Sources and processes affecting the distribution of dissolved Nd isotopes and concentrations in the West Pacific
In the Atlantic, where deep circulation is vigorous, the dissolved neodymium (Nd) isotopic composition (expressed as ɛNd) is largely controlled by water mass mixing. In contrast, the factors influencing the ɛNd distribution in the Pacific, marked by sluggish circulation, is not clear yet. Indication...
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ftpubman:oai:pure.mpg.de:item_3040181 2023-08-20T04:02:30+02:00 Sources and processes affecting the distribution of dissolved Nd isotopes and concentrations in the West Pacific Behrens, M. Pahnke, K. Schnetger, B. Brumsack, H. 2018-02-01 application/pdf http://hdl.handle.net/21.11116/0000-0003-B7AC-D http://hdl.handle.net/21.11116/0000-0003-B7AE-B eng eng http://hdl.handle.net/21.11116/0000-0003-B7AC-D http://hdl.handle.net/21.11116/0000-0003-B7AE-B Geochimica et Cosmochimica Acta info:eu-repo/semantics/article 2018 ftpubman 2023-08-01T23:54:28Z In the Atlantic, where deep circulation is vigorous, the dissolved neodymium (Nd) isotopic composition (expressed as ɛNd) is largely controlled by water mass mixing. In contrast, the factors influencing the ɛNd distribution in the Pacific, marked by sluggish circulation, is not clear yet. Indication for regional overprints in the Pacific is given based on its bordering volcanic islands. Our study aims to clarify the impact and relative importance of different Nd sources (rivers, volcanic islands), vertical (bio)geochemical processes and lateral water mass transport in controlling dissolved ɛNd and Nd concentration ([Nd]) distributions in the West Pacific between South Korea and Fiji. We find indication for unradiogenic continental input from South Korean and Chinese rivers to the East China Sea. In the tropical West Pacific, volcanic islands supply Nd to surface and subsurface waters and modify their ɛNd to radiogenic values of up to +0.7. These radiogenic signatures allow detailed tracing of currents flowing to the east and differentiation from westward currents with open ocean Pacific ɛNd composition in the complex tropical Pacific zonal current system. Modified radiogenic ɛNd of West Pacific intermediate to bottom waters upstream or within our section also indicates non-conservative behavior of ɛNd due to boundary exchange at volcanic island margins, submarine ridges, and with hydrothermal particles. Only subsurface to deep waters (3000 m) in the open Northwest Pacific show conservative behavior of ɛNd. In contrast, we find a striking correlation of extremely low (down to 2.77 pmol/kg Nd) and laterally constant [Nd] with the high-salinity North and South Pacific Tropical Water, indicating lateral transport of preformed [Nd] from the North and South Pacific subtropical gyres into the study area. This observation also explains the previously observed low subsurface [Nd] in the tropical West Pacific. Similarly, Western South Pacific Central Water, Antarctic Intermediate Water, and Lower Circumpolar Deep Water in ... Article in Journal/Newspaper Antarc* Antarctic Max Planck Society: MPG.PuRe Antarctic Pacific |
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Open Polar |
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Max Planck Society: MPG.PuRe |
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ftpubman |
language |
English |
description |
In the Atlantic, where deep circulation is vigorous, the dissolved neodymium (Nd) isotopic composition (expressed as ɛNd) is largely controlled by water mass mixing. In contrast, the factors influencing the ɛNd distribution in the Pacific, marked by sluggish circulation, is not clear yet. Indication for regional overprints in the Pacific is given based on its bordering volcanic islands. Our study aims to clarify the impact and relative importance of different Nd sources (rivers, volcanic islands), vertical (bio)geochemical processes and lateral water mass transport in controlling dissolved ɛNd and Nd concentration ([Nd]) distributions in the West Pacific between South Korea and Fiji. We find indication for unradiogenic continental input from South Korean and Chinese rivers to the East China Sea. In the tropical West Pacific, volcanic islands supply Nd to surface and subsurface waters and modify their ɛNd to radiogenic values of up to +0.7. These radiogenic signatures allow detailed tracing of currents flowing to the east and differentiation from westward currents with open ocean Pacific ɛNd composition in the complex tropical Pacific zonal current system. Modified radiogenic ɛNd of West Pacific intermediate to bottom waters upstream or within our section also indicates non-conservative behavior of ɛNd due to boundary exchange at volcanic island margins, submarine ridges, and with hydrothermal particles. Only subsurface to deep waters (3000 m) in the open Northwest Pacific show conservative behavior of ɛNd. In contrast, we find a striking correlation of extremely low (down to 2.77 pmol/kg Nd) and laterally constant [Nd] with the high-salinity North and South Pacific Tropical Water, indicating lateral transport of preformed [Nd] from the North and South Pacific subtropical gyres into the study area. This observation also explains the previously observed low subsurface [Nd] in the tropical West Pacific. Similarly, Western South Pacific Central Water, Antarctic Intermediate Water, and Lower Circumpolar Deep Water in ... |
format |
Article in Journal/Newspaper |
author |
Behrens, M. Pahnke, K. Schnetger, B. Brumsack, H. |
spellingShingle |
Behrens, M. Pahnke, K. Schnetger, B. Brumsack, H. Sources and processes affecting the distribution of dissolved Nd isotopes and concentrations in the West Pacific |
author_facet |
Behrens, M. Pahnke, K. Schnetger, B. Brumsack, H. |
author_sort |
Behrens, M. |
title |
Sources and processes affecting the distribution of dissolved Nd isotopes and concentrations in the West Pacific |
title_short |
Sources and processes affecting the distribution of dissolved Nd isotopes and concentrations in the West Pacific |
title_full |
Sources and processes affecting the distribution of dissolved Nd isotopes and concentrations in the West Pacific |
title_fullStr |
Sources and processes affecting the distribution of dissolved Nd isotopes and concentrations in the West Pacific |
title_full_unstemmed |
Sources and processes affecting the distribution of dissolved Nd isotopes and concentrations in the West Pacific |
title_sort |
sources and processes affecting the distribution of dissolved nd isotopes and concentrations in the west pacific |
publishDate |
2018 |
url |
http://hdl.handle.net/21.11116/0000-0003-B7AC-D http://hdl.handle.net/21.11116/0000-0003-B7AE-B |
geographic |
Antarctic Pacific |
geographic_facet |
Antarctic Pacific |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
Geochimica et Cosmochimica Acta |
op_relation |
http://hdl.handle.net/21.11116/0000-0003-B7AC-D http://hdl.handle.net/21.11116/0000-0003-B7AE-B |
_version_ |
1774712974290714624 |