River Deformation in the East Foot of the Dabie Mountains and Activity Analysis of Tan-Lu Fault Zone

The response of river to tectonic movement is very sensitive. The study of river topography can reveal the tectonic movement well. Based on Digital Elevation Model (DEM), the ARCGIS software was used to extract the river and its profile across the Tan-Lu fault belt in the eastern foot of the Dabie Mountains and to classify the rivers. Combining remote sensing interpretation and field survey, we study the plane and longitudinal profiles of trans-fault rivers at different levels. It is found that there is no regular deformation direction at all levels of the eastern foot of the Dabie Mountains. Most of the vertical sections of the river do not exist fault horizons across the fault, and there is no deformation across the fault in the T1 class terraces. The above characteristics reflect that the fault may not be active or weak since the Late Pleistocene. A number of fault outcrops were investigated. The ESR ages of the fault mud in the Tongcheng Guache River bedrock fault and the Yinjia Shangwu bedrock fault in Taihu were (507±142) ka BP and (826±99) ka BP, respectively. Synthetically analysis of the deformation characteristics of the rivers in the foot of the Dabie Mountains and the ESR ages of the fault mud and the data from previous studies shows that the Tan-Lu fault zone at the eastern foot of the Dabie Mountains was active during the Middle Pleistocene and may be inactive or weak since the late Pleistocene.