HOW DO THE STRUCTURES OF THE LATE PALEOZOIC OUACHITA THRUST BELT RELATE TO THE STRUCTURES OF THE SOUTHERN OKLAHOMA AULACOGEN
Year of Publication
Arts and Sciences
William A. Thomas
The thin-skinned structures of the late Paleozoic Ouachita thrust belt intersect the basement structures of the Southern Oklahoma aulacogen beneath the Mesozoic strata of the Gulf Coastal Plain in southeastern Oklahoma. The Ouachita thrust belt forms a large northwest-directed salient which extends primarily in the subsurface from central Mississippi northwestward to Arkansas and eastern Oklahoma, and from there, southwestward toward central Texas. Kinematics are complicated in the center of the Ouachita salient, where the average southwesterly strike of thrust faults is nearly perpendicular to average trend of compressional basement structures in the Southern Oklahoma aulacogen (Arbuckle uplift) and Muenster arch. Furthermore, the frontal fault of the Ouachita thrust belt curves sharply eastward around the southeastern end of the Arbuckle uplift, and bends sharply to the west between the Arbuckle uplift and the Muenster arch farther south in Texas. Nine new interpreted structural cross sections show the structural complexity of the area where the Ouachita thrust belt intersects the Arbuckle uplift and Muenster arch. Detailed study of the structural geology of the Ouachita Mountains and Arkoma basin indicates that along-strike changes in structural style evidently are related to along-strike changes in mechanical stratigraphy (relative thicknesses of weak units, in contrast to stiff units). The middle part of the Stanley Group (Formation) evidently serves as a wavelength transition and/or volume compensation zone. Along-strike change in stratigraphic level of detachments and abrupt eastward thickening of the Atoka Formation along the Ouachita thrust front strongly affected the structural style of the Ouachita thrust belt. Regional stratigraphy, palinspastic restorations of the footwall cutoff of the Ti Valley fault, and an abrupt change in character of seismic reflectors indicate an abrupt facies transition in the Middle Ordovician-Mississippian succession along the southeastern flank of the Arbuckle uplift and southwestward toward the deep southeastern part of the Ardmore basin. Out-of-syncline structures in the Bryan smallscale salient, distinct sub-thrust angular unconformities imaged on seismic profiles, and sediment dispersal patterns in the early Atokan-Desmoinesian strata of the northern Fort Worth basin (south of the Muenster arch) all indicate that the Tishomingo-Belton and Muenster structures were pre-thrust structural highs.
Jusczuk, Steven John, "HOW DO THE STRUCTURES OF THE LATE PALEOZOIC OUACHITA THRUST BELT RELATE TO THE STRUCTURES OF THE SOUTHERN OKLAHOMA AULACOGEN" (2002). University of Kentucky Doctoral Dissertations. 363.