QUANTIFIABLE CHARACTERISTICS FOR A STATISTICAL APPROACH TOWARD KARST CLASSIFICATION

Most prior classifications of karst have been largely descriptive, lacking a foundation in quantifiable parameters. A classification of karst should avoid being based solely upon morphologic descriptions of the numerous geomorphic features recognized within karst terrains, and instead be linked to the climatic, geologic and hydrologic characteristics that combine to fully describe karst areas. Identifying such characteristics allows for a statistical comparison of different karst regions, and ultimately a quantitative classification of karst terrains.

We present a list of characteristics common among karst regions, representing quantifiable or semi-quantifiable parameters that can be objectively determined independent of one another. The goal is to identify groupings among karst regions through multivariate statistical methods, such as Principal Components Analysis and Hierarchical Cluster Analysis which can then be applied to an overall classification.

Climatic and physiographic characteristics include mean annual precipitation and temperature, topographic relief, and thickness of insoluble unconsolidated overburden. Hydrologic characteristics include the magnitude and frequency distribution of spring discharge, the percentage of allogenic recharge, and the baseflow depletion coefficient as a measure of storage within an aquifer. Soluble rock properties include matrix porosity, purity, and thickness of the rock package. Geologic structural attributes include inclination of strata, fracture frequency, and degree of deformation. Attributes that describe the morphology of karst features include the spatial density of dolines, length of caves, depth of caves, and cave passage density. Other factors that may exert an influence on modern karstification include the presence of paleokarst, hydrothermal flow, or strong geochemical drivers such as mixing corrosion or the influence of sulfuric acid on speleogenesis. Although we currently consider only carbonate terrains, the approach may be used as an exploratory tool as well as a means of comparison among factors responsible for karstification in a wide range of lithologies.