HYDROLOGIC, GEOMORPHIC, AND STRUCTURAL CONTROLS OF KARST FEATURES AND CAVE PASSAGES IN THE MORRIL'S CAVE AREA, SULLIVAN COUNTY, TENNESSEE

Morril’s cave (aka Worley's Cave) is one of the longest caves in northeastern Tennessee with an active conduit flow system at the lower level of the cave and emerges as Morril’s spring at the lower entrance of the cave. A dye tracing test in the area indicated that this is a highly dendritic conduit flow system with groundwater flow velocity greater than 3000 m/day during a baseflow recession in April 2012. Groundwater flow converges to Morril’s spring, which merges into South Holston River eventually. Outcrops and major joints were mapped in this area. Preliminary mapping demonstrates that groundwater flow is probably controlled by major joints and faults in the Knox limestone formation of the study area. Several collapsed sinkholes on top of the cave were actively connected to the cave conduit system.

U-Th dating of speleothems has been conducted for paleohydrological and paleoclimate studies in the past few years. Age distribution of most speleothems was obtained by dating top and bottom core samples drilled by small diamond core bits. The oldest speleothem age dates changed from approximately 400 ka in the uppermost level to 200 ka in the middle level. This distribution reflects that cave passages were first developed from the uppermost level. The lack of samples from passages extending from the two entrances is due to vandalism, which destroyed most speleothems near both entrances.