Abstract

Rocks exposed in the Oklahoma Ozark area range in age from Precambrian to Middle Pennsylvanian. Early Paleozoic units are beveled by unconformity and are overlapped northward by the Chattanooga black shale (Late Devonian and Early Mississippian).

Post-Chattanooga beds include the St. Joe group (Compton, Northview, and Pierson) of Kinderhookian and Early Osagean age, Reeds Spring and Keokuk formations (Osagean), Moorefield formation (Meramecian), Hindsville, Fayetteville, and Pitkin formations (Chesterian). Osagean units disappear southward by truncation and are overlapped northward by the Moorefield. The latter is beveled northward by unconformity and overlapped by the Hindsville which lies on Osagean cherts in northern exposures. Overlying Fayetteville and Pitkin are truncated northward by pre-Pennsylvanian erosion and are succeeded by Hale, Bloyd, and Atoka formations. (Pennsylvanian).

Northeastern Oklahoma lies on the southwestern end of the Ozark dome. Formations strike in an arcurate pattern and dip gently away from the uplift. Regional dip is interrupted by northeast-trending faults and minor folds which roughly parallel the Ozark axis.

Structural development in northeastern Oklahoma is closely associated with that of the Ozark geanticline which underwent successive emergences, submergences, and tiltings during the Paleozoic. Major deformation occurred in Middle Pennsylvanian (Desmoinesian) time. Folds and faults are post-Boggy and pre-Tiawah (Senora) in age. Parallelism of structures with those in the Arkansas Valley syncline suggest genetic relations. Deformation is largely tensional in nature, resulting from stretching of rock layers across the end of the positive Ozark area following orogenic movement in the Ouachitas and subsequent adjustment in the McAlester basin area.