Radiolarian magnetobiochronology and faunal turnover across the middle/late Eocene boundary at Ocean Drilling Program Site 1052 in the western North Atlantic Ocean

Kamikuri, Shin-ichi; Wade, Bridget S.

doi:10.1016/j.marmicro.2012.03.001

Cited by 22 publications

(21 citation statements)

References 51 publications

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“…The start of this decline at the drop in δ 18 O during latest middle Eocene is matched by a peak in first appearances as new species spring up to replace the old. This faunal turnover was also noted by Kamikuri and Wade (2012) at ODP Site 1052 in the tropical Atlantic, which they refer to as the middle to late Eocene turnover and includes the minor peaks in LADs and FADs at both intervals A and B (Fig, 5). However, the younger pulses of extinctions (Intervals C, D and E) are not matched by several first appearances of new species and the final two larger pulses Westerhold et al (2014) with the paleomagnetic Chrons associated with the middle to late Eocene and early Oligocene.…”

Section: Faunal Turnover and Climate Changesupporting

confidence: 58%

“…With the close constraint of radiolarian datums and the identification of new radiolarian species that first appear in the interval studied here, a more reliable radiolarian biostratigraphy Kamikuri and Wade, 2012;Moore and Kamikuri, 2012) may be employed in the upper Eocene and lower Oligocene of the tropical Pacific in spite of the presence of hiatuses and reworked sediments near the E/O boundary ( Fig. 3; Supplementary Table 1a).…”

Section: Discussionmentioning

confidence: 99%

“…As indicated by Kamikuri and Wade (2012) for the middle to late Eocene boundary and particularly by Funakawa et al (2006) for the E/O boundary, there was a substantial turnover of the radiolarian fauna at these times. This is seen also in the analysis of stratigraphically important species, with most of the last appearances being concentrated in the last 3 Myr of the Eocene.…”

Section: Usefulness Of Eocene Ladsmentioning

confidence: 91%

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Radiolarian stratigraphy near the Eocene–Oligocene boundary

Moore¹,

Kamikuri²,

Erhardt³

et al. 2015

Marine Micropaleontology

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Section: Faunal Turnover and Climate Changesupporting

confidence: 58%

Section: Discussionmentioning

confidence: 99%

Section: Usefulness Of Eocene Ladsmentioning

confidence: 91%

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Radiolarian stratigraphy near the Eocene–Oligocene boundary

Moore¹,

Kamikuri²,

Erhardt³

et al. 2015

Marine Micropaleontology

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“…During the late Eocene there were generally decreasing temperatures [ Lear et al ., ; Coxall and Wilson , ; Wade et al ., ] and 47 radiolarian species and species groups became extinct in a series of three to four extinction events starting at the middle to late Eocene transition ~38 Ma [ Kamikuri and Wade , ] and ending at the EOT itself [ Moore and Kamikuri , ]. This preceded, and thus was not caused by, the onset of a dominant diatom flora in the early Oligocene.…”

Section: Discussionmentioning

confidence: 99%

Equatorial Pacific productivity changes near the Eocene‐Oligocene boundary

et al. 2014

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There is general agreement that productivity in high latitudes increased in the late Eocene and remained high in the early Oligocene. Evidence for both increased and decreased productivity across the Eocene-Oligocene transition (EOT) in the tropics has been presented, usually based on only one paleoproductivity proxy and often in sites with incomplete recovery of the EOT itself. A complete record of the Eocene-Oligocene transition was obtained at three drill sites in the eastern equatorial Pacific Ocean (ODP Site 1218 and IODP Sites U1333 and U1334). Four paleoproductivity proxies that have been examined at these sites, together with carbon and oxygen isotope measurements on early Oligocene planktonic foraminifera, give evidence of ecologic and oceanographic change across this climatically important boundary. Export productivity dropped sharply in the basal Oligocene (~33.7 Ma) and only recovered several hundred thousand years later; however, overall paleoproductivity in the early Oligocene never reached the average levels found in the late Eocene and in more modern times. Changes in the isotopic gradients between deep-and shallow-living planktonic foraminifera suggest a gradual shoaling of the thermocline through the early Oligocene that, on average, affected accumulation rates of barite, benthic foraminifera, and opal, as well as diatom abundance near 33.5 Ma. An interval with abundant large diatoms beginning at 33.3 Ma suggests an intermediate thermocline depth, which was followed by further shoaling, a dominance of smaller diatoms, and an increase in average primary productivity as estimated from accumulation rates of benthic foraminifera.

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“…Knowledge of Middle Eocene-Oligocene single taxa paleoecology, the tolerance of these taxa to different nutrient and temperature conditions, as well as how they relate to paleoclimate variations indicated by stable isotope records, strengthens the known relationship between nannofossils and paleoceanography and can help to identify paleoceanographic events. Many studies have focused on Paleogene microfossil paleoecology and biostratigraphy both at high [e.g., Berggren, 1992;Wei and Wise, 1990;Diester-Haass, 1995;Persico and Villa, 2004;Villa et al, 2008;Funakawa and Nishi, 2008;Huber and Quillévéré, 2005] and mid-low latitudes [e.g., Funakawa et al, 2006;Dunkley Jones et al, 2008;Pearson et al, 2008;Blaj et al, 2009;Edgar et al, 2010;Agnini et al, 2011;Kamikuri and Wade, 2012]. We synthesize results of SO biostratigraphic and paleoclimate studies to better define the late Paleogene greenhouse to icehouse transition, as indicated by nannofossils as paleoclimatic and paleoceanographic proxies.…”

Section: Introductionmentioning

confidence: 99%

Middle Eocene to Late Oligocene Antarctic glaciation/deglaciation and Southern Ocean productivity

et al. 2014

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During the Eocene-Oligocene transition, Earth cooled significantly from a greenhouse to an icehouse climate. Nannofossil assemblages from Southern Ocean sites enable evaluation of paleoceanographic changes and, hence, of the oceanic response to Antarctic ice sheet evolution during the Eocene and Oligocene. A combination of environmental factors such as sea surface temperature and nutrient availability is recorded by the nannofossil assemblages of and can be interpreted as responses to the following changes. A cooling trend, started in the Middle Eocene, was interrupted by warming during the Middle Eocene Climatic optimum and by short cooling episodes. The cooling episode at 39.6 Ma preceded a shift toward an interval that was dominated by oligotrophic nannofossil assemblages from~39.1 to~36.2 Ma. We suggest that oligotrophic conditions were associated with increased water mass stratification, low nutrient contents, and high efficiency of the oceanic biological pump that, in turn, promoted sequestration of carbon from surface waters, which favored cooling. After 36.2 Ma, we document a large synchronous surface water productivity turnover with a dominant eutrophic nannofossil assemblage that was accompanied by a pronounced increase in magnetotactic bacterial abundance. This turnover reflects a response of coccolithophorids to changed nutrient inputs that was likely related to partial deglaciation of a transient Antarctic ice sheet and/or to iron delivery to the sea surface. Eutrophic conditions were maintained throughout the Oligocene, which was characterized by a nannofossil assemblage shift toward cool conditions at the Eocene-Oligocene transition. Finally, a warm nannofossil assemblage in the Late Oligocene indicates a warming phase.

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Radiolarian magnetobiochronology and faunal turnover across the middle/late Eocene boundary at Ocean Drilling Program Site 1052 in the western North Atlantic Ocean

Cited by 22 publications

References 51 publications

Radiolarian stratigraphy near the Eocene–Oligocene boundary

Radiolarian stratigraphy near the Eocene–Oligocene boundary

Equatorial Pacific productivity changes near the Eocene‐Oligocene boundary

Middle Eocene to Late Oligocene Antarctic glaciation/deglaciation and Southern Ocean productivity

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