Identifying and Reconstructing the Pre-Pennsylvanian Surface in the Mammoth Cave National Park Region in South-Central Kentucky
There is considerable importance in reconstructing the pre-Pennsylvanian surface (Absaroka-Kaskaskia sequence boundary) in south central Kentucky because the sequence boundary is associated with economic resources such as oil and gas, groundwater quality issues, and to offer further education to the public in the national park region by providing geologic cross sections and stratigraphic columns. The study area is located from west of the Mammoth Cave National Park (MCNP) to the Upper Green River Biological Preserve, a Western Kentucky University-owned property located approximately two miles upriver from the MCNP.
Reconstruction of the unconformable surface has been greatly aided by the availability of surface and subsurface geological data available online from the Kentucky Geological Society (KGS). While various geophysical well logs are available, E-logs and gamma-ray logs were of particular importance in the study. A pertinent collection of those geophysical well logs offers insight into the subsurface geology, and combined with the surface data, were used to expand upon previous work in identifying the unconformity and in creating new geologic cross sections in the study area. The presence of the NE-SW trending Brownsville Paleovalley (trunk fluvial system) that incised into the underlying Chester strata, as well as its significant SE-NW trending tributary paleovalleys (both incising more than 110 meters), can potentially be used in locating prospective oil and gas traps, as well, as groundwater and contaminant flow paths.
AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009