Eocene circulation of the Southern Ocean: Was Antarctica kept warm by subtropical waters?

Huber, Matthew; Brinkhuis, Henk; Stickley, Catherine E; Döös, Kristofer; Sluijs, Appy; Warnaar, Jeroen; Schellenberg, S. A.; Williams, Graham L.

doi:10.1029/2004pa001014

Cited by 235 publications

(351 citation statements)

References 76 publications

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“…This view is also supported by data-based palaeoceanographic reconstructions (Huber et al, 2004). Lunt et al (2008) also performed experiments using an ice-sheet model to study the development of the Greenland Ice Sheet during the Pliocene (approximately 3 Ma).…”

Section: N Hamon Et Al: Tethys Seaway Closure and Middle Miocene CLmentioning

confidence: 66%

The role of eastern Tethys seaway closure in the Middle Miocene Climatic Transition (ca. 14 Ma)

et al. 2013

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Abstract. The Middle Miocene Climatic Transition (MMCT, approximately 14 Ma) is a key period in Cenozoic cooling and cryospheric expansion. Despite being well documented in isotopic record, the causes of the MMCT are still a matter of debate. Among various hypotheses, some authors suggested that it was due the final closure of the eastern Tethys seaway and subsequent oceanic circulation reorganisation. The aim of the present study is to quantify the impact of varying Tethys seaway depths on middle Miocene ocean and climate, in order to better understand its role in the MMCT.We present four sensitivity experiments with a fully coupled ocean-atmosphere general circulation model. Our results indicate the presence of a warm and salty water source in the northern Indian Ocean when the eastern Tethys is deep open (4000 or 1000 m), which corresponds to the Tethyan Indian Saline Water (TISW) described on the basis of isotopic studies. This water source is absent in the experiments with shallow (250 m) and closed Tethys seaway, inducing strong changes in the latitudinal density gradient and ultimately the reinforcement of the Antarctic Circumpolar Current (ACC). Moreover, when the Tethys seaway is shallow or closed, there is a westward water flow in the Gibraltar Strait that strengthens the Atlantic Meridional Overturning Circulation (AMOC) compared to the experiments with deep-open Tethys seaway. Our results therefore suggest that the shoaling and final closure of the eastern Tethys seaway played a major role in the oceanic circulation reorganisation during the middle Miocene.The results presented here provide new constraints on the timing of the Tethys seaway closure and particularly indicate that, prior to 14 Ma, a deep-open Tethys seaway should have allowed the formation of TISW. Moreover, whereas the final closure of this seaway likely played a major role in the reorganisation of oceanic circulation, we suggest that it was not the main driver of the global cooling and Antarctica ice-sheet expansion during the MMCT. Here we propose that the initiation of the MMCT was caused by an atmospheric pCO 2 drawdown and that the oceanic changes due to the Tethys seaway closure amplified the response of global climate and East Antarctic Ice Sheet.

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Section: N Hamon Et Al: Tethys Seaway Closure and Middle Miocene CLmentioning

confidence: 66%

The role of eastern Tethys seaway closure in the Middle Miocene Climatic Transition (ca. 14 Ma)

et al. 2013

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“…Toward the equator the EACC begins to be influenced by monsoonal variation as it interacts with the seasonally reversing Somali Current (SC), but it is relatively stable and not associated with significant upwelling south of the equator [Schott and McCreary, 2001]. Eocene general circulation models have a similar northward flowing EACC-type current along the western boundary of the Indian Ocean, which is fed by a strong westward flowing SEC-type current between 20 and 30°S [Huber et al, 2004;Thomas et al, 2006]. The consistent presence of a diverse lower photic zone coccolithophore assemblage in the Kilwa Group sediments, from the late Paleocene through to the EOB [Bown et al, 2008b], indicates a long-term stable oligotrophic paleoenvironment, which is consistent with the presence of a northward flowing western boundary current through much of the Paleogene.…”

Section: Paleoceanography Of the Eotmentioning

confidence: 99%

Major shifts in calcareous phytoplankton assemblages through the Eocene‐Oligocene transition of Tanzania and their implications for low‐latitude primary production

et al. 2008

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A high‐resolution record of exceptionally well preserved calcareous nannofossil assemblages from Tanzania is marked by two key transitions closely related to the climatic events of the Eocene‐Oligocene transition (EOT). The first transition, at ∼34.0 Ma, precedes the first positive shift in δ18O and coincides with a distinct interval of very low nannofossil abundance and a cooling in sea surface temperatures (SST). The second, at ∼33.63 Ma, is immediately above the Eocene‐Oligocene boundary (EOB) and is associated with a significant drop in nannofossil diversity. Both transitions involve significant reductions in the abundance of holococcoliths and other oligotrophic taxa. These changes in calcareous phytoplankton assemblages indicate (1) a widespread and significant perturbation to the low‐latitude surface ocean closely tied to the EOB, (2) a potential role for reduced carbonate primary production at the onset of global cooling, and (3) a significant increase in nutrient availability in the low‐latitude surface ocean through the EOT.

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“…The record of Antarctic glaciation, from the time of first ice-sheet inception through the significant periods of climate change during the Cenozoic, is not only of scientific interest but also is of great importance for society. State-of-the-art climate models Pollard, 2003a, 2003b;Huber et al, 2004;DeConto et al, 2007;Pollard and DeConto, 2009) combined with paleoclimatic proxy data (Pagani et al, 2005) suggest that the main triggering mechanism for inception and development of the 6FLHQFH 5HSRUWV Figure 1. Updated Cenozoic pCO2 and stacked deep-sea benthic foraminifer oxygen isotope curve for 0 Ma to 65 Ma.…”

Section: Introductionmentioning

confidence: 99%

“…The East Antarctic Ice Sheet (EAIS), which overlies continental terrains that are largely above sea level, is considered stable and is believed to respond only slowly to changes in climate (Florindo and Antarctic ice sheet was the decreasing levels of CO 2 (and other greenhouse gases) concentrations in the atmosphere Pollard, 2003a, 2003b;Figs 1, 2). The opening of critical Southern Ocean gateways played only a secondary role (Kennett, 1977;DeConto and Pollard, 2003a;Huber et al, 2004 [B] Chronostratigraphic framework for sites drilled during Expedition 318. Timescales are those of Gradstein et al (2004).…”

Section: Introductionmentioning

confidence: 99%

IODP Expedition 318: From Greenhouse to Icehouse at the Wilkes Land Antarctic Margin

Escutia

Brinkhuis

Klaus

2011

Scientific Drilling

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Integrated Ocean Drilling Program (IODP) Expedition 318, Wilkes Land Glacial History, drilled a transect of sites across the Wilkes Land margin of Antarctica to provide a long-term record of the sedimentary archives of Cenozoic Antarctic glaciation and its intimate relationships with global climatic and oceanographic change. The Wilkes Land drilling program was undertaken to constrain the age, nature, and paleoenvironment of the previously only seismicallyinferred glacial sequences. The expedition (January–March 2010) recovered ~2000 meters of high-quality middle Eocene–Holocene sediments from water depths between 400 m and 4000 m at four sites on the Wilkes Land rise (U1355, U1356, U1359, and U1361) and three sites on the Wilkes Land shelf (U1357, U1358, and U1360). These records span ~53 million years of Antarctic history, and the various seismic units (WL-S4–WL-S9) have been successfully dated. The cores reveal the history of the Wilkes Land Antarctic margin from an ice-free “greenhouse” Antarctica, to the first cooling, to the onset and erosional consequences of the first glaciation and the subsequentdynamics of the waxing and waning ice sheets, all the way to thick, unprecedented “tree ring style” records with seasonal resolution of the last deglaciation that began ~10,000 y ago. The cores also reveal details of the tectonic history of the Australo-Antarctic Gulf from 53 Ma, portraying the onset of the second phase of rifting between Australia and Antarctica, to ever-subsiding margins and deepening,to the present continental and ever-widening ocean/continent configuration

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Eocene circulation of the Southern Ocean: Was Antarctica kept warm by subtropical waters?

Cited by 235 publications

References 76 publications

The role of eastern Tethys seaway closure in the Middle Miocene Climatic Transition (ca. 14 Ma)

The role of eastern Tethys seaway closure in the Middle Miocene Climatic Transition (ca. 14 Ma)

Major shifts in calcareous phytoplankton assemblages through the Eocene‐Oligocene transition of Tanzania and their implications for low‐latitude primary production

IODP Expedition 318: From Greenhouse to Icehouse at the Wilkes Land Antarctic Margin

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