Determination of the Mg/Mn ratio in foraminiferal coatings: An approach to correct Mg/Ca temperatures for Mn-rich contaminant phases
The occurrence of manganese-rich coatings on foraminifera can have a significant effect on their bulk Mg/Ca ratios thereby biasing seawater temperature reconstructions. The removal of this Mn phase requires a reductive cleaning step, but this has been suggested to preferentially dissolve Mg-rich bio...
Published in: | Earth and Planetary Science Letters |
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ftpubman:oai:pure.mpg.de:item_2420246 2023-08-20T04:00:16+02:00 Determination of the Mg/Mn ratio in foraminiferal coatings: An approach to correct Mg/Ca temperatures for Mn-rich contaminant phases Hasenfratz, A. Martinez-Garcia, A. Jaccard, S. Vance, D. Walle, M. Greaves, M. Haug, G. 2017 http://hdl.handle.net/11858/00-001M-0000-002D-9533-0 unknown info:eu-repo/semantics/altIdentifier/doi/10.1016/j.epsl.2016.10.004 http://hdl.handle.net/11858/00-001M-0000-002D-9533-0 Earth and Planetary Science Letters info:eu-repo/semantics/article 2017 ftpubman https://doi.org/10.1016/j.epsl.2016.10.004 2023-08-01T22:44:20Z The occurrence of manganese-rich coatings on foraminifera can have a significant effect on their bulk Mg/Ca ratios thereby biasing seawater temperature reconstructions. The removal of this Mn phase requires a reductive cleaning step, but this has been suggested to preferentially dissolve Mg-rich biogenic carbonate, potentially introducing an analytical bias in paleotemperature estimates. In this study, the geochemical composition of foraminifera tests from Mn-rich sediments from the Antarctic Southern Ocean (ODP Site 1094) was investigated using solution-based and laser ablation ICP-MS in order to determine the amount of Mg incorporated into the coatings. The analysis of planktonic and benthic foraminifera revealed a nearly constant Mg/Mn ratio in the Mn coating of ∼0.2 mol/mol. Consequently, the coating Mg/Mn ratio can be used to correct for the Mg incorporated into the Mn phase by using the down core Mn/Ca values of samples that have not been reductively cleaned. The consistency of the coating Mg/Mn ratio obtained in this study, as well as that found in samples from the Panama Basin, suggests that spatial variation of Mg/Mn in foraminiferal Mn overgrowths may be smaller than expected from Mn nodules and Mn–Ca carbonates. However, a site-specific assessment of the Mg/Mn ratio in foraminiferal coatings is recommended to improve the accuracy of the correction. Article in Journal/Newspaper Antarc* Antarctic Southern Ocean Max Planck Society: MPG.PuRe Antarctic Southern Ocean The Antarctic Earth and Planetary Science Letters 457 335 347 |
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Max Planck Society: MPG.PuRe |
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The occurrence of manganese-rich coatings on foraminifera can have a significant effect on their bulk Mg/Ca ratios thereby biasing seawater temperature reconstructions. The removal of this Mn phase requires a reductive cleaning step, but this has been suggested to preferentially dissolve Mg-rich biogenic carbonate, potentially introducing an analytical bias in paleotemperature estimates. In this study, the geochemical composition of foraminifera tests from Mn-rich sediments from the Antarctic Southern Ocean (ODP Site 1094) was investigated using solution-based and laser ablation ICP-MS in order to determine the amount of Mg incorporated into the coatings. The analysis of planktonic and benthic foraminifera revealed a nearly constant Mg/Mn ratio in the Mn coating of ∼0.2 mol/mol. Consequently, the coating Mg/Mn ratio can be used to correct for the Mg incorporated into the Mn phase by using the down core Mn/Ca values of samples that have not been reductively cleaned. The consistency of the coating Mg/Mn ratio obtained in this study, as well as that found in samples from the Panama Basin, suggests that spatial variation of Mg/Mn in foraminiferal Mn overgrowths may be smaller than expected from Mn nodules and Mn–Ca carbonates. However, a site-specific assessment of the Mg/Mn ratio in foraminiferal coatings is recommended to improve the accuracy of the correction. |
format |
Article in Journal/Newspaper |
author |
Hasenfratz, A. Martinez-Garcia, A. Jaccard, S. Vance, D. Walle, M. Greaves, M. Haug, G. |
spellingShingle |
Hasenfratz, A. Martinez-Garcia, A. Jaccard, S. Vance, D. Walle, M. Greaves, M. Haug, G. Determination of the Mg/Mn ratio in foraminiferal coatings: An approach to correct Mg/Ca temperatures for Mn-rich contaminant phases |
author_facet |
Hasenfratz, A. Martinez-Garcia, A. Jaccard, S. Vance, D. Walle, M. Greaves, M. Haug, G. |
author_sort |
Hasenfratz, A. |
title |
Determination of the Mg/Mn ratio in foraminiferal coatings: An approach to correct Mg/Ca temperatures for Mn-rich contaminant phases |
title_short |
Determination of the Mg/Mn ratio in foraminiferal coatings: An approach to correct Mg/Ca temperatures for Mn-rich contaminant phases |
title_full |
Determination of the Mg/Mn ratio in foraminiferal coatings: An approach to correct Mg/Ca temperatures for Mn-rich contaminant phases |
title_fullStr |
Determination of the Mg/Mn ratio in foraminiferal coatings: An approach to correct Mg/Ca temperatures for Mn-rich contaminant phases |
title_full_unstemmed |
Determination of the Mg/Mn ratio in foraminiferal coatings: An approach to correct Mg/Ca temperatures for Mn-rich contaminant phases |
title_sort |
determination of the mg/mn ratio in foraminiferal coatings: an approach to correct mg/ca temperatures for mn-rich contaminant phases |
publishDate |
2017 |
url |
http://hdl.handle.net/11858/00-001M-0000-002D-9533-0 |
geographic |
Antarctic Southern Ocean The Antarctic |
geographic_facet |
Antarctic Southern Ocean The Antarctic |
genre |
Antarc* Antarctic Southern Ocean |
genre_facet |
Antarc* Antarctic Southern Ocean |
op_source |
Earth and Planetary Science Letters |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1016/j.epsl.2016.10.004 http://hdl.handle.net/11858/00-001M-0000-002D-9533-0 |
op_doi |
https://doi.org/10.1016/j.epsl.2016.10.004 |
container_title |
Earth and Planetary Science Letters |
container_volume |
457 |
container_start_page |
335 |
op_container_end_page |
347 |
_version_ |
1774717344731365376 |