金沙江巧家莲塘-龙井湾槽谷成因分析  

Genesis discussion of Qiaojia Liantang-Longjingwan valley in Jinsha River

作　　者：程万强 王运生[2] 宋良 李正友 周宇航 台梓含 CHENG Wanqiang;WANG Yunsheng;SONG Liang;LI Zhengyou;ZHOU Yuhang;TAI Zihan(Powerchina Huadong Engineering Corporation,Hangzhou 311122,China;State Key Laboratory of Geo-Hazard and Geo-Environment Protection,Chengdu University of Technology,Chengdu 610059,China;College of Earth Sciences,Chengdu University of Technology,Chengdu 610059,China)

机构地区：[1]中国电建集团华东勘测设计研究院有限公司,浙江杭州311122 [2]成都理工大学地质灾害防治与地质灾害保护国家重点实验室,四川成都610059 [3]成都理工大学地球科学学院,四川成都610059

出　　处：《人民长江》2023年第5期149-155,共7页Yangtze River

基　　金：国家重点研发计划项目(2017YFC1501000);国家创新研究群体科学基金项目(41521002);国家自然科学基金项目(41877235)。

摘　　要：白鹤滩水电站作为世界装机容量第二大的水电站,在该水电站库区内位于云南省昭通市巧家县城台地后缘发育有一近南北走向的宽缓槽谷,其成因至今未有定论,研究该槽谷的成因对金沙江水系的变迁及巧家莲塘移民安置点场地的稳定性评价具有重要的理论及现实意义。基于详实的野外调查、超深钻孔编录、广域电磁法探测、土壤氡气测量以及测年等方法,研究了莲塘-龙井湾槽谷的地貌学特征、边界特征、充填序列、断陷幅度及其发育时限。结果表明:①莲塘-龙井湾槽谷形态上呈NNW且向东微凸,南北长约8 km,东西均宽约0.8 km,为小江断裂与则木河断裂交汇贯通后断陷形成;②莲塘-龙井湾槽谷基底为巧家拉分断陷盆地堰塞(构造)湖形成,其上覆泥石流冲洪积层和坡洪积层;③槽谷的断陷始于29万a前,终止于2万a前,断层幅度达37.5 m。As the second-largest installed capacity hydropower station in the world,a wide and gentle trough valley develops in the Baihetan Hydropower Station reservoir area,however its cause has not been clear.The study on the cause of the valley has essential theoretical and practical significance for research on the evolution of Jinsha River system and the stability evaluation of a resettlement site.The geomorphic characteristics,boundary characteristics,filling sequence,fault subsidence amplitude and development of the Liantang-Longjingwan through valley were studied based on detailed field investigation,ultra-deep borehole logging,wide-area electromagnetic detection,soil radon measurement,and dating technique.The results showed that:①The shape of Liantang-Longjingwan through valley was NNW and slightly convex to the east.It was about 8 km long from north to south and 0.8 km wide from east to west,which was formed by fault depression after intersection between Xiaojiang fault and Zemuhe fault;②The base of Liantang-Longjingwan valley was formed by Qiaojia fault depression basin,which was covered by debris flows alluvium and diluvium;③The fault depression of this valley developed 0.29 million years ago and ended 0.2 million years ago,with a fault depth of 37.5 m.

关 键 词：莲塘-龙井湾槽谷 小江断裂 则木河断裂 地质钻探 铀系测年 成因分析 金沙江 

分 类 号：P534.63[天文地球—第四纪地质学] P542[天文地球—古生物学与地层学]