Cave Density of the Greenbrier Limestone Group, West Virginia

Abstract

The Greenbrier Limestone Group, known in West Virginia as the “Big Lime,” is an extensive, calcium-pure limestone unit of Mississippian Age (350–340 million years). Deposited in a shallow ocean basin during the Carboniferous, the Big Lime is more than 1,000 feet thick in the Greenbrier Valley of West Virginia. The wet climate of central Appalachia provides the hydraulics and corrosive carbonic acid action necessary to form frequent and sizable karst dissolution features, such as caves, sinkholes, and springs. Some of the world's largest caves form here as contact caves, where the Big Lime meets the underlying McCrady Shale Formation, including Scott Hollow Cave (29.5 miles), Organ Cave (38.5 miles), and The Hole (23 miles). Likewise, thousands of sinkholes and pits have formed via dissolution of bedrock and collapse into subsurface cave passage. These features create geohazards to infrastructure and provide pathways for aquifer contamination through sediment and pollutant transport, thereby requiring a geographic understanding of karst feature density. This research uses the geographic and geologic analysis capabilities of ArcGIS 10 to examine spatial relationships between this stratigraphic unit and the development of karst features to explore any structural or geographic controls on their genesis. Data are derived from the West Virginia Speleological Survey database of more than 5,600 caves and pits, including length, depth, elevation, and stratigraphic unit attributes. Hexagonal bins with a variety of diameters were used for autocorrelational, Getis-Gi hot spot, and Getis-Ord high–low cluster analysis. Each of these tests showed statistically significant spatial relationships for cave sites at all levels of analysis.

Keywords:

• caves
• cluster analysis
• GIS
• karst

Additional information

Notes on contributors

Lee Stocks,

LEE STOCKS, JR. is Assistant Professor of Geography in the Department of Geosciences, Mansfield University, Mansfield, PA 16933. E-mail: [email protected]. His research interests include karst geomorphology and the geohazards and impacts in those environments that are exacerbated by human development.

Andrew Shears

ANDREW SHEARS is Assistant Professor of Geography and Geology in the Department of Geosciences, Mansfield University, Mansfield, PA 16933. E-mail: [email protected]. His research interests include cultural, political, environmental, urban, and technological geographies, approached from a critical perspective.