Print this pageAbstract: Contemporaneous Faults--Mechanism for Control of Sedimentation in Southwestern Arkoma Basin, Oklahoma
Basal Atokan-Morrowan deposition in the Arkoma basin was influenced by down-to-the-basin growth faults similar to those reported from the Gulf Coast. There are abrupt increases in thickness of the lower Atokan and Morrowan strata on the downthrown sides of the faults. Stratigraphic changes in proximity to faults also occur subjacent to the minor faults within the major blocks. The distribution and thickness of the basal Atokan (Spiro) sandstone were controlled by contemporaneous faulting (i.e., growth-fault-controlled sand accumulation).
The Spiro sandstone is subdivided into two facies: (1) a local north-south-trending delta distributary channel sandstone (Spiro B) and (2) an overlying transgressive marine sandstone (Spiro A). The Spiro B represents local seaward-building delta distributary channel systems that may extend up to 20 mi (32 km) in length and range from 1 to 6 mi (1.6 to 10 km) in width. The transgressive marine facies (Spiro A) is believed to be a submarine sand deposited in trends subparallel with paleodepositional strike. The source of the Spiro sand was on the east and southeast, with a limited contribution of sediment from the north.
The growth faults probably originated by movement in the basement and were perpetuated by additional basement movement and/or sedimentary loading and slumping. Contemporaneous movement along the faults began as early as Morrowan time, continued throughout deposition of the Atokan sediments, and apparently ceased by the time of Hartshorne sand (Desmoinesian) deposition.
AAPG Search and Discovery Article #90961©1978 AAPG Annual Convention and Exhibition, Oklahoma City, Oklahoma