EXPLORING BEDDING DEFORMATION AT CAVE HILL (GROTTOES, VA) BY GEOREFERENCING DENSE POINT CLOUDS OF CAVES USING A LIDAR-SLAM SCANNER

Cave Hill is in Grottoes, VA, a historical town and home of Grand Caverns, the oldest show cave in continuous operation in the United States since 1806. In addition, Cave Hill is home to more than 20 surveyed caves and considered as a miniature version of the Appalachian Mountains, due to the internal deformation expressed along the hill. Cave Hill is situated within the Conococheague Formation, a Cambrian aged microcrystalline limestone, interbedded with dolostone and sandstone. For this study, we identified 6 caves along the hill with internal visible bedding exposure that could be used to measure strike and dip. Since strike and dip measurements have only been taken at outcrops along Cave Hill, the goal of this study is to determine how useful strike and dip measurements are inside the caves to observe deformation.

For data collection, we used the GeoSLAM (Simultaneous Localization and Mapping) ZEB Horizon scanner, with scanning capabilities of 300 x 10³ points per second, a range of 100 m, and relative accuracy of up to 6 mm. Point clouds were georeferenced using Topcon HiPer VR (GNSS receiver). All six scans combined have more than 600 x 10⁶ points in total. The average length of the caves is 648 m, the average width is 12 m and the average height is 8 m. In addition, we have measured the distance between the caves, position within Cave Hill, orientation, and general geometry. We implement the following software: GeoSLAM Connect, Nubigon, and CloudCompare (open source) to measure strike and dip along other features at each cave.

The results of this study will provide a better overview of the hydrological dynamics that happen at Cave Hill, as well as contextualizing another concurrent research focusing on paleoclimate. Future work includes the addition of more caves at Cave Hill and the lower non-commercialized section of Grand Caverns.