CONSTRAINING THE TIMING OF CAVE DEVELOPMENT WITH GIS

Cave passages within the same cave level are understood to be speleogenetically linked to a common static base level or stratigraphic control. Cave levels are important aids in deciphering cave development, landscape evolution, and climatic changes. Cosmogenic dating has been successfully used to interpret levels in Mammoth Cave and the Cumberland Plateau; however, this technique is expensive and there are limited funding resources available. Geographic Information Systems (GIS) may be used as a preliminary procedure to identify cave levels and constrain the timing of level development. The GIS method has been applied to the Carter Cave system in northeastern Kentucky. The Carter Cave system is within the karst landscape found along the western edge of the Appalachians and contains multiple daylighted caves at various elevations along valley walls. These characteristics make the Carter Cave system an ideal location to apply GIS to cave level identification and evolution. Cave openings along stream valleys were found by extracting elevation values from a 10 x 10 meter digital elevation model (DEM). Using a histogram generated from the frequency of cave elevations and a natural breaks classifier, the number and elevation of cave levels were determined. An argument can be made for either four or five cave levels in the Carter Cave system; however, other studies have identified four levels in both Mammoth Cave and the Cumberland Plateau. Further analysis suggests the possible fifth level formed as a result of a change in lithology rather than an event that influenced the local base level. The GIS was also used to calculate the volume of material lost within each level. Level thickness lost and published denudation rates were used to calculate the relative time required to form each level. There was not one denudation rate applicable to all levels within the cave system, but the rates varied between 12 m/Ma and 40 m/Ma. Results indicate that the cave system took to between 3.4 and 5.7 Ma to form. This work improves the understanding of the Carter Cave system evolution and contributes a methodology that can be used to ascertain an erosion history of karst systems.