Towards defining, delimiting and classifying epikarst: Its origin, processes and variants of geomorphic evolution

Epikarst is the uppermost weathered zone of carbonate rocks with substantially enhanced and more homogeneously distributed porosity and permeability, as compared to the bulk rock mass below; a regulative subsystem that functions to store, split into several components and temporally distribute authogenic infiltration recharge to the vadose zone. Permeability organization in the epikarst dynamically develops to facilitate convergence of infiltrating water towards deeply penetrating collector structures such as prominent fissures that drain the epikarstic zone. This is manifested by epikarstic morphogenesis that tends to transform dispersed appearance of surface karst landforms into focused appearance adapted to the permeability structure at the base of epikarst. Epikarst is the result of combined action of several agencies including stress release, weathering and dissolution. It is a dynamic system which main characteristics are time-variant, changing in a regular way during the epikarst evolution. This paper examines the main characteristics of epikarst in the light of its origin and evolution.