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Richard H. Fillon1,
Ronald L. Phair2
(1) Texaco Inc, New Orleans, LA
(2) Texaco, Inc, Houston, TX
Abstract: Development of the Gulf of Mexico petroleum system: Re-evaluation of structures from a plate tectonic perspective
Tectonic evolution of the Gulf of Mexico is bracketed by the opening of the North Atlantic beginning ca. 160 Ma and opening of the South Atlantic beginning ca. 130 Ma. Fragmentation of the Pangean super-continent along planes of weakness and concomitant seafloor spreading associated with plate rotations were driven by hot mantle material upwelling beneath an evolving mid-ocean ridge system. The mass of rock involved in mantle plumes imputes a very great momentum, explaining the general constancy of ridge growth as recorded in seafloor magnetic anomalies. The rifting, opening, and structuring of the Gulf of Mexico, and the creation of early depositional elements including evaporites and source rocks should therefore be viewed as part of an overall process in which mantle plumes and spreading directions are very slow to change. In our plate tectonic analysis we view Euler rotation poles conservatively. Rotation of North America relative to Africa about a mean pole located at 63° N 10° W (NATL), and rotation of South America about a mean pole at 42° N 28° W (SATL), also relative to Africa, account well for pre-drift fit; plate margin clearances during opening; and present positions. Adjustments of the south Florida/western Cuban plate fragment which open the eastern Gulf of Mexico are accounted for by minor Jurassic angular deceleration about NATL. The Bahamas fragment requires no adjustment. While necessary movement of the Yucatan plate to open the western Gulf cannot be accommodated by rotation about NATL, conservative angular geometry and excellent fit are provided by rotation about an SATL/NATL resultant pole. Activation between 135 Ma – 92 Ma (Early Cretaceous) is constrained by time-varying resultant velocity vectors. Two episodes of rifting between Yucatan and Texas are implied, with final pre-drift rifting as late as 145 Ma (Tithonian).
AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana