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From
Bureau of Economic Geology, The University of Texas at Austin (www.beg.utexas.edu).
2003 STGS/GCSSEPM One-day Research Conference, San Antonio, Texas, April 11, 2003 Evolution of Late Aptian/Albian Carbonate Platforms of the Northwest Gulf of Mexico Charles Kerans and Robert G. Loucks Abstract: The Albian carbonate platforms of the northwest Gulf of Mexico are among the world's great examples of a carbonate-dominated passive margin. The Albian carbonates are part of a latest Aptian through latest Albian 2nd order supersequence that includes the James-Stuart City in Texas and the Tuxpan, Valles-San Luis Posti, and Coahuilla platforms in northern Mexico. Together, they form a continuous continental margin rimming the southern and eastern margin of North America that Wilson (1975) first synthesized. Much work has subsequently been published on the stratigraphy and sequence stratigraphic evolution of this system such as the work of Scott (1993), Wilson and Ward (1993), Yurewicz et al. (1993), Fitchen et al. (1997), Moore (1996), Goldhammer (1999), Lehmann et al. (1999), and Kerans and Loucks (2002). More local treatments of different elements of this larger system have been provided by many authors over a course of the post WWII era, and this extensive literature base is both the boon and bane of developing a model of this system. In order to develop a sequence model for the latest Aptian through latest Albian carbonate succession in the northwestern Gulf of Mexico, we will draw extensively on a combination of personal experience from outcrop and subsurface studies throughout this supersequence, as well as on available studies of detailed elements of this system by other workers. Perhaps the greatest challenge in defining the sequence framework of the Albian supersequence is not in recognizing the presence of numerous sequences, but in defining the nested cyclic hierarchy of cycles and emphasizing local versus regional or worldwide events. Our working
model includes eighteen 3rd-order sequences within the latest-Aptian-latest
Albian supersequences including; (1) Lower
Cow Creek-Hammett-Pine Island Using the timescale of Gradstien et al (1994), we show that these units represent evenly spaced packages of averaging around 1 m.y. each. The chronostratigraphic chart and schematic cross section represent a working model of the evolving sequence framework that we are currently developing, and are intended as a starting point for future studies rather than as a finished product. Where our framework differs from earlier publications (e.g. Goldhammer 1999, Scott, 1993, Yurewicz et al., 1993) is that we have been able to carry out either subsurface or outcrop studies of all major units within the Albian. Thus, rather than depend on matching sequences to published stratigraphic names (e.g. "Moringsport" sequence) we can develop an even and genetically based existing sequence framework by either dividing traditional formations or combining them as is genetically relevant. Bearing in mind the preliminary nature of the model, there are several important conclusions that evolve. First, the occurrence of producing hydrocarbons from this supersequence is predictive within the transgressive-dominated James through early highstand lower Glen Rose sequences. It is these sequences that have the high initial porosity within aggradational to retrogradational rudist/coral/algal buildups, such as the James and lower Glen Rose. References Fitchen, W. M., Bebout, D. G., and Presbindowski, D. R., Production from Cretaceous high-permeability carbonate grainstones; Alabama Ferry, North Unit, Leon County, Texas, in R. P. Major, ed., Oil and gas on Texas state lands; an assessment of the resource and characterization of type reservoirs, University of Texas at Austin, Bureau of Economic Geology, Report of Investigations no. 241, p. 117-126. Goldhammer, R.K., 1999, Mesozoic sequence stratigraphy and paleogeographic evolution of northeastern Mexico, in Mesozoic sedimentary and tectonic history of north-central Mexico: Geological Society of America Special Paper No. 340, p. 1-59. Gradstein, F.M., Agterberg, F.P., Ogg, J.G., Hardenbol, J., Van Veen, P., Thierry, J., and Huang, Z., 1994, A Mesozoic time scale: Journal of Geophysical Research, v. 99, p. 24051-24074. Kerans, C., Fitchen, W., Zahm, L., and Kempter, K., 1995, High-frequency sequence framework of Cretaceous (Albian) carbonate ramp reservoir analog outcrops, Pecos River Canyon, northwestern Gulf of Mexico Basin: The University of Texas at Austin, Bureau of Economic Geology, Field Trip Guidebook, 105 p. Kerans, Charles, and Loucks, Robert G., 2002, Stratigraphic setting and controls on occurrence of high-energy carbonate beach deposits: Lower Cretaceous of the Gulf of Mexico; Transactions, Gulf Coast Association of Geological Societies, v. 52, p. 517-526. Lehmann, C., Osleger,
D.A., and Montanez, I.P., 1998, Controls on cyclostratigraphy of lower
Cretaceous carbonates and evaporates, Cupido and Coahuila platforms, northeastern
Mexico: Journal of Sedimentary Research, Section B: Stratigraphy and Global
Studies, v. 68 no. 6, p. 1109-1130. Scott, R. W., 1993,
Cretaceous carbonate platform, U.S. Gulf Coast, in Simo, J.A.T., Scott,
R.W., and Masse, J.P., ed. Cretaceous Carbonate Platforms AAPG Memoir
56, p 97-109. Yurewicz, D.A., Marler, T.B., Meyerholtz, K.A., and Siroky, F.X., 1993, Early Cretaceous carbonate platform, north rim of the Gulf of Mexico, Mississippi and Louisiana, in J.A.T., Scott, R.W., and Masse, J.P., ed. Cretaceous Carbonate Platforms AAPG Memoir 56, p 81-96. |