GEOLOGIC MAP OF THE WILLIAMSBURG ANTICLINE, GREENBRIER COUNTY, WV

The Mississippian Greenbrier Group is a series of limestones and thin shales up to 800 feet (244 meters) thick that are known for their karst development. The Williamsburg anticline in southeastern West Virginia is a large fold involving the Greenbrier Group in western Greenbrier County. It contains the small towns of Alderson, Asbury, Alta, Williamsburg, and Trout. There are many caves, sinkholes, sinking streams, springs, and resurgences in the deep karst valleys that make up the flanks of the anticline. The northeastern limb of the anticline is locally known as “Raders Valley”. The stratigraphic contacts of the members of the Greenbrier Group have been identified and mapped in the field. Extensive southeast-dipping reverse faults in the Williamsburg anticline have also been identified recently by the author as a result of field mapping and analysis of Lidar images provided by the U.S. Geologic Survey. Some of these reverse faults extend as much as 20 miles (32 kilometers) along regional strike and involve stratigraphic displacement of over 600 feet (183 meters). The faulting mostly involves the Taggard shale and lower Pickaway limestones, which are both clay rich and therefore more ductile. These two units are frequently missing completely. Near Fort Donally, southwest of Williamsburg, almost the entire upper Greenbrier is faulted out. Many of the major reverse faults can be traced by a distinct line of sinkholes where steeply dipping beds are exposed and surface water is readily captured.