基于Strahler面积—高程分析的云南石林县域喀斯特地貌演化的量化研究

基于异质性喀斯特地貌结构与喀斯特保护地整体保护利用的关系,将水平蚀低垂直加深的喀斯特地貌发育机制落实于地理信息系统支持的Strahler面积—高程分析,形成整体、海拔段和内部洼地的面积—高程曲线与积分值指标组,以量化石林县域喀斯特地貌演化。结果表明不同地貌发育特征的不同地形面具有不同的Strahler值,其差异和规律性有一定的指示价值。石林县四级海拔梯级地貌处于壮年晚期,为断裂切割与巴江侵蚀基准面差异性控制下的孤丘夷平面分解,属同期异构的回春型地貌区。> 2100 m海拔段为孤丘夷平构造侵蚀溶原中山,洼地不发育。1900~2100 m海拔段为孤丘夷平面转向孤丘溶原洼地、峰丛洼地,暗河不发育。1700~1900 m海拔段为溶丘洼地斜坡,由蚀余状石林—剑状石林—覆盖石林—烘烤石林组成的石林垂直层状结构与溶丘—洼地—暗河—泉群—河谷盆地组成的水平梯级地貌结构,它是水平与垂直地貌过程的融合产物。石林发育区既为水源形成区,也为水土流失区。这是石林保护地整体保护利用的地貌动力依据。

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

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.