Radiolarian stratigraphy near the Eocene–Oligocene boundary

Moore, Theodore C.; Kamikuri, Shin-ichi; Erhardt, Andrea M.; Baldauf, J.G.; Coxall, Helen; Westerhold, Thomas

doi:10.1016/j.marmicro.2015.02.002

Cited by 6 publications

(9 citation statements)

References 47 publications

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“…(a) Downcore records of valve preservation, (b) diatom and radiolarian contribution to the <63 µm fraction (relative percent), (c) radiolarian‐bound δ 15 N <63 µm values, and (d) radiolarian first and last occurrence (FAD and LAD, respectively) frequency data [ Moore et al ., ] plotted versus age at Site U1333 across the Eocene‐Oligocene boundary [ Westerhold et al ., ]. The green bar highlights the Eocene‐Oligocene climate transition.…”

Section: Methodsmentioning

confidence: 99%

“…Diatoms are nearly absent in the Eocene and increase to become dominant in the early Oligocene, with significant contributions to both the large and small fractions [Baldauf, 2013]. We measured the δ 15 N in the <63 μm radiolarian fraction and examine these data in the context of radiolarian species turnover (i.e., first and last appearance datums, from Moore et al [2015]), relative contributions of diatoms and radiolarians, and biosiliceous valve preservation. Finally, we present first-order interpretations of the radiolarian δ 15 N record across the Eocene-Oligocene boundary.…”

Section: Eocene-oligocene Climate and Ecosystem Shiftsmentioning

confidence: 99%

“…The standard error for these measurements was 0.4‰ for the recent EEP samples and 0.7‰ for the ancient material. [Moore et al, 2015] plotted versus age at Site U1333 across the Eocene-Oligocene boundary . The green bar highlights the Eocene-Oligocene climate transition.…”

Section: Microfossil-bound δ 15 N Measurementsmentioning

confidence: 99%

“…We measured the δ 15 N in the <63 µm radiolarian fraction and examine these data in the context of radiolarian species turnover (i.e., first and last appearance datums, from Moore et al . []), relative contributions of diatoms and radiolarians, and biosiliceous valve preservation. Finally, we present first‐order interpretations of the radiolarian δ 15 N record across the Eocene‐Oligocene boundary.…”

Section: Introductionmentioning

confidence: 99%

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Evidence for changes in subsurface circulation in the late Eocene equatorial Pacific from radiolarian‐bound nitrogen isotope values

et al. 2015

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Microfossil-bound organic matter represents an important archive of surface ocean environmental information. Sedimentary nitrogen (N) isotope reconstructions of surface nitrate consumption and nitrogen source changes are made using fossil diatom (autotrophs) and planktic foraminiferal (heterotrophs)-bound organic matter with success. However, because diatoms and planktic foraminifera are poorly preserved and sedimentary organic matter content is near zero during the late Eocene, our ability to examine nutrient dynamics across this important climate transition is limited. Here we present new data exploring the use of N isotope records from radiolarian tests. A comparison of surface ocean nitrate and core top bulk and radiolarian N isotope values (as δ N values cooccur with high radiolarian species turnover at~35.5 and 34 Ma, suggestive of a significant ecological change in the EEP, consistent with cooling and water mass distribution changes. The preliminary results suggest that radiolarian-bound organic nitrogen represents another promising archive and underscores the fact that the different microfossil fractions must be separated to ensure robust results.

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Section: Methodsmentioning

confidence: 99%

Section: Eocene-oligocene Climate and Ecosystem Shiftsmentioning

confidence: 99%

Section: Microfossil-bound δ 15 N Measurementsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Evidence for changes in subsurface circulation in the late Eocene equatorial Pacific from radiolarian‐bound nitrogen isotope values

et al. 2015

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“…Furthermore, the EOT is associated with biotic turnover in plants and animals across a range of latitudes and environments (Prothero, 1994). Although not comparable to the "big five" mass extinction events (Raup and Sepkoski, 1982), detailed micro-palaeontological records show that substantial extinction and ecological reorganization is closely coupled to the EOT (Cotton and Pearson, 2012;Coxall and Pearson, 2007;Dunkley Jones et al, 2008;Houben et al, 2013;Moore et al, 2015;Pearson et al, , 2009. These include the extinction of the planktonic foraminiferal Family Hantkeninidae, which marks the EOB (Nocchi et al, 1988;Premoli Silva and Jenkins, 1993), significant extinction in shallow-water benthic foraminifera (Cotton and Pearson, 2012;, radiolaria (Kamikuri and Wade, 2012), and community overturning in the calcareous phytoplankton (Bordiga et al, 2015;Dunkley Jones et al, 2008;Persico and Villa, 2004;Villa et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

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

Mota

Harrington²,

Jones

2020

J. Micropalaeontol.

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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.

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