Assessment of seawater Nd isotope signatures extracted from foraminiferal shells and authigenic phases of Gulf of Guinea sediments
The radiogenic neodymium (Nd) isotope composition of foraminiferal shells provides a powerful archive to investigate past changes in sources and mixing of water masses. However, seawater Nd isotope ratios extracted from foraminiferal shells can be biased by contaminant phases such as organic matter,...
Published in: | Geochimica et Cosmochimica Acta |
---|---|
Main Authors: | , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Elsevier
2013
|
Subjects: | |
Online Access: | https://oceanrep.geomar.de/id/eprint/22205/ https://oceanrep.geomar.de/id/eprint/22205/1/Kraft.pdf https://oceanrep.geomar.de/id/eprint/22205/7/Kraft_Suppl.docx https://doi.org/10.1016/j.gca.2013.07.029 |
id |
ftoceanrep:oai:oceanrep.geomar.de:22205 |
---|---|
record_format |
openpolar |
spelling |
ftoceanrep:oai:oceanrep.geomar.de:22205 2023-05-15T18:01:02+02:00 Assessment of seawater Nd isotope signatures extracted from foraminiferal shells and authigenic phases of Gulf of Guinea sediments Kraft, Steffanie Frank, Martin Hathorne, Ed C. Weldeab, Syee 2013-11-15 text https://oceanrep.geomar.de/id/eprint/22205/ https://oceanrep.geomar.de/id/eprint/22205/1/Kraft.pdf https://oceanrep.geomar.de/id/eprint/22205/7/Kraft_Suppl.docx https://doi.org/10.1016/j.gca.2013.07.029 en eng Elsevier https://oceanrep.geomar.de/id/eprint/22205/1/Kraft.pdf https://oceanrep.geomar.de/id/eprint/22205/7/Kraft_Suppl.docx Kraft, S., Frank, M. , Hathorne, E. C. and Weldeab, S. (2013) Assessment of seawater Nd isotope signatures extracted from foraminiferal shells and authigenic phases of Gulf of Guinea sediments. Geochimica et Cosmochimica Acta, 121 . pp. 414-435. DOI 10.1016/j.gca.2013.07.029 <https://doi.org/10.1016/j.gca.2013.07.029>. doi:10.1016/j.gca.2013.07.029 info:eu-repo/semantics/restrictedAccess Article PeerReviewed 2013 ftoceanrep https://doi.org/10.1016/j.gca.2013.07.029 2023-04-07T15:10:30Z The radiogenic neodymium (Nd) isotope composition of foraminiferal shells provides a powerful archive to investigate past changes in sources and mixing of water masses. However, seawater Nd isotope ratios extracted from foraminiferal shells can be biased by contaminant phases such as organic matter, silicates, or ferromanganese coatings, the removal of which requires rigorous multiple step cleaning of the samples. Here we investigate the efficiency of Flow Through and batch cleaning methods to extract seawater Nd isotope compositions from planktonic foraminifera in a shelf setting in the Gulf of Guinea that is strongly influenced by riverine sediment inputs. Nd isotope analyses of reductively and oxidatively cleaned mono-specific planktonic foraminiferal samples and reductively cleaned mixed benthic foraminifera were complemented by analyses of non-reductively cleaned mono-specific planktonic foraminiferal samples, Fe–Mn coatings of de-carbonated bulk sediment leachates, and the residual detrital fraction of the same sediment. Al/Ca and Mn/Ca ratios of fully cleaned foraminiferal samples reveal indistinguishable levels of cleaning efficiency between the batch and the Flow Through methods and the Nd isotope compositions obtained from application of both methods are identical within error. Furthermore, non-reductively cleaned foraminiferal samples have the same Nd isotope composition as reductively cleaned foraminifera at our study sites. Close to the Niger River mouth the Nd isotope composition of the foraminifera agree with the seawater Nd isotope composition of nearby stations. Based on the combined extracted Nd isotope signatures and element to calcium ratios, as well as rare earth element distribution patterns, we infer that the planktonic foraminiferal Nd isotope signatures reflect bottom water/pore water signatures. The isotopic composition of the bulk de-carbonated sediment leachates (Fe–Mn coatings) differs significantly from the foraminiferal data at this site and probably reflects particles that ... Article in Journal/Newspaper Planktonic foraminifera OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Geochimica et Cosmochimica Acta 121 414 435 |
institution |
Open Polar |
collection |
OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
op_collection_id |
ftoceanrep |
language |
English |
description |
The radiogenic neodymium (Nd) isotope composition of foraminiferal shells provides a powerful archive to investigate past changes in sources and mixing of water masses. However, seawater Nd isotope ratios extracted from foraminiferal shells can be biased by contaminant phases such as organic matter, silicates, or ferromanganese coatings, the removal of which requires rigorous multiple step cleaning of the samples. Here we investigate the efficiency of Flow Through and batch cleaning methods to extract seawater Nd isotope compositions from planktonic foraminifera in a shelf setting in the Gulf of Guinea that is strongly influenced by riverine sediment inputs. Nd isotope analyses of reductively and oxidatively cleaned mono-specific planktonic foraminiferal samples and reductively cleaned mixed benthic foraminifera were complemented by analyses of non-reductively cleaned mono-specific planktonic foraminiferal samples, Fe–Mn coatings of de-carbonated bulk sediment leachates, and the residual detrital fraction of the same sediment. Al/Ca and Mn/Ca ratios of fully cleaned foraminiferal samples reveal indistinguishable levels of cleaning efficiency between the batch and the Flow Through methods and the Nd isotope compositions obtained from application of both methods are identical within error. Furthermore, non-reductively cleaned foraminiferal samples have the same Nd isotope composition as reductively cleaned foraminifera at our study sites. Close to the Niger River mouth the Nd isotope composition of the foraminifera agree with the seawater Nd isotope composition of nearby stations. Based on the combined extracted Nd isotope signatures and element to calcium ratios, as well as rare earth element distribution patterns, we infer that the planktonic foraminiferal Nd isotope signatures reflect bottom water/pore water signatures. The isotopic composition of the bulk de-carbonated sediment leachates (Fe–Mn coatings) differs significantly from the foraminiferal data at this site and probably reflects particles that ... |
format |
Article in Journal/Newspaper |
author |
Kraft, Steffanie Frank, Martin Hathorne, Ed C. Weldeab, Syee |
spellingShingle |
Kraft, Steffanie Frank, Martin Hathorne, Ed C. Weldeab, Syee Assessment of seawater Nd isotope signatures extracted from foraminiferal shells and authigenic phases of Gulf of Guinea sediments |
author_facet |
Kraft, Steffanie Frank, Martin Hathorne, Ed C. Weldeab, Syee |
author_sort |
Kraft, Steffanie |
title |
Assessment of seawater Nd isotope signatures extracted from foraminiferal shells and authigenic phases of Gulf of Guinea sediments |
title_short |
Assessment of seawater Nd isotope signatures extracted from foraminiferal shells and authigenic phases of Gulf of Guinea sediments |
title_full |
Assessment of seawater Nd isotope signatures extracted from foraminiferal shells and authigenic phases of Gulf of Guinea sediments |
title_fullStr |
Assessment of seawater Nd isotope signatures extracted from foraminiferal shells and authigenic phases of Gulf of Guinea sediments |
title_full_unstemmed |
Assessment of seawater Nd isotope signatures extracted from foraminiferal shells and authigenic phases of Gulf of Guinea sediments |
title_sort |
assessment of seawater nd isotope signatures extracted from foraminiferal shells and authigenic phases of gulf of guinea sediments |
publisher |
Elsevier |
publishDate |
2013 |
url |
https://oceanrep.geomar.de/id/eprint/22205/ https://oceanrep.geomar.de/id/eprint/22205/1/Kraft.pdf https://oceanrep.geomar.de/id/eprint/22205/7/Kraft_Suppl.docx https://doi.org/10.1016/j.gca.2013.07.029 |
genre |
Planktonic foraminifera |
genre_facet |
Planktonic foraminifera |
op_relation |
https://oceanrep.geomar.de/id/eprint/22205/1/Kraft.pdf https://oceanrep.geomar.de/id/eprint/22205/7/Kraft_Suppl.docx Kraft, S., Frank, M. , Hathorne, E. C. and Weldeab, S. (2013) Assessment of seawater Nd isotope signatures extracted from foraminiferal shells and authigenic phases of Gulf of Guinea sediments. Geochimica et Cosmochimica Acta, 121 . pp. 414-435. DOI 10.1016/j.gca.2013.07.029 <https://doi.org/10.1016/j.gca.2013.07.029>. doi:10.1016/j.gca.2013.07.029 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1016/j.gca.2013.07.029 |
container_title |
Geochimica et Cosmochimica Acta |
container_volume |
121 |
container_start_page |
414 |
op_container_end_page |
435 |
_version_ |
1766170347710709760 |