CHARACTERIZATION AND SIGNIFICANCE OF A 'FLOWER' STRUCTURE IN WARREN COUNTY, KENTUCKY

Warren County, Kentucky, is located near the eastern terminus of the Pennyrile Fault System, a regional southwest-northeast trending fault system that is connected to the Reelfoot Rift. The structure under investigation is located in the southwestern part of the County near the town of Woodburn. The local area is underlain by the Mississippian St. Louis and Ste. Genevieve limestones which form a mature karst plain with many sinkholes and caves. Examination of 2-D seismic profiles through the area reveals that a number of structural 'pop-ups' exist at different stratigraphic levels. Some of these are traceable downward through the Knox Group and possibly extend to the Precambrian basement along one or two main faults.

Similar structures can be found in many areas of the world where wrench faults occur on a regional scale. Wrench fault systems can produce a variety of compressional and extensional features including the so-called 'flower' structures. These form between two subparallel master faults when opposing forces produce a series of faults that spread upward and outward in a circular pattern resembling the petals of a flower. Compressional force couples produce positive flower structures while extensional forces produce negative flower structures.

The Warren County structure has a surface expression that is discernible through computer-aided viewing of topographic maps. The site also exhibits radial stream drainage and an anomalous concentration of sinkholes aligned parallel to the curvature of the structure on its western, southern, and eastern flanks. A modeling program using GIS/ARCMAP permits detailed analysis of both the subsurface and geomorphic aspects of this 'flower' to aid in developing a prospecting tool for the region's petroleum geologists. Flower structures are known to be productive petroleum traps but in this case results of a borehole test were negative.