Structural limitations in deriving accurate U-series ages from calcitic cold-water corals contrasts with robust coral radiocarbon and Mg/Ca systematics
Radiocarbon and uranium-thorium dating results are presented from a genus of calcitic Antarctic cold-water octocorals (family Coralliidae), which were collected from the Marie Byrd Seamounts in the Amundsen Sea (Pacific sector of the Southern Ocean) and which to date have not been investigated geoch...
Published in: | Chemical Geology |
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Main Authors: | , , , , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
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2013
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Online Access: | https://risweb.st-andrews.ac.uk/portal/en/researchoutput/structural-limitations-in-deriving-accurate-useries-ages-from-calcitic-coldwater-corals-contrasts-with-robust-coral-radiocarbon-and-mgca-systematics(bf98614b-d467-43cf-ab76-ccb7b4fae03e).html https://doi.org/10.1016/j.chemgeo.2013.07.002 http://www.sciencedirect.com/science/article/pii/S0009254113002945 |
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ftunstandrewcris:oai:risweb.st-andrews.ac.uk:publications/bf98614b-d467-43cf-ab76-ccb7b4fae03e 2023-05-15T13:24:01+02:00 Structural limitations in deriving accurate U-series ages from calcitic cold-water corals contrasts with robust coral radiocarbon and Mg/Ca systematics Gutjahr, M. Vance, D. Hoffmann, D. L. Hillenbrand, C-D Foster, G. L. Rae, James William Buchanan Kuhn, G. 2013 https://risweb.st-andrews.ac.uk/portal/en/researchoutput/structural-limitations-in-deriving-accurate-useries-ages-from-calcitic-coldwater-corals-contrasts-with-robust-coral-radiocarbon-and-mgca-systematics(bf98614b-d467-43cf-ab76-ccb7b4fae03e).html https://doi.org/10.1016/j.chemgeo.2013.07.002 http://www.sciencedirect.com/science/article/pii/S0009254113002945 eng eng info:eu-repo/semantics/restrictedAccess Gutjahr , M , Vance , D , Hoffmann , D L , Hillenbrand , C-D , Foster , G L , Rae , J W B & Kuhn , G 2013 , ' Structural limitations in deriving accurate U-series ages from calcitic cold-water corals contrasts with robust coral radiocarbon and Mg/Ca systematics ' , Chemical Geology , vol. 355 , pp. 69-87 . https://doi.org/10.1016/j.chemgeo.2013.07.002 radiocarbon U-series dating cold-water corals Soputhern Ocean radiocarbon ventilation age octocoral Mg/Ca Mg/Li vital effect high Mg calcite uranium diffusion article 2013 ftunstandrewcris https://doi.org/10.1016/j.chemgeo.2013.07.002 2021-12-26T14:23:12Z Radiocarbon and uranium-thorium dating results are presented from a genus of calcitic Antarctic cold-water octocorals (family Coralliidae), which were collected from the Marie Byrd Seamounts in the Amundsen Sea (Pacific sector of the Southern Ocean) and which to date have not been investigated geochemically. The geochronological results are set in context with solution and laser ablation-based element/Ca ratios (Li, B, Mg, Mn, Sr, Ba, U, Th). Octocoral radiocarbon ages on living corals are in excellent agreement with modern ambient deep-water Δ14C, while multiple samples of individual fossil coral specimens yielded reproducible radiocarbon ages. Provided that local radiocarbon reservoir ages can be derived for a given time, fossil Amundsen Sea octocorals should be reliably dateable by means of radiocarbon. In contrast to the encouraging radiocarbon findings, the uranium-series data are more difficult to interpret. The uranium concentration of these calcitic octocorals is an order of magnitude lower than in the aragonitic hexacorals that are conventionally used for geochronological investigations. While modern and Late Holocene octocorals yield initial δ234U in good agreement with modern seawater, our results reveal preferential inward diffusion of dissolved alpha-recoiled 234U and its impact on fossil coral δ234U. Besides alpha-recoil related 234U diffusion, high-resolution sampling of two fossil octocorals further demonstrates that diagenetic uranium mobility has offset apparent coral U-series ages. Combined with the preferential alpha-recoil 234U diffusion, this process has prevented fossil octocorals from preserving a closed system U-series calendar age for longer than a few thousand years. Moreover, several corals investigated contain significant initial thorium, which cannot be adequately corrected for because of an apparently variable initial 232Th/230Th. Our results demonstrate that calcitic cold-water corals are unsuitable for reliable U-series dating. Mg/Ca ratios within single octocoral specimens are ... Article in Journal/Newspaper Amundsen Sea Antarc* Antarctic Southern Ocean University of St Andrews: Research Portal Amundsen Sea Antarctic Byrd Pacific Southern Ocean Chemical Geology 355 69 87 |
institution |
Open Polar |
collection |
University of St Andrews: Research Portal |
op_collection_id |
ftunstandrewcris |
language |
English |
topic |
radiocarbon U-series dating cold-water corals Soputhern Ocean radiocarbon ventilation age octocoral Mg/Ca Mg/Li vital effect high Mg calcite uranium diffusion |
spellingShingle |
radiocarbon U-series dating cold-water corals Soputhern Ocean radiocarbon ventilation age octocoral Mg/Ca Mg/Li vital effect high Mg calcite uranium diffusion Gutjahr, M. Vance, D. Hoffmann, D. L. Hillenbrand, C-D Foster, G. L. Rae, James William Buchanan Kuhn, G. Structural limitations in deriving accurate U-series ages from calcitic cold-water corals contrasts with robust coral radiocarbon and Mg/Ca systematics |
topic_facet |
radiocarbon U-series dating cold-water corals Soputhern Ocean radiocarbon ventilation age octocoral Mg/Ca Mg/Li vital effect high Mg calcite uranium diffusion |
description |
Radiocarbon and uranium-thorium dating results are presented from a genus of calcitic Antarctic cold-water octocorals (family Coralliidae), which were collected from the Marie Byrd Seamounts in the Amundsen Sea (Pacific sector of the Southern Ocean) and which to date have not been investigated geochemically. The geochronological results are set in context with solution and laser ablation-based element/Ca ratios (Li, B, Mg, Mn, Sr, Ba, U, Th). Octocoral radiocarbon ages on living corals are in excellent agreement with modern ambient deep-water Δ14C, while multiple samples of individual fossil coral specimens yielded reproducible radiocarbon ages. Provided that local radiocarbon reservoir ages can be derived for a given time, fossil Amundsen Sea octocorals should be reliably dateable by means of radiocarbon. In contrast to the encouraging radiocarbon findings, the uranium-series data are more difficult to interpret. The uranium concentration of these calcitic octocorals is an order of magnitude lower than in the aragonitic hexacorals that are conventionally used for geochronological investigations. While modern and Late Holocene octocorals yield initial δ234U in good agreement with modern seawater, our results reveal preferential inward diffusion of dissolved alpha-recoiled 234U and its impact on fossil coral δ234U. Besides alpha-recoil related 234U diffusion, high-resolution sampling of two fossil octocorals further demonstrates that diagenetic uranium mobility has offset apparent coral U-series ages. Combined with the preferential alpha-recoil 234U diffusion, this process has prevented fossil octocorals from preserving a closed system U-series calendar age for longer than a few thousand years. Moreover, several corals investigated contain significant initial thorium, which cannot be adequately corrected for because of an apparently variable initial 232Th/230Th. Our results demonstrate that calcitic cold-water corals are unsuitable for reliable U-series dating. Mg/Ca ratios within single octocoral specimens are ... |
format |
Article in Journal/Newspaper |
author |
Gutjahr, M. Vance, D. Hoffmann, D. L. Hillenbrand, C-D Foster, G. L. Rae, James William Buchanan Kuhn, G. |
author_facet |
Gutjahr, M. Vance, D. Hoffmann, D. L. Hillenbrand, C-D Foster, G. L. Rae, James William Buchanan Kuhn, G. |
author_sort |
Gutjahr, M. |
title |
Structural limitations in deriving accurate U-series ages from calcitic cold-water corals contrasts with robust coral radiocarbon and Mg/Ca systematics |
title_short |
Structural limitations in deriving accurate U-series ages from calcitic cold-water corals contrasts with robust coral radiocarbon and Mg/Ca systematics |
title_full |
Structural limitations in deriving accurate U-series ages from calcitic cold-water corals contrasts with robust coral radiocarbon and Mg/Ca systematics |
title_fullStr |
Structural limitations in deriving accurate U-series ages from calcitic cold-water corals contrasts with robust coral radiocarbon and Mg/Ca systematics |
title_full_unstemmed |
Structural limitations in deriving accurate U-series ages from calcitic cold-water corals contrasts with robust coral radiocarbon and Mg/Ca systematics |
title_sort |
structural limitations in deriving accurate u-series ages from calcitic cold-water corals contrasts with robust coral radiocarbon and mg/ca systematics |
publishDate |
2013 |
url |
https://risweb.st-andrews.ac.uk/portal/en/researchoutput/structural-limitations-in-deriving-accurate-useries-ages-from-calcitic-coldwater-corals-contrasts-with-robust-coral-radiocarbon-and-mgca-systematics(bf98614b-d467-43cf-ab76-ccb7b4fae03e).html https://doi.org/10.1016/j.chemgeo.2013.07.002 http://www.sciencedirect.com/science/article/pii/S0009254113002945 |
geographic |
Amundsen Sea Antarctic Byrd Pacific Southern Ocean |
geographic_facet |
Amundsen Sea Antarctic Byrd Pacific Southern Ocean |
genre |
Amundsen Sea Antarc* Antarctic Southern Ocean |
genre_facet |
Amundsen Sea Antarc* Antarctic Southern Ocean |
op_source |
Gutjahr , M , Vance , D , Hoffmann , D L , Hillenbrand , C-D , Foster , G L , Rae , J W B & Kuhn , G 2013 , ' Structural limitations in deriving accurate U-series ages from calcitic cold-water corals contrasts with robust coral radiocarbon and Mg/Ca systematics ' , Chemical Geology , vol. 355 , pp. 69-87 . https://doi.org/10.1016/j.chemgeo.2013.07.002 |
op_rights |
info:eu-repo/semantics/restrictedAccess |
op_doi |
https://doi.org/10.1016/j.chemgeo.2013.07.002 |
container_title |
Chemical Geology |
container_volume |
355 |
container_start_page |
69 |
op_container_end_page |
87 |
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1766376961091829760 |