中国南方表层岩溶带的特征及形成机理

表层岩溶带以密集发育的岩溶微形态呈不规则带状组合于浅层地表为特征。它广布于中国南方岩溶区，但其规模、形态和分布特征三地质、气候等因素的控制。表层岩溶带的存在使南方岩溶区具有浅表层岩溶水循环与地下管道水循环耦合的二次岩溶水循环的结构特征。坚硬纯灰岩的广泛分布，高温多雨、雨热同期的亚热带季风气候为中国南方表层岩溶带的发育提供了极为有利的条件，四大圈层的交汇，碳-水-钙循环活跃，使表层岩溶带的岩溶动力作用明显高于其下部包气带甚至饱水带。表层岩溶带形成是地表强烈岩溶化过程的结果，强的溶蚀动力，水流的快速溶蚀并达到碳酸盐成分饱和状态是表层岩溶带发育机理的关键。

FFATURES OF EPIKARST ZONE IN SOUTH CHINA AND FORMATION MECHANISM

Epikarst zone lies in the shallow surface of carbonate rocks in a irregular shape. It is characterized by the karst complex of abundant knarrens, solutional fissures, solutional pores, solutional pans, lapse, stone teeth, stone forest and so on. It spreads widely. in south China. Its size, landforms and location are influenced by geological and climatic factors. With epikarst zone, the water cycle in karst area can be divided into two parts: shallow water flowing in the epikarst zone and conduit flowing in the deep karst zone. The hard pure limestone and subtropical monsoon climate in south China contribute to the development of epikarst. Because it happens in the cross - over point of atmosphers, lithosphere, biosphere and hydrosphere and the carbon-water -calcium cycle is active, the karst dynamic processes in epikarst zone are much stronger than those of the deep karst part. The strong and rapid karst dynamic processes is the key for the formation of epikarst zone.