Analyse de baumes issus de tête momifiée (Thèbes)

L’étude de trois baumes, prélevés sur un crâne momifié appartenant à la collection du musée des Confluences de Lyon, a pu être réalisée. Les analyses radiographiques et morphologiques ont mis en évidence une perte de substance occipito-pariétale, secondaire à un traumatisme crânien, ayant entraîné la mort du sujet. Ceci a donc permis de comparer les formulations des baumes intra- et extra-crâniens par spectrométrie Infrarouge à transformée de Fourier et chromatographie en phase gaz couplée à la spectrométrie de masse. Les baumes extra-crâniens présentent de fortes teneurs en Hydrocarbures Aromatiques Polycycliques et des traces de composés hopanes et stéranes, indiquant la présence d’un bitume pyrolysé, ainsi que des pimaranes impliquant l’utilisation d’une résine non chauffée provenant d’arbres de l’embranchement des Conifères (ou Pinophyta). L’échantillon prélevé dans l’endocrâne présente une composition très différente avec la présence d’huile ou graisse et d’une résine provenant d’arbres de l’embranchement des Conifères. Nous avons donc pu mettre en évidence une spécificité de technique (chauffage ou non) et de matériaux entre différentes localisations d’un même baume.The study of three balms, sampled from mummified head belonging to the collection of the ”musée des Confluences” in Lyon, was realized. X-ray and morphologic analysis underlined the lost of occipito-parietal material, induced by cranial traumatism, that caused the death of the subject. This allowed to study the differences between intra- and extra-cranial balms formulations by Fourier transform infrared spectrometry and gas chromatography coupled with mass spectrometry. Intra-cranial balms are composed of high concentrations of different Polycyclic Aromatic Hydrocarbons and traces of sterane and hopane compounds from pyrolised bitumen. We also found different pimaranes molecules from non-heating resin taken from trees of the Coniferae phylum. Sample from endocranium had a really different composition with oil or fat mixed with a coniferous resin. Thus, we brought to light the specificity in term of techniques (heating or not) and materials between two different localizations of the same skull

The natural pigments used in Costa-Rica: preliminary analysis of geomaterials and polychromic ceramic shred from Guanacaste

En esta publicación, se aportan datos relacionados con la identificación de las principales fuentes de pigmentos publicadas en la literatura científica. Además, se presenta el análisis fisicoquímico de los geomateriales usados ahora en la zona de Guaitil (Costa Rica) y de seis tipos cerámicos procedentes de diferentes sitios arqueológicos (tipos Jicote Policromo, Jicote variedad felino, Birmania Policromo, Mora Policromo variedad Chircot, Altiplano Policromo, Mora Policromo variedad Guapote), por medio de las técnicas de análisis de fluorescencia de los rayos X (XRF), espectrometría infrarroja (FT-IR) y mi- croscopio electrónico de barrido (SEM-EDS). En el caso de los geomateriales usados por los alfareros de Guaitil como pigmento, (i) los rojos y blancos fueron caolinita con cuarzo y trazas de óxido de hierro, y (ii) el pigmento negro fue una mezcla de cuarzo, óxidos de manganeso, hematita y trazas de caolinita. En el caso de las cerámicas precolombinas, los engobes de Altiplano Policromo, Birmania Policromo y Mora Policromo variedad Chircot tuvieron una composición parecida con altos contenidos de meta-esmectita y cuarzo, aunque el engobe del fragmento de Mora Policromo variedad Guapote se compuso principalmente de meta-caolinita y cuarzo. Por un lado, los tiestos de Jicote tuvieron un engobe de composición diferente con la presencia de meta-emectita, cristobalita y hematita. Por otro lado, los pigmentos rojos fueron he- chos con la mezcla del engobe con un geomaterial rico en hematita. Asimismo, los pigmentos negros se realizaron con geomateriales a base de óxido de manganeso o magnetita.In this publication, we provided data on the main sources of pigments published in the scientifc literature. Furthermore, the geomaterials used nowadays in the Guaitil area (Costa Rica) and six types of ceramic fragments coming from different Costa Rican archaeological sites (Jicote Policromo, Jicote variedad felino, Birmania Policromo, Mora Policromo variedad Chircot, Altiplano Policromo, Mora Policromo variedad Guapote types) were characterized using X-ray fuorescence analysis (XRF), infrared spectrometry (FT-IR) and scanning electron microscope (SEM-EDS). In the geomaterials used by Guaitil potters as pigments, (i) the red and white materials were kaolinites with quartz and traces of iron oxide, and (ii) the black pigment was a mixture of quartz, manganese oxides, hematite and trace of kaolinite. In the case of the pre-Columbian ceramics, the polychrome Altiplano and Mora Policromo engobes were composed of meta-caolinite, meta-esmectite and quartz, while the Jicote Polychromium pot included meta-smectite, crystobalite, anhydrite and hematite in its chemical composition. The red pigments were made with the mixture of the slip with hematite-rich geomaterial, manganese oxide or magnetite depending on the color and the ceramic style.UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Sociales::Centro de Investigaciones Antropológicas (CIAN

Microbial population in cloud water at the Puy de Dôme: implications for the chemistry of clouds

Airborne micro-organisms are ubiquitous in the atmosphere where they can remain alive and be transported over long distances, thus colonizing new environments. Despite their great importance in relation to ecological and socio-economical issues (bio-terrorism, health, etc.) very few studies have been carried out in this field. In this study, the structure of the microbial community present in atmospheric water samples from clouds at the Puy de Dôme (alt 1465 m, Massif Central, France) is described and the metabolic potential of some bacteria is investigated. The total microflora has been quantified by epifluorescence microscopy, while the cultivable aerobic micro-organisms were isolated. Bacteria were identified by 16S DNA sequencing and fungi by morphological criteria. The total bacterial count reached about 3×104 cells m−3 of cloud volume (1×105 cells mL−1 of cloud water), of which less than 1% are cultivable. Most of the isolated micro-organisms, including 12 fungal and 17 bacterial strains, are described here for the first time in atmospheric water. Many bacterial strains seem to be adapted to the extreme conditions found in cloud water (pH, T°, UV radiations, etc.). Comparison of the two samples (March 2003) shows that pH can be a major factor controlling the structure of this community: an acidic pH (Sample 1: pH=4, 9) favours the presence of fungi and spore-forming bacteria, while a more neutral pH (Sample 2: pH=5, 8) favours greater biodiversity. We have also shown, using in situ 1H NMR, that most of the isolated bacteria are able to degrade various organic substrates such as formate, acetate, lactate, methanol and formaldehyde which represent the major organic compounds present in cloud water. In addition, the detection of intermediates indicated preferential metabolic routes for some of the strains

Rapid response to the M_w 4.9 earthquake of November 11, 2019 in Le Teil, Lower Rhône Valley, France

On November 11, 2019, a Mw 4.9 earthquake hit the region close to Montelimar (lower Rhône Valley, France), on the eastern margin of the Massif Central close to the external part of the Alps. Occuring in a moderate seismicity area, this earthquake is remarkable for its very shallow focal depth (between 1 and 3 km), its magnitude, and the moderate to large damages it produced in several villages. InSAR interferograms indicated a shallow rupture about 4 km long reaching the surface and the reactivation of the ancient NE-SW La Rouviere normal fault in reverse faulting in agreement with the present-day E-W compressional tectonics. The peculiarity of this earthquake together with a poor coverage of the epicentral region by permanent seismological and geodetic stations triggered the mobilisation of the French post-seismic unit and the broad French scientific community from various institutions, with the deployment of geophysical instruments (seismological and geodesic stations), geological field surveys, and field evaluation of the intensity of the earthquake. Within 7 days after the mainshock, 47 seismological stations were deployed in the epicentral area to improve the Le Teil aftershocks locations relative to the French permanent seismological network (RESIF), monitor the temporal and spatial evolution of microearthquakes close to the fault plane and temporal evolution of the seismic response of 3 damaged historical buildings, and to study suspected site effects and their influence in the distribution of seismic damage. This seismological dataset, completed by data owned by different institutions, was integrated in a homogeneous archive and distributed through FDSN web services by the RESIF data center. This dataset, together with observations of surface rupture evidences, geologic, geodetic and satellite data, will help to unravel the causes and rupture mechanism of this earthquake, and contribute to account in seismic hazard assessment for earthquakes along the major regional Cévenne fault system in a context of present-day compressional tectonics

Chemical analysis of organic archaeological materials

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Photodégradation de pesticides organophosphorés en solution aqueuse et sur argiles : étude mécanistique

The work presented inhere concerns the study of the photochemical behavior of the organophosphorus azinphos-methyl (AZM) and its model molecule, benzotriazone. For both compounds, the photodegradation efficiency increases with the excitation energy. Such effect can be attributed to a difference in the excited states reactivity or to homolytic bond dissociations of the triazone moiety. The degradation of azinphos-methyl involving direct excitation leads to the formation of benzotriazone which photodegrades in its turn into anthranillic acid. In the case of cyanophos, another organophosphorus pesticide, the degradation involves both singlet and triplet excited state. Several chemical processes were present: homolytic cleavage, hydrolysis. 4-cyanophenol, cyanophos-oxon and [(dimethoxyphosphorothiolyl) oxy] benzoïc acid represent the main observed photoproducts. The study of azinphos-methyl degradation upon direct irradiation has been also studied at the surface of clays (kaolinite, bentonite) and iron oxide (goethite). Adsorption of the pesticide on clays leads to an enhancement of its spectroscopic features permitting a better solar light absorption. Moreover, the photodegradation of AZM appears to be efficient, in Suntest device, on all the studied clays. The efficiency of the reaction depend on the type of clay, thickness, water content, and iron(III) concentration. The degradation of azinphos-methyl involves both direct photochemical reactions and clay photoinduced processes. The involvement of hydroxyl radical was demonstrated by ESR and fluorescence measurements. Among several other products, azinphos-methyl oxon was found to be formed and to accumulate in the medium inducing an increase of the toxicity.Le pesticide organophosphoré azinphos-méthyle (AZM) voit son efficacité de photodégradation augmenter avec l'énergie d'excitation, vraisemblablement dû à des différences de réactivité entre états excités. Sa dégradation sous excitation directe conduit à la formation de benzotrione qui se dégrade en l'acide anthranilique. Un autre organophosphoré, le cyanophos, se dégrade sous excitation directe en faisant intervenir les états excités triplet et singulet pour former : le 4-cyanophénol, le cyanophos-oxon et un dérivé de l'acide benzoïque. Le dépot de l'AZM dans l'argile conduit à une meilleur absorption de la lumière solaire. Sa photodégradation sur argiles et oxyde de fer est efficace, avec une vitesse dépendant essentiellement de la nature et de l'épaisseur du solide du taux d'humidité et de fer(III). L'AZM se dégrade par des processus issus d'une excitation directe et d'autres photoinduits par le support. La formation de radicaux hydroxyles a également été mise en évidenc

Simulated Solar light phototransformation of the organophosphorus azinphos methyl at the surface of clays and goethite.

International audienceThe photochemical behavior of the pesticide azinphos methyl at the surface of clays (kaolinite, bentonite) and goethite was studied using Suntest setup (λ > 300 nm). The quantum yield on the clays was found to be roughly three times lower than that in aqueous solution. However, the photochemical efficiency was much higher at the surface of goethite owing to its photocatalytic activity through the hydroxyl radical production. The added humic substances on kaolonite show an inhibition of azinphos methyl degradation while the incorporation of iron(III) aquacomplexes leads to an important increase of the disappearance together with the formation of iron(II). Hydroxyl radical species were found to be formed either by excitation of goethite or clays. The goethite support acts as a more efficient catalyst for the formation of these reactive oxygen species. The photodecomposition reactions observed were (i) hydrolysis process leading to the formation of benzotriazone and the oxidation of the P = S bond giving rise to the formation of the oxon derivative, and (ii) homolytic cleavage of the N−C and C−S bonds of the organophosphorus bridge leading to the formation of dimers that appear to be specific to the irradiation at the surface of solid supports since they were not observed when the irradiation was performed in aqueous media: a statement that is related to the presence of aggregates at the surface of solid supports

Archeomaterials and organic matters

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Chemical analysis of painting varnishes

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