Recent drilling activity for Jackfork reservoirs in southeastern Oklahoma has renewed interest in the structural and stratigraphic framework of the Ouachita Uplift. Structurally, the uplift can be divided into two areas - (1) a frontal imbricated zone north of the Ti Valley Fault and (2) the central thrust belt south of the Ti Valley Fault with the dominantly platform sediment to the north and basinal deposits to the south.

The Jackfork Group represents an elongate submarine fan complex that extends from Alabama to Oklahoma. The sandstones are composed of slumps, debris flow and turbidites, which were primarily derived from a non-volcanic landmass east of the present-day Black Warrior Basin. Secondarily, these sediments were derived from the north from Simpson outcrops and from a large drainage basin to the northeast, which terminated with advancing deltas through the Reelfoot Rift area. Some sediment may also be derived from the south from the emergent advancing Ouachita thrust belt. Multiple fan models have been used to explain Jackfork deposition. A combination of the Walker and Vail models appears to be most applicable to Jackfork deposition Recent study of Jackfork sequence stratigraphy indicates that the submarine fan may be subdivided into intervals which represent pulses during third-order sea-level changes.

The central Ouachita thrust belt is a largely unexplored zone of over four million acres in Oklahoma and Arkansas, Sohio initiated an exploration program from 1980 to 1988 during which they drilled a large "channel" identified from seismic in a syncline. Although there were multiple gas shows, the well was not

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economic. In 1990 H&H Star began drilling for Spiro along Ti Valley Faults and found several wells with productive Spiro. This resulted in a marginally economic gas play. Most recently Vastar, Texaco, and Chevron have drilled along the Windingstair Fault to evaluate Jackfork potential.

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