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    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. DOI: 10.12029/gc20190613
    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. DOI: 10.12029/gc20190613
    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. DOI: 10.12029/gc20190613
    Citation: 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. DOI: 10.12029/gc20190613

    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

    Characteristics of Cenozoic faults in Langshan area, Inner Mongolia: Constraint on the development of normal faults

    • 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。

       

      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.

       

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