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1. Bolt’s Farm Cave System dans le Cradle of Humankind (Afrique du Sud) : un exemple d’approche multidisciplinaire dans l’étude des sites à primates fossiles

Author

Dominique Gommery, Frank Sénégas, Lazarus Kgasi, Nonhlanhla Vilakazi, Brian Kuhn, James Brink, Martin Pickford, Andy IR Herries, John Hancox, Thibaud Saos, Loïc Ségalen, Julie Aufort, and John Francis Thackeray

Subjects
South Africa, Bolt’s Farm Cave System, primate, palaeodiversity, palaeoenvironment, Science, Zoology, QL1-991
Abstract

The Cradle of Humankind in South Africa, recognized as World Heritage by UNESCO since 1999, contains fossil sites which have yielded hominid remains and/or non-human primates (Cercopithecoidea). Robert Broom was the first to prospect for fossils at Bolt's Farm Cave System (or BFCS), and this since 1936. Research only became regular in 2006 with the creation of the HRU (Hope (Human Origins and Past Environment) Research Unit). BFCS is best known for yielding remains of large cats. Yet some fossils of Cercopithecoidea discovered at BFCS are considered to be references in palaeoprimatology: BF42 (Cercopithecoides williamsi) and BF43 (Parapapio broomi). Waypoint 160 at BFCS yielded the oldest remains of nonhuman primates in the Cradle of Humankind which are dated to the Pliocene. For more information about the geological and palaeoenvironmental context, excavations were conducted since 2011 in some loci based on the surveys carried out by members of HRU. The present challenge is to obtain the maximum amount of data concerning palaeobiodiversity, including the microfauna which must be extracted from the breccia by acid preparation techniques, study of the conditions of fossilization and the preservation of fossils, as well as the determination of the ages of the fossils.

Published
2017
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5. Simulating the binding of key organic functional groups to aqueous calcium carbonate species

Author

Alicia Schuitemaker, Paolo Raiteri, Julie Aufort, Julian D. Gale, Raffaella Demichelis, and Katarzyna B. Koziara

Subjects
Mineral, Aqueous solution, 010304 chemical physics, Ion pairing, Solvation, General Physics and Astronomy, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, Organic molecules, chemistry.chemical_compound, Calcium carbonate, chemistry, Computational chemistry, 0103 physical sciences, Ammonium, Carboxylate, Physical and Theoretical Chemistry
Abstract

The interaction of organic molecules with mineral systems is relevant to a wide variety of scientific problems both in the environment and minerals processing. In this study, the coordination of small organics that contain the two most relevant functional groups for biomineralisation of calcium carbonate, namely carboxylate and ammonium, with the corresponding mineral ions are examined in aqueous solution. Specifically, two force fields have been examined based on rigid-ion or polarisable models, with the latter being within the AMOEBA formalism. Here the parameters for the rigid-ion model are determined to target the accurate reproduction of the hydration structure and solvation thermodynamics, while both force fields are designed to be compatible with the corresponding recently published models for aqueous calcium carbonate. The application of these force fields to ion pairing in aqueous solution is studied in order to quantitatively determine the extent of association.

Published
2021
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6. Magnesium Impurities Decide the Structure of Calcium Carbonate Hemihydrate

Author

Julie Aufort, Raffaella Demichelis, Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Curtin Institute for Computation (CIC), Curtin University [Perth], and Planning and Transport Research Centre (PATREC)-Planning and Transport Research Centre (PATREC)

Subjects
Materials science, 010405 organic chemistry, Magnesium, Hemihydrate, chemistry.chemical_element, General Chemistry, Orientation (graph theory), 010402 general chemistry, Condensed Matter Physics, 01 natural sciences, 0104 chemical sciences, chemistry.chemical_compound, Calcium carbonate, chemistry, Chemical engineering, Impurity, Theoretical methods, [CHIM]Chemical Sciences, General Materials Science
Abstract

The new and recently detected hydromorph of calcium carbonate, CaCO3 center dot 1/2H(2)O hemihydrate, has been analyzed via both first-principles and classical theoretical methods. The orientation of the water molecules, that remained unclear in the experiment, has been determined. A structure with symmetry higher than that originally proposed results from geometry optimization (Pbcn, space group number 60) of the pure phase. The introduction of magnesium impurities causes a distortion in the unit cell, which assumes the monoclinic arrangement (P2(1)/c) originally proposed. This is consistent with the magnesium-rich experimental conditions.

Published
2020
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8. Assessing bone transformation in late Miocene and Plio‐Pleistocene deposits of Kenya and South Africa

Author

Cristina Coelho-Diogo, Nathalie Labourdette, Loïc Ségalen, D. Gommery, Etienne Balan, Julie Aufort, Christel Gervais, Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre de recherche sur la Paléobiodiversité et les Paléoenvironnements (CR2P), Muséum national d'Histoire naturelle (MNHN)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Spectroscopie, Modélisation, Interfaces pour L'Environnement et la Santé (LCMCP-SMiLES), Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP), Collège de France (CdF)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre de Paris (iSTeP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut des matériaux de Paris-Centre (IMPC), Ecole Nationale Supérieure de Chimie de Paris- Chimie ParisTech-PSL (ENSCP)-ESPCI ParisTech-Sorbonne Université (SU), French Région Ile‐de‐France‐SESAME, ANR-11-IDEX-0004-02/10-LABX-0067,MATISSE,MATerials, InterfaceS, Surfaces, Environment(2011), Centre de Recherche en Paléontologie - Paris (CR2P), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS), Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and ANR-11-IDEX-0004,SUPER,Sorbonne Universités à Paris pour l'Enseignement et la Recherche(2011)

Subjects
bone diagenesis, secondary apatite, 010506 paleontology, Archeology, History, preservation, ATR-FTIR spectroscopy, Atr ftir spectroscopy, Plio-Pleistocene, Late Miocene, 010502 geochemistry & geophysics, 01 natural sciences, Transformation (genetics), Paleontology, [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology, Geology, 0105 earth and related environmental sciences
Abstract

International audience; Bone reactivity offers a potential way to record local physical–chemical conditions prevailing in fossilization environments and archaeological sites. In the present study, a series of fossil bone samples from the karstic environments of the Bolt's Farm cave system (Cradle of Humankind, South Africa) and from fluvio‐lacustrine environments of the Tugen Hills (Gregory Rift, Kenya) is analysed. The chemical composition and infrared and nuclear magnetic resonance (NMR) spectroscopic properties of fossil samples point to a transformation of the biogenic apatite and formation of secondary apatite. Depending on the sample, the secondary apatite corresponds to a carbonate‐bearing hydroxy‐ or fluor‐apatite. The maximum fraction of secondary apatite is close to 60%, coinciding with previous observations in experimental alteration of bone in aqueous solutions and suggesting that a fraction of pristine biological apatite is likely to be preserved. The present results also suggest that the acetic acid treatment of fossil samples moderately increases their average crystallinity but may dissolve carbonate‐rich domains of secondary apatite.

Published
2019
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9. Atomic scale transformation of bone in controlled aqueous alteration experiments

Author

Cristina Coelho-Diogo, Nathalie Labourdette, Christophe Lécuyer, Romain Amiot, Christel Gervais, Olivier Beyssac, Julie Aufort, Loïc Ségalen, Etienne Balan, Benoit Baptiste, Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Spectroscopie, Modélisation, Interfaces pour L'Environnement et la Santé (LCMCP-SMiLES), Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP), Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences de la Terre de Paris (iSTeP), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS), Institut des matériaux de Paris-Centre (IMPC), Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), PaleoEnvironnements et PaleobioSphere (PEPS), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Collège de France (CdF)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Ecole Nationale Supérieure de Chimie de Paris- Chimie ParisTech-PSL (ENSCP)-ESPCI ParisTech-Sorbonne Université (SU), Université de Lyon-Université de Lyon, Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)

Subjects
010506 paleontology, Aqueous solution, Fluorapatite, Inorganic chemistry, Paleontology, Hydroxylapatite, 010502 geochemistry & geophysics, Oceanography, 01 natural sciences, Apatite, chemistry.chemical_compound, Crystallinity, chemistry, [SDU]Sciences of the Universe [physics], [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, visual_art, visual_art.visual_art_medium, Carbonate, Dissolution, Fluoride, Ecology, Evolution, Behavior and Systematics, Geology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Earth-Surface Processes
Abstract

International audience; The chemical and isotopic compositions of biogenic apatite are important geochemical markers, which can suffer modifications during fossilisation. Compared with modern ones, fossil apatites generally exhibit variations in carbonate content, enrichment in fluorine, incorporation of trace elements and an increase in crystallinity parameters. Detailed understanding of these transformations induced by fossilisation should help assess the preservation of geochemical records in apatites. In this contribution, we investigate the transformation of modern bone altered under controlled conditions. Modern bone samples were soaked in aqueous solutions of neutral to alkaline pH (9–10) for one and three weeks at various temperatures (20 and 70 °C) and experiments were duplicated in fluorine-free and in 10−2 M NaF solutions. Bone transformation was monitored through the modifications of chemical (F, Ca, P) and isotopic (δ13C, δ18Oc, δ18Op) composition as well as using vibrational (ATR-FTIR, Raman) and solid-state (1H, 13C, 19F) NMR spectroscopies. The observed modifications sustain a transformation mechanism through partial dissolution of biogenic apatite and precipitation of secondary apatite. This transformation occurs irrespective of the presence or absence of fluorine and leads to the formation of carbonate-bearing fluorapatite or carbonate-bearing hydroxylapatite, respectively. The fraction of secondary apatite seems to be limited to ~60%, suggesting that its formation has a protecting role against further dissolution of the primary apatite. The observation of clumped (CO32−, F−) defects in the structural B-site of some samples as well as perturbation of the isotopic compositions attest to carbonate incorporation in the secondary apatite. Although the incorporation of fluoride ions can serve as a probe revealing dissolution-recrystallization of bone, the present study also underlines the difficulty to systematically relate mineralogical transformations to an open-system behaviour in bioapatite.

Published
2019
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10. Modeling the attenuated total reflectance infrared (ATR-FTIR) spectrum of apatite

Author

Etienne Balan, Christian Brouder, Loïc Ségalen, Julie Aufort, Christel Gervais, Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), 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), Biominéralisations et environnements sédimentaires (BES), Institut des Sciences de la Terre de Paris (iSTeP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Spectroscopie, Modélisation, Interfaces pour L'Environnement et la Santé (SMiLES), Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Labex Matisse, ANR-11-IDEX-0004,SUPER,Sorbonne Universités à Paris pour l'Enseignement et la Recherche(2011), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)

Subjects
Infrared, Analytical chemistry, Physics::Optics, Infrared spectroscopy, Effective medium, Bruggeman model, 02 engineering and technology, 010502 geochemistry & geophysics, 01 natural sciences, Apatite, Geochemistry and Petrology, General Materials Science, Fourier transform infrared spectroscopy, 0105 earth and related environmental sciences, [PHYS]Physics [physics], Chemistry, Fluorapatite, [CHIM.MATE]Chemical Sciences/Material chemistry, Fresnel equations, 021001 nanoscience & nanotechnology, Wavelength, visual_art, Attenuated total reflection, visual_art.visual_art_medium, Attenuated total reflectance, 0210 nano-technology, ATR-FTIR, [SDU.STU.MI]Sciences of the Universe [physics]/Earth Sciences/Mineralogy
Abstract

International audience; Attenuated total reflectance (ATR) infrared spectra were measured on a synthetic and a natural fluorapatite sample. A modeling approach based on the computation of the Fresnel reflection coefficient between the ATR crystal and the powder sample was used to analyze the line shape of the spectra. The dielectric properties of the samples were related to those of pure fluorapatite using an effective medium approach, based on Maxwell–Garnett and Bruggeman models. The Bruggeman effective medium model leads to a very good agreement with the experimental data recorded on the synthetic fluorapatite sample. The poorer agreement observed on the natural sample suggests a more significant heterogeneity of the sample at a characteristic length scale larger than the mid-infrared characteristic wavelength, i.e., about 10 micrometers. The results demonstrate the prominent role of macroscopic electrostatic effects over fine details of the microscopic structure in determining the line shape of strong ATR bands.

Published
2016
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11. Line-broadening and anharmonic effects in the attenuated total reflectance infrared spectra of calcite

Author

Etienne Balan, Julie Aufort, Michele Lazzeri, Christian Brouder, Giuseppe D. Saldi, Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Cluster of Excellence MATISSE led by Sorbonne UniversitésCARBORIC (ANR-13-BS06-0013-06), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Calcite, Materials science, Anharmonicity, Analytical chemistry, Infrared spectroscopy, 02 engineering and technology, multi-phonon, 021001 nanoscience & nanotechnology, 01 natural sciences, effective medium, chemistry.chemical_compound, ATR, chemistry, Geochemistry and Petrology, Attenuated total reflection, 0103 physical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], 010306 general physics, 0210 nano-technology, infrared spectroscopy, calcite, Line (formation), [SDU.STU.MI]Sciences of the Universe [physics]/Earth Sciences/Mineralogy
Abstract

International audience; The attenuated total reflectance (ATR) spectra of two calcite samples have been measured using Ge and diamond internal reflection elements. One of the samples was obtained by precipitation from solution and displays sub-micrometer sized particles. The second sample was obtained by grinding a single-crystal of calcite (''Iceland spar'' variety). Theoretical spectra were obtained by computing the reflection coefficient of the interface between the ATR internal reflection element and a homogeneous effective medium representing the powder sample. The dielectric properties of the effective medium have been determined from those of bulk calcite using the Bruggeman approach which is adequate for standard powders with intermediate fractions of solid and empty porosity. Although this modeling approach provides a quantitative interpretation of the broadening of strong absorption bands in the calcite ATR spectra, it fails to reproduce the apparent splitting of the strong nu3 CO3 band. This problem was solved by combining the electrostatic modeling approach with a semi-quantum model of the dielectric tensor of bulk calcite, which allows for a frequency-dependent damping of the nu3 CO3 excitation. The frequency-dependence is ascribed to a multiphonon-related resonance in the nu3 CO3 phonon self-energy at a frequency close to its transverse optical frequency. The combination of approaches exposed in the present study makes it possible to discriminate among physically different processes affecting the powder infrared spectra of calcite, some being related to the long-range nature of electrostatic interactions in polar materials and others being related to atomic-scale anharmonic interactions between vibrational modes.

Published
2019
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12. Unraveling weathering episodes in Tertiary regoliths by kaolinite dating (Western Ghats, India)

Author

Julie Aufort, Jean-Jacques Braun, Etienne Balan, Thierry Allard, Madeleine Selo, Maximilien Mathian, Jean Riotte, Shrema Bhattacharya, Emmanuel Fritsch, Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Géosciences Environnement Toulouse (GET), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), Physical Research Laboratory [Ahmedabad] (PRL), Indian Space Research Organisation (ISRO), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
geography, Plateau, geography.geographical_feature_category, Indian monsoon, 010504 meteorology & atmospheric sciences, Weathering, Geochemistry, Geology, Forcing (mathematics), Laterite, 010502 geochemistry & geophysics, Monsoon, 01 natural sciences, Regolith, EPR dating, 13. Climate action, Kaolinite, Erosion, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, 0105 earth and related environmental sciences, [SDU.STU.MI]Sciences of the Universe [physics]/Earth Sciences/Mineralogy
Abstract

International audience; Secondary minerals in soils can record climatic changes affecting continental surfaces over geological times. Their dating should refine our present knowledge about their potential periods of formation as well as their relations with the ongoing change of climate and erosion/weathering regimes. In the present study, twenty kaolinite samples from two lateritic profiles of the Karnataka plateau, an intensively studied area in the southern India, have been dated using electron paramagnetic resonance (EPR) spectroscopy. Kaolinite ages vary between 0.229±0.24 Ma to 40.73±15.37 Ma. Four different groups of age can be identified with ages clustered around 1.0, 3.5, 9.0 and 39.0 Ma. These groups of age indicate local preferential weathering periods that coincide with distinct Indian climatic events described in independent studies, such as monsoon strengthening. Thus, regional or subcontinental factors likely prevailed over global forcing in the imprint of climatic events in the regolith profiles. These results confirm that despite their simple mineralogy, laterites can contain several relictual and coexisting generations of secondary minerals and that EPR dating of kaolinite contributes to unraveling the complex history of continental surfaces over geological periods.

Published
2019
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13. Macroscopic electrostatic effects in ATR-FTIR spectra of modern and archeological bones

Author

Xavier Gallet, Loïc Ségalen, Julie Aufort, Christian Brouder, Christel Gervais, Etienne Balan, Matthieu Lebon, Institut de minéralogie, de physique des matériaux et de cosmochimie ( IMPMC ), 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 ), Histoire naturelle de l'Homme préhistorique ( HNHP ), Muséum National d'Histoire Naturelle ( MNHN ) -Université de Perpignan Via Domitia ( UPVD ) -Centre National de la Recherche Scientifique ( CNRS ), Biominéralisations et environnements sédimentaires ( BES ), Institut des Sciences de la Terre de Paris ( iSTeP ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Spectroscopie, Modélisation, Interfaces pour L'Environnement et la Santé ( SMiLES ), Laboratoire de Chimie de la Matière Condensée de Paris ( LCMCP ), Centre National de la Recherche Scientifique ( CNRS ) -Collège de France ( CdF ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ) -Collège de France ( CdF ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS), Histoire naturelle de l'Homme préhistorique (HNHP), Muséum national d'Histoire naturelle (MNHN)-Université de Perpignan Via Domitia (UPVD)-Centre National de la Recherche Scientifique (CNRS), Biominéralisations et environnements sédimentaires (BES), Institut des Sciences de la Terre de Paris (iSTeP), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS), Spectroscopie, Modélisation, Interfaces pour L'Environnement et la Santé (SMiLES), Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), 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), Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Université de Perpignan Via Domitia (UPVD), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Collège de France (CdF)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Collège de France (CdF)-Centre National de la Recherche Scientifique (CNRS), and 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)

Subjects
fossilization, 010506 paleontology, Materials science, Enamel paint, ATR-FTIR spectroscopy, Atr ftir spectroscopy, Infrared spectroscopy, electrostatic properties, 010502 geochemistry & geophysics, 01 natural sciences, bone, Apatite, Diagenesis, Ftir spectra, Biomaterials, Geophysics, Geochemistry and Petrology, visual_art, visual_art.visual_art_medium, [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology, [ SDU.STU.MI ] Sciences of the Universe [physics]/Earth Sciences/Mineralogy, 0105 earth and related environmental sciences, Nuclear chemistry, [SDU.STU.MI]Sciences of the Universe [physics]/Earth Sciences/Mineralogy, [ SDU.STU.PG ] Sciences of the Universe [physics]/Earth Sciences/Paleontology
Abstract

International audience; Bones mostly consist of composite materials based on almost equivalent volume fractions of mineral (apatite) and organic (collagen) components. Accordingly, their infrared spectroscopic properties should reflect this composite nature. In this letter, we show by theory and experiment that the variability of the strong phosphate bands in the ATR-FTIR spectra of a series of modern and archeological bone samples can be related to electrostatic interactions affecting apatite particles and depending on the bone collagen content. Key parameters controlling the shape of these bands are the mineral volume fraction and the dielectric constant of the embedding matrix. The magnitude of these effects is larger than the one related to microscopic changes of the apatite structure. Consequently, the interplay of microscopic and macroscopic parameters should be considered when using FTIR spectroscopy to monitor the preservation state of bioapatite during diagenetic and fossilization processes, especially during the degradation of the organic fraction of bone.

Published
2018
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14. Infrared spectroscopic study of sulfate-bearing calcite from deep-sea bamboo coral

Author

Sophie Pouillé, Julie Aufort, Marc Blanchard, Michele Lazzeri, D. Blamart, Etienne Balan, Marie Dabos, Claire Rollion-Bard, Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), 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), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Paléocéanographie (PALEOCEAN), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut de recherche pour le développement [IRD] : UR206-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)

Subjects
Calcite, 010504 meteorology & atmospheric sciences, biology, Infrared, Analytical chemistry, Diamond, Infrared spectroscopy, Mineralogy, engineering.material, 010502 geochemistry & geophysics, biology.organism_classification, 01 natural sciences, Thermal expansion, chemistry.chemical_compound, Bamboo coral, chemistry, Geochemistry and Petrology, Attenuated total reflection, engineering, Sulfate, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [SDU.STU.MI]Sciences of the Universe [physics]/Earth Sciences/Mineralogy
Abstract

The powder infrared spectra of a sulfate-bearing calcitic coral sample are recorded at room temperature in attenuated total reflectance (ATR) geometry and at low temperature in transmission geometry. The comparison of ATR spectra recorded with diamond or Ge crystal confirms that the width and the shape of the prominent absorption bands, related to CO 3 groups, are dominantly affected by macroscopic electrostatic interactions. In contrast, the temperature-dependence of the position and width of weak and narrow absorption bands, related to CO 3 or SO 4 groups, can be interpreted in terms of thermal expansion, anharmonic coupling, and local strain fluctuations. The three SO 4 stretching bands display a contrasted thermal behavior, the frequency of one of them increasing with temperature. Based on first-principles calculation, this unusual temperature dependence is traced back to the anisotropy of calcite thermal expansion. These results sustain the previously proposed atomic-scale model of sulfate in calcite and attest to a dominantly structural nature of sulfate in the investigated sample. Accordingly, structurally substituted sulfur in deep-sea calcitic bamboo coral could be used as proxy of seawater sulfate.

Published
2017
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15. Bolt’s Farm Cave System dans le Cradle of Humankind (Afrique du Sud) : un exemple d’approche multidisciplinaire dans l’étude des sites à primates fossiles

Author

Thibaud Saos, John Hancox, L. Kgasi, Nonhlanhla Vilakazi, Frank Sénégas, Martin Pickford, Loïc Ségalen, Julie Aufort, Dominique Gommery, John Francis Thackeray, Andy I.R. Herries, Brian F. Kuhn, and James S. Brink

Subjects
060101 anthropology, Afrique du Sud, palaeoenvironment, 05 social sciences, Bolt’s Farm Cave System, paléobiodiversité paléoenvironnement, 06 humanities and the arts, primate, palaeodiversity, South Africa, lcsh:Zoology, General Earth and Planetary Sciences, 0501 psychology and cognitive sciences, 0601 history and archaeology, lcsh:Q, 050102 behavioral science & comparative psychology, lcsh:QL1-991, lcsh:Science, General Environmental Science
Abstract

Le Cradle of Humankind en Afrique du Sud présente des sites qui sont tous classés au titre de patrimoine mondial de l’humanité par l’UNESCO depuis 1999 (Thackeray, 2016). Ces sites ont livré des restes d’hominidés et/ou de primates non-humains (Cercopithecoidea). Robert Broom est le premier à rechercher des fossiles dans le Bolt’s Farm Cave System (ou BFCS), et ceci dès 1936. Les recherches n’y deviennent régulières que depuis 2006 avec la création du HRU (Hope (Human Origins and Past Environment) Research Unit). BFCS est surtout connu pour avoir livré des restes de grands félins. Pourtant, certains fossiles de Cercopithecoidea découverts à BFCS sont des références en paléoprimatologie comme BF42 (Cercopithecoides williamsi) et BF43 (Parapapio broomi). Waypoint 160 à BFCS a livré les plus anciens restes de primate non-humain du Cradle of Humankind qui sont datés du Pliocène inférieur. Pour obtenir plus d’informations sur le contexte géologique et le paléoenvironnement, des fouilles sont menées depuis 2011 dans certains loci et viennent remplacer les prospections menées par les membres du HRU. L’enjeu est d’obtenir le maximum de données sur la paléodiversité, notamment la microfaune qui doit être extraite des brèches par des techniques de préparation à l’acide, sur les conditions de fossilisation et de préservation des fossiles, ainsi que de pouvoir replacer ces fossiles dans le temps. The Cradle of Humankind in South Africa, recognized as World Heritage by UNESCO since 1999, contains fossil sites which have yielded hominid remains and/or non-human primates (Cercopithecoidea). Robert Broom was the first to prospect for fossils at Bolt's Farm Cave System (or BFCS), and this since 1936. Research only became regular in 2006 with the creation of the HRU (Hope (Human Origins and Past Environment) Research Unit). BFCS is best known for yielding remains of large cats. Yet some fossils of Cercopithecoidea discovered at BFCS are considered to be references in palaeoprimatology: BF42 (Cercopithecoides williamsi) and BF43 (Parapapio broomi). Waypoint 160 at BFCS yielded the oldest remains of nonhuman primates in the Cradle of Humankind which are dated to the Pliocene. For more information about the geological and palaeoenvironmental context, excavations were conducted since 2011 in some loci based on the surveys carried out by members of HRU. The present challenge is to obtain the maximum amount of data concerning palaeobiodiversity, including the microfauna which must be extracted from the breccia by acid preparation techniques, study of the conditions of fossilization and the preservation of fossils, as well as the determination of the ages of the fossils.

Published
2017

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