REVISING THE KARST MAP OF THE UNITED STATES

The production of the recently published Living with karst: Afragile foundation required a map showing the distribution of karst in the United States. William Davies et al. (1984) produced the last such map. I used their work as the basis in developing a revised US karst map, but delineated karst primarily on lithology rather than cave lengths. The categories are: exposed and buried carbonate and evaporite karst, and volcanic and unconsolidated pseudokarst. The new US karst map updates the previous map with data from more detailed regional karst maps. Scale and information availability limited the accuracy of the new map. Buried evaporites and unconsolidated pseudokarst are underrepresented due to insufficient delineation. I had to interpolate from available information to adjust for discrepancies due to different map projections and differences between maps. The new US karst map improves on earlier versions but is still incomplete and of low precision in some areas. Production of detailed karst maps with drainage basins and other land management factors is best left to state agencies. The US Geological Survey is developing a new US karst map and the NSS Section of Cave Geology and Geography is assisting with that effort. Uniform standards need to be established for definitions, scale, and map projections. Section members include the country’s most knowledgeable karst geoscientists and they play key roles in developing an accurate and definitive US karst ma