EUSTATIC CYCLICITY IN THE PALEOCENE AND EOCENE - DATA FROM THE BRAZOSRIVER VALLEY, TEXAS

Documentation of the geologic history of global sea-level change requi res the analysis of numerous, geographically diverse sections. The Pal eocene through Eocene section of the Brazos River Valley, eastern Texa s, is an area suitable for such analysis which has yet to be studied. Analysis of the Brazos River Valley section for sea-level changes duri ng the Paleocene and Eocene was accomplished by the application of seq uence stratigraphic analysis using seismic, well log and outcrop data. The information obtained from this study was then used in evaluating the published sea-level record. A total of fifteen sequence boundaries and ten maximum flooding surfaces, indicating conditions of falling a nd rising sea level, respectively, were identified in the Paleocene an d Eocene strata of the Brazos River Valley. Results of this study show an excellent correlation with the published record of sea-level chang e in the Paleocene, poor correlation in the Early Eocene, good correla tion in the Middle Eocene and fair correlation in the Late Eocene. The excellent correlation between the results of this study and the publi shed record during the Paleocene provide strong support for eustatic n ature of these events. Poor to fair correlation during the Early and L ate Eocene is attributed to the resolution of the data base and neithe r supports nor refutes the published record. Results of this study in the Middle Eocene provide strong support for the published record with two important exceptions. Published records show a cycle of sea-level change in the earliest part of the Middle Eocene which was not observ ed in this study, and a rise in sea level near the end of the Middle E ocene (Bartonian) may have occurred earlier than that indicated by the published record.