Abstract
This study documents the stratigraphic occurrence of calcareous nannofloral pulses in the middle and upper Eocene, Oligocene and basal Miocene of the Gulf Coastal Plain of Texas and Louisiana. The identified floral pulses, characterized by high abundance and diversity peaks, approximate regional foraminiferal tops and when plotted to the geologic time scale of W. A. Berggren, D. V. Kent, C. C. Swisher III and M.-P. Aubry (1995, SEPM Special Publication 54, 129–212), their relative magnitudes show a sinuous pattern imaging the third-order cycles of B. U. Haq, J. Hardenbol and P. R. Vail (1988, SEPM Special Publication 42, 71–108). Results of comparison suggest that the Reklaw is correlated to the third-order sequence TA3.1, Queen City to TA3.2 and Weches to TA3.3. The Sparta and Cook Mountain consist of three sequences correlated to TA3.4, TA3.5 and TA3.6. The Lower Yegua consists of two sequences correlated to TA4.1 and TA4.2. The Upper Yegua is correlated to TA4.3, the Jackson to TA4.4, and the Vicksburg to TA4.5. The Lower Frio section with regional Anomalina bilateralis was developed during the lowest sea-level cycle TB1.1 in the Oligocene. Two clusters of floral pulses in younger Frio sections are correlated to TB1.2 and TB1.3. Two younger clusters of floral pulses in the Anahuac are correlated to TB1.4 and TB1.5. Ages of these third-order sequences are re-evaluated, based on occurrences of the calcareous nannofossil markers recorded in corresponding floral pulses.
Published Version
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