New Cenozoic Bio-Chrono-Stratigraphic Charts for the Gulf of Mexico Basin

Waterman, Arthur S.¹; Fillon, Richard H.^2
1 Paleo-Data, Inc., New Orleans, LA.
² Earth Studies Group, New Orleans, LA.

The Gulf of Mexico Basin, with its long history of prolific exploration and development drilling, provides one of the largest control databases for Cenozoic and Mesozoic biostratigraphic events in the world. Developing updated biostratigraphic charts for the Gulf of Mexico Basin is therefore a continuing process of exacting biostratigraphic and chronostratigraphic reevaluation as exploration in new geologic trends yields additional information on stratigraphic ranges and relationships of taxa.

The principal challenges faced in correlating Gulf of Mexico Basin marginal sea biostratigraphy to global time scales are: (1) its indirect connection to the world ocean’s planktonic web; and, (2) its widely variable accumulation rates observed in wells, the result of frequent fluvial avulsion of major river systems and the complex, salt-tectonically modified topography of the basin floor. In our study, ages of key Gulf Basin planktonic datums are assigned using the global time scale of Gradstein et al. (2004). We employ a quantitative approach to evaluate key planktonic event datums and an accumulation rate based age model for unknown events, tuned to minimize out-of-order event pairs through successive iterations of data from over 15000 wells. Ages of provincial benthic foraminiferal events and planktonic events not synchronous with global biochronstratigraphic event data are interpolated based on database evaluation of stratigraphic relationships with the key global events. This quantitative multi-well iteration process, on a very large array, constitutes the basis for regional biostratigraphic correlation and for building a coherent and comprehensive chronostratigraphy for the Gulf Basin. Secondary events of limited local or semi-regional application are differentiated from key regional events by assigned generic and observational confidence values. A Gulf Basin chronostratigraphic sequence curve, encompassing transgressive and regressive cycles based on consistently observed regional patterns of planktonic fossil abundance and paleobathymetry, is tied to our new chronology and compared to the worldwide Tethyan sequence curves of Hardenbol, et al. (1998).

AAPG Search and Discovery Article #90090©2009 AAPG Annual Convention and Exhibition, Denver, Colorado, June 7-10, 2009