Tectonic Geomorphology Analysis Based On DEM In Tao River Basin

Tao River basin is located in the northeast Qinghai-Tibet Plateau, which is a tributary of the Yellow River. Turning in Min County, Tao River changed the direction from the west-to-east to north-to-west, liking a "L" shape lying. The evolution of rivers is usually a detailed record of the orogenic plateau subtle changes in the most recent period. So we study the reflection of the neotectonic movement acting on the geomorphology and the neotectonic movement through the distribution of terrain and landscape features. In this paper, we analyses quantitatively the features of tectonic geomorphology and study the the relationship between topography and tectonic movement in Tao River basin. It is important to the study of the formation mechanism of tectonic geomorphology.In order to study the geomorphologic asymmetric characteristics of Tao River drainage basin, a DEM based topographic analysis of mountain belts have been done to extract much drainage and sub-basin information and the drainage geomorphic parameters of Tao River, such as water system's length, amount, density and drainage area, by employing ArcGIS9.2 and 90 m resolution DEM data of studied area, combining with the traditional methods of geological analysis. Almost all the parameters of the upstream northern and downstream southern basins are respectively smaller than those of the upstream southern and downstream eastern ones. The total length, area and density of the downstream eastern is less than the western bank, so the eastern bank is not fully developed or newly generated state; so is the upstream northern. We infer that the northern marginal faults is stronger than the southern marginal faults.Then, the statistical analysis of characteristic parameters such as water system's minimum elevation, maximum elevation, average elevation, average incision depth and relief shows that the southern basins have higher altitude, deeper incision and greater relief than the northern one, which shows that the characteristics of the tectonic movement in this area since the Quaternary is South warped and North prone. As the same time, the western basins have higher altitude, deeper incision and greater relief than the eastern one, and this may be related to the rapid uplift of the eastern mountains, which indicates that the east coast mountains uplift and tectonic belt control the development and evolution.in the east coast of Tao River basin.Finally, we reveal the evolution of Tao River by analysing of river drainage basin topography and development pattern and combining the characteristics with regional fault zones and stratigraphic distribution. Tao River's rapidly changing flows in Min County is the geomorphology response of the Tibetan Plateau and the north-south tectonic belt uplifting. The uplift of Lintan- Dangchang thrust fault is the main reason of forming the geomorphology differences between the downstream and upstream river system. The rapid uplift of the mountain range in the east of Min County interrupted the paleo Tao River, later on, the river from the northeast cutting through the West Qinling Fault zone by headwater erosion, finally captured the paleo Tao River near Min County and formed the new Tao River.