Abstract

Late Paleozoic trace fossils of the Ouachita Mountains are useful in determining relative bathymetry, rates of sedimentation, and top and bottom of beds. A transition from shallow water to deep water sediments is evident from north to south across the Arkoma basin into the Ouachita Mountains. The shallow-water Skolithos facies in the upper Atoka Formation of the Arkoma basin is characterized by Lockeia, Scolicia, and Rosselia. The Cruziana shelf facies contains Conostichus and Asterosoma in the Spiro Sandstone, and Atoka Formation of the Arkoma basin. An outer shelf facies is represented by the Spiro Sandstone and upper, sandy Wapanucka Limestone of the Frontal Ouachita Mountains in which Zoophycos is abundant. A Chondrites assemblage characterizes the slope deposits of the lower Atoka Formation of the Frontal Ouachitas. The deep water Nereites facies in the strata of the Central Ouachita Mountains contains Helminthopsis, Spirophycus, Lophoctenium, Phycosiphon, and Scalarituba. The intensity and preservation of burrows in the Arkoma basin indicate relatively slow and uniform rates of sedimentation. In the deeper water deposits of the Ouachita Mountains sedimentation was apparently sporadically interrupted by rapid deposition of turbidites that may have predepositional burrows as sole casts or shallow top burrows.