Southeastern Section - 63rd Annual Meeting (10–11 April 2014)

Paper No. 2
Presentation Time: 8:30 AM

USING GEOCHEMICAL DATA FROM SPELEOTHEM DRIPS TO INFER HYDROLOGIC CONTROLS ON RECHARGE IN JAMES CAVE, VIRGINIA


SCHREIBER, Madeline E., Department of Geosciences, Virginia Tech, 1405 Perry St, Blacksburg, VA 24061, EAGLE, Sarah D., Department of Geosciences, Virginia Tech, 4044 Derring Hall, Blacksburg, VA 24061, ORNDORFF, William D., Virginia Department of Conservation and Recreation Natural Heritage Program, 8 Radford St, Suite 102A, Christiansburg, VA 24073 and SCHWARTZ, Benjamin F., Edwards Aquifer Research and Data Center, Texas State University, 601 University Drive, San Marcos, TX 78666, mschreib@vt.edu

From 2007-2011, we collected monthly composite samples of speleothem drips from three monitoring sites consisting of ceiling stalactite clusters in James Cave VA, while simultaneously collecting time series data for conductivity, drip rate, and temperature. Composite samples were analyzed for major ion geochemistry, DOC, and water isotopes. Results indicate a strong seasonality of the drip geochemical signatures that corresponds to patterns in the specific conductance and drip rate data. Calcium concentrations are highest in late summer and lowest in fall-early winter, similar to continuous specific conductivity measurements. Strontium to calcium ratios of dripwater increase during baseflow conditions in the fall, suggestive of increasing calcite precipitation and/or decreasing bedrock dissolution within the overlying epikarst during base flow. The combination of geochemical analyses with times series data places constraints on conceptual models of epikarstic processes influencing groundwater recharge.