--> Abstract: Structural Styles and Exploration Strategles along the Leading Edge of Fold and Thrust Belts: Examples from the Ouachita Fold and Thrust Belt, Southeast Oklahoma, by R. D. Cunningham, M. D. Falk, and J. Namson; #91012 (1992).

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ABSTRACT: Structural Styles and Exploration Strategles along the Leading Edge of Fold and Thrust Belts: Examples from the Ouachita Fold and Thrust Belt, Southeast Oklahoma

CUNNINGHAM, RUSS D., and MARK D. FALK, The GHK Company, Oklahoma City, OK, and JAY NAMSON, Davis and Namson Consulting Geologists, Valencia, CA

The leading edge of the Oklahoma portion of the Ouachita fold and thrust belt is characterized by a reglonal surface thrust called the Choctaw fault. Exploration has focused on a complex structural zone in the footwall of the fault, where the structural styles are constrained by subsurface well control, seismic reflection data, and balanced cross sections. Underlying the Choctaw fault is the Choctaw anticlinal trend, which is interpreted to be a fault-bend fold associated with a ramp beginning in Springeran age rocks and progressing through a thick middle Atokan flysch sequence. The thrust has approximately 5 km of slip. Some slip is diverted on a back thrust forming a triangle zone at the front of the anticline, and some slip is transferred into the Arkoma basin foreland where it is onsumed in a series of hydrocarbon-producing folds. South of the Choctaw anticline, the structural style in the footwall of the Choctaw fault is characterized by a series of imbricate thrusts or duplex structures with the lower detachinent in Springeran age rocks and the upper detachment immediately above the Spiro Sandstone.

The main exploration strategy in the thrust belt has been the imbricate fault traps involving the shallow marine, basal Atokan Spiro Sandstone. A relatively undeveloped play is a middle Atokan submarine fan sandstone in the Choctaw anticlinal trend. These middle Atokan, immature sediments were eroded from the northward-advancing thrust system and deposited in the Atokan age foreland basin formed by a series of down-to-the-south normal faults. These faults control the areal extent of the sedimentary units. Post-depositional thrusting has resulted in a complex hydrocarbon trap consisting of a stratigraphic facies change on the forelimb of a fault-bend fold.

 

AAPG Search and Discovery Article #91012©1992 AAPG Annual Meeting, Calgary, Alberta, Canada, June 22-25, 1992 (2009)