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3. Molecular preservation of 1.88 Ga Gunflint organic microfossils as a function of temperature and mineralogy.

Author

Alleon, Julien, Bernard, Sylvain, Le Guillou, Corentin, Marin-Carbonne, Johanna, Pont, Sylvain, Beyssac, Olivier, McKeegan, Kevin D, and Robert, François

Subjects
Carbonates, Silicon Dioxide, Quartz, Microscopy, Electron, Transmission, Preservation, Biological, X-Ray Diffraction, Spectrum Analysis, Raman, Temperature, Geologic Sediments, Paleontology, Fossils, Ontario, Minnesota, X-Ray Absorption Spectroscopy, Microscopy, Electron, Transmission, Preservation, Biological, Spectrum Analysis, Raman
Abstract

The significant degradation that fossilized biomolecules may experience during burial makes it challenging to assess the biogenicity of organic microstructures in ancient rocks. Here we investigate the molecular signatures of 1.88 Ga Gunflint organic microfossils as a function of their diagenetic history. Synchrotron-based XANES data collected in situ on individual microfossils, at the submicrometre scale, are compared with data collected on modern microorganisms. Despite diagenetic temperatures of ∼150-170 °C deduced from Raman data, the molecular signatures of some Gunflint organic microfossils have been exceptionally well preserved. Remarkably, amide groups derived from protein compounds can still be detected. We also demonstrate that an additional increase of diagenetic temperature of only 50 °C and the nanoscale association with carbonate minerals have significantly altered the molecular signatures of Gunflint organic microfossils from other localities. Altogether, the present study provides key insights for eventually decoding the earliest fossil record.

Published
2016

10. 73. Micropyrite in microbialites record S microbial cycling

Author

Marin-Carbonne, Johanna, Decraene, Marie Noelle, Havas, Robin, Alleon, Julien, Pasquier, Virgil, Olivier, Nicolas, Remusat, Laurent, Zeyen, Nina, Benzerara, Karim, Vennin, Emmanuelle, Meibom, Anders, and Thomazo, Christophe

Subjects
ComputingMethodologies_GENERAL
Abstract

Poster presentation

Published
2022
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11. Reply to comment on “Metamorphic origin of anastomosing and wavy laminas overprinting putative microbial deposits from the 3.22 Ga Moodies Group (Barberton Greenstone Belt)”

Author

Saitoh, Masafumi, primary, Olivier, Nicolas, additional, Garçon, Marion, additional, Boyet, Maud, additional, Thomazo, Christophe, additional, Alleon, Julien, additional, Moyen, Jean-François, additional, Motto-Ros, Vincent, additional, and Marin-Carbonne, Johanna, additional

Published
2022
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13. Micropyrite in stromatolite : a time capsule of ancient metabolisms

Author

Marin Carbonne, Johanna, Decraene, Marie Noelle, Dupeyron, Juliette, Alleon, Julien, Pasquier, Virgil, Olivier, Nicolas, and Thomazo, Christophe

Abstract

The identification of ancient microbial signatures preserved in the geological record is crucial for understanding life evolution during the Early Earth. Stromatolites and microbialites are considered among undisputable oldest trace of life but their biogenicity is sometimes disputed. Archean stromatolite contain small sulfides hereafter designed as micropyrite, often enclosed with organic material, that can be formed either by abiotic processes (reaction between H2S and Fe(II)) or by metabolic activity like microbial sulfate reduction (MSR) or dissimilatory iron reduction (DIR). Iron and sulfur isotope compositions offer the most direct means to track the biogeochemical cycling of these elements through time, but their joint use as biosignatures of specific metabolic activity has been relatively limited to date. We have developed a microscale approach using correlative microscopy and SIMS and NanoSIMS analyses that allow to document Fe and S isotope composition at the mineralogical scale of the pyrite grains. Here we will present results obtained on the Tumbiana Formation (2.7 Ga, Western Australia), on the Buck Reef chert (3.41 Ga, basal member of the Kromberg Formation, South Africa), and on the Moodies Group (3.2 Ga, South Africa). Our approach allows to decipher the post-depositional metasomatic influence from the primary microbial signatures inherited during diagenesus. Our results also highlight that pyrite formation record very local conditions at the sediment-interface or at the microbial mats. Our results demonstrate the existence of microbial iron respiration as early as 3.26 Gyr ago, providing new time calibration of the tree of life for this type of metabolism.

Published
2022
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14. Organic geochemical approaches to understanding early life

Author

Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, Alleon, Julien, Summons, Roger E, Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, Alleon, Julien, and Summons, Roger E

Abstract

© 2019 The Authors Here we discuss the early geological record of preserved organic carbon and the criteria that must be applied to distinguish biological from non-biological origins. Sedimentary graphite, irrespective of its isotopic composition, does not constitute a reliable biosignature because the rocks in which it is found are generally metamorphosed to the point where convincing signs of life have been erased. Rather, multiple lines of evidence, including sedimentary textures, microfossils, large accumulations of organic matter and isotopic data for co-existing carbon, nitrogen and sulfur are required before biological origin can be convincingly demonstrated.

Published
2021

16. Organo-mineral associations in chert of the 3.5 Ga Mount Ada Basalt raise questions about the origin of organic matter in Paleoarchean hydrothermally influenced sediments

Author

Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology. Department of Materials Science and Engineering, Alleon, Julien, Ferralis, Nicola, Zhang, Yong, Summons, Roger E, Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology. Department of Materials Science and Engineering, Alleon, Julien, Ferralis, Nicola, Zhang, Yong, and Summons, Roger E

Abstract

Hydrothermal and metamorphic processes could have abiotically produced organo-mineral associations displaying morphological and isotopic characteristics similar to those of fossilized microorganisms in ancient rocks, thereby leaving false-positive evidence for early life in the geological record. Recent studies revealed that geologically-induced alteration processes do not always completely obliterate all molecular information about the original organic precursors of ancient microfossils. Here, we report the molecular, geochemical, and mineralogical composition of organo-mineral associations in a chert sample from the ca. 3.47 billion-year-old (Ga) Mount Ada Basalt, in the Pilbara Craton, Western Australia. Our observations indicate that the molecular characteristics of carbonaceous matter are consistent with hydrothermally altered biological organics, although significantly distinct from that of organic microfossils discovered in a chert sample from the ca. 3.43 Ga Strelley Pool Formation in the same area. Alternatively, the presence of native metal alloys in the chert, previously believed to be unstable in such hydrothermally influenced environments, indicates strongly reducing conditions that were favorable for the abiotic formation of organic matter. Drawing definitive conclusions about the origin of most Paleoarchean organo-mineral associations therefore requires further characterization of a range of natural samples together with experimental simulations to constrain the molecular composition and geological fate of hydrothermally-generated condensed organics., Simons Foundation. Simons Collaboration on the Origins of Life (award #290361), European Union. Horizon 2020 Research and Innovation Programme (STROMATA, grant agreement 759289), National Science Foundation (U.S.) (award number DMR-14-19807)

Published
2020

21. Sub-micrometer pyrites in microbialites record equilibrium S isotope fractionation by Microbial Sulfate Reduction independently of the sulfate concentration of the water

Author

Marin-Carbonne, Johanna, primary, Decraene, Marie-Noëlle, additional, Remusat, Laurent, additional, Havas, Robin, additional, Thomazo, Christophe, additional, Pasquier, Virgil, additional, Alleon, Julien, additional, Zeyen, Nina, additional, Bernard, Sylvain, additional, Escrig, Stéphane, additional, Vennin, Emmanuelle, additional, Meibom, Anders, additional, and Benzerara, Karim, additional

Published
2021
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24. Organic molecular heterogeneities can withstand diagenesis

Author

Alleon, Julien, Bernard, Sylvain, Le Guillou, Corentin, Daval, Damien, Skouri-Panet, Feriel, Kuga, Maïa, Robert, François, Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Institut de recherche pour le développement [IRD] : UR206-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC), Unité Matériaux et Transformations - UMR 8207 (UMET), Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure de Chimie de Lille (ENSCL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Hydrologie et de Géochimie de Strasbourg (LHyGeS), Ecole et Observatoire des Sciences de la Terre (EOST), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Centre National de la Recherche Scientifique (CNRS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Centre National de la Recherche Scientifique (CNRS), Institut National de la Recherche Agronomique (INRA)-Ecole Nationale Supérieure de Chimie de Lille (ENSCL)-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Institut de Chimie du CNRS (INC)-Institut National de la Recherche Agronomique (INRA)-Centre National de la Recherche Scientifique (CNRS)-Université de Lille-Ecole Nationale Supérieure de Chimie de Lille (ENSCL), École Nationale du Génie de l'Eau et de l'Environnement de Strasbourg (ENGEES)-Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Ecole et Observatoire des Sciences de la Terre (EOST), and Université de Strasbourg (UNISTRA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], Science, Medicine, [CHIM]Chemical Sciences, Article, [SDU.STU.MI]Sciences of the Universe [physics]/Earth Sciences/Mineralogy
Abstract

Reconstructing the original biogeochemistry of organic fossils requires quantifying the extent of the chemical transformations that they underwent during burial-induced maturation processes. Here, we performed laboratory experiments on chemically different organic materials in order to simulate the thermal maturation processes that occur during diagenesis. Starting organic materials were microorganisms and organic aerosols. Scanning transmission X-ray microscopy (STXM) was used to collect X-ray absorption near edge spectroscopy (XANES) data of the organic residues. Results indicate that even after having been submitted to 250 °C and 250 bars for 100 days, the molecular signatures of microorganisms and aerosols remain different in terms of nitrogen-to-carbon atomic ratio and carbon and nitrogen speciation. These observations suggest that burial-induced thermal degradation processes may not completely obliterate the chemical and molecular signatures of organic molecules. In other words, the present study suggests that organic molecular heterogeneities can withstand diagenesis and be recognized in the fossil record., Scientific Reports, 7, ISSN:2045-2322

Published
2017

25. Organic molecular heterogeneities can withstand diagenesis.

Author

Alleon J, Bernard S, Le Guillou C, Daval D, Skouri-Panet F, Kuga M, and Robert F

Abstract

Reconstructing the original biogeochemistry of organic fossils requires quantifying the extent of the chemical transformations that they underwent during burial-induced maturation processes. Here, we performed laboratory experiments on chemically different organic materials in order to simulate the thermal maturation processes that occur during diagenesis. Starting organic materials were microorganisms and organic aerosols. Scanning transmission X-ray microscopy (STXM) was used to collect X-ray absorption near edge spectroscopy (XANES) data of the organic residues. Results indicate that even after having been submitted to 250 °C and 250 bars for 100 days, the molecular signatures of microorganisms and aerosols remain different in terms of nitrogen-to-carbon atomic ratio and carbon and nitrogen speciation. These observations suggest that burial-induced thermal degradation processes may not completely obliterate the chemical and molecular signatures of organic molecules. In other words, the present study suggests that organic molecular heterogeneities can withstand diagenesis and be recognized in the fossil record.

Published
2017
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