Geomorphic features of the Qingshui River Basin and their significance for the northeastern margin of the Qinghai-Tibet Plateau
Since the Cenozoic era,the Tibetan Plateau has risen rapidly under the influence of intense collisions and convergence between the Indian Plate and the Eurasian Plate.Its tectonic deformation has continued to expand and extrude to the northeast to create a unique tectonic geomorphological pattern of the Qingshuihe River Basin and surrounding areas.Research on the tectonic geomorphology of the Qingshuihe River Basin can reveal the mechanism of deformation and geomorphological evolution of the northeastern margin of the Tibetan Plateau since the late Cenozoic.In this study,we used DEM(digital elevation model)data at a resolution of 30 m with ArcGIS 10.2 software to extract the geomorphic parameters of the Qingshuihe River Basin.We accurately calculated the four geomorphologic indices of the stream length-gradient index(SL),Hack profile,hypsometric integral(HI),and the asymmetry factor(AF)and elongation ratio(Re)of the drainage basin to obtain its quantitative geomorphic characteristics.Following this,we obtained the index of relative active tectonics(Iat)of each sub-basin by combining these four parameters,and analyzed the degree of relative tectonic activity in the study area.The following conclusions were obtained:(1)The distribution of SL values in the study area ranged from 70.1 to 353.9,indicating that there were regional differences in structural activity,and large deformations were observed throughout the basin.(2)Under the influence of the Haiyuan fault zone and Xiangshan-Tianjingshan fault zone,the average values of the HI and AF indices in the west bank of the basin were higher than those in its east bank,while the average value of Re was lower than that in the east bank.This suggests that tectonic activity in the west bank was more intense than in the east bank.(3)The index of relative active tectonics(Iat)of the study area was of the first and second orders,80％of which was distributed in the west bank.This indicates that tectonic activity was strong in the entire basin,and gradually increased from east to west.Furthermore,we used the relevant geological data to comprehensively assess tectonic activity in the basin,and used it to analyze the development of the river and tectonic movement.
northeastern margin of Qinghai-Tibet PlateauCenozoicDEMtectonic landformsrelative activity
万方数据
维普
