Paper No. 6
Presentation Time: 3:10 PM
EMPLOYING GIS TO INVESTIGATE KARST REGIONS: A QUANTITATIVE ASSESSMENT
Cave levels, passages found at similar elevations and formed during the same stable base level event, reveal information about paleoclimates and karst geomorphology. Cosmogenic dating has been used to interpret levels in Mammoth Cave and the Cumberland Plateau. This absolute dating technique has proven successful in determining cave paleoclimates and regional geomorphic history, but is expensive and requires datable material. The use of a Geographic Information System (GIS) may provide a cheaper means of conducting a preliminary assessment of a region’s speleogenesis. Employing a GIS, denudation rates and Stream Power Index (SPI) were used to investigate the cave levels of the Carter Cave system in northeastern Kentucky. This fluviokarst system is within a 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 Caves an ideal location to apply GIS to cave level identification and evolution. The GIS was used to calculate the volume of surficial material lost within each level as a result of degradational geomorphic processes. 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 each level within the cave system, but the rates varied between 12 m/Ma and 40 m/Ma. These rates indicate that the cave system took between 3.4 and 5.7 Ma to form. SPI determines the erosive power of overland flow based on the assumption that flow accumulation and slope are proportional to potential for sediment entrainment. Limestone units in the area have a higher erosion potential than the clastic units. However, the higher SPI values did not correlate to locations of cave formation. Perhaps what is really occurring is that caves are located where there are low SPI thresholds indicating that if a gully is present (i.e. a high SPI value), water flows into the gully instead of entering the cave system. Caves could be located in areas that deflect water to the sub-surface instead of allowing the water to flow across the ground and enter surface streams. Our results indicate that remote sensing and GIS techniques can provide predictive insight into speleogenetic processes.