Morphometric characterization of a karstic surface in the tropical rainforest of São Paulo

Abstract

A method to obtain morphometric parameters of karst surfaces is proposed based on GIS techniques. An example of application is presented resulting in a quantitative signature of the total carbonatic surface area as well as in an individual characterization analysis of closed depressions. The following parameters were calculated: roughness, slope, topographic amplitudes, drainage density and circularity of closed depressions. Spatial and correlation analysis of the main parameters were done. The results show that more circular depressions are characterized by smaller areas and little drainage development. Larger depressions present lower circularity and possess well developed drainage networks and a higher topographic range. Based on the spatial distribution of the parameters and on the circularity values, the planimetric form of the depressions is interpreted as a result ofanisotropy of the resistance of bedrock to drainage development.