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Christopher P. Saxon1, C. Treska1
(1) Chevron U.S.A. Production Company, Houston, TX

Abstract: Basement influence of ramp geometry in an arbuckle detachment, Sherman Field, Grayson County, Texas

A recent proprietary 3-D survey has led to a better understanding of the structural style of the Sherman Anticline, a NW-SE trending, SW-vergent anticline in the Southern Oklahoma Foldbelt. Sherman Anticline is a complex, thin-skinned, doubly plunging anticline, in the hangingwall of a detachment within the Arbuckle Group. Located adjacent to the Bryant Salient of the Ouachita Thurst Belt. The Sherman Anticline lies astride an old rift margin which drops the basement down to the north along flexural hinges and normal faults. Smaller normal faults oriented at high angles to the strike of the hinge further segment the basement blocks. the structural style of the Sherman Anticline changes abruptly along strike in direct relation to variations in the geometry of the basement-involved block faulting below the Arbuckle detachment. From the central portion of the Sherman Anticline to the NW plunge the style changes from fault-propagation fold to fault-bend fold back to fault propagation fold. As the hangingwall was thrust to the SW the topography of the detachment was controlled by basement hinges and normal faults. Thrust ramps are located above normal fault scarps. Changes in the geometry of the hangingwall folds resulting from corrugations in the thrust surface are evidence along strike in the Sherman Anticline, as interpreted from the 3-D survey.

AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana