ALLEGHANIAN CUMBERLAND OVERTHRUST AT SYCAMORE FALLS, FIERY GIZZARD, TRACY CITY, TENNESSEE

The Cumberland Overthrust of Alleghanian age is well exposed in a 128m-long section of bluff immediately south of Sycamore Falls in Fiery Gizzard, near Tracy City, TN. Folds and thrusts in sandstones, shales, and coals of the early Pennsylvanian Raccoon Mountain Formation, youngest formation in the Gizzard Group on the Cumberland Plateau, are prominent and underlie the more mildly deformed Warren Point Sandstone. Major structures include NW-verging folds (some overturned) deforming more than 15m of sandstone, with fold axes averaging N31E. In the lower portion of the exposure about 50m south of the falls, a partly-concealed lens-shaped horse, 6-8m thick by 25m long, is bounded by sheared bituminous coals. Immediately north and south of the falls, deformation is characterized by brecciated sandstone pervasively broken at a 2-10cm scale and underlain by a decollement of sheared bituminous coal. Transport direction, determined from fold orientations and slickenlines, is N 59 W. The deformed zone is thought to connect to the Sequatchie Thrust, exposed 14 km to the SE of Fiery Gizzard.