PAULI, DAVID A.
Weyerhaeuser Mineral Resources, Federal Way, WA

Abstract: Submarine Channel Sandstones in the Jackfork Group - SE Oklahoma

The Jackfork Group in SE Oklahoma consists of over 6,500 feet of sedimentary rocks that have historically been interpreted as deep marine turbidites deposited in a distal submarine fan setting. Jackfork sedimentary features such as Bouma cycles, sole markings and trace fossils have previously been used to infer a turbidite origin. An eastern sediment source for the Jackfork has been interpreted from paleocurrent data and the presence of proximal submarine fan facies (i.e. submarine channels) in Arkansas.

Less well-documented are the presence of thick submarine channel facies in the Jackfork Group in SE Oklahoma. Sandrich submarine channel sandstones are exposed in Oklahoma in the Lynn Mountain Syncline, well beyond the distal submarine fan facies proposed in older depositional models for the Jackfork sedimentary sequence. They consist predominantly of friable, medium-grained quartz arenite. Sedimentary features include both tabular-planar and trough-like crossbedding, ripple bedding, scoured contacts, and southwarddirected paleocurrent indicators. Sole marks are rare and Bouma cycles are absent.

A revised depositional model is proposed for the Jackfork Group. The model incorporates the presence of proximal submarine fan facies in SE Oklahoma and a significant northern sediment source.

In outcrop, Jackfork submarine channel sandstones appear to have good reservoir potential. The Jackfork currently produces natural gas from channel sandstones and other submarine fan facies in the Frontal Ouachita Thrust Belt in Latimer County, Oklahoma.

AAPG Search and Discovery Article #90928©1999 AAPG Annual Convention, San Antonio, Texas