羌塘地块中西部布木错走滑断裂系的第四纪晚期地表变形特征与构造意义  

Late Quaternary surface deformation and tectonic implications of the Bue Co strike-slip fault system in central-western Qiangtang block

作　　者：韩帅 吴中海[1,2,3] 王世锋 高扬[1,4] 张圣听 陆诗铭 张铭杲 HAN Shuai;WU Zhonghai;WANG Shifeng;GAO Yang;ZHANG Shengting;LU Shiming;ZHANG Minggao(Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 100081,China;Key Laboratory of Active Tectonics and Geological Safety,Ministry of Natural Resources,Beijing 100081,China;Research Center of Neotectonism and Crustal Stability,China Geological Survey,Beijing 100081,China;School of Earth and Space Sciences,Peking University,Beijing 100871,China;China Unitersity of Geoscience,Beijing 100083,China)

机构地区：[1]中国地质科学院地质力学研究所,北京100081 [2]自然资源部活动构造与地质安全重点实验室,北京100081 [3]中国地质调查局新构造与地壳稳定性研究中心,北京100081 [4]北京大学地球与空间科学学院,北京100871 [5]中国地质大学,北京100083

出　　处：《地质力学学报》2024年第2期298-313,共16页Journal of Geomechanics

基　　金：国家自然科学基金项目(42202259);中国地质科学院地质力学研究所中央财政科研项目结余经费新开项目(所科研56);中国地质调查局地质调查项目(DD20221644)。

摘　　要：班公-怒江缝合带(班怒带)是青藏高原内部羌塘地块与拉萨地块之间的重要边界,研究该边界带上共轭走滑断裂第四纪晚期的几何结构与变形特性对于理解高原内部在印度-欧亚板块碰撞作用下形成的空间差异响应和构造模型具有重要意义。位于班怒带西段的布木错断裂系包括北东向布木错断裂和北西向纳屋错断裂,通过遥感解译和野外地质调查,明确了这两条断裂在第四纪晚期的构造特征和最新的地表变形特征。结果显示,两条断裂自第四纪晚期以来的活动特征明显,并且近期都经历过一次大地震,产生了地表破裂。据此推测班怒带西段北西、北东两组断裂的最新活动强度接近,羌塘地块南部边界现今变形可能受控于两组断裂的共同影响,并已延伸至块体内部。以上发现进一步证明,青藏高原内部物质受中—下地壳流的驱动作用,通过走滑断层和正断层持续向北扩展。[Objective]The Bangong-Nujiang Suture Zone(BNSZ)serves as a boundary between the Qiangtang and Lhasa terranes of the Tibetan Plateau.The geometric structure and deformation characteristics of the“V”-shaped conjugate strike-slip faults along this late Quaternary boundary are important for understanding the spatially variable responses and tectonic models formed within the plateau as a result of the India-Eurasia plate collision.However,previous studies have primarily focused on the kinematic properties and activity rates of strike-slip faults in the eastern segment of the suture zone.The scarcity of information on the activity characteristics of strike-slip faults and paleoseismic events in the western segment of the suture zone has hindered our understanding of regional tectonic deformation and seismic activity.The Bue Co fault system,located in the western section of the BNSZ,is a(conjugate)strike-slip fault system consisting of the NE-trending Bue Co and NW-trending Lamu Co faults.[Methods]This study employs a combination of remote sensing interpretation and field surveys,utilizing high-resolution Digital Surface Models(DSM)collected by unmanned aerial vehicles(UAV)to conduct a detailed analysis of surface ruptures and systematically decipher the geometric morphologies and late Quaternary deformation evidence of the NE-trending Bue Co Fault and the NW-trending Lamu Co Fault in the western section of the BNSZ.[Results]This study revealed significant fault activity since the late Quaternary period,with evidence of recent large earthquakes that caused surface ruptures extending>60 km along both faults.The Bue Co fault exhibits left-lateral strike-slip,with recent seismic displacements ranging from 3.7 to 4.2 m,whereas the Lamu Co fault shows right-lateral strike-slip with minimum displacements of 2.7 m.Both faults display normal faulting components in their surface rupture zones,and the vertical displacements are cumulative across landforms of various ages,indicating long-term fault activity.The latest activit

关 键 词：班公-怒江缝合带 布木错断裂 纳屋错断裂 共轭走滑 地表破裂 青藏高原 

分 类 号：P54[天文地球—构造地质学] P597[天文地球—地质学] P59