藏南聂拉木-措勤裂谷南段第四纪正断层作用的时空特征  

Spatial-Temporal Activity of Quaternary Faults at Southern End of Nyalam-Coqen Rift,Southern Tibet

作　　者：高扬 吴中海[1,3] 左嘉梦 王世锋 盖海龙[4] 田婷婷 Gao Yang;Wu Zhonghai;Zuo Jiameng;Wang Shifeng;Gai Hailong;Tian Tingting(Institute of Geomechanics,Chinese Academy of Geological Sciences,Beijing 100081,China;School of Earth and Space Sciences,Peking University,Beijing 100871,China;Key Laboratory of Active Tectonics and Geological Safety,Ministry of Natural Resources,Beijing 100081,China;Qinghai Earthquake Agency,Xining 810001,China)

机构地区：[1]中国地质科学院地质力学研究所,北京100081 [2]北京大学地球与空间科学学院,北京100871 [3]自然资源部活动构造与地质安全重点实验室,北京100081 [4]青海省地震局,青海西宁810001

出　　处：《地球科学》2024年第7期2552-2569,共18页Earth Science

基　　金：国家自然科学基金联合基金项目(No.U2002211);中国地质调查局项目(No.DD20221644);西藏自治区第一次全国自然灾害综合风险普查项目(Nos.XZLX-BMC-2021-307,XZLX-BMC-2022-053)。

摘　　要：全面认识藏南裂谷近南北向正断层活动的时空特征及其差异性是深入理解其成因机制的关键.通过遥感解译、构造地貌分析、地表调查和无人机测量等方法,结合已有的年代学资料,对藏南聂拉木-措勤裂谷南段主要近南北向地堑及其边界正断层的第四纪活动和时空差异性进行了研究.结果表明,研究区第四纪正断层活动存在明显的时空差异性.在时间上,主要近南北向正断层的活动性存在前第四纪、早-中更新世和晚第四纪3个不同的期次.在空间上,近南北向地堑断陷范围自中新世晚期以来发生了明显萎缩,其活动范围自聂拉木一带逐渐萎缩至佩枯错和穆林错-错戳龙一带.另外,分析藏南裂谷的成因机制需考虑各裂谷近南北向正断层作用的时空差异性和特征.A comprehensive understanding of the spatial and temporal differences in the activity of north-south trending normal faults is important to understand the formation of the southern Tibet Rifts.Here,we use the interpretation of high-resolution remote sensing images,structural geomorphology,ground survey,Unmanned Aerial Vehicles(UVA)systems for photogrammetric surveys,and published chronological data to investigate the Quaternary activities and spatial and temporal differences of the main north-south graben and its boundary normal faults at the southern end of the Nyalam-Coqen rift.It is found that the Quaternary activity of normal faults at the southern end of the Nyalam-Coqen rift show obvious spatial and temporal differences.In time,activity of normal faults at the southern end of the Nyalam-Coqen rift presents three periods of pre-Quaternary,Early and Middle Pleistocene,and Late Quaternary.In space,the rifting range of the near north-south grabens has shrunk significantly since the Late Miocene,and its rifting range gradually has shrunk from Nyalam area to Peiku Co and Mulin Co,and Drolung.In addition,the spatial and temporal differences and characteristics of the north-south normal faulting in each rift should be considered to analyze the formation mechanism of the southern Tibet rifts.

关 键 词：青藏高原 近南北向裂谷 活动断裂 近东西向伸展变形 佩枯错地堑 构造地质学 

分 类 号：P546[天文地球—构造地质学]