Antarctic intermediate water circulation in the South Atlantic over the past 25,000 years
Author Posting. © American Geophysical Union, 2016. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 31 (2016): 1302–1314, doi:10.1002/2016PA002975. Antarctic Intermediate Water...
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ftwhoas:oai:darchive.mblwhoilibrary.org:1912/8607 2023-05-15T13:48:30+02:00 Antarctic intermediate water circulation in the South Atlantic over the past 25,000 years Howe, Jacob N. W. Piotrowski, Alexander M. Oppo, Delia W. Huang, Kuo-Fang Mulitza, Stefan Chiessi, Cristiano M. Blusztajn, Jerzy S. 2016-10-05 https://hdl.handle.net/1912/8607 en_US eng John Wiley & Sons https://doi.org/10.1002/2016PA002975 Paleoceanography 31 (2016): 1302–1314 https://hdl.handle.net/1912/8607 doi:10.1002/2016PA002975 Paleoceanography 31 (2016): 1302–1314 doi:10.1002/2016PA002975 Antarctic Intermediate Water Neodymium isotopes Degalciation South Atlantic Article 2016 ftwhoas https://doi.org/10.1002/2016PA002975 2022-05-28T22:59:48Z Author Posting. © American Geophysical Union, 2016. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 31 (2016): 1302–1314, doi:10.1002/2016PA002975. Antarctic Intermediate Water is an essential limb of the Atlantic meridional overturning circulation that redistributes heat and nutrients within the Atlantic Ocean. Existing reconstructions have yielded conflicting results on the history of Antarctic Intermediate Water penetration into the Atlantic across the most recent glacial termination. In this study we present leachate, foraminiferal, and detrital neodymium isotope data from three intermediate-depth cores collected from the southern Brazil margin in the South Atlantic covering the past 25 kyr. These results reveal that strong chemical leaching following decarbonation does not extract past seawater neodymium composition in this location. The new foraminiferal records reveal no changes in seawater Nd isotopes during abrupt Northern Hemisphere cold events at these sites. We therefore conclude that there is no evidence for greater incursion of Antarctic Intermediate Water into the South Atlantic during either the Younger Dryas or Heinrich Stadial 1. We do, however, observe more radiogenic Nd isotope values in the intermediate-depth South Atlantic during the mid-Holocene. This radiogenic excursion coincides with evidence for a southward shift in the Southern Hemisphere westerlies that may have resulted in a greater entrainment of radiogenic Pacific-sourced water during intermediate water production in the Atlantic sector of the Southern Ocean. Our intermediate-depth records show similar values to a deglacial foraminiferal Nd isotope record from the deep South Atlantic during the Younger Dryas but are clearly distinct during the Last Glacial Maximum and Heinrich Stadial 1, demonstrating that the South Atlantic remained chemically stratified during Heinrich Stadial 1. NERC Grant Numbers: ... Article in Journal/Newspaper Antarc* Antarctic Southern Ocean Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) Antarctic Southern Ocean Pacific Paleoceanography 31 10 1302 1314 |
institution |
Open Polar |
collection |
Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) |
op_collection_id |
ftwhoas |
language |
English |
topic |
Antarctic Intermediate Water Neodymium isotopes Degalciation South Atlantic |
spellingShingle |
Antarctic Intermediate Water Neodymium isotopes Degalciation South Atlantic Howe, Jacob N. W. Piotrowski, Alexander M. Oppo, Delia W. Huang, Kuo-Fang Mulitza, Stefan Chiessi, Cristiano M. Blusztajn, Jerzy S. Antarctic intermediate water circulation in the South Atlantic over the past 25,000 years |
topic_facet |
Antarctic Intermediate Water Neodymium isotopes Degalciation South Atlantic |
description |
Author Posting. © American Geophysical Union, 2016. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 31 (2016): 1302–1314, doi:10.1002/2016PA002975. Antarctic Intermediate Water is an essential limb of the Atlantic meridional overturning circulation that redistributes heat and nutrients within the Atlantic Ocean. Existing reconstructions have yielded conflicting results on the history of Antarctic Intermediate Water penetration into the Atlantic across the most recent glacial termination. In this study we present leachate, foraminiferal, and detrital neodymium isotope data from three intermediate-depth cores collected from the southern Brazil margin in the South Atlantic covering the past 25 kyr. These results reveal that strong chemical leaching following decarbonation does not extract past seawater neodymium composition in this location. The new foraminiferal records reveal no changes in seawater Nd isotopes during abrupt Northern Hemisphere cold events at these sites. We therefore conclude that there is no evidence for greater incursion of Antarctic Intermediate Water into the South Atlantic during either the Younger Dryas or Heinrich Stadial 1. We do, however, observe more radiogenic Nd isotope values in the intermediate-depth South Atlantic during the mid-Holocene. This radiogenic excursion coincides with evidence for a southward shift in the Southern Hemisphere westerlies that may have resulted in a greater entrainment of radiogenic Pacific-sourced water during intermediate water production in the Atlantic sector of the Southern Ocean. Our intermediate-depth records show similar values to a deglacial foraminiferal Nd isotope record from the deep South Atlantic during the Younger Dryas but are clearly distinct during the Last Glacial Maximum and Heinrich Stadial 1, demonstrating that the South Atlantic remained chemically stratified during Heinrich Stadial 1. NERC Grant Numbers: ... |
format |
Article in Journal/Newspaper |
author |
Howe, Jacob N. W. Piotrowski, Alexander M. Oppo, Delia W. Huang, Kuo-Fang Mulitza, Stefan Chiessi, Cristiano M. Blusztajn, Jerzy S. |
author_facet |
Howe, Jacob N. W. Piotrowski, Alexander M. Oppo, Delia W. Huang, Kuo-Fang Mulitza, Stefan Chiessi, Cristiano M. Blusztajn, Jerzy S. |
author_sort |
Howe, Jacob N. W. |
title |
Antarctic intermediate water circulation in the South Atlantic over the past 25,000 years |
title_short |
Antarctic intermediate water circulation in the South Atlantic over the past 25,000 years |
title_full |
Antarctic intermediate water circulation in the South Atlantic over the past 25,000 years |
title_fullStr |
Antarctic intermediate water circulation in the South Atlantic over the past 25,000 years |
title_full_unstemmed |
Antarctic intermediate water circulation in the South Atlantic over the past 25,000 years |
title_sort |
antarctic intermediate water circulation in the south atlantic over the past 25,000 years |
publisher |
John Wiley & Sons |
publishDate |
2016 |
url |
https://hdl.handle.net/1912/8607 |
geographic |
Antarctic Southern Ocean Pacific |
geographic_facet |
Antarctic Southern Ocean Pacific |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_source |
Paleoceanography 31 (2016): 1302–1314 doi:10.1002/2016PA002975 |
op_relation |
https://doi.org/10.1002/2016PA002975 Paleoceanography 31 (2016): 1302–1314 https://hdl.handle.net/1912/8607 doi:10.1002/2016PA002975 |
op_doi |
https://doi.org/10.1002/2016PA002975 |
container_title |
Paleoceanography |
container_volume |
31 |
container_issue |
10 |
container_start_page |
1302 |
op_container_end_page |
1314 |
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1766249338746437632 |