Stratigraphy and Petrology of Petroleum-Producing Waulsortian-Type Carbonate Mounds in Fort Payne Formation (Lower Mississippian) of North-Central Tennessee

Abstract

The petroleum-producing subsurface mounds of the Fort Payne Formation (Lower Mississippian) in north-central Tennessee represent a facies that is generally absent or poorly developed in surface sections to the west, near the Cincinnati arch, and to the east, in the Appalachian fold belt. The cross section and isopach maps of the Fort Payne mound unit and submound unit, and a structural map of the underlying Chattanooga Shale provide evidence for predicting undiscovered mounds by interpolating and extrapolating along several northeast-southwest mound trends. A petrologic study of cores and well cuttings indicates the character of facies, microfacies, sedimentary structures, porosity, and morphology of mounds, which provide a basis for interpreting sedimentary environments and the history of mound development. Interpretations are based on subsurface data, and they are reinforced by a comparison with the analogous Waulsortian mounds and lenses of the same age in Europe. Waulsortian-type mounds are widespread on the surface of western Europe and North America. However, differences in morphology, porosity development, and the emplacement of petroleum in Fort Payne mounds are related to local paleogeography in a shallow cratonic-shelf sea subjected to cyclic regression and transgression due to regional tectono-eustatic events. Fort Payne mounds produced more than 5.5 million bbl of oil through 1980. Although the source beds have not been identified, petroleum may have been derived from the submound or mound units of the Fort Payne Formation, or from the underlying Chattanooga Shale.