Sequence Stratigraphy of the Pachuta-Marianna Interval (Upper Eocene-Lower Oligocene) in the U.S. Gulf Coast


The qualitative and quantitative characteristics of palynofacies and dinocyst assemblages have been used to interpret the sequence stratigraphy of upper Eocene-lower Oligocene strata in southern Mississippi and Alabama (U,S, Gulf Coast), In southern Mississippi, we identified a latest Eocene maximum flooding surface in the middle of the Shubuta Clay, but this surface was identified at the top of Shubuta Clay in southern Alabama, where the Eocene-Oligocene boundary was placed within a condensed section (of approximately 0.19 million years duration). This condensation, which was identified at the Shubuta Clay-Vicksburg Group contact, is equivalent to the accumulation of the upper Shubuta Clay and Red Bluff Clay in southern Mississippi, We also interpreted the Forest Hill-Mint Spring contact as a sequence boundary which coincides with a transgressive surface, but this interpretation differs from that of Pasley and Hazel (1995). In southern Mississippi, the Pachuta Marl and the lower Shubuta Clay comprise a late Eocene transgressive systems tract, whereas the same systems tract consists of the Pachuta and the entire Shubuta Clay in southern Alabama, The overlying early Oligocene highstand systems tract was represented by the upper Shubuta, and the Bumpnose/Red Bluff/ForestHill Formations, Although a very thin sandstone in the Mint Spring in one southern Mississippi section was interpreted as a possible lowstand deposit, the Mint Spring, along with the Marianna Limestone, constitute the transgressive systems tract in the other four sections.

Meeting Name

IX International Palynological Congress (1996: Jun. 23-28, Houston, TX)


Geosciences and Geological and Petroleum Engineering

Geographic Coverage

U.S. Gulf Coast

Time Period


International Standard Book Number (ISBN)


Document Type

Article - Conference proceedings

Document Version


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© 2001 American Association of Stratigraphic Palynologists (AASP), All rights reserved.

Publication Date

01 Jan 2001