a mountain-building event that resulted in the folding and faulting of exposed strata in the Ouachita Geosyncline in the southern portion of the United States in Arkansas, Oklahoma, and the Marathon uplift region of West Texas. The deformation is Late Paleozoic (Paleozoic Era) in age, probably culminating between the Late Pennsylvanian and the Early Permian (about 280,000,000 years ago). The orogeny resulted in a northward and westward compression in the geosynclinal strata onto adjacent platform rocks.