THREE-DIMENSIONAL GEOLOGIC FRAMEWORK MODELING IN THE BUFFALO NATIONAL RIVER, ARKANSAS

A detailed geologic framework of surface and subsurface geology is necessary to sufficiently characterize the hydrology of a karst system. Building the geologic framework commonly begins with large-scale geologic mapping. Geographic Information System databases can be designed to digitally capture these geologic map data in their true spatial context. In this format, these data can be analyzed and integrated with other geospatial data in a common environment. In this study, digital geologic map data, structure contours, and digital elevation models were integrated using a Geographic Information System and three-dimensional geologic modeling software. The three-dimensional geologic framework model was developed for a karst region encompassing 939 square kilometers adjacent to and within the Buffalo National River, Arkansas. The model captures the major stratigraphic and structural features including fourteen lithostratigraphic units, thirty-two faults, and several folds. Comparison of the computed model to geologic cross-sections indicates that the digital model adequately reflects our conceptual model of the subsurface. This geologic framework model is critical for visualizing three-dimensional geologic structures, is an important tool for understanding interbasin transfer of ground water, and aids in the evaluation of potential contaminant-transport pathways through the karst system.