Investigation of sediment pathways in Hidden River Cave, Kentucky

Abstract

Karstic cave systems are intricately related to surficial processes and the study of cave sediments is a growing field of research. Sediment deposits in caves are protected from surficial weathering processes, and are therefore often preserved. Cave sediments have applications in studies for paleoclimatic reconstruction, contaminant transport, and paleoflood and stream incision rates, making them valuable contributors to other areas of geoscience. Hidden River Cave is an active, multi-level cave system in the town of Horse Cave, Kentucky with over 33 km of mapped passages. A history of anthropogenic impacts on the cave system include uses for hydroelectric power generation, a water source, and a show cave until it closed in 1943 due to severe contamination from domestic and industrial waste. This study reports on the analysis of sediment cores collected from the cave system which show distinct concentrations of metals within the sediment from chrome plating plant effluent. Relative concentrations of metals in the core record were obtained using an ITRAX core scanner, and were observed to decrease moving downstream from the chrome plating plant contamination source. Sediment core analysis allows depositional patterns in the cave system to be observed and related to historic surficial processes. The chronology of sedimentation events was determined using Pb-210 analysis of core sediment and indicates a strong connection between historical contaminating events in the town of Horse Cave and cave sediment deposition. Sediment core analysis has thus allowed depositional patterns in the cave system to be determined and related to historic surficial processes. These findings can be applied to enhance understanding of the combined effects of landscape evolution and anthropogenic impacts which may be used to inform decision making processes for communities overlying both Hidden River Cave and other karstic cave systems.