An integrated geophysical analysis of crustal structure in the Wichita Uplift region of southern Oklahoma

The Southern Oklahoma Aulacogen (SOA) is a northwest-trending failed arm of a Cambrian triple junction. Significant structures along the SOA include the Wichita Uplift and the Anadarko Basin in southwest Oklahoma. The rift underwent a complex geologic history of bimodal volcanism, faulting, and subsidence before Pennsylvanian compression inverted and uplifted the structure as part of the formation of the Ancestral Rocky Mountains. This study employed data from a wide-aperture seismic survey shot in 1985 across the Hardeman Basin, Wichita Uplift, and the Anadarko Basin as a joint effort between the University of Texas at El Paso (UTEP) and the University of Texas at Dallas (UTD). Using modern software and processing techniques, I picked numerous refracted and reflected phases and then performed ray-tracing modeling of these picks to build a P-wave seismic-velocity model of the upper crust underneath the Wichita Uplift. I integrated the seismic data with gravity and magnetic data, well data, industry reflection data, and the results of previous studies to arrive at my final geologic model, which includes well-constrained fault locations. This model shows that the granite and rhyolite sequence present beneath the uplift is thicker and more continuous than previously modeled. Thick sequences of what may be metasediments are present adjacent to the Proterozoic basin at the southern end of the model. Dense mafic layers extending to a depth of 15 km form the core of the uplift, revealing the impressive scale of crustal modification in the rifting process. INTRODUCTION