Bioprovinciality Within Foraminiferal Assemblages- Cenomanian/Turonian Texas Gulf Coast

Dragana D. Nebrigic
Reservoir Studies Division, DeGolyer and MacNaughton, Dallas, TX

Foraminiferal biogeographic diversification/reduction bioevents involve shifts in paleobiogeographic boundaries which lead to increase ecological complexity or community disruption.

The distribution of Cenomanian-Turonian planktic foraminiferal assemblages reflects biogeoproivinciality and environmental conditions in the Tethyan, Boreal and Transitional domains which resulted in selection and adaptation processes until biota became stabilized.

Analysis of planktic foraminiferal assemblages, their paleobiogeographic distributional patterns during the Cenomanian/Turonian time, Texas Gulf Coast, reveals the presence of two major subprovinces -Southern and Northern Subrovinces of Tethyan Province. Variations in foraminiferal assemblage - composition result from changes in salinity, oxygenation, and temperature that followed from changing sea-level and coincident variability in freshwater runoff and productivity. Detailed analysis of foraminiferal assemblages reveal characteristically low numbers of keeled foraminiferal species within western part of Dallas County could deliniate boundary between Northern and Southern Subprovinces of Tethyan Province.

AAPG Search and Discover Article #90078©2008 AAPG Annual Convention, San Antonio, Texas