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13 Research products, page 1 of 2

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  • 2018-2022
  • IPERION CH
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  • Mémoires en Sciences de l'Information et de la Communication
  • Hyper Article en Ligne - Sciences de l'Homme et de la Société

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  • Open Access English
    Authors: 
    Corentin Reynaud; Mathieu Thoury; Alexandre Dazzi; Gaël Latour; Mario Scheel; Jiayi Li; Ariane Thomas; Christophe Moulherat; Aurore Didier; Loïc Bertrand;
    Publisher: HAL CCSD
    Country: France
    Project: EC | IPERION CH (654028), ANR | MORPHOSCOPE 2 (ANR-11-EQPX-0029), ANR | NANOIMAGESX (ANR-11-EQPX-0031)

    The understanding of fossilization mechanisms at the nanoscale remains extremely challenging despite its fundamental interest and its implications for paleontology, archaeology, geoscience, and environmental and material sciences. The mineralization mechanism by which cellulosic, keratinous, and silk tissues fossilize in the vicinity of archaeological metal artifacts offers the most exquisite preservation through a mechanism unexplored on the nanoscale. It is at the center of the vast majority of ancient textiles preserved under nonextreme conditions, known through extremely valuable fragments. Here we show the reconstruction of the nanoscale mechanism leading to the preservation of an exceptional collection of ancient cellulosic textiles recovered in the ancient Near East (4,000 to 5,000 years ago). We demonstrate that even the most mineralized fibers, which contain inorganic compounds throughout their histology, enclose preserved cellulosic remains in place. We evidence a process that combines the three steps of water transport of biocidal metal cations and soil solutes, degradation and loss of crystallinity of cellulosic polysaccharides, and silicification. Significance We report on the oldest archaeological textiles studied in detail for the mechanisms leading to their exceptional preservation, issued from archaeological excavations in the Ancient East and from collections of the Louvre Museum. We have studied these fossilized hybrid organic–mineral systems at high spatial resolution, from nano- to microscale, using a combination of nanoinfrared near-field spectroscopy, second harmonic generation microscopy, semiquantitative synchrotron X-ray microtomography, and electron microscopy. We establish a physicochemical pathway leading to their exceptional preservation. We show the joint involvement of the two main long-standing paradigms of mineralization and silicification in the process. We consistently identified “pockets of molecular preservation” with a demonstration of the in-place preservation of cellulose microfibrillar assemblies from SHG microscopy.

  • Open Access English
    Authors: 
    Stefan Röhrs; Gaia Fenoglio; Ina Reiche; Lothar Lambacher;
    Publisher: HAL CCSD
    Country: France
    Project: EC | IPERION CH (654028)

    International audience; Medieval champlevé enamelled objects are from copper sheets decorated with glass. The enamels were analysed by Raman spectroscopy to study the compositional differences in the glass matrix. Additional analyses were carried out by element analytical methods such µ-X-ray fluorescence analysis and environmental scanning electron microscopy with energy dispersive X-ray analysis. The two most frequently used glass types are mineral soda lime glass opacified with antimony compounds and vegetal soda lime glass with a more significant addition of PbO, opacified with SnO2. The enamel composition can succour the classification of the object regarding production time and place. The wavenumber of the bending and stretching regions, δmax and nu max, and the polymerisation index Ip were extracted from Raman spectra and results were interpreted with respect to the so-called glass families from the literature. The two most frequently used glass types can be distinguished in the plot of Ip vs. nu max. For further differentiation, the Si-O stretching nu max against Si-O bending δmax plot was exploited. This plot allowed a separation of glass types which superimposed in the plot of Ip vs. nu max, such as mixed alkaline glass and soda lime glass with added PbO. The small spot size and sensitivity of Raman analysis for lead and alkaline components allows to obtain complimentary data on compositional differences and heterogeneities of the glass matrix, which are difficult to detect by common laboratory micro-X-ray fluorescence analysis.

  • Open Access English
    Authors: 
    Lara Maldanis; Keyron Hickman-Lewis; Mariana Verezhak; Pierre Gueriau; Manuel Guizar-Sicairos; Plinio Jaqueto; Ricardo I.F. Trindade; André L. Rossi; Felisa Berenguer; Frances Westall; +2 more
    Publisher: HAL CCSD
    Country: France
    Project: EC | PSI-FELLOW-II-3i (701647), EC | MASE (607297), EC | IPERION CH (654028)

    AbstractPrecambrian cellular remains frequently have simple morphologies, micrometric dimensions and are poorly preserved, imposing severe analytical and interpretational challenges, especially for irrefutable attestations of biogenicity. The 1.88 Ga Gunflint biota is a Precambrian microfossil assemblage with different types and qualities of preservation across its numerous geological localities and provides important insights into the Proterozoic biosphere and taphonomic processes. Here we use synchrotron-based ptychographic X-ray computed tomography to investigate well-preserved carbonaceous microfossils from the Schreiber Beach locality as well as poorly-preserved, iron-replaced fossil filaments from the Mink Mountain locality, Gunflint Formation. 3D nanoscale imaging with contrast based on electron density allowed us to assess the morphology and carbonaceous composition of different specimens and identify the minerals associated with their preservation based on retrieved mass densities. In the Mink Mountain filaments, the identification of mature kerogen and maghemite rather than the ubiquitously described hematite indicates an influence from biogenic organics on the local maturation of iron oxides through diagenesis. This non-destructive 3D approach to microfossil composition at the nanoscale within their geological context represents a powerful approach to assess the taphonomy and biogenicity of challenging or poorly preserved traces of early microbial life, and may be applied effectively to extraterrestrial samples returned from upcoming space missions.

  • Open Access English
    Authors: 
    Rafaella Georgiou; Pierre Gueriau; Christoph J. Sahle; Sylvain Bernard; Alessandro Mirone; Romain Garrouste; Uwe Bergmann; Jean-Pascal Rueff; Loïc Bertrand;
    Publisher: American Association for the Advancement of Science
    Country: France
    Project: EC | E-RIHS PP (739503), EC | IPERION CH (654028)

    The in situ two-dimensional (2D) and 3D imaging of the chemical speciation of organic fossils is an unsolved problem in paleontology and cultural heritage. Here, we use x-ray Raman scattering (XRS)–based imaging at the carbon K-edge to form 2D and 3D images of the carbon chemistry in two exceptionally preserved specimens, a fossil plant dating back from the Carboniferous and an ancient insect entrapped in 53-million-year-old amber. The 2D XRS imaging of the plant fossil reveals a homogeneous chemical composition with micrometric “pockets” of preservation, likely inherited from its geological history. The 3D XRS imaging of the insect cuticle displays an exceptionally well preserved remaining chemical signature typical of polysaccharides such as chitin around a largely hollowed-out inclusion. Our results open up new perspectives for in situ chemical speciation imaging of fossilized organic materials, with the potential to enhance our understanding of organic specimens and their paleobiology. X-ray Raman multispectral imaging identifies the 3D chemistry of carbon in entire organic paleontological specimens.

  • Open Access English
    Authors: 
    Marta Sánchez de la Torre; A. Angyal; Zsófia Kertész; Stéphan Dubernet; François-Xavier Le Bourdonnec; Enikő Papp; Zoltán Szoboszlai; Zsófia Török; Ákos Csepregi; Zita Szikszai;
    Publisher: HAL CCSD
    Countries: France, Spain, Spain
    Project: EC | IPERION CH (654028), EC | IPERION CH (654028)

    International audience; This paper contributes to an understanding of the distances and choices involved in raw material procurement strategies by Upper Palaeolithic communities through a Pyrenean geo-archaeological case study. Methodologically, it involved using Particle Induced X-ray Emission (PIXE) with a focused proton beam to determine the concentration and distribution of elements in geological samples from three natural primary outcrops belonging to two geological formations outcropping in the French side of the Pyrenees. While it was not possible to distinguish the formation through reference to major and minor elements, some variations were revealed at the trace elemental level. With the aim to determine if these elements were associated with the Si matrix or to a specific inclusion, elemental maps were acquired, and the elemental composition of the identified inclusions were also determined. These chemical signatures were then compared to those generated from archaeological artefacts from sites in northern Spain as a means of reconstructing the catchment areas used by prehistoric groups for their chert procurement. The results indicate the existence of trans-Pyrenean long distance procurement strategies during the Magdalenian (13,700 to the 18,800 cal BP).

  • Open Access English
    Authors: 
    Xueshi Bai; Apolline Pin; Jingjun Lin; Maxime Lopez; Corinna Ludovica Koch Dandolo; Pascale Richardin; Vincent Detalle;
    Publisher: HAL CCSD
    Country: France
    Project: ANR | PATRIMEX (ANR-11-EQPX-0034), EC | IPERION CH (654028)

    International audience; We provide in this study a new application of laser-induced breakdown spectroscopy (LIBS) to evaluate whether ancient bones contain sufficient organic material before radiocarbon dating, which can avoid a complex preliminary analysis on the samples or unnecessary sampling. We first examined the plasma induced by UV (266 nm) ns-laser on pellets of compressed bone powder, and in a second step the plasma induced on raw bones using different gas environment. Firstly, we carried out a common method of analyzing the organic material using LIBS by observing C-N band emission in Ar-He mixture environment, the sample of non-undergone significant diagenesis, which contents enough collagen, can be well discriminated for further radiocarbon dating. Then spectral emission from nitrogen and carbon atoms was also recorded for these two types of samples in He and air environments. Calibration curves for carbon and nitrogen concentration of the bone were built to indicate the residual amount of collagen after undergoing the diagenesis (or degradation) and also to illustrate the possible carbonaceous pollution. The results proved that even if only several µg of material is analyzed for each laser shot, LIBS has a potential to carry out in situ measurements in archeological context while simultaneously performing a quantitative analysis.

  • Closed Access English
    Authors: 
    Jiayi Li; Pierre Gueriau; Marta Bellato; Andrew King; Luc Robbiola; Mathieu Thoury; Martin Baillon; Cécile Fossé; Serge X. Cohen; Christophe Moulherat; +3 more
    Publisher: HAL CCSD
    Country: France
    Project: EC | IPERION CH (654028), EC | E-RIHS PP (739503)

    International audience; The detailed description of corrosion processes in ancient and historical metal artifacts currently relies on the in-depth study of prepared cross sections. The in-plane elemental and phase distributions can be established from a combination of light and electron microscopy characterization. Here, we show that high-resolution virtual sectioning through synchrotron X-ray microcomputed tomography allows a precise noninvasive 3D description of the distribution of both internal and external mineral phases in whole objects. In fragments of early copper artifacts (third–second millennium BC) from Southern Mesopotamia and the Indus valley, this approach provided essential clues on long-term corrosion processes. Major and minor phases were identified through semiquantitative evaluation of attenuation coefficients using polychromatic X-ray illumination. We found evidence for initially unidentified phases through statistical processing of images. We discuss interpretation of the distribution of these phases. A good correlation between the corrosion phases identified by CT and by invasive BSE-SEM is demonstrated. In addition to the stratigraphy of the copper corrosion compounds, we examine and discuss the variations observed in the attenuation coefficients of Cu(I) phases. Semiquantitative synchrotron X-ray microtomography phase mapping requires no specific sample preparation, in particular polishing or surface finishing, and any material tearing or displacement is avoided. We also provide evidence for the noninvasive observation of phases rapidly altered upon preparation of real cross sections. The method can be applied when cross-sectioning even of minute fragments is impossible.

  • English
    Authors: 
    Calligaro, Thomas; Arean, Luis; Pacheco, Claire; Lemasson, Quentin; Pichon, Laurent; Moignard, Brice; Boust, Clotilde; Bertrand, Loïc; Schoeder, Sebastian; Thoury, Mathieu; +5 more
    Publisher: HAL CCSD
    Country: France
    Project: EC | IPERION CH (654028)

    We report the development of a 3D positioner for the elemental mapping of non-flat surfaces of heritage targets and its implementation in the external beam of the AGLAE accelerator, a joint research activity of the IPERION-CH European program.The positioner operates in two steps: 1) object surface is digitized using a 3D scanner implemented in the beamline. Surface points are interpolated onto a rectangular grid suitable for beam scanning. 2) Object is scanned under the beam using X/Y/Z stages holding a hexapod robot for rotations. During scanning, target surface is positioned with the Z stage and oriented perpendicular to the beam using hexapod rotations. Areas up to 100 × 100 mm2 with a resolution of 50 µm and 30° curvature of can be mapped on objects of 200 mm and 5 kg max. System operation was tested by recording PIXE maps on the polychrome decoration of a curved porcelain pot.

  • Open Access English
    Authors: 
    Davesne, Donald; Gueriau, Pierre; Dutheil, Didier B.; Bertrand, Loïc;
    Publisher: HAL CCSD
    Countries: United Kingdom, France, France
    Project: UKRI | How do palaeontological d... (NE/J022632/1), EC | IPERION CH (654028)

    International audience; Acanthomorph teleosts (spiny-rayed fishes) account for approximately a third of extant vertebrate species. They appeared during the Late Cretaceous and have been a major component of aquatic biodiversity since the early Cenozoic. They occupy today most trophic levels and ecological niches in aquatic environments, however very little is known about those that were adopted by the earliest representatives of the group. Here, we report on an exceptional glimpse into the ecological diversity of early spiny-rayed fishes provided by the unusual preservation of a newly discovered specimen of the freshwater acanthomorph Spinocaudichthys from the Upper Cretaceous of Morocco. A combination of major-to-trace elemental mapping methods reveals that the gross morphology of the specimen's intestine has been remarkably preserved owing to the rapid mineralization of iron hydroxides around it. Differing with the typically short and straight intestinal tract of carnivorous teleosts, the intestine in Spinocaudichthys is long and highly convoluted, indicating a probable herbivorous diet. Acanthomorphs would therefore have conquered various ecological niches in their early evolutionary history, prior to their subsequent phylogenetic diversification in both marine and freshwater environments that followed the K-Pg extinction event.

  • Open Access English
    Authors: 
    Loïc Bertrand; Claire Gervais; Admir Masic; Luc Robbiola;
    Country: France
    Project: EC | E-RIHS PP (739503), SNSF | New techniques for ancien... (138986), EC | IPERION CH (654028)

    International audience; The process of mimicking properties of specific interest (such as mechanical, optical, and structural) observed in ancient and historical systems is designated here as paleo-inspiration. For instance, recovery in archae- ology or paleontology identifies materials that are a posteriori extremely resilient to alteration. All the more encouraging is that many ancient materials were synthesized in soft chemical ways, often using low-energy resources and sometimes rudimentary manufacturing equipment. In this Minireview, ancient systems are presented as a source of inspiration for innovative material design in the Anthropocene.

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