Abstract: Structures in Outcropping Permian Rocks of Western Oklahoma Indicate Deep-Seated Structures
Kenneth S. Johnson
Permian outcrops in southwestern Oklahoma mantle deep-seated structures that were developed mainly during Pennsylvanian tectonic activity. Surface mapping of the Blaine Formation and associated Permian strata shows that a number of faults, flexures, and folds, with vertical displacement of less than several hundred feet, overlie similar deep-seated structures with several thousand feet of relief. Structures in outcropping Permian strata result from late-stage tectonic adjustments along pre-existing (Pennsylvanian) structures, and/or from differential compaction of thick-versus-thin sequences of sediments on either side of deep-seated faults or basement highs.
The three major structural provinces of southwestern Oklahoma are, from north to south: the Anadarko basin, which contains up to 40,000 ft of Paleozoic sediments: the west-northwest-trending Wichita uplift, which is covered by about 1,000-3,000 ft of latest Pennsylvanian and Early Permian sediments in the study area; and the Hollis basin, which typically has 6,000-12,000 ft of Paleozoic sediments. The veneer of outcropping Permian strata responded passively to forces deeper in the crust and within the mantle. Stresses on these strata were mostly vertical, because block faulting and broad folding are the only results observed, and at no place do the structures contain evidence of compression.
AAPG Search and Discovery Article #90957©1995 AAPG Mid-Continent Section Meeting, Tulsa, Oklahoma