A COMPARISON OF SINKHOLE EXPRESSION AND KARST FEATURES IN THREE REGIONS OF WEST VIRGINIA

Sinkhole and karst abundance in West Virginia varies across the state and between carbonate units. High spatial resolution LiDAR-derived digital elevation data recently became available statewide making it more feasible to map sinkholes over larger spatial extents. Three regions with significant karst features but different geologic settings and formations are compared in this study: Berkeley-Jefferson, Pendleton, and Greenbrier counties. In Berkeley-Jefferson, most carbonate units are in the highly folded and faulted Cambro-Ordovician units of the Great Valley. In Pendleton, the majority of karst formation occurs in the Ordovician Valley and Ridge carbonates, with minor development through Mississippian carbonates. Greenbrier primarily contains Mississippian carbonates of the Appalachian Plateau and has subdued folding. In this study, sinkhole data was processed for each of the regions before being normalized by mapped carbonate bedrock area. The data compared include the density of sinkholes (per unit of mapped carbonates), the structural setting, length of cave per mapped carbonate unit, average depth of cave per unit, and density of entrances.

In Pendleton and Berkeley-Jefferson, the St. Paul, Trenton, and Black River groups are the primary sinkhole formers. Berkley-Jefferson has a higher density of sinkholes within these groups, however, Pendleton contains a greater average depth and length of mapped cave passages. In Pendleton, the Mississippian Greenbriar Group has minimal sinkhole development, whereas the Greenbriar in Greenbriar county had the largest concentration of sinkholes, number of caves, and cave lengths of all studied areas. The comparison of the Ordovician carbonates in Berkeley-Jefferson versus Pendleton indicates structural controls that contribute to the ability of Pendleton to form deep cave systems within these carbonates. By comparing similar groups of carbonates within these three diverse regions, variables impacting sinkhole and cave development can be determined.