Morphometric techniques for orientation analysis of karst in northern Florida

Morphometric techniques for the analysis of karst landscape orientation data based on swallet catchment areas can be highly inadequate. The long axes of catchment areas may not coincide with structural control, especially in regions having very low relief. Better structural correlation was observed using multiply linear trend measurements of closed depressions rather than drainage basins. Trend analysis was performed on four areas, approximately 25 km/sup 2/ each, forming a sequence from the Suwannee River to the Cody Escarpment in northern Florida. This area is a karst plain, mantled by 12 to 25 meters of unconsolidated sands and clays. Structural control was examined by tabulating the azimuths of distinct linear trends as determined from depression shape based on 1:24,000 topographic maps. The topography was characterized by 1872 individual swallet catchment areas or 1457 closed depressions. The common geomorphic technique of analyzing orientation data in 10/sup 0/ increments beginning with O/sup 0/ may yield incorrect peak width and placement. To correctly detect all significant orientation peaks all possible combinations of peak width and placement must be tested. Fifty-five different plots were reviewed and tested for each area.