ENHANCED 3D STRUCTURAL INTERPRETATION OF THE EASTERN ARKOMA FOREDEEP
The Arkoma Basin is a foreland basin located in the southern midcontinent of the United States along the Ouachita Fold and Thrust Belt. This study focuses on a portion of the foredeep depozone in the eastern portion of the basin. Three-dimensional seismic data provided by Southwestern Energy (SWN) were used to develop a high resolution picture of the subsurface that was incorporated into the regional tectonic framework of the southeastern portion of North America. My interpretation shows that there are two separate structural systems present in the eastern Arkoma Basin indicated by two sets of faults. The two fault sets are distinguished by a deep set of high-angle normal faults and a shallow set of lower-angle normal faults. The deep set of faults predominantly trend NE/SW in the eastern portion of the study area and NW/SE in the western portion of the study area. The NW/SE faults are interpreted to have experienced a large amount of strike-slip. Shallow faults uniquely trend in an E/W direction. The orientation of faults suggests that dip-slip along the deep set of faults did not directly drive the formation of the shallow faults. Rather, I interpret that reactivation of the deep faults in an oblique-slip motion is responsible for generating the en echelon array of faults structurally above the reactivated deep faults. Relative timing of faulting for the study area began with deep, down-to-the-southeast normal terrace faults. Continued deformation progressed with dextral-slip along the central NW/SE-trending deep fault. Reactivation of NE/SW-trending deep faults in a dextral-slip motion generated the en echelon array of faults in the shallow section. Regional extension is interpreted to generate the final amount of slip observed along all deep faults and the shallow faults structurally above. Two structural models were developed using the relative timing mentioned to illustrate deformation in the study area. The first structural model considers post-Ouachita deformation and includes effects from Mesozoic rifting. The second structural model attempts to follow past literature and consider deformation only up to Late Pennsylvanian time.