金沙江上游德格-白玉段流域地貌特征及影响因素分析  

Analysis on geomorphological characteristics of catchments and its influencing factors in Dege-Baiyu section of the upper Jinsha River

作　　者：陈兴长[1,2] 郭晓军[3] 陈慧[1,2] CHEN Xingzhang;GUO Xiaojun;CHEN Hui(School of Environment and Resource,Southwest University of Science and Technology,Mianyang 621010,Sichuan;Tianfu Institute of Research and Innovation,Southwest University of Science and Technology,Chengdu 610299,Sichuan;Institute of Mountain Hazards and Environment,Chinese Academy of Sciences,Chengdu 610299,Sichuan)

机构地区：[1]西南科技大学环境与资源学院,四川绵阳621010 [2]西南科技大学四川天府新区创新研究院,四川成都610299 [3]中国科学院成都山地灾害与环境研究所,四川成都610299

出　　处：《第四纪研究》2023年第5期1269-1281,共13页Quaternary Sciences

基　　金：科技部第二次青藏高原综合科学考察研究项目(批准号:2019QZKK0902)资助。

摘　　要：地形地貌既是泥石流等山地灾害发生的环境背景条件,也是流域输沙行为的结果。地形地貌特征及其关键影响因素研究,对山地灾害发展趋势分析具有重要意义。本研究基于流域面积-高程积分、河道凹度指数和陡峭指数等地貌指标,分析了金沙江上游德格-白玉段的地貌特征及其主控因素。结果表明,金沙江主河两岸小流域的面积-高程积分在0.45~0.65之间,积分曲线大都呈右“凸”形,表明各流域均处于地貌演化的早期阶段,流域内可供侵蚀的潜在物质较多;河道凹度指数在0.18~2.07之间,仅有29%的河道凹度指数分布在0.30~0.60之间,视为稳态河道,71%的流域河道处于不稳定状态;标准化陡峭指数在124~627之间,与祁连山北翼、庐山和阿尔金山东段相比,明显更大;这些指标均表明研究区的地壳抬升明显且更加剧烈。地壳快速抬升是研究区地貌发育特征及其演化的主控因素。它导致大部分流域处于地貌演化早期,河道处于不稳定状态,从而导致流域内可供侵蚀的潜在物质较多,具备形成泥石流等山地灾害的物质和能量条件;在未来气候变化的大环境下,区内泥石流等山地灾害将更加频繁。Dege-Baiyu section(31.051°~32.168°N,98.163°~98.964°E)of the upper Jinsha River is located at the northwest edge of Sichuan-Yunnan block.It is characterized by high elevation,complex geological conditions,active neotectonics and frequent geological hazards.This work takes the Dege-Baiyu section as study area and the first order tributaries on both sides of the Jinsha River as main research objects.The geomorphic characteristics and the main controlling factors of geomorphic evolution were analyzed based on the two geomorphic indicators of hypsometric integral and channel steepness index/concavity index.The area-altitude analysis shows that the hypsometric integral value(HI)is in the range of 0.45~0.65,which indicates that these catchments are mainly in their prime and young adulthood.The hypsometric integral curves are right"convex"overall indicates that there are many potential materials for erosion in the catchments,which means these catchments have the material and energy conditions for mountain hazards occurrence.The calculation results of gully index show that the distribution of concave index is in the range of 0.18~2.07,with only 29%of gully indexes concentrated in the range of 0.30~0.60,which can be regarded as steady-stated,while the other 71%gullies are in an unbalanced state.The standardized steepness index is distributed between 124 and 627,which is significantly larger comparing with other places,e.g.the northern flank of the Qilian Mountain,the Lushan Mountain and the eastern section of the Altyn Mountain.The aforementioned indexes indicate that the crustal uplift in the study area is more significant and intense,which can be regarded as the main controlling factor for the current geomorphic characteristics and landform evolution.As a result,most of the basins are in the early geomorphic evolution stage,with gullies at an unbalanced stage,resulting in more available materials and beneficial energy conditions to form mountain hazards such as debris flows.The results are of significance for the haz

关 键 词：面积-高程积分 河道陡峭指数 地貌演化 河道演化 金沙江上游 

分 类 号：P931.1[天文地球—自然地理学] P954