Bolboforma as monitors of Cenozoic palaeoceanographic changes in the Southern Ocean

Cooke, Penelope J.; Nelson, Campbell S.; Crundwell, Martin P.; Spiegler, Dorothee

doi:10.1016/s0031-0182(02)00531-x

Cited by 19 publications

(13 citation statements)

References 85 publications

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“…The similarity in ε Nd ( t ) trends to more negative values at the Southern Kerguelen Plateau and Maud Rise suggests that both locations were likely influenced by a common water mass, such as proto‐CDW (Figure ). We interpret the water mass around Sites 744 and 748 to include a significant proto‐CDW component during our study period, based on the integration of our Nd isotope records with the interpreted location of proto‐PF (Cooke et al, ) and water mass from Nd isotope records from other Southern Ocean sites (Scher et al, ).…”

Section: Discussionmentioning

confidence: 99%

No Change in Southern Ocean Circulation in the Indian Ocean From the Eocene Through Late Oligocene

Wright

Scher

Seton

et al. 2018

Paleoceanog and Paleoclimatol

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Deciphering the evolution of Southern Ocean circulation during the Eocene and Oligocene has important implications for understanding the development of the Antarctic Circumpolar Current and transition to Earth's “icehouse” climate. To better understand ocean circulation patterns in the Indian Ocean sector of the Southern Ocean, we generated a new fossil fish tooth neodymium isotope record (εNd) from the upper Eocene to upper Oligocene sections (36–23 Ma) of Ocean Drilling Program Sites 744 and 748 (Kerguelen Plateau, Indian Ocean). Reconstructed seawater εNd values from fossil fish teeth are used to trace changes in water masses across ocean basins. The records from Site 748 and Site 744 reveal a gradual shift from εNd values around −6.5 to −7.5 in the late Eocene to εNd values between −7.5 and −8.3 by the late Oligocene, consistent with a Circumpolar Deep Water (CDW) influence at the Kerguelen Plateau throughout the Oligocene. We interpret the shift to less radiogenic values to reflect the increased export of Northern Component Water to the Southern Ocean, likely into the proto‐CDW. However, the records show no major change in water mass composition around the Kerguelen Plateau that would accompany an increase in Pacific throughflow related to the opening of Drake Passage and imply that Pacific throughflow via the Drake Passage occurred by the late Eocene. High‐frequency variability in ɛNd values at Site 744 is interpreted as an imprint of Oligocene glacial activity, with a particularly pronounced excursion at 32.6 Ma roughly coinciding with other glacial weathering indicators around Antarctica.

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Section: Discussionmentioning

confidence: 99%

No Change in Southern Ocean Circulation in the Indian Ocean From the Eocene Through Late Oligocene

Wright

Scher

Seton

et al. 2018

Paleoceanog and Paleoclimatol

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“…It is also possible that the development of fronts, which are water mass boundaries for surface water, influenced the distribution of e Nd values in Atlantic sector surface waters. Reconstructions of Eocene paleofront positions based on microfossil distributions indicate a proto-Polar Front very close to Maud Rise (27), a front whose existence is supported by large variations in paleoproductivity during the middle Eocene (6).…”

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confidence: 94%

Timing and Climatic Consequences of the Opening of Drake Passage

Scher

Martin

2006

Science

506

372

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Age estimates for the opening of Drake Passage range from 49 to 17 million years ago (Ma), complicating interpretations of the relationship between ocean circulation and global cooling. Secular variations of neodymium isotope ratios at Agulhas Ridge (Southern Ocean, Atlantic sector) suggest an influx of shallow Pacific seawater approximately 41 Ma. The timing of this connection and the subsequent deepening of the passage coincide with increased biological productivity and abrupt climate reversals. Circulation/productivity linkages are proposed as a mechanism for declining atmospheric carbon dioxide. These results also indicate that Drake Passage opened before the Tasmanian Gateway, implying the late Eocene establishment of a complete circum-Antarctic pathway.

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“…This species is relatively well documented in Middle Miocene sediments from the North Atlantic to the Southern Oceans (e.g. Spezzaferri & Spiegler, 1998a;Cooke et al, 2002). Its presence in Middle Miocene sediments from the Mediterranean Basin is reported in Spiegler & Daniels (1991) and Spiegler & Rögl (1992).…”

Section: Systematic Descriptions Family Bolboformaceaementioning

confidence: 87%

“…Although recent studies have shown that the isotopic composition of Bolboforma is typical of tychoplancton (Spiegler & Erlenkauser, 2001), which include organisms occasionally carried into the plankton by chance factors such as turbulence, the taxonomic position and the life strategy of Bolboforma is still poorly known. However, a strong resistance to dissolution and the high stratigraphic potential, especially for the Miocene, make the Bolboforma an important and exceptional microfossil group for interpreting the stratigraphy and palaeoceanography of sediments from cool and temperate regions (Spezzaferri & Spiegler, 1998a;Spezzaferri et al, 2001;Cooke et al, 2002). In many cases Bolboforma biostratigraphy may improve upon and, in some cases, supplement the standard zonations based on other microfossil groups from Early Eocene to Early Pliocene sediments (Spiegler & Daniels, 1991).…”

Section: Introductionmentioning

confidence: 99%

<i>Bolboforma</i> (Phytoplankton Incertae Sedis), <i>Bachmayerella</i> and other Calciodinelloidea (Phytoplankton) from the Middle Miocene of the Alpine–Carpathian Foredeep (Central Paratethys)

Spezzaferri¹,

Rögl

2004

J. Micropalaeontol.

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Abstract. Bolboforma is a microfossil of uncertain origin with affinities to protophytic algae. It generally occurs at high latitudes and/or in cool and temperate waters and has a high stratigraphic potential especially for the Miocene. Calcareous cysts of dinoflagellates represent the ‘benthic cyst stage’ of unicellular organisms belonging to the marine phytoplankton.The occurrence of Bolboforma, Bachmayerella is documented here and, for the first time, some calcareous cysts of dinoflagellates tentatively attributed to Alasphaera and Pithonella from Badenian (Langhian–Middle Miocene) sediments in Austrian and Moravian localities. Alasphaera and Pithonella were previously described from Cretaceous and Danian sediments only, therefore, their range has been extended into the Paratethyan Middle Miocene.Correlation of Bolboforma bioevents with standard geological time-scales allows confirmation, and in some cases refinement, of age assignments based on other microfossil groups, such as foraminifera and calcareous nannofossils, in Paratethyan areas. In particular, this paper presents a case study of the biostratigraphy of the Grund Formation outcropping at its type locality in Lower Austria. Age attribution of the Grund Formation has been uncertain for some time. The recovery of Praeorbulina glomerosa circularis and Uvigerina macrocarinata, associated with Bolboforma reticulata, allows the correlation of the Grund Formation with the Early Badenian (Middle Miocene). As planktonic foraminifera are generally very rare or absent in shelf deposits of many other Austrian and Moravian Middle Miocene sedimentary sequences, Bolboforma, and in particular B. reticulata, remains an important biomarker to identify lower Badenian sediments.Additionally, the new species Bolboforma gneixendorfensis Spezzaferri & Rögl is described. It is generally double-chambered with a weakly reticulate wall texture and is associated with Bolboforma reticulata, B. bireticulata and/or B. moravica.

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Bolboforma as monitors of Cenozoic palaeoceanographic changes in the Southern Ocean

Cited by 19 publications

References 85 publications

No Change in Southern Ocean Circulation in the Indian Ocean From the Eocene Through Late Oligocene

No Change in Southern Ocean Circulation in the Indian Ocean From the Eocene Through Late Oligocene

Timing and Climatic Consequences of the Opening of Drake Passage

<i>Bolboforma</i> (Phytoplankton Incertae Sedis), <i>Bachmayerella</i> and other Calciodinelloidea (Phytoplankton) from the Middle Miocene of the Alpine–Carpathian Foredeep (Central Paratethys)

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Bolboforma as monitors of Cenozoic palaeoceanographic changes in the Southern Ocean

Cited by 19 publications

References 85 publications

No Change in Southern Ocean Circulation in the Indian Ocean From the Eocene Through Late Oligocene

No Change in Southern Ocean Circulation in the Indian Ocean From the Eocene Through Late Oligocene

Timing and Climatic Consequences of the Opening of Drake Passage

&lt;i&gt;Bolboforma&lt;/i&gt; (Phytoplankton Incertae Sedis), &lt;i&gt;Bachmayerella&lt;/i&gt; and other Calciodinelloidea (Phytoplankton) from the Middle Miocene of the Alpine–Carpathian Foredeep (Central Paratethys)

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<i>Bolboforma</i> (Phytoplankton Incertae Sedis), <i>Bachmayerella</i> and other Calciodinelloidea (Phytoplankton) from the Middle Miocene of the Alpine–Carpathian Foredeep (Central Paratethys)