西藏雅鲁藏布江大拐弯地区量化地貌特征及其成因  

Quantitative Terrain Analysis of the Great Canyon Region of Yalungzangbo River,Tibet and Discussion of Its Origin

作　　者：张沛全[1] 高明星[2] 雷永良[3] 刘小汉[1] 

机构地区：[1]中国科学院青藏高原研究所,北京100085 [2]中国地质大学地球科学与资源学院,北京100083 [3]中国石油勘探开发研究院,中国石油天然气股份有限公司盆地构造与油气成藏重点实验室,北京100083

出　　处：《地球科学（中国地质大学学报）》2009年第4期595-603,共9页Earth Science-Journal of China University of Geosciences

基　　金：中科院知识创新工程重要方向项目(No.kzcx3-sw-143)

摘　　要：以数字高程分析、实地地貌调查及沉积物年代学为手段,开展了西藏雅鲁藏布江大拐弯地区地貌特征及其成因研究,采用SRTM-DEM数据对地貌进行了量化分析.区域地貌总体特征为高海拔、高起伏、平山顶(北区).在ArcGIS平台中运用条带法获得该区的最大高程-平均高程-最小高程剖面,剖面特征显示最大高程控制平均高程;利用最大和最小高程剖面定量计算各地质单元的水系下切深度.实地调查及年代学研究发现该地区河谷沉积物以晚更新世以来的冰碛物和冰湖相沉积物为主.结果表明,在雅鲁藏布江大拐弯地区地貌演化过程中,高山冰雪作用是地貌'削高'、'去顶'的重要外动力因素,也是有助于'修平'山顶并形成齐一峰顶面的参与因素;流水'切割'和'搬运'作用是形成地表高起伏的重要原因;外流水系大大削弱了地貌'填低'作用,也是导致河谷山谷沉积物年轻化的原因.In this paper, we take new SRTM-DEM data for digital elevation analysis, field surveying and chronology of sedi ments as means to study topographic features and its origin in the great canyon region of Yalung Zangbo River in Tibet. The new SRTM-DEM data are used for quantitative analysis for terrain. The overall geomorphic features are the high-altitude, high-relief and flat peaks （North）. ArcGIS software, an analysis platform, is used to obtain statistics for Maximum-Mean- Minimum elevation profiles from a strip area in its SRTM-DEM. These profiles show that the change of Mean elevation is controlled by the change of Maximum elevation. Incision depth of different geological units can be calculated by Max and Min elevation profiles. Sediments in valleys include moraines and icy lake sediments formatted after late Pleistocene which is confirmed by our field investigation and chronological data of sediments. To sum up, glacier, drainage network incision and outflow drainage system control the geomorphology in the great canyon region of Yalungzangbo River during the cause of terrain formation. The Glacier on the high mountain is an important external factor that controls ＇unroofing＇. Drainage network incision and erosion play an important role of relief terrain. Due to the fact that basin filling is limited by outflow drainage system, not only deposits in moraines but also icy lake sediments in valleys are younger.

关 键 词：数字高程剖面 水系下切 冰川作用 地貌 雅鲁藏布江大拐弯 

分 类 号：P931.2[天文地球—自然地理学] P343.1