Geomorphic Features of the Hongshuiba River Drainage Basin in Qilianshan Mountain and Its Insight into Tectonic Implications

详细信息   

• 责任者：Wang Yizhou (State Key Laboratory of Earthquake Dynamics ; Institute of Geology ; China Earthquake Administration ; Beijing 100029 ; China) ; Zhang Huiping
• 刊名：Quaternary Sciences
• 出版年：2013
• 卷期：33(4)
• 关键词：流水地貌 ; fluvial features ; 祁连山 ; Qilian Mountains
• 页码：p.737-745
• 图表：5 illus., 3 tables, 47 refs.
• 分类号：1400
• issnNo：ISSN1001-7410
• isbnNo：CN11-2708/P

摘要

     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 ratio may not reflect the tectonic movement.However,the increasing basin relief and the activity of Changma Fault can reflect the increasing impact of tectonic disturbance.In the north part with a high average altitude of 3800m,the basin relief is over 2000m and the bifurcation ratio is above 4.50,both of which indicate that this area has experienced intensive tectonic movement.As a result of the thrust uplift of the east part of Fodongmiao-Hongyazi fault,Hongshuiba River incises terrace deeply near the piedmont outlet.Although the basin relief varies in accord with the tectonic movement,average altitude and slope do not show the same tendency.The increasing average altitude may be resulted from the tectonic background and the slope indicating the local topography steepness may be affected by climate or lithology,both of which require more research.