DISTRIBUTION OF BEDROCK COLLAPSE SINKHOLES IN WARREN COUNTY, KENTUCKY

Warren County, Kentucky is located atop bedrock consisting of Mississippian-age limestones eroded by dissolution which formed sinking streams, springs, caverns and sinkholes. Though sinkholes are common throughout the state, southcentral Kentucky has the highest density. The most common type of sinkhole in Kentucky are solution, where slightly acidic meteoric water dissolves cavities in the soil-covered, intensely-fractured bedrock. The sediment moves down into the expanding cavity forming a circular depression. The second type of sinkhole is called a collapse, which contains two subtypes: sediment collapse and bedrock collapse. Sediment collapse, where sediment collapses into the underlying void, is considered the most common. Bedrock collapses occur when the ceiling of a cave collapses, exposing the cave passage. This type of collapse is considered rare. The purpose of this study is to determine occurrence and distribution of bedrock collapse sinkholes, relationships to known cave passages, and comparison to distribution of other types of sinkholes. Methods include the use of remote-sensing, GIS, cave data and maps to interpret bedrock collapse frequency and cave passage relationships. There are over 200 cave entrances in Warren County and more than 30 km of cave passages. Preliminary results indicate bedrock collapse sinkholes are more common than originally thought.