High‐resolution integrated calcareous plankton biostratigraphy and magnetostratigraphy at the Oligocene–Miocene transition in Southwestern Atlantic Ocean

Gennari, Rocco; Persico, Davide; Turco, Elena; Villa, Giuliana; Iaccarino, S.; Florindo, Fabio; Lurcock, Pontus; Zerfass, Geise de Santana dos Anjos

doi:10.1002/gj.2945

Cited by 5 publications

(3 citation statements)

References 53 publications

(201 reference statements)

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“…ODP Hole 929A [ Fig. 1; 5°58.573′N (87,88). All ages are reported on the Geologic Time Scale 2012 (84) (GTS2012).…”

Section: Methodsmentioning

confidence: 99%

“…For Hole 516F, the age model above 259.5 mbsf is based on magnetostratigraphy ( 86 ) with biostratigraphic datums from ref. 87 . Below 264 mbsf, ages are constrained by biostratigraphic datums ( 87 , 88 ).…”

Section: Methodsmentioning

confidence: 99%

“… 87 . Below 264 mbsf, ages are constrained by biostratigraphic datums ( 87 , 88 ). All ages are reported on the Geologic Time Scale 2012 ( 84 ) (GTS2012).…”

Section: Methodsmentioning

confidence: 99%

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The enigma of Oligocene climate and global surface temperature evolution

O'Brien

Huber

Thomas

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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Falling atmospheric CO2 levels led to cooling through the Eocene and the expansion of Antarctic ice sheets close to their modern size near the beginning of the Oligocene, a period of poorly documented climate. Here, we present a record of climate evolution across the entire Oligocene (33.9 to 23.0 Ma) based on TEX86 sea surface temperature (SST) estimates from southwestern Atlantic Deep Sea Drilling Project Site 516 (paleolatitude ∼36°S) and western equatorial Atlantic Ocean Drilling Project Site 929 (paleolatitude ∼0°), combined with a compilation of existing SST records and climate modeling. In this relatively low CO2 Oligocene world (∼300 to 700 ppm), warm climates similar to those of the late Eocene continued with only brief interruptions, while the Antarctic ice sheet waxed and waned. SSTs are spatially heterogenous, but generally support late Oligocene warming coincident with declining atmospheric CO2. This Oligocene warmth, especially at high latitudes, belies a simple relationship between climate and atmospheric CO2 and/or ocean gateways, and is only partially explained by current climate models. Although the dominant climate drivers of this enigmatic Oligocene world remain unclear, our results help fill a gap in understanding past Cenozoic climates and the way long-term climate sensitivity responded to varying background climate states.

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“…ODP Hole 929A [ Fig. 1; 5°58.573′N (87,88). All ages are reported on the Geologic Time Scale 2012 (84) (GTS2012).…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

The enigma of Oligocene climate and global surface temperature evolution

O'Brien

Huber

Thomas

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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Age Assignment, Palaeoecology and Sequence Stratigraphic Framework of the Nukhul Formation at Wadi Baba, West-Central Sinai (Egypt)

Shama

El-Nahrawy

Farouk

2023

Palaeobio Palaeoenv

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The Nukhul Formation has been a point of controversy until now due to a lack of index fossils, varied facies modifications, and different time gaps. As a result, the calcareous nannofossils of the exposed Miocene rocks at Wadi Baba, west-central Sinai have been studied quantitatively for the first time. An important sequence of calcareous nannofossil bioevents has been recorded in the Nukhul Formation, including the FOs of Discoaster druggii, Sphenolithus dissimilis, Helicosphaera ampilaperta, and Sphenolithus disbelemnos, which correspond to the Aquitanian age of upper NN1 and NN2 zones. The Nukhul Formation contains four intervals that reflect eutrophic conditions in the nearshore habitats with substantial nutrient input from the terrigenous influx, as shown by the dominance of cool-water taxa, Coccoliths pelagicus and Reticulofenestra minuta. The lithofacies, microfacies types, abundance, dominance, and diversity of nannofossil assemblages classified the studied interval into two depositional sequences with four system tracts. These tracts refer to fluctuations in relative sea level changes in response to the eustatic sea-level curve.

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Adaptations of Coccolithophore Size to Selective Pressures During the Oligocene to Early Miocene High CO₂ World

Guitián

Jones

Hernández‐Almeida

et al. 2020

Paleoceanog and Paleoclimatol

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Culture experiments with coccolithophore algae—the dominant group of marine calcifying phytoplankton—imply a strong sensitivity in growth rate, degree of cellular calcification, and cell size to changes in the carbon chemistry of their growth environment. These results underpin recent studies that have explored how these physiological parameters have varied on geological time scales, in response to changing surface ocean habitats and the concentrations of carbon in the ocean‐atmosphere system. Here, we add to this work with a study of reticulofenestrid coccolith size—the dominant coccolithophore family of the Cenozoic—over the Oligocene to Early Miocene time interval. We examine sediments from contrasting latitudes and regional environmental settings, comparing sites using coherent, updated age models to distinguish globally synchronous trends in cell size from regional trends. Our results confirm several changes in coccolith size—which is strongly correlated to cell size—that are globally reproducible within the ~1 Myr age uncertainty, including a reduction in mean size by >2 μm from 30.2 to 27 and 24.5 to 23 Ma, and then increase in mean size after 20 Ma. The main difference among regions is the presence/absence of coccoliths larger than 8 μm. We evaluate which scenarios of change in carbon dioxide, temperature, and nutrient availability could have exerted selective pressure on cell size for different size classes to produce the observed size trends at each studied site. These million‐year scale adaptations of ancient coccolithophores contribute to the understanding of phytoplankton physiology in the transition to the modern “icehouse” world.

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High‐resolution integrated calcareous plankton biostratigraphy and magnetostratigraphy at the Oligocene–Miocene transition in Southwestern Atlantic Ocean

Cited by 5 publications

References 53 publications

The enigma of Oligocene climate and global surface temperature evolution

The enigma of Oligocene climate and global surface temperature evolution

Age Assignment, Palaeoecology and Sequence Stratigraphic Framework of the Nukhul Formation at Wadi Baba, West-Central Sinai (Egypt)

Adaptations of Coccolithophore Size to Selective Pressures During the Oligocene to Early Miocene High CO₂ World

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High‐resolution integrated calcareous plankton biostratigraphy and magnetostratigraphy at the Oligocene–Miocene transition in Southwestern Atlantic Ocean

Cited by 5 publications

References 53 publications

The enigma of Oligocene climate and global surface temperature evolution

The enigma of Oligocene climate and global surface temperature evolution

Age Assignment, Palaeoecology and Sequence Stratigraphic Framework of the Nukhul Formation at Wadi Baba, West-Central Sinai (Egypt)

Adaptations of Coccolithophore Size to Selective Pressures During the Oligocene to Early Miocene High CO2 World

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Adaptations of Coccolithophore Size to Selective Pressures During the Oligocene to Early Miocene High CO₂ World