PROVENANCE OF THE WEDINGTON MEMBER OF THE FAYETTEVILLE SHALE FROM DETRITAL ZIRCONS

The Wedington member of the Fayetteville formation is a fine to medium grained, subrounded sandstone of the Chesterian succession. The unit is stratigraphically located in the upper half of the Fayetteville Shale, which is in turn bounded by the Hindsville Limestone below and Pitkin Limestone above. The Wedington is of thin to moderate thickness and is of limited lateral extent, stretching from eastern Oklahoma into Northwest Arkansas in a belt approximately sixty miles wide. Deposition occurred in a small constructive delta complex that prograded during highstand conditions following organic rich shale deposition on the northern Arkansas structural platform. Delta geometry indicates that progradation occurred from the northwest to the southeast. The source of the clastic sediment is problematic because the adjacent areas were covered by carbonates and the nearest elevated source areas were to the south and east. To determine the source of sediment, samples were collected from the various lithofacies of the Wedington sandstone. Detrital zircons were analyzed using LA-ICP-MS to determine U-Pb ratios, which gives an absolute age of the crystalline rock that the zircon originated from. The absolute ages must fit within a stratigraphic, paleographic, and tectonic framework. This framework is established through paleocurrent measurements, stratigraphic study, ternary diagrams of sandstone components, and paleographic reconstructions. All zircon age populations within the Wedington Sandstone must be constrained within this framework to fully determine provenance.