Radiocarbon evidence for a possible abyssal front near 3.1 km in the glacial equatorial Pacific Ocean
Author Posting. © The Author(s), 2014. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Earth and Planetary Science Letters 425 (2015): 93-104, doi:10.1016/j.epsl.2015.05.025....
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ftwhoas:oai:darchive.mblwhoilibrary.org:1912/7457 2023-05-15T18:01:07+02:00 Radiocarbon evidence for a possible abyssal front near 3.1 km in the glacial equatorial Pacific Ocean Keigwin, Lloyd D. Lehman, Scott J. 2014-09 application/pdf https://hdl.handle.net/1912/7457 en_US eng https://doi.org/10.1016/j.epsl.2015.05.025 https://hdl.handle.net/1912/7457 Radiocarbon Foraminifera Ocean ventilation Pacific Ocean Preprint 2014 ftwhoas https://doi.org/10.1016/j.epsl.2015.05.025 2022-05-28T22:59:23Z Author Posting. © The Author(s), 2014. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Earth and Planetary Science Letters 425 (2015): 93-104, doi:10.1016/j.epsl.2015.05.025. We investigate the radiocarbon ventilation age in deep equatorial Pacific sediment cores using the difference in conventional 14C age between coexisting benthic and planktonic foraminifera, and integrate those results with similar data from around the North Pacific Ocean in a reconstruction for the last glaciation (15 to 25 conventional 14C ka). Most new data from both the Equatorial Pacific and the Emperor Seamounts in the northwestern Pacific come from maxima in abundance of benthic taxa because this strategy reduces the effect of bioturbation. Although there remains considerable scatter in the ventilation age estimates, on average, ventilation ages in the Equatorial Pacific were significantly greater below 3.2 km (~3080 ±1125 yrs, n=15) than in the depth interval 1.9 to 3.0 km (~1610 ± 250 yrs, n=12). When compared to the average modern seawater Δ14C profile for the North Pacific, the Equatorial Pacific glacial data suggest an abyssal front located somewhere between 3.0 and 3.2 km modern water depth. Above that depth, the data may indicate slightly better ventilation than today, and below that depth, glacial Equatorial Pacific data appear to be as old as last glacial maximum (LGM) deep water ages reported for the deep southern Atlantic. This suggests that a glacial reservoir of aged waters extended throughout the circumpolar Southern Ocean and into the Equatorial Pacific. Renewed ventilation of such a large volume of aged (and, by corollary, carbon-rich) water would help to account for the rise in atmospheric pCO2 and the fall in Δ14C as the glaciation drew to a close. This work was funded by NSF grants OCE-1031224 and OCE-0424861 to LDK and 0851391 to SJL. Report Planktonic foraminifera Southern Ocean Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) Southern Ocean Pacific Earth and Planetary Science Letters 425 93 104 |
institution |
Open Polar |
collection |
Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) |
op_collection_id |
ftwhoas |
language |
English |
topic |
Radiocarbon Foraminifera Ocean ventilation Pacific Ocean |
spellingShingle |
Radiocarbon Foraminifera Ocean ventilation Pacific Ocean Keigwin, Lloyd D. Lehman, Scott J. Radiocarbon evidence for a possible abyssal front near 3.1 km in the glacial equatorial Pacific Ocean |
topic_facet |
Radiocarbon Foraminifera Ocean ventilation Pacific Ocean |
description |
Author Posting. © The Author(s), 2014. This is the author's version of the work. It is posted here by permission of Elsevier for personal use, not for redistribution. The definitive version was published in Earth and Planetary Science Letters 425 (2015): 93-104, doi:10.1016/j.epsl.2015.05.025. We investigate the radiocarbon ventilation age in deep equatorial Pacific sediment cores using the difference in conventional 14C age between coexisting benthic and planktonic foraminifera, and integrate those results with similar data from around the North Pacific Ocean in a reconstruction for the last glaciation (15 to 25 conventional 14C ka). Most new data from both the Equatorial Pacific and the Emperor Seamounts in the northwestern Pacific come from maxima in abundance of benthic taxa because this strategy reduces the effect of bioturbation. Although there remains considerable scatter in the ventilation age estimates, on average, ventilation ages in the Equatorial Pacific were significantly greater below 3.2 km (~3080 ±1125 yrs, n=15) than in the depth interval 1.9 to 3.0 km (~1610 ± 250 yrs, n=12). When compared to the average modern seawater Δ14C profile for the North Pacific, the Equatorial Pacific glacial data suggest an abyssal front located somewhere between 3.0 and 3.2 km modern water depth. Above that depth, the data may indicate slightly better ventilation than today, and below that depth, glacial Equatorial Pacific data appear to be as old as last glacial maximum (LGM) deep water ages reported for the deep southern Atlantic. This suggests that a glacial reservoir of aged waters extended throughout the circumpolar Southern Ocean and into the Equatorial Pacific. Renewed ventilation of such a large volume of aged (and, by corollary, carbon-rich) water would help to account for the rise in atmospheric pCO2 and the fall in Δ14C as the glaciation drew to a close. This work was funded by NSF grants OCE-1031224 and OCE-0424861 to LDK and 0851391 to SJL. |
format |
Report |
author |
Keigwin, Lloyd D. Lehman, Scott J. |
author_facet |
Keigwin, Lloyd D. Lehman, Scott J. |
author_sort |
Keigwin, Lloyd D. |
title |
Radiocarbon evidence for a possible abyssal front near 3.1 km in the glacial equatorial Pacific Ocean |
title_short |
Radiocarbon evidence for a possible abyssal front near 3.1 km in the glacial equatorial Pacific Ocean |
title_full |
Radiocarbon evidence for a possible abyssal front near 3.1 km in the glacial equatorial Pacific Ocean |
title_fullStr |
Radiocarbon evidence for a possible abyssal front near 3.1 km in the glacial equatorial Pacific Ocean |
title_full_unstemmed |
Radiocarbon evidence for a possible abyssal front near 3.1 km in the glacial equatorial Pacific Ocean |
title_sort |
radiocarbon evidence for a possible abyssal front near 3.1 km in the glacial equatorial pacific ocean |
publishDate |
2014 |
url |
https://hdl.handle.net/1912/7457 |
geographic |
Southern Ocean Pacific |
geographic_facet |
Southern Ocean Pacific |
genre |
Planktonic foraminifera Southern Ocean |
genre_facet |
Planktonic foraminifera Southern Ocean |
op_relation |
https://doi.org/10.1016/j.epsl.2015.05.025 https://hdl.handle.net/1912/7457 |
op_doi |
https://doi.org/10.1016/j.epsl.2015.05.025 |
container_title |
Earth and Planetary Science Letters |
container_volume |
425 |
container_start_page |
93 |
op_container_end_page |
104 |
_version_ |
1766170470169706496 |