MAPPING THE WEST VIRGINIA PORTIONS OF THE CUMBERLAND AND CRESAPTOWN QUADRANGLES AND THE CHALLENGES OF INCORPORATING MODERN, LIDAR MAPPING WITHIN A LEGACY, PRE-LIDAR FRAMEWORK.

Mapping of the West Virginia portions of the 1:24,000 (24k) scale Cumberland and Cresaptown quadrangles took place from the fall of 2023 through summer 2024 utilizing modern technology (e.g. GPS, GIS, and LiDAR) and filled the final mapping gap within the Cumberland 1:100,000 (100k) quadrangle sheet. Previous mapping, conducted in the 1990’s, had completed all but these two quadrangles contained within the 100k sheet, but solely utilized paper mapping on less accurate topographic bases. High-resolution, LiDAR-based geologic mapping has revolutionized the practice by allowing for far more accurate location of bedding and marker beds but has also allowed for the introduction of edge-matching errors when new maps are adjacent to mapping performed during the pre-LiDAR age. Completing the mapping and integrating newly acquired data with previously published data presented a number of challenges ranging from structural complexity to addressing pre-LiDAR linework and topographic inconsistencies, and pre-GPS plotting of locations. Mapping within the structurally complex Wills Mountain Anticlinorium was greatly aided by the ability to trace important, resistant marker beds over long distances. However, LiDAR also exposed the unintentional overthickening of some of these resistant units due to the lack of high-resolution terrain models offered by traditional 24k topographic maps. Updating of the pre-LiDAR topographic quadrangles has also altered the topographic models displayed on such maps, thereby creating fresh inconsistencies in how geologic contacts are drawn relative to the terrain. Both instances have raised questions on how to accurately make the necessary changes to the previous mapping, especially in areas where LiDAR signatures are not readily apparent. Lastly, while LiDAR is an invaluable tool for understanding geologic relationships, it does not replace the need for “boots-on-the-ground” geologic mapping practices. While mapping in the Wills Mountain Anticlinorium was aided by LiDAR, complex geologic structures in less-competent units were effectively masked. It was only through traditional field mapping and structural cross section construction that this complexity could be identified, and effectively conveyed via traditional geologic map, albeit in a GIS format.