Planktonic Foraminifera and Calcareous Nannoplankton Data Used to Define the Regional Geologic Framework of the Neogene in the Southern Laguna Madre-Tuxpan Continental Shelf, Eastern Mexico

Edgar H. Guevara¹, Hector F. Ruiz-Ruiz², William A. Ambrose¹, Julieta Martínez-García², Timothy F. Wawrzyniec³, Juan Rico-Pérez⁴, Khaled Fouad¹, and Mario Aranda-García^2
1 Bureau of Economic Geology, Jackson School of Geosciences, The University of Texas at Austin
² Pemex Exploración y Producción, Poza Rica, México
³ University of New Mexico, Albuquerque, New Mexico
⁴ Pemex Exploración y Producción, Tampico, México

Biostratigraphic information helped define the geological setting of the Miocene in the Eastern Mexico continental shelf and upper slope between the Veracruz and Burgos Basins. This study forms part of a joint Bureau of Economic Geology-Pemex Exploración y Producción investigation of Neogene hydrocarbon plays in Tertiary coastal basins of eastern and southeastern Mexico.

Planktonic foraminifera and calcareous nannoplankton data define the chronostratigraphy of intervals examined in the study area. These intervals, each comprising more than one third-order stratigraphic sequence, are bounded by sequence boundaries (unconformities) and maximum flooding surfaces correlated and delineated by integrated biostratigraphic, seismic, and well-data analysis.

Ages were assigned on the basis of interpreted species extinction (downhole first appearance) and/or planktonic foraminifera and calcareous nannoplankton biozone tops. The microfossils used for Pliocene age determinations were Discoaster brouweri, Discoaster pentaradiatus, Reticulofenestra pseudoumbilica, Sphenolithus abies, Globigerinoides obliquus extremus, and Globorotalia margaritae margaritae. Similarly, Sphaeroidinellopsis disjuncta, Globorotaloides variabilis, Discoaster quinqueramus, Triquetrorhabdulus rugosus, and Discoaster berggrenii were used to define the late Miocene. The middle Miocene was defined by Globorotalia mayeri, Globorotalia fohsi s.l., and Discoaster hamatus, and the early Miocene by Globigerinoides bisphericus, Catapsydrax dissimilis, and Sphenolithus dissimilis.

Comparison and integration of the results of this study with those of other coastal basins in eastern and southeastern Mexico, and in the adjacent Texas coastal plain and offshore areas, should result in unified biostratigraphic criteria for future age determinations of Neogene intervals in the southwestern Gulf of Mexico.

AAPG Search and Discovery Article #90032©2004 GCAGS 54th Annual Convention, San Antonio, Texas, October 10-12, 2004