Observations on the capability of the Criner fault, southern Oklahoma

Abstract

Results of previous investigations have indicated the possibility that recent deformation has occurred on the Criner fault of southern Oklahoma. The Criner fault is located in Carter and Love Counties, Oklahoma, approximately 100 kilometers southeast and along strike of the Meers fault. The Criner fault separates strongly folded Ordovician limestone of the Criner Hills from the more easily eroded Pennsylvanian limestone, sandstone and shale of the Marietta Basin to the southwest. Uplift originated in the Ordovician rocks of the Criner Hills during the early Pennsylvanian Wichita Orogeny. Renewed deformation is documented to have occurred during the late Pennsylvanian Arbuckle Orogeny, forming the Criner fault. Concern about the capability of the Criner fault arises because of its proximity to the Meers fault, which is documented to have been reactivated within the last 1200 years. Such findings contradict the prevailing view that the inner continent of North America is a stable tectonic regime. Furthermore, previous investigators have identified numerous geologic and geomorphic features along the Criner fault trace which are indicative of recent tectonic activity. However, none of these features are unequivocal indicators of active faulting. Results of the present study suggest that the Criner fault is an old tectonic feature with a deceptively youthful geomorphic appearance. Differential erosion has likely exhumed the Criner fault-line scarp in the resistant Ordovician limestone of the Criner Hills. The vertical nature of the fault plane and the limestone's impedance of net scarp recession apparently account for this prominent geomorphic feature. Two exposures excavated across faults in the region reveal that the most recent activation of the Criner fault probably occurred after the deposition of the Pennsylvanian Hoxbar Group and before the cessation of Cretaceous deposition. Therefore, this paleoseismic study indicates that the Criner fault is not capable of generating large magnitude earthquakes in the near future.