Raman Spectroscopy in Art and Archaeology

International audienceThis paper gives a short overview of the Special Issue on Raman Spectroscopy in Art and Archaeology with the papers collected after the “3rd International Conference on the Application of Raman Spectroscopy in Art and Archaeology” held at the University Pierre et Marie Curie-Paris 6, Paris, France, August 31-Spetember 3, 2005. The contributions present an extended view of works in the field, from technical developments, special analytical procedures to various applications

L’archéométrie une discipline du passé ou un enjeu interdisciplinaire pour l’avenir ?

À l’occasion du colloque du GMPCA organisé à Rennes en 2017 (quarantième anniversaire de la première édition) ont eu lieu une série de conférences invitées destinées à ouvrir une réflexion historiographique sur l’archéométrie. Cet article présente cette initiative et introduit les contributions issues de ces conférences qui sont rassemblées dans ce numéro de la revue ArcheoSciences – Revue d’archéométrie. Au-delà, nous exprimons quelques points de vue sur la pratique et la structuration actuelle et future de l’archéométrie en France. Plus largement nous questionnons la place et la nature de l’interdisciplinarité dans les différents volets des archéosciences.At the GMPCA symposium held in Rennes in 2017 (fortieth anniversary of the first edition) a series of invited lectures were given to open a historical reflection on archaeometry. This paper presents this initiative and introduces the contributions resulting from these conferences which are collected in this issue of ArcheoSciences – Revue d'archéométrie. Beyond this we express some points of view on the current and future practice and structure of archaeometry in France. More broadly, we question the place and nature of interdisciplinarity in the different aspects of archaeosciences

Structural characterisation of corrosion products on archaeological iron. An integrated analytical approach to establish corrosion forms

International audienceThe description and identification of corrosion products formed on archaeological iron artefacts needs various approaches at different observation scales. For this study, samples of five different sites were prepared using two techniques. The first one consists in cutting cross sections perpendicular to corrosion layers. This allows local observations and analysis of the corrosion layer stratigraphy at different levels. The second one consists in performing manual grinding or abrading of the corrosion layers starting from the current surface of the excavated artefact to the metal core. It allows the description of the successive layers and is well adapted for the analysis on a larger scale. In addition to these two observation scales, the identification of the iron oxides formed needs the coupling of several complementary techniques. Elementary compositions were determined by SEM-EDX and Electron Micro-Probe Analysis (EMPA). Structural identification was performed by X-ray micro Diffraction under synchrotron radiation (µXRD) and micro Raman spectroscopy. These analyses were performed on the same samples both with X-ray diffraction and Raman spectroscopy in order to ensure a reliable characterisation. In some cases there are some ambiguities or overlapping between signatures of different phases by micro X-rays diffraction (as maghemite/magnetite) or Raman spectroscopy (as goethite/magnetite) which can be raised by the association of the two methods. The final aim is to set up an analytical methodology that will be the best for the study of ancient iron corrosion products. It is the first step of the study of long term mechanisms of iron in soil

Transparent varnishes on copper alloys dating from the 19th century: characterization and identification strategies

International audienceMany varnished copper-based artefacts dating from the 19th century can be found in museum collections. Although conservators deal on a daily basis with these surface finishes, few studies on this topic have been conducted during the last few decades on European objects. A more thorough understanding of these historical coatings would be helpful to establish accurate diagnoses and to contextualise the results with respect to the historical written sources. This paper presents the first results of the LacCa (Lacquered Copper Alloys) project currently being undertaken by an international multidisciplinary team. LacCa aims to develop a methodology that conservators can apply to identify and preserve these coatings. To this end, both historical objects and ancient varnish recipes have been studied. In a first step, the identification and characterisation protocol was validated using mock-ups, the results of which are presented in this paper

Вплив різних видів анестезіологічного забезпечення на неспецифічну ланку імунітету вагітних під час кесарева розтину

Компоненты хирургической операции – операционная травма, стресс, общая анестезия, кровопотеря, антибактериальная – терапия приводят к снижению защиты иммунной системы и развитию вторичной иммунной недостаточности. В результате операционно-анестезиологического стресса в организме больного возникает состояние иммунодепрессии, которое необходимо нивелировать путем выбора анестетиков, минимально угнетающих иммунные реакции. Такой подход дает возможность разработать и внедрить в клиническую практику оптимальные методы анестезии у беременных. Проведенное исследование показало, что операционный стресс негативно влияет на неспецифический иммунитет беременных. В зависимости от вида анестезии проявления негативного влияния будет различным. Установлено, что спинальная анестезия сопровождается минимальным влиянием на фагоцитарную активность лейкоцитов, а общая анестезия имеет депрессивное влияние, которое сопровождается более пяти дней.Components surgery . surgical trauma, stress, general anesthesia, blood loss, antibiotic . therapy leads to a decrease in defense of the immune system and the development of secondary immune deficiency. As a result of operational and anesthetic stress in the patient.s body a state of immunosuppression, which is necessary to level by selecting the anesthetic minimally depressing the immune response. This approach provides an opportunity to develop and introduce into clinical practice the best methods of anesthesia in pregnant women. The study showed that operational stress affects the nonspecific immunity of pregnant women. Depending on the type of anesthesia, manifestations of the negative impact will be different. Established that spinal anesthesia with a minimum influence on the phagocytic activity of leukocytes and general anesthesia has a depressive effect which is accompanied by more than five days

Raman Investigations to Identify Corallium rubrum in Iron Age Jewelry and Ornaments

International audienceDuring the Central European Iron Age, more specifically between 600 and 100 BC, red precious corals (Corallium rubrum) became very popular in many regions, often associated with the so-called (early) Celts. Red corals are ideally suited to investigate several key questions of Iron Age research, like trade patterns or social and economic structures. While it is fairly easy to distinguish modern C. rubrum from bone, ivory or shells, archaeologists are confronted with ancient, hence altered, artifacts. Due to ageing processes, archaeological corals lose their intensive red color and shiny surface and can easily be confused with these other light colored materials. We propose a non-destructive multi-stage approach to identify archaeological corals amongst other biominerals used as ornament during the central European Iron Age with emphasis on optical examination and mobile Raman spectroscopy. Our investigations suggest that the noticeably high amount of misidentifications or at least uncertain material declarations existing in museums or even in the literature (around 15%) could be overcome by the proposed approach. Furthermore, the range of different materials is higher than previously expected in archaeological research. This finding has implications for contemporary concepts of social structures and distribution networks during the Iron Age

Application des micro-spectrométries infrarouge et Raman à l’étude des processus diagénétiques altérant les ossements paléolithiques

Différents processus post-mortem peuvent altérer les ossements et limiter l’utilisation de leur composition élémentaire et isotopique comme marqueurs paléo-environnementaux/climatiques, paléo-alimentaires ou encore géochronologiques. De part leur structure complexe et hiérarchisée, les ossements in vivo sont des tissus hétérogènes. La prise en compte de cette hétérogénéité, renforcée au cours de la fossilisation, nécessite l’utilisation de techniques d’analyses adaptées permettant l’étude des variations de structure et de compositions à micro-échelle. De précédents travaux ont montré que des techniques de micro-spectrométrie vibrationnelle telle que la micro-spectrométrie infrarouge pouvait permettre de caractériser les modifications induites par les processus diagénétiques et de déterminer les états de préservation des échantillons fossiles. Dans cette étude, des indices permettant de déterminer la composition d’ossements fossiles ont été acquis en spectrométrie infrarouge et Raman, ceci dans le but de comparer les informations fournies par ces deux techniques. Les micro-spectrométries IR et Raman ont ensuite été appliquées à des échantillons fossiles préparés sous forme de coupes minces ou de lames épaisses. Ces premiers résultats de cartographie obtenus par micro-spectrométrie Raman permettent de mettre en évidence l’apport de cette technique à la compréhension des processus diagénétiques en permettant de déterminer la répartition des principaux composés des ossements fossiles (teneur en collagène, en carbonates, cristallinité de la phase minérale, etc.).Various post-mortem processes can alter bone materials and then limit the use of their elemental or isotopic composition as markers for palaeo-environmental/climatic, paleodiet, or geochronological studies. Due to their complex and hierarchical structure, in vivo bones correspond to a highly heterogeneous tissue. The study of this heterogeneity, reinforced during fossilization processes, requires the use of adapted analytical techniques to investigate the variation of composition at microscale. Previous works have demonstrated that vibrational spectroscopic techniques like infrared micro-spectroscopy can be used to characterize the modification of composition induced by diagenetic processes and to determine the preservation state of the fossil samples. In this study, some spectral parameters, used to determine the composition of fossil bones, were measured by both infrared and Raman spectroscopy in order to compare the information supplied by these two techniques. Infrared and Raman micro-spectroscopy were then applied to fossil samples prepared as thin sections or polished thick sections. These first results of chemical mapping obtained on fossil bones by Raman micro-spectroscopy are in good agreement with the data obtained by FTIR micro-spectroscopy. These results demonstrated the capacity of this method for the understanding of diagenetic processes by monitoring the main components of fossil bone tissues (carbonates and collagen content, mineral crystallinity, etc.)

On-Site Identification of Early Böttger Red Stoneware Using Portable XRF/Raman Instruments: 2, Glaze & Gilding Analysis

Twenty‐one glazed red stoneware objects, with gilded or gold‐painted decor from different collections (Cité de la Céramique, Sèvres, France; Art Institute of Chicago, USA; a private collection) attributed to 18th century Böttger, Meissen (Saxony) have been analyzed with a portable X‐ray fluorescence spectrometer (XRF) and portable or fixed Raman micro‐spectrometer in laboratory/museum/collector rooms. Analysis was aimed at gaining a deeper understanding of the technology of production of the gilding and black glaze, to augment what is known from the limited literature. Three different techniques to obtain a golden décor emerged as a result of this study: (i) a true gilding with gold, (ii) gold with mercury, and (iii) an alloy of copper and zinc

Tratamiento de espectros FTIR con el programa PALME: una nueva herramienta para diagnosticar el estado de conservación de hierros arqueológicos

International audienceEl proceso que va del descubrimiento de una pieza arqueológica a su musealización pasa necesariamente por una fase de restauración. En el caso de piezas de naturaleza metálica la restauración puede comportar la eliminación mecánica de las costras de degradación más externas. Los fragmentos eliminados contienen una gran cantidad de información que, si es extrapolada, puede ayudar a los restauradores a elegir los tratamientos más adecuados de conservación. Por esta razón, con el presente trabajo se pretende desarrollar un nuevo método que permita semicuantificar de manera rápida y fiable las fases de corrosión contenidas en los residuos de limpieza de hierros arqueológicos. Para realizar el trabajo ha sido utilizado el software PALME para el tratamiento de los resultados obtenidos mediante espectroscopia infrarroja (FTIR) sobre mezclas de corrosiones puras a concentración conocida. Gracias a los resultados obtenidos se puede afirmar que el método desarrollado, una vez optimizado, representará una herramienta útil para la rápida semicuantificación de las corrosiones que normalmente afectan los hierros arqueológicos

Le Mas de Vignoles X (Nîmes, Gard) : un établissement de plein air du Néolithique ancien

National audienceSeveral emergency excavations recently brought to light an open air site, near Nîmes (South of France), which can be dated from the Early Neolithic. Called 'Mas de Vignole', this site consists on a well preserved soil, scattered with several categories of artefacts, and with stones and pebbles. The spatial analysis of all these objects makes it possible to propose the hypothetical restitution of at least about ten 'houses'. All artefacts, as well as radiocarbon datings, allot this village to the Early Epicardial, towards 5200-5000 BC cal.Plusieurs opérations d'archéologie préventive ont récemment permis la fouille d'un site de plein air du Néolithique ancien épicardial, sur la commune de Nîmes (Gard, France). Ce gisement du Mas de Vignole se caractérise par un sol d'habitat relativement bien conservé, parsemé de mobilier archéologique, de pierres et de galets. L'analyse spatiale de la dispersion de ces objets permet de proposer la restitution hypothétique d'un village d'au moins une dizaine de constructions. Tous les vestiges mobiliers ainsi que les datations radiocarbone attribuent cette occupation à l'Epicardial ancien, soit vers 5200-5000 avant notre ère