| 华北中地壳滑脱面及其活动分区的天然地震研究 |
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| 引用本文： | 李涛,周世卿.华北中地壳滑脱面及其活动分区的天然地震研究[J].现代地质,2009,23(6). |
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| 作者姓名： | 李涛 周世卿 |
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| 作者单位： | 1. 中国地震局,地质研究所,北京,100029
2. 湖北省地质调查院,湖北,武汉,430022 |
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| 基金项目： | 国土资源部国土资源大调查项目 |
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| 摘 要： | 华北的上部地壳以脆性变形为主,下部地壳以韧性伸展为主,两种截然不同的变形状态却有着相同伸展方向、相同伸展量,使得上下地壳之间因差异运动而形成一个区域性界面——华北中地壳顶部滑脱面。以这个滑脱面为底边界发育起来的上地壳的结构构造,是控制华北盆山格局、基底构造发育形成的直接原因。华北构造是地壳脆性域"薄皮"伸展变形。滑脱面在华北基本上是连续分布的,呈断坡—断坪状,南北分带、东西分片,深度为12~22 km,一般为15~18 km,可识别出11个层状拆离区;上地壳以断块方式变形,断块的位置、形态及活动方式受滑脱面的断坡—断坪产状、与滑脱方向垂直的断叉线和与滑脱方向平行的调整断裂的组合控制,可识别出3个主裂陷轴、2条主断叉线和3条主调整断裂带。
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| 关 键 词： | 地壳 伸展体制 滑脱层 韧性变形 脆性变形 华北 |
A Seismic Study on the Detachment Layer in Middle Crust and Its Relation to Subdivision of Active Tectonics in North China |
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| LI Tao,ZHOU Shi-qing.A Seismic Study on the Detachment Layer in Middle Crust and Its Relation to Subdivision of Active Tectonics in North China[J].Geoscience——Journal of Graduate School,China University of Geosciences,2009,23(6). |
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| Authors: | LI Tao ZHOU Shi-qing |
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| Abstract: | In North China the upper crust is dominated by brittle deformation and lower crust is characterized by ductile extension. However these two styles of different deformation have the same extensional direction and the similar extension amount, which resulted in the development of a regional detachment layer along the top of the middle crust in North China due to differential movement between the upper and lower crust. The detachment structure has controlled the development of the basin-range pattern and the basement of North China Block. The tectonics in this region is produced by thin-skinned extension in the brittle upper crust.The stair-shape detachment layer in North China Block is distributed continuously at depth 12-22 km (mostly at 15-18 km). Eleven detached units (or regions) can be identified. Brittle faulting mainly occurs in the upper crust. The locations of the faulted blocks, configuration and their deformation manners are dictated jointly by occurrence of the ramp-flat detachment, cutoff lines perpendicular to the detachment and accommodation faults parallel to the detachment. Three primary axes of the rifted-depression, two main cutoff lines and three main accommodating faults have been recognized. |
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| Keywords: | crust extension regime detachment layer ductile deformation brittle deformation North China |
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