Abstract: Structural Inversion in Southern Oklahoma by Late Paleozoic Transpression, a Working Hypothesis

THOMPSON, THOMAS L.

The tectonic history of southern Oklahoma, guided by Precambrian structural trends, includes massive rifting accompanied by a thick accumulation (about 6 miles or 10 km) of early to middle Cambrian mafic igneous rocks and associated clastic sediment overlain by a 1 mile (1.6 km) thickness of late Cambrian rhyolite. Early Paleozoic thermal subsidence allowed deposition of a 3 mile (5 km) thickness of preorogenic sediment.

Late Paleozoic transpression across rifted and subsided Precambrian basement blocks in southern Oklahoma (during the assembly of Pangaea) accounts for dominant structural styles along the Wichita-Marietta block, the Ardmore basin block, and several blocks of the Arbuckle Mountains. Although complex in detail, the various structures and their mechanical linkages find common explanation in context of east-west to northeast-southwest compression and reactivation of northwest trending basement faults. This fault reactivation and associated basin inversion resulted in structural relief of at least 6 miles (10 km) and accumulation of a 3 mile (5 km) thickness of synorogenic sediment, extensive thrusting, and left-slip faulting. Dip-slip shortening of the preorogenic rocks amounts to about 9 miles (15 km) whereas net left-slip displacement exceeds 18 miles (30 km).

Dynamic interplay among basement blocks under transpression inverted igneous filled graben and formed several types of mechanically linked structures in the overlying sedimentary sequences: (1) Northwesterly trending, left-reverse, oblique-slip faults vary in attitude depending on the attitude of basement block interfaces with greater structural relief and imbricate faulting at confining bends in the basement block pattern, for examples, the Wichita uplift-Cyril basin pair and the Criner Hills-Ardmore deep pair; (2) Northeasterly trending basement fractures apparently provided antithetic adjustment to the dominant northwest trending en echelon folds and faults, influenced the plunge of folds, and caused confining bends during slippage along basement block boundaries; and (3) Flower structures formed at several scales including the complex Cumberland anticline and faulting above the Criner, Tishomingo, and Wichita-Marietta basement blocks.

AAPG Search and Discovery Article #90944©1997 AAPG Mid-Continent Section Meeting, Oklahoma City, Oklahoma