The Fort Worth Basin, in North-Central Texas, is a late Paleozoic foreland basin that was downwarped during the Early to Middle Pennsylvanian Period in response to tectonic stresses that also produced the Ouachita Thrust Belt. The Atoka Group was deposited during the initial westward progradation of chert-rich terrigenous clastics derived both from the Ouachita Thrust Belt and locally from the Muenster Arch across the northern part of the basin. At the northern end of the basin, the Atoka Group interfingers with arkosic conglomerates (granite wash) derived from the Red River-Electra Arch.

Oakwood salt dome in Leon and Freestone Counties, Texas, has a core composed of a diapiric salt stock at a depth of 355 m. A vertical borehole in the center of the salt stock yielded 57.3 m of continuous rock-salt core overlain by 137 m of anhydrite-calcite cap rock. The lower 55.3 m of rock salt exhibits a strong, penetrative schistosity and parallel cleavage dipping at 30� to 40� and more than 60 variably dipping layers of disseminated anhydrite. Anhydrite constitutes 1.3 � 0.7 percent of the rock-salt core.

Surficial geologic investigations at Palestine, Keechi, and Oakwood salt domes have provided information necessary for evaluating these domes as nuclear waste repositories. Diapir growth uplifted sediments to form domes and created complex radial faulting. Cretaceous rocks crop out at Palestine and Keechi Domes, whereas only Eocene Claiborne sediments are exposed over Oakwood Dome. Annular drainage patterns at Oakwood and Palestine Domes reflect the domal structure.

Red beds, evaporites, and carbonates of the upper Clear Fork and Glorieta Formations (Permian) of the Texas Panhandle form an association of facies deposited in nearshore and supratidal environments along an arid coastline. Carbonates were deposited in inner-shelf depositional environments and exhibit upward-shoaling, sabkha-like successions of dolomitic mudstones containing nodular anhydrite. Landward of the shoaling carbonates was a vast salt plain, or sabkha, in which evaporites were deposited in supratidal brine pans and salt flats.