SEDIMENTOLOGICAL ANALYSIS OF WELLS CAVE SEDIMENTS AND THEIR IMPLICATIONS FOR FLOOD HISTORIES IN THE CUMBERLAND PLATEAU

Cave systems in the Cumberland Plateau are primarily developed from allogenic stream networks enabling sediment transportation and deposition within those caves. The stored sediments can provide a record of floods and human influence on erosional processes and can provide insight into future flood impacts on those living in the Plateau. Using sediment characterization from an excavated trench passage in Wells Cave (WC) we assess the ability of these deposits to provide a record of historic flood behavior. The aim of this research is to gain insights into the sedimentological characteristics and depositional history of this tributary to Buck Creek in Pulaski Co., Kentucky. The sediments were logged in-situ for grain size and sedimentary structures. The results revealed distinct lithofacies and sedimentary features within the trench. The topmost sediments (188 cm) appeared disturbed, indicating post-depositional disturbances or bioturbation. Two distinct fining upward sequences at 137-134 cm and 134-129.5 cm suggested changing energy conditions during deposition, possibly due to flood events. The top of an angular unconformity was identified at 108 cm, signifying periods of erosion or quiescence in sediment deposition. Beneath the unconformity (100 cm), the sediments generally exhibited clay layers with occasional oxidized sand lenses, suggesting low-energy depositional environments with occasional high-energy and subsequent subaqueous conditions. These observations collectively signify a complex depositional history and changes in sedimentation dynamics within the downstream section of WC and have important implications for flooding dynamics on the Plateau. The initial low flow conditions and the subsequent erosion period suggest a relative stability in water flow, potentially reducing the risk of severe flooding during those periods. However, the emergence of modern high-energy flow regimes introduces the potential for increased flooding hazards. The deposition of larger sand and silt deposits indicates the capacity for greater sediment transport and accumulation, which can lead to channel obstructions, altered drainage patterns, and heightened flood risks in the vicinity. These changes could result from variations in precipitation patterns, land use practices, or climatic shifts.