PREHISTORIC WALL PAINTINGS: THE CASE OF THE DOMUS DE JANAS NECROPOLIS (SARDINIA,ITALY)*

The Domus de Janas (Home of the Fairies, or Home of the Witches) are Neolithic hypogea located throughout Sardinia (Italy) and decorated with red and black wall paintings. The objective of this study was to define the painting technique through the analytical characterization of the pigments and binding media. Samples of painting film from different graves have been examined by means of various analytical techniques. XRD, Raman and SEM–EDX analyses identified the red and black pigments respectively as red ochre rich in hematite and carbon black, while GC–MS analyses characterized the organic binder as egg.     

A TECHNOLOGICAL EXAMINATION OF NINTH–TENTH CENTURY AD ABBASID BLUE‐AND‐WHITE WARE FROM IRAQ,AND ITS COMPARISON WITH EIGHTH CENTURY AD CHINESE BLUE‐AND‐WHITE SANCAI WARE*

Eight sherds of ninth–tenth century ad Abbaesid blue‐and‐white glazed earthenware, excavated in 1931 at Hira in western Iraq, were analysed using, variously, quantitative wavelength‐dispersive spectrometry (WDS) and energy‐dispersive spectrometry (EDS) in association with scanning electron microscopes (SEM), and semi‐quantitative X‐ray fluorescence spectrometry (XRF). In order to compare the compositions of the cobalt pigments used, the glazes of seven complete vessels of eighth century ad Chinese Tang blue‐and‐white sancai were also analysed semi‐quantitatively using XRF. The Abbasid wares were shown to have used traditional Mesopotamian alkali–lime glazes applied to calcareous clay bodies. Half the glazes examined were opacified with tin oxide. Three types of blue decoration (i.e., raised; spreading; and flat, non‐spreading) were produced using a variety of formulations, including a mixture of cobalt pigment with lead oxide. The sources of the ores used for the cobalt pigments have not been identified. However, the analytical data showed that the cobalt ore used for the Abbasid blue‐and‐white ware could be distinguished from that used for the Tang blue‐and‐white sancai by its higher iron content and by the presence of a significant amount of zinc. The use of cobalt‐blue decoration on the ninth–tenth century ad Abbasid ware was anticipated in China by eighth century ad Tang blue‐and‐white sancai wares. However, whether its introduction by the Abbasid potters should be seen as an independent invention that followed the introduction of tin‐opacified glazes in Iraq, or whether it was influenced in some way by Chinese originals, is still unresolved.     

Strontium Isotopes in the Investigation of Early Glass Production: Byzantine and Early Islamic Glass from the Near East*

⁸⁷Sr/⁸⁶Sr ratios have been determined for glasses from four production sites, dated to between the sixth and the 11th centuries, in the Eastern Mediterranean region. On the basis of elemental analyses, the glasses at each location are believed to have been melted from different raw materials. Two glass groups, from Bet Eli‘ezer and Bet She‘an, in Israel, are believed to have been based upon mixtures of Levantine coastal sands and natron, and have ⁸⁷Sr/⁸⁶Sr ratios close to 0.7090, plus high elemental strontium, confirming a high concentration of modern marine shell (⁸⁷Sr/⁸⁶Sr ~ 0.7092) in the raw materials. The isotopic compositions of these two groups of glasses differ slightly, however, probably reflecting a varying ratio of limestone to shell because the sands that were utilized were from different coastal locations. Natron‐based glasses from a workshop at Tel el Ashmunein, Middle Egypt, have ⁸⁷Sr/⁸⁶Sr values of 0.70794–0.70798, and low elemental strontium, consistent with the use of limestone or limestone‐rich sand in the batch. High‐magnesia glasses based on plant ash, from Banias, Israel, have ⁸⁷Sr/⁸⁶Sr values of 0.70772–0.70780, probably reflecting the isotopic composition of the soils that were parental to the plants that were ashed to make the glass. Strontium and its isotopes offer an approach to identifying both the raw materials and the origins of ancient glasses, and are a potentially powerful tool in their interpretation.     

Adhesive Production and Pottery Function During the Iron Age at the Site of Grand Aunay (Sarthe,France)*

A combination of elemental, functional and molecular analyses performed on amorphous organic residues dating from the Iron Age was developed in order to identify these remains and to understand their relationship with ceramic vessels in which some of them were found. These analyses made it possible to distinguish between ceramic vessels used for the production or storage of adhesive materials, mainly birch bark tar, and those dedicated to the preparation of culinary commodities, which contained animal fats. The organization of the production of adhesives is described and the addition of beeswax to birch bark tar is reported for the first time. The use of birch bark tar for coating ceramic vessels is also discussed.     

EVALUATION OF ARCHAEOLOGICAL LAYERS AIDED BY SPECTROMETRY AND ROBOTICS*

All archaeologists have faced the problem of interpreting stratigraphy. While this task can sometimes be very clear and unambiguous, this is far from always being the case. Because human beings are limited in their appreciation of soil by subjectivity and by the ability of their senses, it can be useful to turn to technology for help. Here, we present our research on the characterization of archaeological soils by spectrometric analyses, and we demonstrate the perspectives offered by robotics to excavate in fieldwork and to record the stiffness of the earth.     

RECONSTRUCTING ANCIENT YEMENI COMMERCIAL ROUTES DURING THE MIDDLE AGES USING STRUCTURAL CHARACTERIZATION OF TERPENOID RESINS*

Following the discovery of items that look like resins at the medieval site of Sharma (Hadramawt coast, Yemen, c. 11th century ad ), chemical investigations were carried out in order to determine their nature and geographic origin. By combining visual observation, infrared spectroscopy, direct inlet electron ionization – mass spectrometry (DI EI–MS) and pyrolysis gas chromatography – mass spectrometry (Py GC–MS) or gas chromatography – mass spectrometry (GC–MS) analyses, it was demonstrated that 84% of the samples were harvested from Hymenaea trees growing in Madagascar and East Africa. Contrary to what was thought previously, frankincense, identified with certainty in only two samples, was thus not the main resin exploited at Sharma. These results are of prime importance for reconsidering the trading routes of resins passing through Sharma, a site that was obviously strongly connected with Africa during the Middle Ages.