| South China Karst became the sixth World Natural Heritage of China in June 2007, including three World Heritage sites: Libo in Guizhou, Wulong in Chongqing, Shilin in Yunnan. The paper researches in Libo World Heritage site and considers cone karst as the research object, through researching on the temporal and spatial evolution models to enhance the research on the history of landform evolution in Libo. Through the investigation on the spot, the paper uses the methods of geographical comprehensive and regional research, and makes morphometric analysis on cone karst using the software such as GIS and SPSS. The paper demonstrates the evolution of cone karst system using the theory of dissipative structures for the first time and establishes the temporal and spatial evolution models of cone karst through the qualitative and quantitative analysis on landform evolution. The main research contents include: impact of physical geographical factors on the evolution of cone karst; morphometric analysis on cone karst; dividing karst evolution periods since the Neogene. The conclusions are as follows:①In the Libo World Heritage site, the typical cone karst, with symmetrical slopes and average gradient about 45°, is formed by the integrated effect of physical geographical factors;②At the initial stage of karst development, the tectonics obviously influenced the landform development, the conical hill became round gradually and enhanced the symmetry with the strengthen of karst corrosion;③The distribution serial of surface karst landforms is the response to underground hydrological system, and appears as positive evolution or rejuvenescent evolution;④Dividing the evolution of cone karst in Libo as three periods since the Neogene: the Shanpen period, the Wujiang dale period, the Wujiang gorge period;⑤The cone karst of Libo is an open system, the system continually perfects the structure and function of system through the inputs and outputs of materials and energy, and transforms from disorder to order to achieve dissipation structure gradually;⑥The temporal and spatial evolution of cone karst, in the ideal conditions, is as follow sequence: Upland-doline→Fengcong- doline→Fengcong-depression→Fenglin-depression→Fenglin-basin→Fenglin-plain. Fengcong changes to Fenglin when the depression arrives at the undercurrent base;⑦Therefore, the excellent cone karst landscape of Libo is formed by the effect of physical geographical factors in long history. It has not only exceptional natural beauty and aesthetic value, but also reflects the outstanding examples representing major stages of the earth evolutionary history, and satisfies the standard of World Heritage criteria (viii). |
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