Changes in Pacific Ocean circulation following the Miocene onset of permanent Antarctic ice cover
We integrate micropaleontological and geochemical records (benthic stable isotopes, neodymium isotopes, benthic foraminiferal abundances and XRF-scanner derived elemental data) from well-dated Pacific Ocean successions (15-12.7 Ma) to monitor circulation changes during the middle Miocene transition...
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ftoregonstate:ir.library.oregonstate.edu:x633f558r 2024-09-15T17:45:07+00:00 Changes in Pacific Ocean circulation following the Miocene onset of permanent Antarctic ice cover Holbourn, Ann Kuhnt, Wolfgang Frank, Martin Haley, Brian A. College of Oceanic and Atmospheric Sciences https://ir.library.oregonstate.edu/concern/articles/x633f558r English [eng] eng unknown Elsevier https://ir.library.oregonstate.edu/concern/articles/x633f558r Copyright Not Evaluated Article ftoregonstate 2024-07-22T18:06:04Z We integrate micropaleontological and geochemical records (benthic stable isotopes, neodymium isotopes, benthic foraminiferal abundances and XRF-scanner derived elemental data) from well-dated Pacific Ocean successions (15-12.7 Ma) to monitor circulation changes during the middle Miocene transition into a colder climate mode with permanent Antarctic ice cover. Together with previously published records, our results show improvement in deep water ventilation and strengthening of the meridional overturning circulation following major ice expansion at ~ 13.9 Ma. Neodymium isotope data reveal, however, that the provenance of intermediate and deep water masses did not change markedly between 15 and 12.7 Ma. We attribute the increased δ¹³C gradient between Pacific deep and intermediate water masses between ~ 13.6 and 12.7 Ma to more vigorous entrainment of Pacific Central Water into the wind-driven ocean circulation due to enhanced production of intermediate and deep waters in the Southern Ocean. Prominent 100 kyr ventilation cycles after 13.9 Ma reveal that the deep Pacific remained poorly ventilated during warmer intervals at high eccentricity, whereas colder periods (low eccentricity) were characterized b 26 y a more vigorous meridional overturning circulation with enhanced carbonate preservation. The long-term δ¹³C decline in Pacific intermediate and deep water sites between 13.5 and 12.7 Ma reflects a global trend, probably related to a re-adjustment response of the global carbon cycle following the last 400 kyr carbon maximum (CM6) of the “Monterey Excursion”. KEYWORDS: Benthic stable isotopes, Pacific Ocean circulation, Middle Miocene, Nd isotopes Article in Journal/Newspaper Antarc* Antarctic Southern Ocean ScholarsArchive@OSU (Oregon State University) |
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Open Polar |
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ScholarsArchive@OSU (Oregon State University) |
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ftoregonstate |
language |
English unknown |
description |
We integrate micropaleontological and geochemical records (benthic stable isotopes, neodymium isotopes, benthic foraminiferal abundances and XRF-scanner derived elemental data) from well-dated Pacific Ocean successions (15-12.7 Ma) to monitor circulation changes during the middle Miocene transition into a colder climate mode with permanent Antarctic ice cover. Together with previously published records, our results show improvement in deep water ventilation and strengthening of the meridional overturning circulation following major ice expansion at ~ 13.9 Ma. Neodymium isotope data reveal, however, that the provenance of intermediate and deep water masses did not change markedly between 15 and 12.7 Ma. We attribute the increased δ¹³C gradient between Pacific deep and intermediate water masses between ~ 13.6 and 12.7 Ma to more vigorous entrainment of Pacific Central Water into the wind-driven ocean circulation due to enhanced production of intermediate and deep waters in the Southern Ocean. Prominent 100 kyr ventilation cycles after 13.9 Ma reveal that the deep Pacific remained poorly ventilated during warmer intervals at high eccentricity, whereas colder periods (low eccentricity) were characterized b 26 y a more vigorous meridional overturning circulation with enhanced carbonate preservation. The long-term δ¹³C decline in Pacific intermediate and deep water sites between 13.5 and 12.7 Ma reflects a global trend, probably related to a re-adjustment response of the global carbon cycle following the last 400 kyr carbon maximum (CM6) of the “Monterey Excursion”. KEYWORDS: Benthic stable isotopes, Pacific Ocean circulation, Middle Miocene, Nd isotopes |
author2 |
College of Oceanic and Atmospheric Sciences |
format |
Article in Journal/Newspaper |
author |
Holbourn, Ann Kuhnt, Wolfgang Frank, Martin Haley, Brian A. |
spellingShingle |
Holbourn, Ann Kuhnt, Wolfgang Frank, Martin Haley, Brian A. Changes in Pacific Ocean circulation following the Miocene onset of permanent Antarctic ice cover |
author_facet |
Holbourn, Ann Kuhnt, Wolfgang Frank, Martin Haley, Brian A. |
author_sort |
Holbourn, Ann |
title |
Changes in Pacific Ocean circulation following the Miocene onset of permanent Antarctic ice cover |
title_short |
Changes in Pacific Ocean circulation following the Miocene onset of permanent Antarctic ice cover |
title_full |
Changes in Pacific Ocean circulation following the Miocene onset of permanent Antarctic ice cover |
title_fullStr |
Changes in Pacific Ocean circulation following the Miocene onset of permanent Antarctic ice cover |
title_full_unstemmed |
Changes in Pacific Ocean circulation following the Miocene onset of permanent Antarctic ice cover |
title_sort |
changes in pacific ocean circulation following the miocene onset of permanent antarctic ice cover |
publisher |
Elsevier |
url |
https://ir.library.oregonstate.edu/concern/articles/x633f558r |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_relation |
https://ir.library.oregonstate.edu/concern/articles/x633f558r |
op_rights |
Copyright Not Evaluated |
_version_ |
1810492830106255360 |