Preservation of Fe/Mn-redox fronts in sediments of an oligotrophic, oxygenated deep-water lake (Lago Fagnano, Tierra del Fuego)

Changing redox conditions in water columns or sediment–water interfaces of lakes are captured as sedimentary archives, and are often influenced by climate. Their study therefore permits the reconstruction of past climate change on (sub-) annual to longer timescales. In Lago Fagnano (54°S Argentina/C...

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Autores: Neugebauer, Ina, Thomas, Camile, Ordoñez, Luis, Waldmann, Nicolas D., Recasens, Cristina, Vizcaino, Alexis, Jiménez-Espejo, Francisco J., Ariztegui, Daniel
Formato: artículo
Estado:Versión publicada
Fecha de publicación:2022
País:España
Recursos:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/358156
Acesso em linha:http://hdl.handle.net/10261/358156
Access Level:acceso abierto
Palavra-chave:Early diagenesis
Fe-/Mn-oxides
Mixed lakes
Redox fronts
Sedimentary geochemistry
Southern Hemisphere Westerlies
Southernmost Patagonia
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spelling Preservation of Fe/Mn-redox fronts in sediments of an oligotrophic, oxygenated deep-water lake (Lago Fagnano, Tierra del Fuego)Neugebauer, InaThomas, CamileOrdoñez, LuisWaldmann, Nicolas D.Recasens, CristinaVizcaino, AlexisJiménez-Espejo, Francisco J.Ariztegui, DanielEarly diagenesisFe-/Mn-oxidesMixed lakesRedox frontsSedimentary geochemistrySouthern Hemisphere WesterliesSouthernmost PatagoniaChanging redox conditions in water columns or sediment–water interfaces of lakes are captured as sedimentary archives, and are often influenced by climate. Their study therefore permits the reconstruction of past climate change on (sub-) annual to longer timescales. In Lago Fagnano (54°S Argentina/Chile), a large oligotrophic and deep-oxygenated lake, alternations of light grey clay and dark greenish and black laminae are preserved throughout the Holocene sedimentary record. This study aims to clarify the mechanism of laminae formation and preservation in Lago Fagnano, and their relation to changing redox conditions in the lake. High-resolution major element scanning and mapping along with detailed mineralogical analyses of sediment cores allowed identifying Fe-oxides, Mn-oxides and Fe-(mono) sulphides as responsible for the lamination. Based on the interpretation of redox processes at the current sedimentary redox boundary and of buried palaeo-redox fronts underlying mass-transported deposits, the greenish laminae enriched in Fe-oxides are interpreted as palaeo-redox fronts. The preservation of such former interfaces in Lago Fagnano sediments is most likely promoted by rapid increases of sedimentation due to higher runoff related to stronger Southern Hemisphere Westerlies. The formation of black laminae, showing only traces of Fe-(mono) sulphides and organic matter, is obscured by oxidation and early diagenetic processes, i.e. degradation and partial pyritization. These layers were presumably generated by small changes in bottom-water oxygenation due to reduced mixing and/or higher productivity. This study highlights the value of high-resolution sediment−geochemical analyses to better understand redox and diagenetic processes in oligotrophic mixed lakes.This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 706244, and from the Swiss National Science Foundation SNSF (grant No. 200021_166308/1). We thank Hendrik Vogel and Flavio Anselmetti (University of Bern) for hospitality and assistance during ITRAX-XRF measurements, Agathe Martignier (University of Geneva) for assisting the SEM, Michael Köhler (MKfactory, Stahnsdorf) for thin section preparation, Michèle Dinies (Freie Universität Berlin) for pollen extraction, and Rik Tjallingii (GFZ Potsdam) for advice in XRF data processing. We declare that there is no conflict of interest concerning this research. Open Access Funding provided by Universite de Geneve.Wiley-VCHUniversity of BernEuropean CommissionFreie Universität BerlinConsejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]2024202420222024info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Publisher's versioninfo:eu-repo/semantics/publishedVersionhttp://hdl.handle.net/10261/358156reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Inglés#PLACEHOLDER_PARENT_METADATA_VALUE#info:eu-repo/grantAgreement/EC/H2020/706244http://dx.doi.org/10.1111/sed.12976Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/3581562026-05-22T06:33:51Z
dc.title.none.fl_str_mv Preservation of Fe/Mn-redox fronts in sediments of an oligotrophic, oxygenated deep-water lake (Lago Fagnano, Tierra del Fuego)
title Preservation of Fe/Mn-redox fronts in sediments of an oligotrophic, oxygenated deep-water lake (Lago Fagnano, Tierra del Fuego)
spellingShingle Preservation of Fe/Mn-redox fronts in sediments of an oligotrophic, oxygenated deep-water lake (Lago Fagnano, Tierra del Fuego)
Neugebauer, Ina
Early diagenesis
Fe-/Mn-oxides
Mixed lakes
Redox fronts
Sedimentary geochemistry
Southern Hemisphere Westerlies
Southernmost Patagonia
title_short Preservation of Fe/Mn-redox fronts in sediments of an oligotrophic, oxygenated deep-water lake (Lago Fagnano, Tierra del Fuego)
title_full Preservation of Fe/Mn-redox fronts in sediments of an oligotrophic, oxygenated deep-water lake (Lago Fagnano, Tierra del Fuego)
title_fullStr Preservation of Fe/Mn-redox fronts in sediments of an oligotrophic, oxygenated deep-water lake (Lago Fagnano, Tierra del Fuego)
title_full_unstemmed Preservation of Fe/Mn-redox fronts in sediments of an oligotrophic, oxygenated deep-water lake (Lago Fagnano, Tierra del Fuego)
title_sort Preservation of Fe/Mn-redox fronts in sediments of an oligotrophic, oxygenated deep-water lake (Lago Fagnano, Tierra del Fuego)
dc.creator.none.fl_str_mv Neugebauer, Ina
Thomas, Camile
Ordoñez, Luis
Waldmann, Nicolas D.
Recasens, Cristina
Vizcaino, Alexis
Jiménez-Espejo, Francisco J.
Ariztegui, Daniel
author Neugebauer, Ina
author_facet Neugebauer, Ina
Thomas, Camile
Ordoñez, Luis
Waldmann, Nicolas D.
Recasens, Cristina
Vizcaino, Alexis
Jiménez-Espejo, Francisco J.
Ariztegui, Daniel
author_role author
author2 Thomas, Camile
Ordoñez, Luis
Waldmann, Nicolas D.
Recasens, Cristina
Vizcaino, Alexis
Jiménez-Espejo, Francisco J.
Ariztegui, Daniel
author2_role author
author
author
author
author
author
author
dc.contributor.none.fl_str_mv University of Bern
European Commission
Freie Universität Berlin
Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv Early diagenesis
Fe-/Mn-oxides
Mixed lakes
Redox fronts
Sedimentary geochemistry
Southern Hemisphere Westerlies
Southernmost Patagonia
topic Early diagenesis
Fe-/Mn-oxides
Mixed lakes
Redox fronts
Sedimentary geochemistry
Southern Hemisphere Westerlies
Southernmost Patagonia
description Changing redox conditions in water columns or sediment–water interfaces of lakes are captured as sedimentary archives, and are often influenced by climate. Their study therefore permits the reconstruction of past climate change on (sub-) annual to longer timescales. In Lago Fagnano (54°S Argentina/Chile), a large oligotrophic and deep-oxygenated lake, alternations of light grey clay and dark greenish and black laminae are preserved throughout the Holocene sedimentary record. This study aims to clarify the mechanism of laminae formation and preservation in Lago Fagnano, and their relation to changing redox conditions in the lake. High-resolution major element scanning and mapping along with detailed mineralogical analyses of sediment cores allowed identifying Fe-oxides, Mn-oxides and Fe-(mono) sulphides as responsible for the lamination. Based on the interpretation of redox processes at the current sedimentary redox boundary and of buried palaeo-redox fronts underlying mass-transported deposits, the greenish laminae enriched in Fe-oxides are interpreted as palaeo-redox fronts. The preservation of such former interfaces in Lago Fagnano sediments is most likely promoted by rapid increases of sedimentation due to higher runoff related to stronger Southern Hemisphere Westerlies. The formation of black laminae, showing only traces of Fe-(mono) sulphides and organic matter, is obscured by oxidation and early diagenetic processes, i.e. degradation and partial pyritization. These layers were presumably generated by small changes in bottom-water oxygenation due to reduced mixing and/or higher productivity. This study highlights the value of high-resolution sediment−geochemical analyses to better understand redox and diagenetic processes in oligotrophic mixed lakes.
publishDate 2022
dc.date.none.fl_str_mv 2022
2024
2024
2024
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
Publisher's version
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/358156
url http://hdl.handle.net/10261/358156
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv #PLACEHOLDER_PARENT_METADATA_VALUE#
info:eu-repo/grantAgreement/EC/H2020/706244
http://dx.doi.org/10.1111/sed.12976
Sí
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv Wiley-VCH
publisher.none.fl_str_mv Wiley-VCH
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15,81155

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