| 晚上新世龙门山南段斜向逆冲作用和区域应力场转换 |
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| 引用本文： | 李志刚,刘静,贾东,孙闯,王伟,姚文倩.晚上新世龙门山南段斜向逆冲作用和区域应力场转换[J].地质通报,2016,35(11):1829-1844. |
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| 作者姓名： | 李志刚 刘静 贾东 孙闯 王伟 姚文倩 |
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| 作者单位： | 1. 地震动力学国家重点实验室, 中国地震局地质研究所, 北京 100029;2. 南京大学地球科学与工程学院, 江苏 南京 210093 |
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| 基金项目： | 国家自然科学基金项目（批准号：41502187）、国家杰出青年科学基金项目（批准号：41225010）和中国博士后科学基金项目（批准号：2015M571079、2016T90121） |
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| 摘 要： | 2008年汶川地震(Mw 7.9)同震滑移结果表明,今地壳缩短为近EW向,与龙门山褶皱冲断带斜交。这一斜向逆冲作用的准确起始时间一直未得到很好的约束。基于龙门山南段山前大邑背斜区三维地震解释和构造建模,结合野外地质调查和年代学数据,确定了晚新生代存在NE向和近NS向2期构造变形。120km长的NS向构造切割了NE向构造,表明近NS向构造形成时间较晚。山前大邑和邛西背斜区近NS向断层和褶皱的活动,均反映了龙门山南段局部或区域上水平最大主应力方向的转换过程,渐新世—早上新世的NW—SE向转变为晚上新世—全新世的近EW向。龙门山南段山前发育的NS向构造和汶川地震同震变形均反映出青藏高原东缘最新的EW向地壳缩短过程,为理解青藏高原东缘的隆升机制提供了新的视角。
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| 关 键 词： | 汶川地震 龙门山 斜向逆冲作用 构造应力场转换 地壳缩短 |
| 收稿时间： | 2016/3/30 0:00:00 |
| 修稿时间： | 2016/6/6 0:00:00 |
Late Pliocene oblique thrusting and regional stress field changes in southern Longmen Mountain, eastern Tibet |
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| LI Zhigang,LIU Jing,JIA Dong,SUN Chuang,WANG Wei and YAO Wenqian.Late Pliocene oblique thrusting and regional stress field changes in southern Longmen Mountain, eastern Tibet[J].Geologcal Bulletin OF China,2016,35(11):1829-1844. |
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| Authors: | LI Zhigang LIU Jing JIA Dong SUN Chuang WANG Wei and YAO Wenqian |
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| Institution: | 1. State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing 100029, China;2. Department of Earth Sciences, Nanjing University, Nanjing 210093, Jiangsu, China |
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| Abstract: | The co-seismic slip sense of the 2008 Wenchuan earthquake (Mw 7.9) has demonstrated the present east-west (E-W) crustal shortening and oblique thrusting across the Longmen Mountain. However, the oblique thrusting and its initial time remain poorly investigated. By using 3-D seismic reflection data, field investigation, and published dating results, the authors investigated the E-W crustal shortening in the Dayi Fault System (DYFS), and determined tectonic stress field changes during the Late Cenozoic. Two-period tectonic deformations were found in the DYFS, which correspond to the NE-and NS-trending structures, respectively. The activities of the DYFS and Qiongxi Fault System reflect a change in the direction of the tectonic stress, from NW-SE during the Oligocene and Early Pliocene to E-W from the Late Pliocene to Holocene. The 120km NS-trending structures in the southern Longmen Mountain range front as well as the Wenchuan earthquake co-seismic ruptures are assumed to reflect the active, E-W crustal shortening in Longmen Mountain, eastern Tibet plateau. The results obtained by the authors provide a new perspective for the uplift mechanisms of eastern margin of the Tibetan Plateau. |
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| Keywords: | Wenchuan earthquake Longmen Mountain oblique thrusting tectonic stress field changes crustal shortening |
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