Geomorphologic features of river basins in the Zhongtiao Mountains and their tectonic significance

Abstract

Abstract: The Zhongtiao Mountain region is located in the collision zone of the two ancient plates of North China and South China, and belongs to the southern edge of the North China Plateau, which is of important tectonic and geomorphologic significance. The systematic analysis of geomorphic indices helps to understand the characteristics of neotectonic activities in the orogenic belt of this region. Based on the ASTER GDEM topographic data, the geomorphic parameters of the Zhongtiao Mountain area are extracted and calculated by each basin, the geomorphic morphologic features of each basin in the section are quantitatively obtained, and finally the relative degree of tectonic activity in the study area is analyzed. Combined with stratigraphic and tectonic data, the tectonic geomorphic features of the Zhongtiao Mountain region were discussed. The results show that, among the 33 rivers analyzed, the asymmetry degree of basin basin (AF) indicates that the Zhongtiao Mountains in the study area are tilted from the middle to the sides, and the morphology of basin basin changes from asymmetry to symmetry, while the high and low values of basin shape index (Bs) show an irregular mosaic. The distribution basin elongation (Re) shows that the basin on the north side of the Zhongtiao Mountains is significantly narrower than that on the south side of the Zhongtiao Mountains, but it is more inclined to be due to early tectonic activities or slow adjustment and deformation after the crustal cessation of movement. The standardized slope-loss index (SL) results show that the high values are mainly distributed on or near the Shuangquan-Linyi concealed rupture and the Huashan pre-mountain rupture, which also indicates that the geomorphic evolution of these rupture segments is more active than that of other segments. The area elevation integral (HI) values range from 0.1 to 0.55, and the sub-basins with HI<0.3 account for 55% of the total basin area, indicating that their geomorphic evolution is in the old age stage. On the whole, the average value of HI in the Zhongtiao Mountains is 0.31, and the area elevation curve is an S-shape close to a concave shape, which indicates that the geomorphic evolution of the Zhongtiao Mountains region is in the "prime of life" to the "old age" stage. This indicates that the geomorphologic evolution of the Zhongtiao Mountains region is in the transition from the "prime" to the "old age" stage; the spatial variability of neotectonic activity (rupture activity) in the Zhongtiao Mountains region exists, with the northern part of the region having stronger activity and the southern part having relatively weaker activity.