LATE PALEOZOIC DEFORMATION OF THE ARDMORE BASIN: SOUTHERN OKLAHOMA USA

The Ardmore Basin is a prolific hydrocarbon system located within the southeastern portion of the Greater Ancestral Rocky Mountain region. Abundant well control along with an extensive seismic database and scattered outcrops provide a virtual laboratory for the investigation of the style and intensity of late Paleozoic structural deformation within a portion of the GARM. A series of NE-SW oriented, structurally balanced and restored cross sections along a 60 mile trend reveal a consistent theme of either northeast or southwest-verging, basement-involved compressional structures. Restoration of the serial structural sections documents a consistently distributed amount of strain ranging from 20-26%. The consistency of the strain does not support the interpretation that significant strike-slip is responsible for the deformation. Several of the large mountain-front folds display a considerable component of “basement overhang” along low to moderate angle, northeast-verging thrust faults. Classic fault-propagation folding, along with a complex style of ramp and flat geometries can be interpreted along the Arbuckle Anticline. The angle and location of the ramps were controlled by a pre-existing Cambrian-aged rift system that was bounded to the north by major listric normal faults extending down into the upper mantle. It is proposed that late Paleozoic inversion of this rift was accomplished by slightly oblique slip along a master floor thrust that soles near the contact between the Cambrian-aged Carlton Rhyolite Group, and the underlying pre-Cambrian granitic basement. The structural style and inferred stress orientations documented by late Paleozoic deformation within the Ardmore Basin help constrain the reconstruction of potential plate positions that drove the structural development of the entire GARM region.