GSA Connects 2023 Meeting in Pittsburgh, Pennsylvania

Paper No. 41-3
Presentation Time: 8:00 AM-5:30 PM

VARIABILITY OF PHYSICAL AND GEOCHEMICAL PROPERTIES OF CAVE ECOSYSTEMS: A CASE STUDY IN WATER SINKS CAVE, HIGHLAND COUNTY, VIRGINIA


HARPER, Eden, Hydrology, University of Arizona, 2 W University Blvd, Apt. 2105, Tucson, AZ 85705, WIJESINGHE, Dhanuska, Department of Geology and Environmental Sciences, James Madison University, MSC 6903, Harrisonburg, VA 22807, PETROVA, Maria, Department of Geology and Environmental Science, James Madison University, Harrisonburg, VA 22807-1004 and GARCIA Jr., Angel, Department of Geology and Environmental Science, James Madison University, 801 Carrier Drive, Harrisonburg, VA 22807

The sediment composition within caves provides valuable insights into water flow patterns during various stages of cave development, protected from the influences of the local climate. The study was conducted at Water Sinks Cave in Highland County, Virginia, where a discovery in November 2007 revealed upper-level passages with substantial flowstone and sediment banks reaching nearly 25 feet in height. The primary objective of this research was to understand how environmental variations impact cave sedimentation by examining the physical and geochemical properties of the sediment layer inside the Water Sinks Cave. Additionally, we aimed to construct a 3D image of the cave system, including the sediment pile in Water Sinks Cave and nearby Owl Cave, using a 3D LiDAR scanner. As the initial step soil samples were collected every 20 cm from the accumulated clastic sediments, which were then transported to the soil laboratory for a laser diffraction particle size analysis (LPSA) to determine the sand, silt, and clay percentages. The soil organic carbon (SOC) content was also analyzed using the loss on ignition method (LOI). To create the 3D image of the cave a 3D LiDAR scanner was employed, both inside and outside (attached to a drone) the cave. Preliminary findings from the study indicated that regardless of the depth, the silt content of the cave sediments was significantly higher than sand and clay contents. Nevertheless, there was no significant difference in particle size distribution with the sediment depth. On the other hand, the organic carbon (%) contents of the sediment samples exhibited a significant increase with the sediment depth. Currently, we are in the process of processing LiDAR data to generate 3D images. We hope that these images will aid in determining the pathways of sediment movement as well as the variability in the sediment composition within the Water Sinks Cave system.

Key words: Sediment, LiDAR, 3D image.