Neodymium isotopes and concentrations in aragonitic scleractinian cold-water coral skeletons - Modern calibration and evaluation of palaeo-applications
Cold-water corals (CWCs) are unique archives of mid-depth ocean chemistry and have been used successfully to reconstruct the neodymium (Nd) isotopic composition of seawater from a number of species. High and variable Nd concentrations in fossil corals however pose the question as to how Nd is incorp...
Published in: | Chemical Geology |
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Main Authors: | , , , , , , , , , |
Other Authors: | , , |
Format: | Article in Journal/Newspaper |
Language: | unknown |
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Elsevier
2017
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Online Access: | http://hdl.handle.net/10044/1/44234 https://doi.org/10.1016/j.chemgeo.2017.01.022 |
id |
ftimperialcol:oai:spiral.imperial.ac.uk:10044/1/44234 |
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record_format |
openpolar |
institution |
Open Polar |
collection |
Imperial College London: Spiral |
op_collection_id |
ftimperialcol |
language |
unknown |
topic |
Science & Technology Physical Sciences Geochemistry & Geophysics Neodymium isotopes Rare earth elements Cold-water corals Seawater Sediments Drake Passage RARE-EARTH-ELEMENTS DEEP-SEA CORAL SOUTHERN-OCEAN LOPHELIA-PERTUSA ATLANTIC SECTOR PALEOENVIRONMENTAL RECONSTRUCTIONS DESMOPHYLLUM-CRISTAGALLI NORTHEASTERN ATLANTIC LAST DEGLACIATION 0402 Geochemistry 0403 Geology 0406 Physical Geography And Environmental Geoscience |
spellingShingle |
Science & Technology Physical Sciences Geochemistry & Geophysics Neodymium isotopes Rare earth elements Cold-water corals Seawater Sediments Drake Passage RARE-EARTH-ELEMENTS DEEP-SEA CORAL SOUTHERN-OCEAN LOPHELIA-PERTUSA ATLANTIC SECTOR PALEOENVIRONMENTAL RECONSTRUCTIONS DESMOPHYLLUM-CRISTAGALLI NORTHEASTERN ATLANTIC LAST DEGLACIATION 0402 Geochemistry 0403 Geology 0406 Physical Geography And Environmental Geoscience Struve, T Van de Flierdt, T Burke, A Robinson, LF Hammond, SJ Crocket, KC Bradtmiller, LI Auro, ME Mohamedi, KJ White, NJ Neodymium isotopes and concentrations in aragonitic scleractinian cold-water coral skeletons - Modern calibration and evaluation of palaeo-applications |
topic_facet |
Science & Technology Physical Sciences Geochemistry & Geophysics Neodymium isotopes Rare earth elements Cold-water corals Seawater Sediments Drake Passage RARE-EARTH-ELEMENTS DEEP-SEA CORAL SOUTHERN-OCEAN LOPHELIA-PERTUSA ATLANTIC SECTOR PALEOENVIRONMENTAL RECONSTRUCTIONS DESMOPHYLLUM-CRISTAGALLI NORTHEASTERN ATLANTIC LAST DEGLACIATION 0402 Geochemistry 0403 Geology 0406 Physical Geography And Environmental Geoscience |
description |
Cold-water corals (CWCs) are unique archives of mid-depth ocean chemistry and have been used successfully to reconstruct the neodymium (Nd) isotopic composition of seawater from a number of species. High and variable Nd concentrations in fossil corals however pose the question as to how Nd is incorporated into their skeletons. We here present new results on modern specimens of Desmophyllum dianthus, Balanophyllia malouinensis, and Flabellum curvatum, collected from the Drake Passage, and Madrepora oculata, collected from the North Atlantic. All modern individuals were either collected alive or uranium-series dated to be < 500 years old for comparison with local surface sediments and seawater profiles. Modern coral Nd isotopic compositions generally agree with ambient seawater values, which in turn are consistent with previously published seawater analyses, supporting small vertical and lateral Nd isotope gradients in modern Drake Passage waters. Two Balanophyllia malouinensis specimens collected live however deviate by up to 0.6 epsilon units from ambient seawater. We therefore recommend that this species should be treated with caution for the reconstruction of past seawater Nd isotopic compositions. Seventy fossil Drake Passage CWCs were furthermore analysed for their Nd concentrations, revealing a large range from 7.3 to 964.5 ng/g. Samples of the species D. dianthus and Caryophyllia spp. show minor covariation of Nd with 232Th content, utilised to monitor contaminant phases in cleaned coral aragonite. Strong covariations between Nd and Th concentrations are however observed in the species B. malouinensis and G. antarctica. In order to better constrain the source and nature of Nd in the cleaned aragonitic skeletons, a subset of sixteen corals was investigated for its rare earth element (REE) content, as well as major and trace element geochemistry. Our new data provide supporting evidence that the applied cleaning protocol efficiently removes contaminant lithogenic and ferromanganese oxyhydroxide phases. Mass balance calculations and seawater-like REE patterns rule out lithogenic and ferromanganese oxyhydroxide phases as a major contributor to elevated Nd concentrations in coral aragonite. Based on mass balance considerations, geochemical evidence, and previously published independent work by solid-state nuclear magnetic resonance (NMR) spectroscopy, we suggest authigenic phosphate phases as a significant carrier of skeletal Nd. Such a carrier phase could explain sporadic appearance of high Nd concentrations in corals and would be coupled with seawater-derived Nd isotopic compositions, lending further confidence to the application of Nd isotopes as a water mass proxy in CWCs. |
author2 |
Commission of the European Communities The Leverhulme Trust Natural Environment Research Council (NERC) |
format |
Article in Journal/Newspaper |
author |
Struve, T Van de Flierdt, T Burke, A Robinson, LF Hammond, SJ Crocket, KC Bradtmiller, LI Auro, ME Mohamedi, KJ White, NJ |
author_facet |
Struve, T Van de Flierdt, T Burke, A Robinson, LF Hammond, SJ Crocket, KC Bradtmiller, LI Auro, ME Mohamedi, KJ White, NJ |
author_sort |
Struve, T |
title |
Neodymium isotopes and concentrations in aragonitic scleractinian cold-water coral skeletons - Modern calibration and evaluation of palaeo-applications |
title_short |
Neodymium isotopes and concentrations in aragonitic scleractinian cold-water coral skeletons - Modern calibration and evaluation of palaeo-applications |
title_full |
Neodymium isotopes and concentrations in aragonitic scleractinian cold-water coral skeletons - Modern calibration and evaluation of palaeo-applications |
title_fullStr |
Neodymium isotopes and concentrations in aragonitic scleractinian cold-water coral skeletons - Modern calibration and evaluation of palaeo-applications |
title_full_unstemmed |
Neodymium isotopes and concentrations in aragonitic scleractinian cold-water coral skeletons - Modern calibration and evaluation of palaeo-applications |
title_sort |
neodymium isotopes and concentrations in aragonitic scleractinian cold-water coral skeletons - modern calibration and evaluation of palaeo-applications |
publisher |
Elsevier |
publishDate |
2017 |
url |
http://hdl.handle.net/10044/1/44234 https://doi.org/10.1016/j.chemgeo.2017.01.022 |
geographic |
Drake Passage Southern Ocean |
geographic_facet |
Drake Passage Southern Ocean |
genre |
Antarc* Antarctica Drake Passage Lophelia pertusa North Atlantic Southern Ocean |
genre_facet |
Antarc* Antarctica Drake Passage Lophelia pertusa North Atlantic Southern Ocean |
op_source |
168 146 |
op_relation |
Chemical Geology |
op_rights |
© 2017 The Authors. Published by Elsevier B.V. This AAM is published online and distributed under a CC-BY license 4.0 (https://creativecommons.org/licenses/by/4.0/) |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.1016/j.chemgeo.2017.01.022 |
container_title |
Chemical Geology |
container_volume |
453 |
container_start_page |
146 |
op_container_end_page |
168 |
_version_ |
1766255015546060800 |
spelling |
ftimperialcol:oai:spiral.imperial.ac.uk:10044/1/44234 2023-05-15T13:51:15+02:00 Neodymium isotopes and concentrations in aragonitic scleractinian cold-water coral skeletons - Modern calibration and evaluation of palaeo-applications Struve, T Van de Flierdt, T Burke, A Robinson, LF Hammond, SJ Crocket, KC Bradtmiller, LI Auro, ME Mohamedi, KJ White, NJ Commission of the European Communities The Leverhulme Trust Natural Environment Research Council (NERC) 2017-01-24 http://hdl.handle.net/10044/1/44234 https://doi.org/10.1016/j.chemgeo.2017.01.022 unknown Elsevier Chemical Geology © 2017 The Authors. Published by Elsevier B.V. This AAM is published online and distributed under a CC-BY license 4.0 (https://creativecommons.org/licenses/by/4.0/) CC-BY 168 146 Science & Technology Physical Sciences Geochemistry & Geophysics Neodymium isotopes Rare earth elements Cold-water corals Seawater Sediments Drake Passage RARE-EARTH-ELEMENTS DEEP-SEA CORAL SOUTHERN-OCEAN LOPHELIA-PERTUSA ATLANTIC SECTOR PALEOENVIRONMENTAL RECONSTRUCTIONS DESMOPHYLLUM-CRISTAGALLI NORTHEASTERN ATLANTIC LAST DEGLACIATION 0402 Geochemistry 0403 Geology 0406 Physical Geography And Environmental Geoscience Journal Article 2017 ftimperialcol https://doi.org/10.1016/j.chemgeo.2017.01.022 2018-09-16T05:58:05Z Cold-water corals (CWCs) are unique archives of mid-depth ocean chemistry and have been used successfully to reconstruct the neodymium (Nd) isotopic composition of seawater from a number of species. High and variable Nd concentrations in fossil corals however pose the question as to how Nd is incorporated into their skeletons. We here present new results on modern specimens of Desmophyllum dianthus, Balanophyllia malouinensis, and Flabellum curvatum, collected from the Drake Passage, and Madrepora oculata, collected from the North Atlantic. All modern individuals were either collected alive or uranium-series dated to be < 500 years old for comparison with local surface sediments and seawater profiles. Modern coral Nd isotopic compositions generally agree with ambient seawater values, which in turn are consistent with previously published seawater analyses, supporting small vertical and lateral Nd isotope gradients in modern Drake Passage waters. Two Balanophyllia malouinensis specimens collected live however deviate by up to 0.6 epsilon units from ambient seawater. We therefore recommend that this species should be treated with caution for the reconstruction of past seawater Nd isotopic compositions. Seventy fossil Drake Passage CWCs were furthermore analysed for their Nd concentrations, revealing a large range from 7.3 to 964.5 ng/g. Samples of the species D. dianthus and Caryophyllia spp. show minor covariation of Nd with 232Th content, utilised to monitor contaminant phases in cleaned coral aragonite. Strong covariations between Nd and Th concentrations are however observed in the species B. malouinensis and G. antarctica. In order to better constrain the source and nature of Nd in the cleaned aragonitic skeletons, a subset of sixteen corals was investigated for its rare earth element (REE) content, as well as major and trace element geochemistry. Our new data provide supporting evidence that the applied cleaning protocol efficiently removes contaminant lithogenic and ferromanganese oxyhydroxide phases. Mass balance calculations and seawater-like REE patterns rule out lithogenic and ferromanganese oxyhydroxide phases as a major contributor to elevated Nd concentrations in coral aragonite. Based on mass balance considerations, geochemical evidence, and previously published independent work by solid-state nuclear magnetic resonance (NMR) spectroscopy, we suggest authigenic phosphate phases as a significant carrier of skeletal Nd. Such a carrier phase could explain sporadic appearance of high Nd concentrations in corals and would be coupled with seawater-derived Nd isotopic compositions, lending further confidence to the application of Nd isotopes as a water mass proxy in CWCs. Article in Journal/Newspaper Antarc* Antarctica Drake Passage Lophelia pertusa North Atlantic Southern Ocean Imperial College London: Spiral Drake Passage Southern Ocean Chemical Geology 453 146 168 |