ABSTRACT

Structural field evidence indicates that the Potato Hills, located in the central zone of the Ouachita Moutains of Oklahoma, represent a series of fault-drag folds created by imbricate thrust faulting and back thrusting. An analysis of mesoscopic structures, combined with detailed mapping, reveals a complex structural and tectonic history of the area. Deformation in this area is the result of a progressive deformational event directed to the north to northwest. Thrust faults are found on either the north or south sides of major anticlines called fault-drag folds. These anticlines were created as lower Paleozoic strata were thrust over Mississippian and Pennsylvanian strata. All thrust faults, except the North Potato Hills thrust, are imbricate, north-directed thrusts from the Windingstair fault decollement. The North Potato Hills thrust is a south-directed back thrust. The Potato Hills are a direct result of movement on the Windingstair fault and represent a leading imbricate-fan thrust system. The Windingstair fault is the leading thrust in this system.