ABSTRACT

An investigation of the lithostratigraphy and depositional history of the Mississippian Sycamore Formation was conducted along the northern flank of the Arbuckle Anticline and to the subsurface to the west and northwest, in the area of the Sho-Vel-Tum, Sholem Alechem, and Golden Trend oil fields. The Sycamore Formation unconformably overlies the Woodford Shale and is in turn conformably overlain by the Caney Shale. The data base included five measured stratigraphic sections, three cores, and approximately 470 well logs.

The Sycamore Formation can be divided into six facies based upon lithology. These facies are:

• Glauconitic Shale
• Bioturbated Shale
• Fossiliferous Mudstones and Wackestones
• Organic Shale
• Silty Pelletal Packstone
• Pellet Rich Siltstone

Construction of structural, isopach, and carbonate lithofacies maps and stratigraphic cross sections revealed the depositional environments of the lithofacies and the factors controlling their distribution. The glauconitic shale was deposited in a shallow marine environment following transgression of the sea over the exposed Woodford Shale. The bioturbated shales and fossiliferous mudstones and wackestones were also deposited in a shallow marine environment. The silty pelletal packstone and pellet rich siltstones were deposited in the deeper, basinal environment of the Southern Oklahoma Aulocogen. These sediments show evidence of storm dominated deposits, indicating that they were deposited below normal wave base but above storm wave base. The organic shales were deposited in a quiet, deep water environment.

Present day facies distribution is strongly influenced by post-depositional tectonic activity along the Washita Valley Fault system.