Development features and original altitude of a karst planation surface: Preliminary review

Abstract

Traditional theories of geographical cycle and pediplain cannot describe correctly the development of planation surfaces in karst regions. Authors, therefore, put forward conception of karst planation and karst planation surface, suggesting that karst planation is another type of planation process characterized by chemical erosion and transformation. To identify the distinction between evolution features of normal landforms and those of karst landforms developed in the South China, authors suggest karst planation surfaces under similar environmental conditions may reach a lower altitude and gradient ratio, in contrast with normal landform areas. This may be applied to researching on Tibetan Plateau uplift.Planation surface is employed widely as a kind of abstract stratum [1] for geomorphologic analysis and paleoenvironmental reconstruction. Since the interest in uplift of the Tibetan Plateau increases internationally, the research on nature, range, age and rate of plateau uplift depended on the understanding of planation surfaces has become a hotspot [2][3][4] . Karst planation surfaces composed of covered karst and red weathering crust are widespread on plateau, and are one of the main research objects for plateau evolution [5][6][7][8] . Planation surfaces formed by different planation processes have different implications for research on plateau uplift [9] , therefore study on environment, development condition, nature and types of planation is necessary.Since theory of geographical cycle [10] was first proposed by Euro-American researchers and refined theories of planation surface from various conditions under which planation surface developed [11][12][13][14][15][16][17] . In brief, Davis' geographical cycle [10] and King's pediplain [12] depended on two planation processes: peneplanation and pediplanation respectively, and corresponding planation surface types are peneplain 1) and pediplain. Recently, however, the authors have discovered that these planation surface models do not fit the Tibetan Plateau and its eastern adjacent districts. Field investigation and previous research can be used to discuss the features of planation in karst areas, put forward new conception of planation suitable for karst region, and the main characteristics of planation surface, as a theoretical base for research on uplift of Tibetan Plateau.

The development and evolution of landform based on neotectonic movement: The Sancha river catchment in the southwestern China

“…The original planation surface has deformed by the influence of the uplift and lateral growth of the Tibetan Plateau, showing high in northwest, but low in southeast (figure 5). According to generation environment of the red weathering crust of Shanpen period planation surface (Lin 1985;Li et al 2001), the crustal uplift amplitude may reach 1000-2000 m from northwest to southeast in the study area under the background of neotectonics. The 10 subsidence regions (A, B, C, D, E, F, G, H, I, J) in the study area were formed under the background of syncline.…”