Benthic foraminiferal Mg/Ca-paleothermometry: a revised core-top calibration
Core-top samples from different ocean basins have been analyzed to refine our current understanding of the sensitivity of benthic foraminiferal calcite magnesium/calcium (Mg/Ca) to bottom water temperatures (BWT). Benthic foraminifera collected from Hawaii, Little Bahama Bank, Sea of Okhotsk, Gulf o...
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ftunivcardiff:oai:https://orca.cardiff.ac.uk:1288 2023-05-15T18:25:41+02:00 Benthic foraminiferal Mg/Ca-paleothermometry: a revised core-top calibration Lear, Caroline Helen Rosenthal, Yair Slowey, Niall 2002-10-01 https://orca.cardiff.ac.uk/id/eprint/1288/ https://doi.org/10.1016/S0016-7037(02)00941-9 unknown Elsevier Lear, Caroline Helen https://orca.cardiff.ac.uk/view/cardiffauthors/A048848V.html orcid:0000-0002-7533-4430 orcid:0000-0002-7533-4430, Rosenthal, Yair and Slowey, Niall 2002. Benthic foraminiferal Mg/Ca-paleothermometry: a revised core-top calibration. Geochimica Et Cosmochimica Acta 66 (19) , pp. 3375-3387. 10.1016/S0016-7037(02)00941-9 https://doi.org/10.1016/S0016-7037%2802%2900941-9 doi:10.1016/S0016-7037(02)00941-9 GC Oceanography QE Geology Article PeerReviewed 2002 ftunivcardiff https://doi.org/10.1016/S0016-7037(02)00941-9 2022-10-20T22:31:53Z Core-top samples from different ocean basins have been analyzed to refine our current understanding of the sensitivity of benthic foraminiferal calcite magnesium/calcium (Mg/Ca) to bottom water temperatures (BWT). Benthic foraminifera collected from Hawaii, Little Bahama Bank, Sea of Okhotsk, Gulf of California, NE Atlantic, Ceara Rise, Sierra Leone Rise, the Ontong Java Plateau, and the Southern Ocean covering a temperature range of 0.8 to 18°C were used to revise the Cibicidoides Mg/Ca-temperature calibration. The Mg/Ca–BWT relationship of three common Cibicidoides species is described by an exponential equation: Mg/Ca = 0.867 ± 0.049 exp (0.109 ± 0.007 × BWT) (stated errors are 95% CI). The temperature sensitivity is very similar to a previously published calibration. However, the revised calibration has a significantly different preexponential constant, resulting in different predicted absolute temperatures. We attribute this difference in the preexponential constant to an analytical issue of accuracy. Some genera, notably Uvigerina, show apparently lower temperature sensitivity than others, suggesting that the use of constant offsets to account for vital effects in Mg/Ca may not be appropriate. Downcore Mg/Ca reproducibility, as determined on replicate foraminiferal samples, is typically better than 0.1 mmol mol−1 (2 S.E.). Thus, considering the errors associated with the Cibicidoides calibration and the downcore reproducibility, BWT may be estimated to within ±1°C. Application of the revised core-top Mg/Ca–BWT data to Cenozoic foraminiferal Mg/Ca suggests that seawater Mg/Ca was not more than 35% lower than today in the ice-free ocean at 50 Ma. Article in Journal/Newspaper Southern Ocean Cardiff University: ORCA (Online Research @ Cardiff) Okhotsk Southern Ocean Geochimica et Cosmochimica Acta 66 19 3375 3387 |
institution |
Open Polar |
collection |
Cardiff University: ORCA (Online Research @ Cardiff) |
op_collection_id |
ftunivcardiff |
language |
unknown |
topic |
GC Oceanography QE Geology |
spellingShingle |
GC Oceanography QE Geology Lear, Caroline Helen Rosenthal, Yair Slowey, Niall Benthic foraminiferal Mg/Ca-paleothermometry: a revised core-top calibration |
topic_facet |
GC Oceanography QE Geology |
description |
Core-top samples from different ocean basins have been analyzed to refine our current understanding of the sensitivity of benthic foraminiferal calcite magnesium/calcium (Mg/Ca) to bottom water temperatures (BWT). Benthic foraminifera collected from Hawaii, Little Bahama Bank, Sea of Okhotsk, Gulf of California, NE Atlantic, Ceara Rise, Sierra Leone Rise, the Ontong Java Plateau, and the Southern Ocean covering a temperature range of 0.8 to 18°C were used to revise the Cibicidoides Mg/Ca-temperature calibration. The Mg/Ca–BWT relationship of three common Cibicidoides species is described by an exponential equation: Mg/Ca = 0.867 ± 0.049 exp (0.109 ± 0.007 × BWT) (stated errors are 95% CI). The temperature sensitivity is very similar to a previously published calibration. However, the revised calibration has a significantly different preexponential constant, resulting in different predicted absolute temperatures. We attribute this difference in the preexponential constant to an analytical issue of accuracy. Some genera, notably Uvigerina, show apparently lower temperature sensitivity than others, suggesting that the use of constant offsets to account for vital effects in Mg/Ca may not be appropriate. Downcore Mg/Ca reproducibility, as determined on replicate foraminiferal samples, is typically better than 0.1 mmol mol−1 (2 S.E.). Thus, considering the errors associated with the Cibicidoides calibration and the downcore reproducibility, BWT may be estimated to within ±1°C. Application of the revised core-top Mg/Ca–BWT data to Cenozoic foraminiferal Mg/Ca suggests that seawater Mg/Ca was not more than 35% lower than today in the ice-free ocean at 50 Ma. |
format |
Article in Journal/Newspaper |
author |
Lear, Caroline Helen Rosenthal, Yair Slowey, Niall |
author_facet |
Lear, Caroline Helen Rosenthal, Yair Slowey, Niall |
author_sort |
Lear, Caroline Helen |
title |
Benthic foraminiferal Mg/Ca-paleothermometry: a revised core-top calibration |
title_short |
Benthic foraminiferal Mg/Ca-paleothermometry: a revised core-top calibration |
title_full |
Benthic foraminiferal Mg/Ca-paleothermometry: a revised core-top calibration |
title_fullStr |
Benthic foraminiferal Mg/Ca-paleothermometry: a revised core-top calibration |
title_full_unstemmed |
Benthic foraminiferal Mg/Ca-paleothermometry: a revised core-top calibration |
title_sort |
benthic foraminiferal mg/ca-paleothermometry: a revised core-top calibration |
publisher |
Elsevier |
publishDate |
2002 |
url |
https://orca.cardiff.ac.uk/id/eprint/1288/ https://doi.org/10.1016/S0016-7037(02)00941-9 |
geographic |
Okhotsk Southern Ocean |
geographic_facet |
Okhotsk Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_relation |
Lear, Caroline Helen https://orca.cardiff.ac.uk/view/cardiffauthors/A048848V.html orcid:0000-0002-7533-4430 orcid:0000-0002-7533-4430, Rosenthal, Yair and Slowey, Niall 2002. Benthic foraminiferal Mg/Ca-paleothermometry: a revised core-top calibration. Geochimica Et Cosmochimica Acta 66 (19) , pp. 3375-3387. 10.1016/S0016-7037(02)00941-9 https://doi.org/10.1016/S0016-7037%2802%2900941-9 doi:10.1016/S0016-7037(02)00941-9 |
op_doi |
https://doi.org/10.1016/S0016-7037(02)00941-9 |
container_title |
Geochimica et Cosmochimica Acta |
container_volume |
66 |
container_issue |
19 |
container_start_page |
3375 |
op_container_end_page |
3387 |
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1766207294631051264 |