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