Acta Geographica Sinica ›› 2018, Vol. 73 ›› Issue (5): 973-985.doi: 10.11821/dlxb201805015

• Earth Surface Process • Previous Articles     Next Articles

A quantitative study on the karst geomorphic evolution of Shilin county in Yunnan province of China based on Strahler hypsometric analysis

LI Yuhui(),DING Zhiqiang,WU Xiaoyue   

  1. School of Tourism and Geographical Sciences, Yunnan Normal University, Kunming 650500, China
  • Received:2017-04-06 Online:2018-05-03 Published:2018-05-03
  • Supported by:
    National Natural Science Foundation of China, No.41371514

Abstract:

Based on the relationship between the heterogeneous karst geomorphic structure and the integral protection and utilization of the karst reserve, Strahler hypsometric (area-altitude) analysis is used to quantify the karst geomorphic evolution of Shilin county in Yunnan province of China. The Strahler hypsometric values of the whole area (catchment), elevation zones' terrains and their depressions are measured. Supported by Geographical Information System (GIS) technologies, these Strahler hypsometric measurements are designed based on the development mechanism of karst landform, which includes height-reduction horizontal erosions and depth-increase vertical erosions. The results indicate that landscapes with different development features on various topographic surfaces have different Strahler values. The differences and patterns could be used as an indicator to reflect the evolution of landscapes. Shilin county's geomorphic structure has four levels of terrains with different altitudes at the late period of mature stage. Such a structure is formed from the decomposition of the monadnock karst planation plateau with an interplay of the faults and the erosion base of Bajiang river. Shilin county has a rejuvenating geomorphic structure, which is heterogeneous from other geomorphic structures of the same stage. The terrain above 2100 metres of altitude is the structural erosion karst plateau middle mountain evolved from the monadnock karst planation plateau with less depressions. The terrain with an altitude of 1900-2100 metres shifts from the monadnock karst planation into the monadnock karst plateau depressions and cone karst depressions with less underground rivers. The elevation zone with an altitude of 1700-1900 metres is a karst hill slope. The zone is composed of the vertical layer structure of the Stone Forest and the horizontal terrace geomorphic structure. The vertical layer structure of the Stone Forest comprises stone forest remains, pinnacle-shaped stone forest, buried stone forest, and baked stone forest. The horizontal terrace geomorphic structure contains karst hills, stone forest, karst depressions, underground rivers, karst springs, and Bajiang river-basin. The landform is shaped from the mixed functions of vertical and horizontal karst processes, with water resources produced and water-soil eroded off. This is the theoretical foundation for the comprehensive protection and utilization of the Stone Forest reserve.

Key words: geomorphic evolution, Strahler hypsometric analysis, Geographical Information System, stone forest, water and soil resource, karst reserve