Photogeologic fracture traces and lineaments in the Wartburg Basin section of the Cumberland Plateau Physiographic Subprovince, Tennessee

Photogeologic fracture trace and lineament mapping of the eastern portion of the Wartburg Basin, Tennessee provides important new data on the structural framework of the Cumberland Plateau and makes possible some correlation between remotely sensed linear fractures and bedrock structure.

Fracture traces and lineaments are generally believed to represent the surface expression of joints, faults, or zones of structural weakness in areas of exposed bedrock. The current investigation attempts to relate photogeologic linear features to bedrock structures in an area where the bedrock is obscured by a deeply-weathered regolith and dense vegetation.

Interpretation of conventional black-and-white panchromatic aerial photographs and other imagery revealed numerous fracture traces and lineaments whose strike frequencies were determined from histograms. Histograms of bedrock fracture orientations were compiled and compared to the photointerpretative data on a regional basis. Gross similarities of strike maxima existed between corresponding photogeologic linear and bedrock fracture histograms. Results were found to be highly dependent upon imagery type and presence or absence of outcrop.

Strike orientations of bedrock fractures and photogeologic linears were directly compared at several sites of known fracture trace or lineament intersection. Comparison revealed a significant parallelism between the strike directions of photogeologic linears and joints that deviated no more than 4 degrees at any of the sites.

Data collected during the investigation indicate that photogeologic fracture traces and lineaments are useful for locating major bedrock structures and areas of increased fracture density. The mapping, although of reconnaissance nature, should provide a basis for future detailed fracture analysis in the Wartburg Basin.