Pyrite morphology and sulfur isotopes refine taphonomic models for the 2.1 Ga Francevillian biota, Gabon
Abstract Pyritization is a key taphonomic process that preserves some of Earth’s oldest fossils. It is influenced by various factors such as organic matter type, the availability of iron and sulfur, and sedimentation rates. In this study, we analyzed pyritized biotic and abiotic structures from 2.1 ...
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Nature Portfolio
2025-06-01
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| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-025-04512-4 |
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| author | Anna El Khoury Farid Saleh Abderrazak El Albani Claude Fontaine Claire Rollion-Bard Ibtissam Chraiki Jérémie Aubineau Julie Ngwal’ghoubou Ikouanga Mohamed Bhilisse Maryem Zguaid Andrea Somogyi Ernest Chi Fru |
| author_facet | Anna El Khoury Farid Saleh Abderrazak El Albani Claude Fontaine Claire Rollion-Bard Ibtissam Chraiki Jérémie Aubineau Julie Ngwal’ghoubou Ikouanga Mohamed Bhilisse Maryem Zguaid Andrea Somogyi Ernest Chi Fru |
| author_sort | Anna El Khoury |
| collection | DOAJ |
| description | Abstract Pyritization is a key taphonomic process that preserves some of Earth’s oldest fossils. It is influenced by various factors such as organic matter type, the availability of iron and sulfur, and sedimentation rates. In this study, we analyzed pyritized biotic and abiotic structures from 2.1 Ga deposits in Gabon’s Francevillian Basin, to reconstruct their taphonomic pathway at the micron scale. Using secondary ion mass spectrometry and scanning electron microscopy, we examine sulfur isotope compositions, pyrite morphology and grain size within individual fossils and compare them to abiotic pyritic concretions from the same stratigraphic level. Our results reveal differences in pyrite grain size and sulfur isotope composition between fossils and concretions. More importantly, chemical and morphological variations are observed within individual fossils, likely due to distinct reactive environments for pyrite mineralization, linked to organic matter, sulfate and iron availability during early diagenesis. This remarkable variation in pyrite morphology and δ34S values in the fossilized specimens, indicates that they were compositionally more complex than the substrate that formed the homogeneously pyritized concretions. This well-preserved ecological window represents an exceptional record of the earliest multicellular life forms on Earth. |
| format | Article |
| id | doaj-art-d6fe1edfa7484a61b6c48e4a66be3b0f |
| institution | OA Journals |
| issn | 2045-2322 |
| language | English |
| publishDate | 2025-06-01 |
| publisher | Nature Portfolio |
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| series | Scientific Reports |
| spelling | doaj-art-d6fe1edfa7484a61b6c48e4a66be3b0f2025-08-20T02:05:38ZengNature PortfolioScientific Reports2045-23222025-06-0115111110.1038/s41598-025-04512-4Pyrite morphology and sulfur isotopes refine taphonomic models for the 2.1 Ga Francevillian biota, GabonAnna El Khoury0Farid Saleh1Abderrazak El Albani2Claude Fontaine3Claire Rollion-Bard4Ibtissam Chraiki5Jérémie Aubineau6Julie Ngwal’ghoubou Ikouanga7Mohamed Bhilisse8Maryem Zguaid9Andrea Somogyi10Ernest Chi Fru11IC2MP, UMR 7285, CNRS, Université de PoitiersInstitute of Earth Sciences, University of LausanneIC2MP, UMR 7285, CNRS, Université de PoitiersIC2MP, UMR 7285, CNRS, Université de PoitiersLaboratoire des Sciences du Climat et de l’Environnement (LSCE), CNRS, CEA, UVSQ, Université Paris-SaclayIC2MP, UMR 7285, CNRS, Université de PoitiersObservatoire Midi-Pyrénées, Géosciences Environnement Toulouse, CNRS UMR 5563 (CNRS/UPS/IRD/CNES), Université de ToulouseIC2MP, UMR 7285, CNRS, Université de PoitiersFaculty of Sciences Semlalia, Cadi Ayyad UniversityEcole des Mines de ParisNANOSCOPIUM Beamline, Synchrotron SOLEILSchool of Earth and Ocean Sciences, Cardiff UniversityAbstract Pyritization is a key taphonomic process that preserves some of Earth’s oldest fossils. It is influenced by various factors such as organic matter type, the availability of iron and sulfur, and sedimentation rates. In this study, we analyzed pyritized biotic and abiotic structures from 2.1 Ga deposits in Gabon’s Francevillian Basin, to reconstruct their taphonomic pathway at the micron scale. Using secondary ion mass spectrometry and scanning electron microscopy, we examine sulfur isotope compositions, pyrite morphology and grain size within individual fossils and compare them to abiotic pyritic concretions from the same stratigraphic level. Our results reveal differences in pyrite grain size and sulfur isotope composition between fossils and concretions. More importantly, chemical and morphological variations are observed within individual fossils, likely due to distinct reactive environments for pyrite mineralization, linked to organic matter, sulfate and iron availability during early diagenesis. This remarkable variation in pyrite morphology and δ34S values in the fossilized specimens, indicates that they were compositionally more complex than the substrate that formed the homogeneously pyritized concretions. This well-preserved ecological window represents an exceptional record of the earliest multicellular life forms on Earth.https://doi.org/10.1038/s41598-025-04512-4 |
| spellingShingle | Anna El Khoury Farid Saleh Abderrazak El Albani Claude Fontaine Claire Rollion-Bard Ibtissam Chraiki Jérémie Aubineau Julie Ngwal’ghoubou Ikouanga Mohamed Bhilisse Maryem Zguaid Andrea Somogyi Ernest Chi Fru Pyrite morphology and sulfur isotopes refine taphonomic models for the 2.1 Ga Francevillian biota, Gabon Scientific Reports |
| title | Pyrite morphology and sulfur isotopes refine taphonomic models for the 2.1 Ga Francevillian biota, Gabon |
| title_full | Pyrite morphology and sulfur isotopes refine taphonomic models for the 2.1 Ga Francevillian biota, Gabon |
| title_fullStr | Pyrite morphology and sulfur isotopes refine taphonomic models for the 2.1 Ga Francevillian biota, Gabon |
| title_full_unstemmed | Pyrite morphology and sulfur isotopes refine taphonomic models for the 2.1 Ga Francevillian biota, Gabon |
| title_short | Pyrite morphology and sulfur isotopes refine taphonomic models for the 2.1 Ga Francevillian biota, Gabon |
| title_sort | pyrite morphology and sulfur isotopes refine taphonomic models for the 2 1 ga francevillian biota gabon |
| url | https://doi.org/10.1038/s41598-025-04512-4 |
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