Abstract

Sequence stratigraphy for tectonically active foreland basins, such as the western Arkoma basin, differs appreciably from that for relatively passive marginal basins. Owing to its greater geographical confinement and narrowness, the basin can be completely filled by deposits. The sediments can accumulate above sea level, until an increasing but sporadic subsidence or a rise in global sea level occurs. Another important difference is that the orogenic belt bordering the basin maintains its high relief and remains a strong contributor of sediment even during eustatic sea-level rises. In contrast, the cratonic shelf sediment influx diminishes from that cratonic source, resulting in a cratonward shift of the sediment depocenter. Depocenter deposits average about four times thicker than correlative deposits on the cratonic shelf. Compressional stresses produced during episodic thrusting in the Ouachita orogenic belt were transmitted throughout much of the basin and cratonic shelf, diminishing with distance from the orogenic belt. Tectonic stress resulted in syndepositional folds, faults, local unconformities, hinge-line flexures, and occasional reactivation of ancient arches (e.g., the Chautauqua and Bourbon arches) and flanking uplifts (e.g., the Nemaha ridge and Ozark uplift).