Identification and removal of Mn-Mg-rich contaminant phases in foraminiferal tests: Implications for Mg/Ca past temperature reconstructions

The geochemical composition of foraminifera shells from an Ocean Drilling Program site in the Panama Basin has been analyzed by several analytical techniques (LA-ICP-MS, ICP-MS, XRD, SEM, EDX) in order to identify and evaluate the occurrence of contaminant phases which may bias paleoenvironmental re...

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Autores: Pena González, Leopoldo David, Calvo, Eva, Cacho Lascorz, Isabel, Eggins, S., Pelejero Bou, Carles
Tipo de recurso: artículo
Fecha de publicación:2006
País:España
Institución:Universidad de Barcelona
Repositorio:Dipòsit Digital de la UB
OAI Identifier:oai:diposit.ub.edu:2445/34589
Acceso en línea:https://hdl.handle.net/2445/34589
Access Level:acceso abierto
Palabra clave:Foraminífers
Geoquímica
Foraminifera
Geochemistry
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spelling Identification and removal of Mn-Mg-rich contaminant phases in foraminiferal tests: Implications for Mg/Ca past temperature reconstructionsPena González, Leopoldo DavidCalvo, EvaCacho Lascorz, IsabelEggins, S.Pelejero Bou, CarlesForaminífersGeoquímicaForaminiferaGeochemistryThe geochemical composition of foraminifera shells from an Ocean Drilling Program site in the Panama Basin has been analyzed by several analytical techniques (LA-ICP-MS, ICP-MS, XRD, SEM, EDX) in order to identify and evaluate the occurrence of contaminant phases which may bias paleoenvironmental reconstructions. LA-ICP-MS results on uncleaned tests indicate the presence of Mn-Mg-rich contaminant phases at the inner surfaces of the foraminiferal shells (which have Mn/Ca ratios up to 400 mmol mol-1 and Mg/Ca ratios up to 50 mmol mol-1). We have rigorously assessed the ability of different cleaning protocols to remove these contaminant phases and have obtained satisfactory results only when a reductive step is included. The analysis of cleaning residuals collected after each of the different cleaning steps applied reveals that high Mn values are associated with at least two different contaminant phases, of which only one is linked to high Mg values. XRD analysis further reveals that the Mn-Mg-rich phase is the Ca-Mn-Mg carbonate kutnahorite (Ca(Mn, Mg)(CO3)2). Our results demonstrate that the presence of kutnahorite-like minerals can bias Mg/Ca ratios toward higher values (by 7-36%) and lead to significant overestimation of past seawater temperatures (by 0.9 up to 6.2°C, in the case of these Panama Basin samples).2006info:eu-repo/semantics/articleapplication/pdfhttps://hdl.handle.net/2445/34589Articles publicats en revistes (Dinàmica de la Terra i l'Oceà)reponame:Dipòsit Digital de la UBinstname:Universidad de BarcelonaInglésGeochemistry Geophysics Geosystems, 2006, vol. 6, p. doi:10.1029/200(c) American Geophysical Union (AGU), 2006info:eu-repo/semantics/openAccessoai:diposit.ub.edu:2445/345892026-05-27T06:46:51Z
dc.title.none.fl_str_mv Identification and removal of Mn-Mg-rich contaminant phases in foraminiferal tests: Implications for Mg/Ca past temperature reconstructions
title Identification and removal of Mn-Mg-rich contaminant phases in foraminiferal tests: Implications for Mg/Ca past temperature reconstructions
spellingShingle Identification and removal of Mn-Mg-rich contaminant phases in foraminiferal tests: Implications for Mg/Ca past temperature reconstructions
Pena González, Leopoldo David
Foraminífers
Geoquímica
Foraminifera
Geochemistry
title_short Identification and removal of Mn-Mg-rich contaminant phases in foraminiferal tests: Implications for Mg/Ca past temperature reconstructions
title_full Identification and removal of Mn-Mg-rich contaminant phases in foraminiferal tests: Implications for Mg/Ca past temperature reconstructions
title_fullStr Identification and removal of Mn-Mg-rich contaminant phases in foraminiferal tests: Implications for Mg/Ca past temperature reconstructions
title_full_unstemmed Identification and removal of Mn-Mg-rich contaminant phases in foraminiferal tests: Implications for Mg/Ca past temperature reconstructions
title_sort Identification and removal of Mn-Mg-rich contaminant phases in foraminiferal tests: Implications for Mg/Ca past temperature reconstructions
dc.creator.none.fl_str_mv Pena González, Leopoldo David
Calvo, Eva
Cacho Lascorz, Isabel
Eggins, S.
Pelejero Bou, Carles
author Pena González, Leopoldo David
author_facet Pena González, Leopoldo David
Calvo, Eva
Cacho Lascorz, Isabel
Eggins, S.
Pelejero Bou, Carles
author_role author
author2 Calvo, Eva
Cacho Lascorz, Isabel
Eggins, S.
Pelejero Bou, Carles
author2_role author
author
author
author
dc.subject.none.fl_str_mv Foraminífers
Geoquímica
Foraminifera
Geochemistry
topic Foraminífers
Geoquímica
Foraminifera
Geochemistry
description The geochemical composition of foraminifera shells from an Ocean Drilling Program site in the Panama Basin has been analyzed by several analytical techniques (LA-ICP-MS, ICP-MS, XRD, SEM, EDX) in order to identify and evaluate the occurrence of contaminant phases which may bias paleoenvironmental reconstructions. LA-ICP-MS results on uncleaned tests indicate the presence of Mn-Mg-rich contaminant phases at the inner surfaces of the foraminiferal shells (which have Mn/Ca ratios up to 400 mmol mol-1 and Mg/Ca ratios up to 50 mmol mol-1). We have rigorously assessed the ability of different cleaning protocols to remove these contaminant phases and have obtained satisfactory results only when a reductive step is included. The analysis of cleaning residuals collected after each of the different cleaning steps applied reveals that high Mn values are associated with at least two different contaminant phases, of which only one is linked to high Mg values. XRD analysis further reveals that the Mn-Mg-rich phase is the Ca-Mn-Mg carbonate kutnahorite (Ca(Mn, Mg)(CO3)2). Our results demonstrate that the presence of kutnahorite-like minerals can bias Mg/Ca ratios toward higher values (by 7-36%) and lead to significant overestimation of past seawater temperatures (by 0.9 up to 6.2°C, in the case of these Panama Basin samples).
publishDate 2006
dc.date.none.fl_str_mv 2006
dc.type.none.fl_str_mv info:eu-repo/semantics/article
format article
dc.identifier.none.fl_str_mv https://hdl.handle.net/2445/34589
url https://hdl.handle.net/2445/34589
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv Geochemistry Geophysics Geosystems, 2006, vol. 6, p. doi:10.1029/200
dc.rights.none.fl_str_mv (c) American Geophysical Union (AGU), 2006
info:eu-repo/semantics/openAccess
rights_invalid_str_mv (c) American Geophysical Union (AGU), 2006
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.source.none.fl_str_mv Articles publicats en revistes (Dinàmica de la Terra i l'Oceà)
reponame:Dipòsit Digital de la UB
instname:Universidad de Barcelona
instname_str Universidad de Barcelona
reponame_str Dipòsit Digital de la UB
collection Dipòsit Digital de la UB
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15.301603

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