Geomorphic feature and tectonic implications of the Hanjiang River basin in the northern Dabashan
The northern Dabashan region is located at the leading edge of the eastward expansion of the Tibetan Plateau.Studying the tectonic geomorphological characteristics and spatial differentiation in the degree of tectonic activity recorded in the fluvial systems and drainage basins of the northern Dabashan region,can help to deepen our understanding of the remote uplift effect of the Tibetan Plateau in the region and effectively limit the degree and scope of its growth towards the east.Based on the ASTER GDEM data,the drainage basins in the study area were extracted and analyzed for characteristics of the watersheds basin through the hypsometric integral(HI),standardized stream length-gradient index(SL/K)and Hack profile,drainage basin asymmetry factor(AF),valley floor width-to-height ratio(VF),and the elongation ratio(Re).The results indicate that 46 of 48 sub-catchments in the study area have HI values less than 0.5 and the hypsometric curves are S-shaped and concave,indicating that the northern Dabashan area is in the early-old stage of geomorphological evolution.Based on the analysis of the five geomorphic indices,the main faults in the study area are tectonically active,with the Ningshan fault and Chengkou-Fangxian fault having stronger tectonic activity,while the Ankang fault has weaker activity.The eastward expansion of the Tibetan Plateau has already affected the northern Dabashan region,and the tectonic deformation and modern landscape pattern of the Hanjiang River basin in the northern Dabashan are controlled by the tectonic forces of the eastward expansion of the Tibetan Plateau.
Northern DabashanHanjiang River basinGeomorphological featureGeomorphic indices