Organic-walled dinoflagellate cyst biostratigraphy of the upper Eocene to lower Oligocene Yazoo Formation, US Gulf Coast
<p>New data from a continuously cored succession, the Mossy Grove core, near Jackson, central Mississippi, recovered <span class="inline-formula">∼137</span> m of marine clays (Yazoo Formation), spanning <span class="inline-formula">∼5</span&...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2020-01-01
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| Series: | Journal of Micropalaeontology |
| Online Access: | https://www.j-micropalaeontol.net/39/1/2020/jm-39-1-2020.pdf |
| Summary: | <p>New data from a continuously cored succession, the Mossy Grove core, near Jackson, central Mississippi, recovered <span class="inline-formula">∼137</span> m of
marine clays (Yazoo Formation), spanning <span class="inline-formula">∼5</span> 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 <span class="inline-formula">∼2.1</span> to
<span class="inline-formula">∼4.7</span> cm kyr<span class="inline-formula"><sup>−1</sup></span> – is observed at a core depth of
<span class="inline-formula">∼89.1</span> m (<span class="inline-formula">∼34.4</span> Ma). In the new age model the
section is significantly older than previously thought, by up to 1 Ma, with
the Eocene-Oligocene boundary (<span class="inline-formula">∼33.89</span> Ma) placed
<span class="inline-formula">∼34</span> 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.</p> |
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| ISSN: | 0262-821X 2041-4978 |