Deep circulation changes in the central South Atlantic during the past 145 kyrs reflected in a combined 231 Pa/ 230 Th, Neodymium isotope and benthic δ 13 C record
Previous work showed that South Atlantic sediments have lower glacial than Holocene (231)pa/Th-230, which was attributed to a switch in the flow direction of Atlantic deep-water. Debate exists, however as to the degree to which two processes - circulation and scavenging - determine sedimentary Pa-23...
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Online Access: | http://hdl.handle.net/11858/00-001M-0000-0029-21BF-9 |
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ftpubman:oai:pure.mpg.de:item_2231277 2024-09-09T19:56:50+00:00 Deep circulation changes in the central South Atlantic during the past 145 kyrs reflected in a combined 231 Pa/ 230 Th, Neodymium isotope and benthic δ 13 C record Jonkers, L. Zahn, R. Thomas, A. Henderson, G. Abouchami, W. Francois, R. Masque, P. Hall, I. Bickert, T. 2015 http://hdl.handle.net/11858/00-001M-0000-0029-21BF-9 unknown info:eu-repo/semantics/altIdentifier/doi/10.1016/j.epsl.2015.03.004 http://hdl.handle.net/11858/00-001M-0000-0029-21BF-9 Earth and Planetary Science Letters info:eu-repo/semantics/article 2015 ftpubman https://doi.org/10.1016/j.epsl.2015.03.004 2024-07-31T09:31:28Z Previous work showed that South Atlantic sediments have lower glacial than Holocene (231)pa/Th-230, which was attributed to a switch in the flow direction of Atlantic deep-water. Debate exists, however as to the degree to which two processes - circulation and scavenging - determine sedimentary Pa-231/Th-230, making this interpretation contentious. Here we address this issue using 145-kyr records of paleocirculation proxies. Benthic foraminiferal delta C-13, neodymium isotopes (epsilon(Nd)) and sedimentary Pa-231/Th-230 were all measured in a single sediment core from the South Atlantic subtropical gyre. This site largely excludes the influence of local productivity changes on Pa-231/Th-230 records. Measured Pa-231/Th-230 ranges between similar to 0.041 during glacials and similar to 0.055 during interglacial periods and is consistently lower than the production ratio, indicating export of Pa-231 from the central South Atlantic for the entire duration of the record. The lower glacial Pa-231/Th-230 is regionally consistent, suggesting that basin-scale oceanographic processes cause the decrease. In turn, less radiogenic epsilon(Nd) and lower benthic delta C-13 confirm the classical picture of an increase in Southern Component Water (SCW) influence in the Atlantic during glacial periods and point to a circulation control on the observed (231)pa/Th-230 decrease rather than a local productivity change. We suggest that associated with this change in water mass distribution the dominant sink for Pa-231 shifted from the margins of the South Atlantic and/or the Southern Ocean during interglacials, to the North Atlantic during glacial periods. Indeed, elevated Pa-231/Th-230 in the deep North Atlantic during glacials supports this mechanism of northward transport of Pa-231 by SCW. (C)2015 Elsevier B.V. All rights reserved. Article in Journal/Newspaper North Atlantic Southern Ocean Max Planck Society: MPG.PuRe Southern Ocean Earth and Planetary Science Letters 419 14 21 |
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Open Polar |
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Max Planck Society: MPG.PuRe |
op_collection_id |
ftpubman |
language |
unknown |
description |
Previous work showed that South Atlantic sediments have lower glacial than Holocene (231)pa/Th-230, which was attributed to a switch in the flow direction of Atlantic deep-water. Debate exists, however as to the degree to which two processes - circulation and scavenging - determine sedimentary Pa-231/Th-230, making this interpretation contentious. Here we address this issue using 145-kyr records of paleocirculation proxies. Benthic foraminiferal delta C-13, neodymium isotopes (epsilon(Nd)) and sedimentary Pa-231/Th-230 were all measured in a single sediment core from the South Atlantic subtropical gyre. This site largely excludes the influence of local productivity changes on Pa-231/Th-230 records. Measured Pa-231/Th-230 ranges between similar to 0.041 during glacials and similar to 0.055 during interglacial periods and is consistently lower than the production ratio, indicating export of Pa-231 from the central South Atlantic for the entire duration of the record. The lower glacial Pa-231/Th-230 is regionally consistent, suggesting that basin-scale oceanographic processes cause the decrease. In turn, less radiogenic epsilon(Nd) and lower benthic delta C-13 confirm the classical picture of an increase in Southern Component Water (SCW) influence in the Atlantic during glacial periods and point to a circulation control on the observed (231)pa/Th-230 decrease rather than a local productivity change. We suggest that associated with this change in water mass distribution the dominant sink for Pa-231 shifted from the margins of the South Atlantic and/or the Southern Ocean during interglacials, to the North Atlantic during glacial periods. Indeed, elevated Pa-231/Th-230 in the deep North Atlantic during glacials supports this mechanism of northward transport of Pa-231 by SCW. (C)2015 Elsevier B.V. All rights reserved. |
format |
Article in Journal/Newspaper |
author |
Jonkers, L. Zahn, R. Thomas, A. Henderson, G. Abouchami, W. Francois, R. Masque, P. Hall, I. Bickert, T. |
spellingShingle |
Jonkers, L. Zahn, R. Thomas, A. Henderson, G. Abouchami, W. Francois, R. Masque, P. Hall, I. Bickert, T. Deep circulation changes in the central South Atlantic during the past 145 kyrs reflected in a combined 231 Pa/ 230 Th, Neodymium isotope and benthic δ 13 C record |
author_facet |
Jonkers, L. Zahn, R. Thomas, A. Henderson, G. Abouchami, W. Francois, R. Masque, P. Hall, I. Bickert, T. |
author_sort |
Jonkers, L. |
title |
Deep circulation changes in the central South Atlantic during the past 145 kyrs reflected in a combined 231 Pa/ 230 Th, Neodymium isotope and benthic δ 13 C record |
title_short |
Deep circulation changes in the central South Atlantic during the past 145 kyrs reflected in a combined 231 Pa/ 230 Th, Neodymium isotope and benthic δ 13 C record |
title_full |
Deep circulation changes in the central South Atlantic during the past 145 kyrs reflected in a combined 231 Pa/ 230 Th, Neodymium isotope and benthic δ 13 C record |
title_fullStr |
Deep circulation changes in the central South Atlantic during the past 145 kyrs reflected in a combined 231 Pa/ 230 Th, Neodymium isotope and benthic δ 13 C record |
title_full_unstemmed |
Deep circulation changes in the central South Atlantic during the past 145 kyrs reflected in a combined 231 Pa/ 230 Th, Neodymium isotope and benthic δ 13 C record |
title_sort |
deep circulation changes in the central south atlantic during the past 145 kyrs reflected in a combined 231 pa/ 230 th, neodymium isotope and benthic δ 13 c record |
publishDate |
2015 |
url |
http://hdl.handle.net/11858/00-001M-0000-0029-21BF-9 |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
North Atlantic Southern Ocean |
genre_facet |
North Atlantic Southern Ocean |
op_source |
Earth and Planetary Science Letters |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.epsl.2015.03.004 http://hdl.handle.net/11858/00-001M-0000-0029-21BF-9 |
op_doi |
https://doi.org/10.1016/j.epsl.2015.03.004 |
container_title |
Earth and Planetary Science Letters |
container_volume |
419 |
container_start_page |
14 |
op_container_end_page |
21 |
_version_ |
1809927683955490816 |