A comparative petrographic study of three Upper Mississippian (Chesterian) sandstones in northern Arkansas

There is an unresolved lithostratigraphic problem in the Upper Mississippian (Chesterian) section of northern Arkansas. A sandstone at the base of the section in far northwestern Arkansas (near Fayetteville) is mapped as belonging to the Batesville Formation. This seems unlikely because, as one moves west from the type locality at Batesville, Independence County, Arkansas, the silici-clastic part of the Batesville pinches out. By the time one reaches Fayetteville in extreme northwestern Arkansas (140 miles from Batesville), the interval is represented by the Hindsville Member, which is a limestone. This distance and lack of persistency suggest that this anomalous sandstone in the Fayetteville area is a different lithostratigraphic unit with a different source than the Batesville. The name Wyman is available from the literature for this unit (Branner, 1891). The Wyman might reflect a northwestern source, and a precursor to the deltaic system that deposited the Wedington Member of the Fayetteville Shale, which succeeds the Hindsville-Batesville interval.;Both a comparative petrographic study and a lithostratigraphic analysis of these three sandstones (Batesville, Wedington, and Wyman) were performed to shed light on this problem. The lithostratigraphic analysis confirmed that the Wyman Sandstone does indeed represent a different depositional system than the Batesville Sandstone by showing a significant lateral discontinuity between the Batesville type locality and the Wyman area. A petrographic study did not reveal any compositional or textural components that were significant enough to suggest different sediment sources.;One additional contribution from this study is a quantitative petrographic name to describe the Wedington Sandstone. A compositional petrographic study of the Wedington Sandstone had never been performed prior to this study, which demonstrates that it is usually a wacke or sublitharenite.