Quantitative Analysis of Biofacies and Genetic Sequence Stratigraphy of the Yegua Formation, Houston Salt Embayment, Northern Gulf of Mexico, U.S.A.
Qing Fang, 2003. "Quantitative Analysis of Biofacies and Genetic Sequence Stratigraphy of the Yegua Formation, Houston Salt Embayment, Northern Gulf of Mexico, U.S.A.", Micropaleontologic Proxies for Sea-Level Change and Stratigraphic Discontinuities, Hilary Clement Olson, R. Mark Leckie
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The Yegua Formation is a unique unit in the Paleogene of the Gulf Coast in its progradation during an overall marine transgression in the Eocene. A comprehensive quantitative analysis of foraminiferal data reveals the relationship of biofacies and genetic sequence stratigraphy and the depositional history of the Yegua Formation.
The quantitative methods used for the biofacies analysis include cluster analysis and factor analysis. Eleven biofacies are recognized from marginal marine to middle bathyal environments. The Yegua Formation was deposited in a variety of depositional environments, including fluvial, shore-zone, deltaic, shelf, and slope fan systems in waterdepths ranging from 0 to over 500 m. Frequent fluctuations of sea level created complex patterns of progradational and retrogradational deposition of the Yegua.
Four genetic sequences, bounded by maximum flooding surfaces, are recognized on the evidence of faunal and depositional changes. The genetic sequence boundaries (maximum flooding surfaces) correspond with biofacies changes and correlate to anomalies in the entire fauna. Comprehensive analysis of the foraminiferal information is required to find out the real paleoenvironmental meaning of the micropaleontological data.
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Micropaleontology and biostratigraphy play vital roles for deciphering the stratigraphic record produced by changes in relative sea level, interpreting the history of global sea-level change, and testing models for the causes of sea-level fluctuations due to the variable influences of tectonics, glacio-eustasy, and climate. The stratigraphic architecture developed in response to changing eustasy, accommodation space, and sediment supply along continental margins, in epicontinental seas, and on carbonate platforms can be interpreted using the tools of marine micropaleontology. Microfossils provide chronostratigraphic control and a wealth of paleoenvironmental information about depositional environments as well as post-depositional changes to those environments. This volume demonstrates clearly that micropaleontologic proxies of environmental change provide a powerful dimension to the interpretive potential of stratigraphic sequences produced by changes in relative sea level and eustasy. Studies in the volume range from paralic to bathyal environments, span Pennsylvanian through Holocene stratigraphy, encompass a variety of microfossil groups and include a wide spectrum of techniques and paleoenvironmental proxies. The volume has been designed for graduate students and professionals interested in a wide range of subjects.