The characteristics of the fluvial geomorphic parameters and its formed dynamic analysis for the Seerteng Mountain, northern margin of the Hetao basin
Topography is formed by the complex interactions between tectonics and erosional surface processes, which is primarily mediated by tectonic activity and bedrock erodibility. The rock uplift by tectonics can be negligible in the ancient orogens for its tiny tectonic activity, then it is possible to study the contribution of rock erodibility to the landscape evolution. However, most recent results show that topography is mainly controlled by tectonics in the active orogens, and the reports of lithological control on landscape evolution are not involved. As the controlling fault for the Hetao basin, the Seerteng mountain-front fault had been active since the Holocene, which caused the M 6.4 and M 5.9 earthquake in the 1979 and 1934. Previous studies show that the center section (such as the Wujiahe site) has stronger activity than its west and east sections. However, the researches on geomorphic parameters are limited compared to other faults in the northern margin of Hetao basin (such as the Langshan fault, Wulashan fault and Daqingshan fault), which will hinder to understand its deformation dynamics. Using the 30 m DEM, we extracted the Hypsometric integral of 33 subbasins in the Seerteng Mountain and normalized channel steepness, longitudinal profile and the knickpoint of the corresponding streams. The HI values are clustered between 0.40 and 0.66 with the highest value at the Wujiahe town, indicating that the evolution stage of the Seerteng Mountain is the "Middle" stage. The transient and steady rivers are all distributed along the fault, which reveal that the rivers in the Seerteng mountain-front are developed during the transient state and then evolved to the steady state. By comparing the knickpoint and lithology, we find that the knickpoints are under-controlled by tectonic uplift and/or lithology. The channel steepness (Ksn) has a character of spatial difference. The Ksn near the Wujiahe town is the highest, and it gradually decreases to the east and west part, then it increases to the west part at the River S8. By analyzing the rock lithology, precipitation and tectonic, the channel steepness (Ksn) is controlled by the lithology, and its spatial distribution is in accord with the fault activity (vertical slip rates and offsets). The landscape of the Seerteng Mountain is the results of the tectonic uplift and rock lithology.
万方数据
维普
