Migration characteristics of the watershed between Nanpan River and Red River based on morphotectonics
The Red River once originated in the Tibetan Plateau in the Late Paleocene-Eocene,and its drainage area gradually shrank since the Oligocene.Since the Oligocene,a series of large-scale strike-slip faults have developed in the southeastern margin of the Qinghai-Tibet Plateau,which can affect the flow direction,slope and channel morphology of rivers.Under the influence of these strike-slip faults,does the basin area of the Red River Basin change regularly?This paper takes the watershed of Nanpan River and Red River as the research object to explore the migration characteristics of the watershed of Honghe River under the influence of strike-slip faults such as Honghe fault,Jianshui fault and Wenma fault.In this paper,a 90 m resolution DEM was used to extract 33 sub-basins of the Honghe River and Nanpan River,and four geomorphic parameters were obtained by calculating the area elevation integral(HI),valley floor width-height ratio(VF),river steepness index(Ksn)and chi(χ)value.Combined with field investigation,the difference of tectonic activity and the variation of watershed in the study area were revealed.The results show that the watershed changes in the study area are segmentally:the section from Longshu village to Dianfang village migrates to Nanpan River;as the Dianfangcun-Lameicun section migrated to the Red River,the results of HI value,VF value and Ksn value were different from those of chi(χ)value for Malushan-Longshu section.On the whole,the Red River is gradually losing its drainage area.Non-structural factors(rainfall and lithology)are not the main factors controlling the migration of the watershed in the study area.The migration of the watershed in the study area is mainly affected by the tectonic activity of Honghe fault,Jianshui fault,Qujiang fault,Wenma fault and the southern section of Xiaojiang fault.
Red RiverNanpan RiverWatershedTectonic geomorphic parametersRelative tectonic activity
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