An Integrated 3-D Gravity and Seismic Study of the Ouachita Frontal Thrust Belt, Pittsburg and Latimer Counties, Oklahoma
Holly Hunter-Huston, E. F. Greene, C. L. V. Aiken, 1998. "An Integrated 3-D Gravity and Seismic Study of the Ouachita Frontal Thrust Belt, Pittsburg and Latimer Counties, Oklahoma", Geologic Applications of Gravity and Magnetics: Case Histories, Richard I. Gibson, Patrick S. Millegan
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The study area is located in the Ouachita frontal thrust belt between the Choctaw thrust fault and the Ti Valley thrust fault in Pittsburg and Latimer Counties, Oklahoma (Figure 1). Although previous studies are available on the compressional structures in this area, few studies have analyzed the deep Ordovician extensional structures we focused on. A detailed gravity survey was acquired to complement an existing 3-D seismic survey shot by Texaco and Weeks Exploration. The seismic data set is ambiguous at the Ordovician level; 3-D gravity modeling proved to be critical in confirming large, deep structural highs within these strata.
Deep extensional structures of the Ouachita frontal thrust belt were developed during Precambrian rifting that created the Arkoma Basin shelf. Reactivation along these basement faults tilted and truncated the section during post-Hunton time, causing erosion of the Hunton Group in many parts of the Arkoma Basin and Ouachita overthrust belt (Tilford, l990). These faults are characterized by localized horst and graben features. On seismic data, some of these faults appear to be high-angle thrust faults. The throw probably was reversed during the period of Ouachita Mountain overthrusting (Tilford, l990; Valderrama, 1994).
Compressional structures of the Ouachita frontal thrust belt are comprised of deep and shallow regimes. These structures formed during the compression of the Ouachita Mountains overthrust orogeny in late Atokan through Des Moinesian time (Arbenz, l989). The shallow compressional structures consist of asymmetric north-verging faults. Most of these faults become listric at depth and parallel the Choctaw and Ti Valley thrust faults. Deeper compressional structures