Analytical strategies for discriminating archaeological fatty substances from animal origin

International audienceMass spectrometry (MS) is an essential tool in the field of biomolecular archeology to characterize amorphous organic residues preserved in ancient ceramic vessels. Animal fats of various nature and origin, namely subcutaneous fats of cattle, sheep, goats, pigs, horses, and also of dairy products, are those most commonly identified in organic residues in archeological pottery. Fats and oils of marine origin have also been revealed. Since the first applications of MS coupled with gas chromatography (GC) in archeology at the end of 1980s, several developments have occurred, including isotopic determinations by GC coupled to isotope ratio MS and identification of triacylglycerols (TAGs) structure by soft ionization techniques (ESI and APCI). The combination of these methods provides invaluable insights into the strategies of exploitation of animal products in prehistory. In this review, I focus on the analytical strategies based upon MS that allow elucidation of the structure of biomolecular constituents and determination of their isotopic values to identify the nature of animal fat components preserved in highly complex and degraded archeological matrices.

Contribution méthodologique à l’analyse fonctionnelle des céramiques d’un habitat néolithique : l’exemple de Kovačevo (6 200-5 500 av. J.-C., Bulgarie)

L’analyse d’une centaine de vases parmi les plus complets a été réalisée afin d’appréhender leurs fonctions et modes d’utilisation. Une approche interdisciplinaire située à la frontière de l’archéologie, de la chimie et de la tracéologie a dès lors été développée. Elle combine analyse morphométrique des céramiques, caractérisation des résidus et observation des traces d’usure. Les récipients en terre cuite de l’habitat néolithique de Kovačevo ont, semble-t-il, connu un usage fréquent (usure prononcée de certains fonds, bases et préhensions de vases), des fonctions variées (préparation, cuisson, consommation et stockage) et ce dès le début de l’occupation du site. Ils forment un assemblage fonctionnel tout à fait cohérent de récipients. Cette batterie de cuisine fut par ailleurs conçue par des potiers qui, lors de la phase de fabrication des vases, ont opéré des choix dont une partie relève indiscutablement de facteurs fonctionnels. Pleinement intégrées aux diverses activités, ces toutes premières productions céramiques du Néolithique balkanique se différencient du point de vue de leur statut de celles du Néolithique grec. Ces dernières sont en effet considérées comme un bien de prestige. Les recherches futures viseront à comprendre les raisons de cette frontière culturelle : reflète-t-elle l’existence de deux courants diachroniques de néolithisation effectués par des populations attribuant une valeur différente à leurs récipients ou traduit-elle une évolution chronologique de la fonction des plus anciennes céramiques grecques ?The analysis of about one hundred vessels amongst the most complete have been carried out in order to better understand their functions and ways of use. We developed a multidisciplinary approach based on archaeology, chemistry and use-wear study. This approach combines the study of the shapes of ceramics, analysis of residues and observations of use-wear. From the beginning of the settlement occupation, pottery has been used frequently (worn deeply on the bottom and the handles), and for many different functions (preparation, cooking, consumption, storage). They constitute a coherent functional group. Furthermore, at Kovačevo, some of the vessels have been manufactured by potters who, during the fabrication phase, have made some choices in relation to their primary function. The status of first Balkan ceramic productions seems also different from the Greek one. Indeed, the Greek pottery dated from the Early Neolithic period are considered as prestigious goods. The future searchs will perhaps allow to understand the reasons of this cultural border: is it the consequence of the existence of a diachronic way of neolithization made by populations attributing different values to their containers or is it the consequence of a possible chronologic evolution of the oldest Greek ceramics function

L'exploitation des matériaux colorants au Paléolithique supérieur. Quelles stratégies d'approvisionnements, quelles transformations pour quelles utilisations ?

Peer reviewe

The Missing Step of Pottery chaîne opératoire : Considering Post-firing Treatments on Ceramic Vessels Using Macro- and Microscopic Observation and Molecular Analysis

Post-firing treatments, produced by the interaction of an organic material with the hot surface of a ceramic, are frequently described in ethnographic literature, but have rarely been identified in archaeological ceramic assemblages. In order to address this question, this paper describes a methodology that combines macro- and microscopic observation and molecular analysis. The study of experimental ceramic vessels provided diagnostic tools to identify the type of substances, their liquid or solid state, and their mode of application and attested that the post-firing treatments do not completely waterproof the ceramics. The difficulty to observe macro- and microscopic evidence of post-firing treatments when pots are fired in reducing atmosphere suggests that these processes are probably underestimated in archaeological assemblages. Furthermore, the identification of molecular thermal transformation markers, such as ketones, calls into question their classical interpretation as markers for the cooking of fatty content. This pioneering work highlights the complexity of studying post-firing treatments, which leave small traces that are easily missed or misinterpreted. In order to address this issue, we propose a multi-analytical approach, which can serve as a basis for future studies to explore the full diversity of post-firing treatments mentioned in ethnoarchaeological literature

Exploitation of beehive products, plant exudates and tars in Corsica during the early Iron Age

International audienceIn the northwestern Mediterranean area, the first Iron Age is characterized by intense contacts and cultural interactions between populations. Archaeological remains such as ceramic vessels or metal and glass objects are usually good indicators of the nature and the intensity of these exchanges, but can also be used to determine the way in which these populations were living at their time. In contrast, organic substances, despite their importance in a wide variety of activities, are rarely investigated due to their low degree of preservation. The recent discovery of a series of amorphous organic residues with adhesive properties at the site of Cuciurpula provided a unique opportunity to address questions related to the types of natural substances exploited, their provenance, their uses and their informational input to intercultural relationships. Our results, based on GC and GC–MS analysis of organic residues preserved at the site of Cuciurpula, provide strong evidence for the most southern use of birch bark tar in Western Europe, and also for the simultaneous use of this substance with pine resin. Beeswax was also identified in some samples. The combined study of residue composition, aspect and location on ceramic sherds reveals a variety of uses, highlighting a complex technical system

Domestic activities and pottery use in the Iron Age Corsican settlement of Cuciurpula revealed by organic residue analysis

The excavation of the protohistoric site of Cuciurpula (South Corsica, France) revealed a significant amount of potsherds, often bearing visible surface crusts, sometimes very thick. This exceptional case in the Mediterranean region, suggesting a good preservation of organic substances, provided a unique opportunity to address questions related to pottery function and natural organic substances exploited in Corsica during the first half of the 1st millennium BC. The molecular analysis (GC and GC/MS) of organic residues from three houses of the site, preserved in both pottery walls and charred surface crusts, highlighted the wide diversity and the various roles of substances contained and processed in ceramic vessels: animal fats, plant oils and waxes, beeswax, and conifer resin. These molecular data, considered together with the shapes of the vessels and their location into the habitation units, revealed the diversity of pottery function (culinary and technical) and spatial organisation of domestic activities between houses or in a house (distinction between storage and cooking areas)

Assessing Hafting Adhesive Efficiency in the Experimental Shooting of Projectile Points: A new Device for Instrumented and Ballistic Experiments

International audienceWith the aim of providing better control of shooting experiments performed with replicas of prehistoric projectiles, we have conducted an instrumental archaeology study on the efficiency of prehistoric projectile points by placing emphasis on their adhesion and ballistic characteristics. In order to avoid any reproducibility problems, hafting adhesives were made with controlled mixtures of commercial rosin (also called ‘colophany’) and beeswax added as a plasticizer. An original experimental device has been developed to instrument a bow, allowing the control of both the trajectories and the velocities of the different shoots. In the course of an experimental programme on Sauveterrian microliths from the Mesolithic period of the South of France, the experimental system was applied to composite replica projectile tips of Mesolithic hunters. Arrows being shot at transparent targets were filmed in order to evaluate the penetration length and residual damage. Interestingly, this study reveals that the properties of the mixture are highly dependent on the velocity of the arrows. It was shown that—contrary to previous experiments that usually used a mixture in which rosin predominates— the most efficient adhesive is made of 70 wt% beeswax with only 30 wt% rosin. This result is of great importance for improving further shooting experiments and overcoming the problems frequently mentioned due to the loss of the flint armatures before they reach the animal target, or at least before penetration. When using this appropriate mixture, the lateral armatures are resistant to most of the shots. Experiments performed on real boars’ flesh have also shown that the presence of lateral microliths allows the laceration inflicted on the target to be enlarged. Finally, a critical parameter has been identified, which is the location on the arrow of the microlithic element