UPPER JURASSIC TRANSGRESSIVE-REGRESSIVE CYCLES, NORTHEASTERN GULF OF MEXICO

Three transgressive-regressive cycles (T-R J1, T-R J2 and T-R J3) are recognized in Upper Jurassic strata of the northern Gulf of Mexico. These Oxfordian to lower Valanginian cycles consist of a transgressive backstepping interval and a regressive infilling interval. The Oxfordian to lower Kimmeridgian T-R J1 cycle also includes a lower transgressive aggrading interval. Norphlet non-marine deposits are interpreted as the aggrading interval, lower Smackover carbonates as the backstepping interval, and upper Smackover carbonates and Buckner sabkha anhydrite beds as the infilling interval. The surface of maximum transgression occurs in Smackover carbonates. The lower Kimmeridgian to Tithonian T-R J2 cycle includes Buckner subaqueous anhydrite and Haynesville interbedded shale and anhydrite and interbedded shale and limestone beds as the backstepping interval, and Haynesville interbedded shale and sandstone and Shongaloo sandstone beds as the infilling interval. The surface of maximum transgression occurs in Haynesville interbedded shale and limestone and interbedded shale and sandstone beds. The Tithonian to lower Valanginian T-R J3 cycle consists of backstepping deposits of the Dorcheat shale beds and infilling deposits of the Knowles limestone beds. A surface of maximum transgression occurs in the upper Dorcheat shale beds. These T-R cycles have utility for regional correlation across the northern Gulf of Mexico. The upper two cycles show correspondence with Upper Jurassic and Lower Cretaceous T-R facies cycles in Western Europe, and therefore, have potential for global correlation. The lower T-R J1 cycle has limited global correlation potential, for this cycle records the tectonic effects of the early post-rift geohistory of the Gulf of Mexico.