金沙江虎跳峡段末次冰盛期以来滑坡堵江-溃坝洪水事件研究  

Landslide dams and dam-break flood events in the Hutiaoxia section of Jinshajiang River since the last glaciations maximum

作　　者：童康益 王萍[2] TONG Kangyi;WANG Ping(Shanghai Geological&Mineral Engineering Investigation Co.,Ltd,Shanghai 200072,China;State Key Laboratory of Earthquake Dynamics,Institute of Geology,China Earthquake Administration,Beijing 100029,China)

机构地区：[1]上海地矿工程勘察有限公司,上海200072 [2]中国地震局地质研究所地震动力学国家重点实验室,北京100029

出　　处：《上海国土资源》2020年第4期72-78,共7页Shanghai Land & Resources

基　　金：国家自然科学基金项目(41772199);中央级公益性科研院所基本科研业务专项(JB-17-13)。

摘　　要：“长江第一湾”位于金沙江虎跳峡河段,其河谷地貌富有特色。“古堰塞湖、堰塞坝和溃坝洪水”三位一体沉积体系的提出,指导了对金沙江虎跳峡河段沉积特征的野外地质调查与年代学样品的测试分析。本文的调查研究表明:龙蟠乡多期混杂堆积体的发育,造成金沙江2次堰塞堵江,形成2期古堰塞湖;古堰塞湖沉积特征,构成拔河高度为~15m和~25m的两级湖相阶地;虎跳峡下游大具盆地发育大范围多期的洪水堆积。通过多个典型沉积剖面的OSL测年显示:2期古堰塞湖的沉积年龄分别为11.50~14.01ka、1.53ka,龙蟠乡堰塞坝体在18.49~21.25ka期间已经存在,大具盆地洪水沉积样品年龄为5.65~6.46ka。所有年代学样品揭示,金沙江虎跳峡段堵江—溃坝事件均为末次冰盛期以来发生。The first bay of the Yangtze River is located in the Hutiaoxia reach of the Jinshajiang River.The introduction of the trinity system of ancient landslide dams,damming,and dam-break floods has guided the field geological investigation of the river valley topography and deposits in the Qizong Village–Daju Basin reach and the analysis of sediment dating samples.The ancient landslide dam deposits were widely distributed in the section from Shigu Town to Longpan Village,forming terraces of^15 m and^25 m,respectively.The Daju Basin in the lower reaches of the Hutiaoxia River is characterized by multiple platforms and large-scale flood deposits.The optically stimulated luminescence dating results of the typical sedimentary profiles show that the sedimentary ages of the second stage of the ancient landslide dam were 11.50–14.01 Ka and 1.53 Ka,respectively.The Longpan Village damming dam already existed between 18.49–21.25 Ka.The T2 terrace flood sediment samples in the Daju Basin were 5.65–6.46 Ka old,all from the last glacial maximum of the ancient barrier lake dam failure event.

关 键 词：第四纪地质 沉积地层 洪水堆积 湖相阶地 古堰塞湖 末次冰盛期 光释光测年 金沙江虎跳峡 

分 类 号：P534.63[天文地球—第四纪地质学]