Nd and Sr isotope compositions of different phases of surface sediments in the South Pacific: Extraction of seawater signatures, boundary exchange, and detrital/dust provenance
The radiogenic isotope composition of neodymium (Nd) and strontium (Sr) are useful tools to investigate present and past oceanic circulation or input of terrigenous material. We present Nd and Sr isotope compositions extracted from different sedimentary phases, including early diagenetic Fe-Mn coati...
Published in: | Geochemistry, Geophysics, Geosystems |
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2014
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Online Access: | https://oceanrep.geomar.de/id/eprint/25591/ https://oceanrep.geomar.de/id/eprint/25591/1/Molina-Kescher%20et.al.pdf https://doi.org/10.1002/2014GC005443 |
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ftoceanrep:oai:oceanrep.geomar.de:25591 2023-05-15T13:49:04+02:00 Nd and Sr isotope compositions of different phases of surface sediments in the South Pacific: Extraction of seawater signatures, boundary exchange, and detrital/dust provenance Molina-Kescher, Mario Frank, Martin Hathorne, Ed C. 2014-09-02 text https://oceanrep.geomar.de/id/eprint/25591/ https://oceanrep.geomar.de/id/eprint/25591/1/Molina-Kescher%20et.al.pdf https://doi.org/10.1002/2014GC005443 en eng AGU (American Geophysical Union) Wiley https://oceanrep.geomar.de/id/eprint/25591/1/Molina-Kescher%20et.al.pdf Molina-Kescher, M., Frank, M. and Hathorne, E. C. (2014) Nd and Sr isotope compositions of different phases of surface sediments in the South Pacific: Extraction of seawater signatures, boundary exchange, and detrital/dust provenance. Open Access Geochemistry, Geophysics, Geosystems, 15 (9). pp. 3502-3520. DOI 10.1002/2014GC005443 <https://doi.org/10.1002/2014GC005443>. doi:10.1002/2014GC005443 info:eu-repo/semantics/openAccess Article PeerReviewed 2014 ftoceanrep https://doi.org/10.1002/2014GC005443 2023-04-07T15:14:15Z The radiogenic isotope composition of neodymium (Nd) and strontium (Sr) are useful tools to investigate present and past oceanic circulation or input of terrigenous material. We present Nd and Sr isotope compositions extracted from different sedimentary phases, including early diagenetic Fe-Mn coatings, ‘‘unclean’’ foraminiferal shells, fossil fish teeth, and detritus of marine surface sediments (core-tops) covering the entire midlatitude South Pacific. Comparison of detrital Nd isotope compositions to deep water values from the same locations suggests that "boundary exchange" has little influence on the Nd isotope composition of western South Pacific seawater. Concentrations of Rare Earth Elements (REE) and Al/Ca ratios of "unclean" planktonic foraminifera suggest that this phase is a reliable recorder of seawater Nd isotope composition. The signatures obtained from fish teeth and "nondecarbonated" leachates of bulk sediment Fe-Mn oxyhydroxide coatings also agree with "unclean" foraminifera. Direct comparison of Nd isotope compositions extracted using these methods with seawater Nd isotope compositions is complicated by the low accumulation rates yielding radiocarbon ages of up to 24 kyr, thus mixing the signal of different ocean circulation modes. This suggests that different past seawater Nd isotope compositions have been integrated in authigenic sediments from regions with low sedimentation rates. Combined detrital Nd and Sr isotope signatures indicate a dominant role of the Westerly winds transporting lithogenic material from South New Zealand and Southeastern Australia to the open South Pacific. The proportion of this material decreases toward the east, where supply from the Andes increases and contributions from Antarctica cannot be ruled out. Article in Journal/Newspaper Antarc* Antarctica Planktonic foraminifera OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) New Zealand Pacific Geochemistry, Geophysics, Geosystems 15 9 3502 3520 |
institution |
Open Polar |
collection |
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
op_collection_id |
ftoceanrep |
language |
English |
description |
The radiogenic isotope composition of neodymium (Nd) and strontium (Sr) are useful tools to investigate present and past oceanic circulation or input of terrigenous material. We present Nd and Sr isotope compositions extracted from different sedimentary phases, including early diagenetic Fe-Mn coatings, ‘‘unclean’’ foraminiferal shells, fossil fish teeth, and detritus of marine surface sediments (core-tops) covering the entire midlatitude South Pacific. Comparison of detrital Nd isotope compositions to deep water values from the same locations suggests that "boundary exchange" has little influence on the Nd isotope composition of western South Pacific seawater. Concentrations of Rare Earth Elements (REE) and Al/Ca ratios of "unclean" planktonic foraminifera suggest that this phase is a reliable recorder of seawater Nd isotope composition. The signatures obtained from fish teeth and "nondecarbonated" leachates of bulk sediment Fe-Mn oxyhydroxide coatings also agree with "unclean" foraminifera. Direct comparison of Nd isotope compositions extracted using these methods with seawater Nd isotope compositions is complicated by the low accumulation rates yielding radiocarbon ages of up to 24 kyr, thus mixing the signal of different ocean circulation modes. This suggests that different past seawater Nd isotope compositions have been integrated in authigenic sediments from regions with low sedimentation rates. Combined detrital Nd and Sr isotope signatures indicate a dominant role of the Westerly winds transporting lithogenic material from South New Zealand and Southeastern Australia to the open South Pacific. The proportion of this material decreases toward the east, where supply from the Andes increases and contributions from Antarctica cannot be ruled out. |
format |
Article in Journal/Newspaper |
author |
Molina-Kescher, Mario Frank, Martin Hathorne, Ed C. |
spellingShingle |
Molina-Kescher, Mario Frank, Martin Hathorne, Ed C. Nd and Sr isotope compositions of different phases of surface sediments in the South Pacific: Extraction of seawater signatures, boundary exchange, and detrital/dust provenance |
author_facet |
Molina-Kescher, Mario Frank, Martin Hathorne, Ed C. |
author_sort |
Molina-Kescher, Mario |
title |
Nd and Sr isotope compositions of different phases of surface sediments in the South Pacific: Extraction of seawater signatures, boundary exchange, and detrital/dust provenance |
title_short |
Nd and Sr isotope compositions of different phases of surface sediments in the South Pacific: Extraction of seawater signatures, boundary exchange, and detrital/dust provenance |
title_full |
Nd and Sr isotope compositions of different phases of surface sediments in the South Pacific: Extraction of seawater signatures, boundary exchange, and detrital/dust provenance |
title_fullStr |
Nd and Sr isotope compositions of different phases of surface sediments in the South Pacific: Extraction of seawater signatures, boundary exchange, and detrital/dust provenance |
title_full_unstemmed |
Nd and Sr isotope compositions of different phases of surface sediments in the South Pacific: Extraction of seawater signatures, boundary exchange, and detrital/dust provenance |
title_sort |
nd and sr isotope compositions of different phases of surface sediments in the south pacific: extraction of seawater signatures, boundary exchange, and detrital/dust provenance |
publisher |
AGU (American Geophysical Union) |
publishDate |
2014 |
url |
https://oceanrep.geomar.de/id/eprint/25591/ https://oceanrep.geomar.de/id/eprint/25591/1/Molina-Kescher%20et.al.pdf https://doi.org/10.1002/2014GC005443 |
geographic |
New Zealand Pacific |
geographic_facet |
New Zealand Pacific |
genre |
Antarc* Antarctica Planktonic foraminifera |
genre_facet |
Antarc* Antarctica Planktonic foraminifera |
op_relation |
https://oceanrep.geomar.de/id/eprint/25591/1/Molina-Kescher%20et.al.pdf Molina-Kescher, M., Frank, M. and Hathorne, E. C. (2014) Nd and Sr isotope compositions of different phases of surface sediments in the South Pacific: Extraction of seawater signatures, boundary exchange, and detrital/dust provenance. Open Access Geochemistry, Geophysics, Geosystems, 15 (9). pp. 3502-3520. DOI 10.1002/2014GC005443 <https://doi.org/10.1002/2014GC005443>. doi:10.1002/2014GC005443 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1002/2014GC005443 |
container_title |
Geochemistry, Geophysics, Geosystems |
container_volume |
15 |
container_issue |
9 |
container_start_page |
3502 |
op_container_end_page |
3520 |
_version_ |
1766250797845184512 |