WESTERNMOST EXPOSURE OF THE CUMBERLAND OVERTHRUST AT SHORT MOUNTAIN, TENNESSEE

Short Mountain, a topographic outlier and klippe 50 km west of the western escarpment of the Cumberland Plateau, is part of the Cumberland Overthrust, a system of faults and folds seen in lower Pennsylvanian sections of the Plateau. In contrast to Plateau exposures where coal seams typically form the decollement, there is no coal at Short Mountain, and here the lower Pennsylvanian section has been thrust along colluvium-mantled Mississippian shales of the Pennington Formation. Strain below the decollement that is consistent with northwest-directed stess is also documented by weakly-developed tectonic stylolites in the Mississippian Monteagle Limestone. The Sewanee Conglomerate above the decollement forms the base of the Pennsylvanian section at Short Mountain and is cut by vertical faults (primarily reactivated joints trending NE and NW), with horizontal slip recorded by slickenfibers and fault mullion. The dominant trend of the faults is NE, and the sense of motion is typically right-lateral. The horizontal slip recorded on vertical fault faces in the Sewanee Conglomerate terminates abruptly at bedding planes and is similar to deformation of the Pennsylvanian Warren Point Sandstone above the decollement in Mitchell Cove on the Cumberland Plateau.