Arbuckle source for Atoka Formation Flysch, Ouachita Mountains Frontal Belt, Oklahoma

The 10-mi wide Ouachita Mountains frontal belt consists of Morrowan-Atokan flysch exposed in steeply south-dipping imbricate thrust slices. Two spatially distinct groups of paleocurrents were recognized during detailed mapping of 120 mi/sup 2/ in the frontal belt (between 95/sup 0/15'W and 95/sup 0/30'W). The east-west-trending Morrowan shallow-water shelf margin (now allochthonous) marks the boundary between these two domains. Westerly azimuths (259/sup 0/n = 213), typical of almost the entire Ouachita flysch sequence, are from the Atoka Formation south of the shelf margin. Easterly azimuths (66/sup 0/n = 75), previously unrecognized in the Ouachitas, are from the Atoka Formation where it overlies Wapanucka Limestone north of the margin. A third group of paleocurrents (193/sup 0/n = 21) are from the Johns Valley Shale (an olisto-strome that is the basinward equivalent of the Wapanucka Limestone). Easterly paleocurrent azimuths indicate a western source for the Atoka Formation north of the Morrowan shelf margin. Sediment from the Arbuckle uplift was apparently channeled northeastward down a trough that was isolated from the Ouachita basin to the south where sediment had an Appalachian provenance. The authors suggest that a trough was formed by listric fault blocks (tilted toward the continent) of the foundered Morrowan shelf margin.more » The bounding faults would be the southernmost of a series of northward younging south-side-down growth faults that have been recognized in the subsurface of the Arkoma basin to the north.« less