ABSTRACT

Structural and stratigraphic relationships along the Mountain View-Wayne fault in T. 5 N., Rs. 2-5 W., indicate that one to three miles of left-slip occurred during the Wichita orogeny (Morrow-Atoka) of the early Pennsylvanian with movement possibly continuing into the Desmoinesian. Isochore maps of the Woodford, Hunton, total Woodford-Hunton and Viola to 1st Bromide (Simpson) suggest that the amount of slip increases westward along the fault from one to one and one-half miles in T. 5 N., R. 3 W., to three miles in T. 5 N., R. 5 W. A greater amount of shortening on the south side of the fault, structural interference by the southern termination of the Nemaha Ridge (McClain County fault) in T. 5 N., R. 3 W., movement along several subparallel faults, or some combination of these can account for the difference in the amount of offset. Major thrust faults (Apache, Chickasha, and Carter Knox) south of the Mountain View-Wayne fault and west of the study area suggest that this larger scale shortening should cause the relative amount of left-slip to increase westward toward western Oklahoma along the fault. Whereas compressional features are evident north of the Mountain View-Wayne fault (e.g., Fort Cobb and Cordell anticlines) deformation did not reach the extent of the features to the south. The five miles of left-slip noted along the Mountain View-Wayne fault at the Cement oil field in the Marchand and Madrano sands (Thorman, 1965) together with structural closure of Permian strata at Cement and Carter Knox oil fields indicate or depict increased strike-slip movement toward the west.

The observations made in this and other recent studies (e.g., Carter, 1979) indicate that southern Oklahoma must be considered a region of tectonic overprinting. A rift system and extensional regime initiated in the late Precambrian characterized the area until the late Ordovician. Mild compressional stresses imposed either by subduction in an ocean basin to the southeast or orogenic convergence in the northeast (Taconic-Acadian orogenies) apparently caused the reactivation of rift-related normal faults as incipient wrench faults during the Silurian and Devonian. Major strike-slip motion occurred during the Pennsylvanian as compressional forces related to convergence along the Appalachian-Ouachita trend reached a climax. An extensional regime concurrent with the opening and subsidence of the Gulf of Mexico presumably characterized the Oklahoma region since the breakup of Pangaea.