摘要
晚新生代以来,伴随祁连山强烈隆起而塑造的水系流域地貌,其典型特征指示了该区域的最新构造活动。以发源于祁连山中部的洪水坝河为研究对象,利用GIS空间分析工具,提取了整体流域与5个亚流域的河网分支比、地势起伏、平均高程等地貌参数,并对整个流域地形做坡谱分析,获得了洪水坝河水系流域地貌特征。研究表明,洪水坝河流域整体地形起伏大、坡度陡、水系发育程度低,并且流域内部从南向北,河网分支比和地势起伏显著增大。在分析地层岩性和冰川作用等相关因素的基础上,认为这种变化表明流域所受构造活动的影响从南向北显著增强:南部受构造活动的影响微弱,地势平坦,可能是残存的古侵蚀面,亦或是受山间盆地的沉积作用影响;中部区域由于被昌马断裂东段切穿,断裂带附近区域较弱的抗侵蚀能力与河流的快速下切共同造成了地势起伏的增加;北部区域受佛洞庙-红崖子断裂西段逆冲活动的影响,坡度及地势起伏大幅增加,表现为地势起伏骤增和强烈的河流下切等地貌特征。上述地貌分析研究,为认识和理解祁连山造山带地貌演化以及控制因素提供了基础数据和思路。
Owing to the intensive uplift of Qilianshan Mountain since Late Cenozoic,the drainage basins that originated the mountain have experienced strong tectonic deformation.So the typical drainage basin characteristics may indicate the tectonic movement of this region.In order to reveal the characteristics of tectonic geomorphology,we carried out our present research on the Hongshuiba River drainage basin,which originates from the interior of the Qilianshan Mountain in the northeastern Tibetan Plateau.Stream networks of Hongshuiba River drainage basin （38°55＇~39°30＇N,98°10＇~98°45＇E） were extracted from the DEM data and graded into five levels with Strahler method.Five sub-catchments,Heishui drainage basin,Yanglu drainage basin,Zhangrui drainage basin,Sanchahe drainage basin and upstream region were further chosen for detailed analysis.The bifurcation ratio,basin relief,mean elevation,basin area,stream length,drainage density,and average slope of Hongshuiba drainage basin and the sub-catchments were determined with GIS tools.In addition,we analyzed the slope spectrum of the Hongshuiba drainage basin.Both drainage density and basin area are low,which indicate the drainage network here is still on a primary stage.High bifurcation shows that the drainage basin has experienced intensive tectonic disturbance.From south to north,the bifurcation ratio varies largely.We eliminate the impact of lithology,and regard the difference of bifurcation ratio as an indication of spatial diversity of tectonic movement.In the south part with a high average altitude of 4000m,the bifurcation ratio is 4.08,which reflects less tectonic disturbance.The gentle slope occupies so large area proportion that the slope spectrum shows a bimodal pattern and a peak value is in low slope region.The area with low relief may be regarded as a residual planation surface or the result of fluvial deposition.The middle part may be affected by glacier owing to its high altitude,so the network here were developed not perfectly and the bifurcation
出处
《第四纪研究》
CAS
CSCD
北大核心
2013年第4期737-745,共9页
Quaternary Sciences
基金
中国地震局地质研究所中央公益性科研院所基本科研业务专项项目(批准号:IGCEA1115)
国家自然科学基金项目(批准号:41272215
41272196和41030317)共同资助
关键词
祁连山
地貌
DEM
GIS
祁连山中部洪水坝河
Qilianshan Mountain geomorphology DEM GIS Hongshuiba River in the interior of the Qilianshan Mountain
