Organic-walled dinoflagellate cyst biostratigraphy of the upper Eocene to lower Oligocene Yazoo Formation, US Gulf Coast

Research output: Contribution to journalArticle

Authors

External organisations

  • School of Geography, Earth and Environmental Sciences, University of Birmingham
  • PetroStrat

Abstract

New data from a continuously cored succession, the Mossy Grove core, near Jackson, central Mississippi, recovered ∼ 137 m of marine clays (Yazoo Formation), spanning ∼ 5 Ma and including the critical Eocene-Oligocene transition (EOT) event. These clay-rich sediments yield well-preserved calcareous microfossil and palynomorph assemblages. Here, we present a new organic-walled dinoflagellate cyst (dinocyst) biostratigraphic framework, including the recognition of 23 dinocyst bioevents. These are integrated with new age constraints based on calcareous nannofossil biostratigraphy and a reassessment of the existing radiometric dates and planktonic foraminiferal biostratigraphy, permitting the establishment of a robust and significantly refined age model for the core. According to this new age model, a major increase in sedimentation rate - from ∼ 2:1 to ∼ 4:7 cm kyr -1 - is observed at a core depth of ∼ 89:1 m (∼ 34:4 Ma). In the new age model the section is significantly older than previously thought, by up to 1 Ma, with the Eocene-Oligocene boundary (∼ 33:89 Ma) placed ∼ 34 m below the level previously identified. With these more accurate age estimates, future isotopic and palaeoecological work on this core can be more precisely integrated with other, globally distributed records of the EOT.

Details

Original languageEnglish
Pages (from-to)1-26
Number of pages26
JournalJournal of Micropalaeontology
Volume39
Issue number1
Publication statusPublished - 3 Jan 2020

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