Eocene Cooling Linked to Early Flow across the Tasmanian Gateway
The warmest global temperatures of the past 85 million years occurred during a prolonged greenhouse episode known as the Early Eocene Climatic Optimum (52–50 Ma). The Early Eocene Climatic Optimum terminated with a long-term cooling trend that culminated in continental-scale glaciation of Antarctica...
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ftmontclairstuni:oai:digitalcommons.montclair.edu:earth-environ-studies-facpubs-1046 2023-07-23T04:15:20+02:00 Eocene Cooling Linked to Early Flow across the Tasmanian Gateway Bijl, Peter K. Bendle, James Bohaty, Steven M Pross, Jörg Schouten, Stefan Tauxe, Lisa Stickley, Catherine E. McKay, Robert Röhl, Ursula Olney, M. P. Sluijs, Appy Escutia, Carlota Brinkhuis, Henk 2013-01-01T08:00:00Z https://digitalcommons.montclair.edu/earth-environ-studies-facpubs/47 http://www.pnas.org/content/110/24/9645 unknown Montclair State University Digital Commons https://digitalcommons.montclair.edu/earth-environ-studies-facpubs/47 http://www.pnas.org/content/110/24/9645 Department of Earth and Environmental Studies Faculty Scholarship and Creative Works climate cooling dinoflagellate cysts organic palaeothermometry paleoceanography Geology Paleontology text 2013 ftmontclairstuni 2023-07-03T21:42:31Z The warmest global temperatures of the past 85 million years occurred during a prolonged greenhouse episode known as the Early Eocene Climatic Optimum (52–50 Ma). The Early Eocene Climatic Optimum terminated with a long-term cooling trend that culminated in continental-scale glaciation of Antarctica from 34 Ma onward. Whereas early studies attributed the Eocene transition from greenhouse to icehouse climates to the tectonic opening of Southern Ocean gateways, more recent investigations invoked a dominant role of declining atmospheric greenhouse gas concentrations (e.g., CO2). However, the scarcity of field data has prevented empirical evaluation of these hypotheses. We present marine microfossil and organic geochemical records spanning the early-to-middle Eocene transition from the Wilkes Land Margin, East Antarctica. Dinoflagellate biogeography and sea surface temperature paleothermometry reveal that the earliest throughflow of a westbound Antarctic Counter Current began ∼49–50 Ma through a southern opening of the Tasmanian Gateway. This early opening occurs in conjunction with the simultaneous onset of regional surface water and continental cooling (2–4 °C), evidenced by biomarker- and pollen-based paleothermometry. We interpret that the westbound flowing current flow across the Tasmanian Gateway resulted in cooling of Antarctic surface waters and coasts, which was conveyed to global intermediate waters through invigorated deep convection in southern high latitudes. Although atmospheric CO2 forcing alone would provide a more uniform middle Eocene cooling, the opening of the Tasmanian Gateway better explains Southern Ocean surface water and global deep ocean cooling in the apparent absence of (sub-) equatorial cooling. Text Antarc* Antarctic Antarctica East Antarctica Southern Ocean Wilkes Land Montclair State University Digital Commons Antarctic Southern Ocean East Antarctica Wilkes Land ENVELOPE(120.000,120.000,-69.000,-69.000) |
institution |
Open Polar |
collection |
Montclair State University Digital Commons |
op_collection_id |
ftmontclairstuni |
language |
unknown |
topic |
climate cooling dinoflagellate cysts organic palaeothermometry paleoceanography Geology Paleontology |
spellingShingle |
climate cooling dinoflagellate cysts organic palaeothermometry paleoceanography Geology Paleontology Bijl, Peter K. Bendle, James Bohaty, Steven M Pross, Jörg Schouten, Stefan Tauxe, Lisa Stickley, Catherine E. McKay, Robert Röhl, Ursula Olney, M. P. Sluijs, Appy Escutia, Carlota Brinkhuis, Henk Eocene Cooling Linked to Early Flow across the Tasmanian Gateway |
topic_facet |
climate cooling dinoflagellate cysts organic palaeothermometry paleoceanography Geology Paleontology |
description |
The warmest global temperatures of the past 85 million years occurred during a prolonged greenhouse episode known as the Early Eocene Climatic Optimum (52–50 Ma). The Early Eocene Climatic Optimum terminated with a long-term cooling trend that culminated in continental-scale glaciation of Antarctica from 34 Ma onward. Whereas early studies attributed the Eocene transition from greenhouse to icehouse climates to the tectonic opening of Southern Ocean gateways, more recent investigations invoked a dominant role of declining atmospheric greenhouse gas concentrations (e.g., CO2). However, the scarcity of field data has prevented empirical evaluation of these hypotheses. We present marine microfossil and organic geochemical records spanning the early-to-middle Eocene transition from the Wilkes Land Margin, East Antarctica. Dinoflagellate biogeography and sea surface temperature paleothermometry reveal that the earliest throughflow of a westbound Antarctic Counter Current began ∼49–50 Ma through a southern opening of the Tasmanian Gateway. This early opening occurs in conjunction with the simultaneous onset of regional surface water and continental cooling (2–4 °C), evidenced by biomarker- and pollen-based paleothermometry. We interpret that the westbound flowing current flow across the Tasmanian Gateway resulted in cooling of Antarctic surface waters and coasts, which was conveyed to global intermediate waters through invigorated deep convection in southern high latitudes. Although atmospheric CO2 forcing alone would provide a more uniform middle Eocene cooling, the opening of the Tasmanian Gateway better explains Southern Ocean surface water and global deep ocean cooling in the apparent absence of (sub-) equatorial cooling. |
format |
Text |
author |
Bijl, Peter K. Bendle, James Bohaty, Steven M Pross, Jörg Schouten, Stefan Tauxe, Lisa Stickley, Catherine E. McKay, Robert Röhl, Ursula Olney, M. P. Sluijs, Appy Escutia, Carlota Brinkhuis, Henk |
author_facet |
Bijl, Peter K. Bendle, James Bohaty, Steven M Pross, Jörg Schouten, Stefan Tauxe, Lisa Stickley, Catherine E. McKay, Robert Röhl, Ursula Olney, M. P. Sluijs, Appy Escutia, Carlota Brinkhuis, Henk |
author_sort |
Bijl, Peter K. |
title |
Eocene Cooling Linked to Early Flow across the Tasmanian Gateway |
title_short |
Eocene Cooling Linked to Early Flow across the Tasmanian Gateway |
title_full |
Eocene Cooling Linked to Early Flow across the Tasmanian Gateway |
title_fullStr |
Eocene Cooling Linked to Early Flow across the Tasmanian Gateway |
title_full_unstemmed |
Eocene Cooling Linked to Early Flow across the Tasmanian Gateway |
title_sort |
eocene cooling linked to early flow across the tasmanian gateway |
publisher |
Montclair State University Digital Commons |
publishDate |
2013 |
url |
https://digitalcommons.montclair.edu/earth-environ-studies-facpubs/47 http://www.pnas.org/content/110/24/9645 |
long_lat |
ENVELOPE(120.000,120.000,-69.000,-69.000) |
geographic |
Antarctic Southern Ocean East Antarctica Wilkes Land |
geographic_facet |
Antarctic Southern Ocean East Antarctica Wilkes Land |
genre |
Antarc* Antarctic Antarctica East Antarctica Southern Ocean Wilkes Land |
genre_facet |
Antarc* Antarctic Antarctica East Antarctica Southern Ocean Wilkes Land |
op_source |
Department of Earth and Environmental Studies Faculty Scholarship and Creative Works |
op_relation |
https://digitalcommons.montclair.edu/earth-environ-studies-facpubs/47 http://www.pnas.org/content/110/24/9645 |
_version_ |
1772189339623620608 |