EFFECTS OF JOINT SYSTEMS ON KARST FEATURES AND WATER FLOW IN LOST COVE, SEWANEE QUADRANGLE, TENNESSEE

Lost Cove, a topographic depression draining 39 sq km, is located in the Sewanee Quadrangle near the eastern edge of the Southern Cumberland Plateau. The cove is rimmed by Warren Point Sandstone bluffs of early Pennsylvanian age which overlie late Mississippian Pennington and Bangor Limestones. The lower slopes and floor of the cove are fossiliferous and oolitic Mississippian Monteagle Limestone, and exhibit typical karst features that include numerous sinks and springs along Lost Creek and its tributaries. Several times in a typical year rainfall exceeds the capacity of the sinks for a few days at a time, and an impoundment of up to 10 acres forms adjacent to the lowest point within the cove, the Big Sink. The Big Sink/Buggytop cave system at the southern end of Lost Cove is the only documented joint-controlled karst conduit in the area, but this study also demonstrates strong joint control of cave passages in the vicinity of Kirk Spring and other openings in the upper Monteagle Limestone near the floor of Lost Cove. Surface and subsurface flows in the vicinity of Kirk Spring typically change direction over the course of several precipitation events. The strongest fracture trends are concentrated at azimuths of 25, 40, and 126 degrees, with the 126-degree trend the most consistent throughout the Mississippian-Pennsylvanian section. The fieldwork investigates the relationship between major fracture trends and the volume and direction of flow in sinks and springs at times of drought and high water.