ABSTRACT

The Stanley Group (Mississippian) crops out in the Ouachita Mountains of southeastern Oklahoma and west-central Arkansas. This study is confined to the exposed Oklahoma portion of the Ouachita foldbelt. Sedimentary and stratigraphic data were collected from which the depositional environment can be interpreted. Particular emphasis has been placed on the sedimentary structures that can be used as paleocurrent indicators.

The Stanley Group is interpreted as a flysch deposit with the present exposures revealing mainly the axial portion of the trough. The normal environment was one of mud accumulation under reducing conditions in a poorly circulated, possibly deep water basin. Siliceous shales mark occasional, widespread, quiescent conditions. Volcanism occurred during the infilling of the trough

The rapid introduction of sand frequently interrupted the normal setting. Turbidity currents, triggered by the instability associated with rapid subsidence and an active source area, brought in the sand from the marginal source areas to the southeast. Local uplifts and instability within the basin gave rise to several internal flows. An axial trend of transport was present and became progressively better developed in the later stages.