological and Resource Exploration of Inner Mongoli,Chifeng |
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| Abstract: | Abstract The Louzidian metamorphic core complex (LMCC) in southern Chifeng is located on the northern margin of the North China craton. Structural analyses of the LMCC and its extensional detachment system indicate that the LMCC experienced two‐stage extension. The ductile regime experienced top‐to‐northeast shearing extension and the brittle detachment fault underwent top‐down‐outwards slipping. Between these two stages, a semi‐ductile regime recorded the transition from ductile to brittle. The hanging wall of the detachment fault is similar to those classic supradetachment basins in western North America. Analyses of provenance and paleocurrent directions in the basins show that there were two filling stages. In the early stage, materials came from the southwest margin of the basin and the hanging wall of the detachment system and were transported from southwest to northeast; while in the late stage, deposits were derived from the footwall of the detachment fault and transported outwards to the two sides of the core complex. Since the filling period of the basins is from the late Jurassic to the late Cretaceous and it is coeval with the extension, the two filling stages reflect the two‐stage history of the detachment fault. The large‐scale late Jurassic underplating in the deep crust of the Chifeng area led to thickening and heating of the middle‐upper crust and trigged the extension at depths and volcanism on the surface. In the early Cretaceous the upper plate of the detachment fault moved northeastwards and sediments were transported from southwest to northeast, while in the late Cretaceous the core complex was uplifted rapidly, the original basin was separated by the uplifted core, and lower‐plate‐derived debris was deposited in the adjacent upper‐plate basins of the detachment fault. Evidentially, the development of the supradetachment basins were controlled by the extension and in turn the fillings in the basins recorded information of the extension, which has provided new evidence for kinematic interpretation of the Louzidian core complex. |
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| Keywords: | Metamorphic core complex extension stage supradetachment basin Louzidian southern Chifeng |
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