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引用本文:赵衡,张进,李岩峰,曲军峰,张北航,张义平,云龙,王艳楠. 内蒙古狼山地区新生代断层活动特征:对正断层生长的限定[J]. 中国地质, 2019, 46(6): 1433-1453.
ZHAO Heng,ZHANG Jin,LI Yanfeng,Qü Junfeng,ZHANG Beihang,ZHANG Yiping,YUN Long,WANG Yannan. Characteristics of Cenozoic faults in Langshan area, Inner Mongolia: Constraint on the development of normal faults[J]. Geology in China, 2019, 46(6): 1433-1453(in Chinese with English abstract).
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内蒙古狼山地区新生代断层活动特征:对正断层生长的限定
赵衡1, 张进1, 李岩峰2, 曲军峰1, 张北航1, 张义平3, 云龙4, 王艳楠5
1.中国地质科学院地质研究所, 北京 100037;2.中国地震应急搜救中心, 北京 100049;3.中国地质科学院, 北京 100037;4.核工业北京地质研究院, 北京 100029;5.河北工程大学地球科学与工程学院, 河北 邯郸 056000
摘要:
阿拉善地块东北缘的狼山地区新生代发育有3期构造,分别为中新世NW-SE向挤压形成的逆断层,NNE向挤压形成的左行走滑断层以及晚新生代NW-SE向伸展形成的高角度正断层。结合阿拉善地块东缘的新生代构造,认为狼山地区新生代断层的活动与青藏高原东北缘的逐步扩展、应力场逐渐调整有关。狼山山前正断层目前是一条贯通的断层,其演化基本符合恒定长度断层生长模型,断层中间部位滑动速率最大,向断层两侧逐渐递减。从不同方法得出的滑动速率来看,进入全新世以来,断层滑动速率有逐渐变小的趋势。结合阿拉善地块内部及东缘断层震源机制解以及断层的几何学、运动学特征,认为河套—吉兰泰盆地和银川盆地属于两个性质不同的伸展盆地,两者通过构造转换带相连,转换区内断层表现为右行走滑。转换区5级以上地震可能是受区域性NE-SW向挤压,近南北向右行断层活动的表现。
关键词:  狼山  正断层  断层生长  阿拉善  青藏高原  地质调查工程
DOI:10.12029/gc20190613
分类号:
基金项目:国家自然科学基金(41572190)、国家重点基础研究发展计划(2017YFC0601301)和中国地质调查局项目(DD20190004)联合资助。
Characteristics of Cenozoic faults in Langshan area, Inner Mongolia: Constraint on the development of normal faults
ZHAO Heng1, ZHANG Jin1, LI Yanfeng2, Qü Junfeng1, ZHANG Beihang1, ZHANG Yiping3, YUN Long4, WANG Yannan5
1.Institute of Geology, Chinese Academy of Geological Sciences, Beijing, 100037, China;2.National Earthquake Response Support Service, Beijing, 100049, China;3.Chinese Academy of Geological Sciences, Beijing, 100037, China;4.Beijing Research Institute of Uranium Geology, Beijing, 100029, China;5.School of Earth Science and Engineering, Hebei University of Engineering, Handan 056000, Hebei, China
Abstract:
The Langshan area, located on the northeastern margin of the Alxa block, was subjected to 3 deformation stages during the Cenozoic, which produced thrust faults formed by NW-SE compression in the late Miocene, left-lateral strike-slip faults caused by NNE compression and active normal faults in the late Cenozoic. Based on peripheral Cenozoic structures around the eastern Alxa margin, the authors infer that these Cenozoic faults were related to the gradual propagation of northeast Tibetan Plateau and the readjustment of the stress field. The Langshan piedmont fault zone is now at a stage of linkup, which is compatible with the constant-length fault model with the highest slip rate in the central part. The slip rate from Holocene seems to tend to become lower relative to the slip rate since late Pleistocene. Combined with the focal mechanisms as well as geometries and kinematics of faults in and around the Alxa block, the authors tentatively propose that the Hetao-Jilantai basin and the Yinchuan basin are two different extensional basins linked by a transfer zone, in which nearly NNE-trending dextral faults are developed. The Mw >5 earthquakes within the transfer zone probably occurred on the steep dextral faults as the result of regional SW-NE compression.
Key words:  Langshan  normal faults  fault growth  Alxa  Tibetan Plateau  geological survey engineering