Differential preservation in a lacustrine fossil assemblage from the Cretaceous Bauru basin, Brazil

Lakes are engaging environments for fossil diagenesis studies because of their potential for fossil preservation. One such example is the Upper Cretaceous São Carlos Shale, which corresponds to the paleolake, which is not documented anywhere in the Bauru Basin. The fossil assemblages were composed o...

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Detalles Bibliográficos
Autores: Oliveira, A. B. [UNESP], Callefo, F., Ricardi-Branco, F., Batezelli, A., Galante, D.
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2025
País:Brasil
Institución:Universidade Estadual Paulista (UNESP)
Repositorio:Repositório Institucional da UNESP
Idioma:inglés
OAI Identifier:oai:repositorio.unesp.br:11449/297999
Acceso en línea:http://dx.doi.org/10.1016/j.jsames.2024.105337
https://hdl.handle.net/11449/297999
Access Level:acceso abierto
Palabra clave:Bauru basin
Biofilms
EPS
Fossil diagenesis
Paleolake
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spelling Differential preservation in a lacustrine fossil assemblage from the Cretaceous Bauru basin, BrazilBauru basinBiofilmsEPSFossil diagenesisPaleolakeLakes are engaging environments for fossil diagenesis studies because of their potential for fossil preservation. One such example is the Upper Cretaceous São Carlos Shale, which corresponds to the paleolake, which is not documented anywhere in the Bauru Basin. The fossil assemblages were composed of plants, vertebrates, and invertebrates. Fossil diagenesis analyses were performed to understand the taphonomic conditions, chemical composition, and state of preservation of the constituents. Scanning electron microscopy (SEM) and electron detector spectroscopy (EDS) were used to determine the elemental composition and visualise framboidal pyrite inside the invertebrate fossils and the remains of biofilms intimately linked to them. Micro X-ray fluorescence (μ-XRF) mapping revealed the elemental distribution related to the original composition of carapace and vertebrate remains. X-ray diffraction of the bulk rock helped the mineralogical characterisation of the shales. Sulfate-reducing bacteria was found at the bottom of the lacustrine environment, resulting in the precipitation of pyrite via organic matter decomposition. Establishing low pH conditions promoted the partial dissolution of calcite carapaces, followed by apatite precipitation and the preservation of chitinous conchostracan carapaces. This change in the diagenetic conditions was not significant for charcoal preservation. In turn, teleost bones were preserved, likely because of their high P concentrations. Thus, even if controlled by low pH conditions, the chemical structural stability of bioapatite can be maintained during fossil diagenesis. The sources of these elements were likely runoff-reworked sediments derived from intermediate and felsic rocks on the paleolake. Although rich in vertebrate fossils, the assemblage studied shows a differentiated preservation for the Bauru basin, expanding the possibilities of the record for this exceptional basin of the South American plate.Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Postgraduate Program in Agronomy (Soil Science) School of Agricultural and Veterinarian Science (FCAV) São Paulo State University (UNESP), Via de acesso Prof. Paulo Donato Castellane s/n., Jaboticabal, SPBrazilian Synchrotron Light Laboratory, Rua Giuseppe Máximo Scolfaro, 10.000, Polo II de Alta Tecnologia de Campinas, São PauloPostgraduate Program in Geosciences. Geosciences Institute State University of Campinas (UNICAMP), 250 Carlos Gomes St, SPGeosciences Institute São Paulo University (USP), Rua do Lago, 562, São PauloPostgraduate Program in Agronomy (Soil Science) School of Agricultural and Veterinarian Science (FCAV) São Paulo State University (UNESP), Via de acesso Prof. Paulo Donato Castellane s/n., Jaboticabal, SPUniversidade Estadual Paulista (UNESP)Brazilian Synchrotron Light LaboratoryUniversidade Estadual de Campinas (UNICAMP)Universidade de São Paulo (USP)2025-04-29T18:35:51Z2025-02-15info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlehttp://dx.doi.org/10.1016/j.jsames.2024.105337Journal of South American Earth Sciences, v. 153.0895-9811https://hdl.handle.net/11449/29799910.1016/j.jsames.2024.1053372-s2.0-85214332854Scopusreponame:Repositório Institucional da UNESPinstname:Universidade Estadual Paulista (UNESP)instacron:UNESPengJournal of South American Earth Sciencesinfo:eu-repo/semantics/openAccessOliveira, A. B. [UNESP]Callefo, F.Ricardi-Branco, F.Batezelli, A.Galante, D.2025-10-22T11:18:09Zoai:repositorio.unesp.br:11449/297999Repositório InstitucionalPUBhttp://repositorio.unesp.br/oai/requestrepositoriounesp@unesp.bropendoar:29462025-10-22T11:18:09Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)false
dc.title.none.fl_str_mv Differential preservation in a lacustrine fossil assemblage from the Cretaceous Bauru basin, Brazil
title Differential preservation in a lacustrine fossil assemblage from the Cretaceous Bauru basin, Brazil
spellingShingle Differential preservation in a lacustrine fossil assemblage from the Cretaceous Bauru basin, Brazil
Oliveira, A. B. [UNESP]
Bauru basin
Biofilms
EPS
Fossil diagenesis
Paleolake
title_short Differential preservation in a lacustrine fossil assemblage from the Cretaceous Bauru basin, Brazil
title_full Differential preservation in a lacustrine fossil assemblage from the Cretaceous Bauru basin, Brazil
title_fullStr Differential preservation in a lacustrine fossil assemblage from the Cretaceous Bauru basin, Brazil
title_full_unstemmed Differential preservation in a lacustrine fossil assemblage from the Cretaceous Bauru basin, Brazil
title_sort Differential preservation in a lacustrine fossil assemblage from the Cretaceous Bauru basin, Brazil
dc.creator.none.fl_str_mv Oliveira, A. B. [UNESP]
Callefo, F.
Ricardi-Branco, F.
Batezelli, A.
Galante, D.
author Oliveira, A. B. [UNESP]
author_facet Oliveira, A. B. [UNESP]
Callefo, F.
Ricardi-Branco, F.
Batezelli, A.
Galante, D.
author_role author
author2 Callefo, F.
Ricardi-Branco, F.
Batezelli, A.
Galante, D.
author2_role author
author
author
author
dc.contributor.none.fl_str_mv Universidade Estadual Paulista (UNESP)
Brazilian Synchrotron Light Laboratory
Universidade Estadual de Campinas (UNICAMP)
Universidade de São Paulo (USP)
dc.subject.por.fl_str_mv Bauru basin
Biofilms
EPS
Fossil diagenesis
Paleolake
topic Bauru basin
Biofilms
EPS
Fossil diagenesis
Paleolake
description Lakes are engaging environments for fossil diagenesis studies because of their potential for fossil preservation. One such example is the Upper Cretaceous São Carlos Shale, which corresponds to the paleolake, which is not documented anywhere in the Bauru Basin. The fossil assemblages were composed of plants, vertebrates, and invertebrates. Fossil diagenesis analyses were performed to understand the taphonomic conditions, chemical composition, and state of preservation of the constituents. Scanning electron microscopy (SEM) and electron detector spectroscopy (EDS) were used to determine the elemental composition and visualise framboidal pyrite inside the invertebrate fossils and the remains of biofilms intimately linked to them. Micro X-ray fluorescence (μ-XRF) mapping revealed the elemental distribution related to the original composition of carapace and vertebrate remains. X-ray diffraction of the bulk rock helped the mineralogical characterisation of the shales. Sulfate-reducing bacteria was found at the bottom of the lacustrine environment, resulting in the precipitation of pyrite via organic matter decomposition. Establishing low pH conditions promoted the partial dissolution of calcite carapaces, followed by apatite precipitation and the preservation of chitinous conchostracan carapaces. This change in the diagenetic conditions was not significant for charcoal preservation. In turn, teleost bones were preserved, likely because of their high P concentrations. Thus, even if controlled by low pH conditions, the chemical structural stability of bioapatite can be maintained during fossil diagenesis. The sources of these elements were likely runoff-reworked sediments derived from intermediate and felsic rocks on the paleolake. Although rich in vertebrate fossils, the assemblage studied shows a differentiated preservation for the Bauru basin, expanding the possibilities of the record for this exceptional basin of the South American plate.
publishDate 2025
dc.date.none.fl_str_mv 2025-04-29T18:35:51Z
2025-02-15
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/article
format article
status_str publishedVersion
dc.identifier.uri.fl_str_mv http://dx.doi.org/10.1016/j.jsames.2024.105337
Journal of South American Earth Sciences, v. 153.
0895-9811
https://hdl.handle.net/11449/297999
10.1016/j.jsames.2024.105337
2-s2.0-85214332854
url http://dx.doi.org/10.1016/j.jsames.2024.105337
https://hdl.handle.net/11449/297999
identifier_str_mv Journal of South American Earth Sciences, v. 153.
0895-9811
10.1016/j.jsames.2024.105337
2-s2.0-85214332854
dc.language.iso.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv Journal of South American Earth Sciences
dc.rights.driver.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.source.none.fl_str_mv Scopus
reponame:Repositório Institucional da UNESP
instname:Universidade Estadual Paulista (UNESP)
instacron:UNESP
instname_str Universidade Estadual Paulista (UNESP)
instacron_str UNESP
institution UNESP
reponame_str Repositório Institucional da UNESP
collection Repositório Institucional da UNESP
repository.name.fl_str_mv Repositório Institucional da UNESP - Universidade Estadual Paulista (UNESP)
repository.mail.fl_str_mv repositoriounesp@unesp.br
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