Syntectonic Depositional Systems Within the Mt. Enterprise Fault Zone

Gary C. Lee
Stephen F. Austin State University, Nacogdoches, TX

Central basin faulting such as the Mt. Enterprise Fault Zone (MEFZ) has recently been of interest in the pursuit of new oil and gas plays within the East Texas Basin. The MEFZ, in the central part of the basin, has been the source of debate concerning the nature of tectonic activity and resultant, syn-tectonic depositional systems. Possible Tithonian extensional forces developed grabens in which accommodation space has potentially provided hydrocarbon traps. Jurassic rifting and basin subsidence allowed a restricted environment depositing an estimated 1500 meters of salt in the central basin followed by late Jurassic Smackover and Haynesville carbonate deposition. By Kimmeridgian time, deposition had changed in the basin and syndepositional faulting apparently began in the study area. Cotton Valley and Hosston Formations of Tithonian through Barremian age dominated the depositional environment in the form of deltaic systems prograding into the basin and have likely been affected by faulting. Such deposits not only provide source rocks for hydrocarbon development but also some may prove to be reservoirs for petroleum. Determining the timing of tectonics is important for understanding the syntectonic depositional system and reservoir quality within the study area.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005