Glass gilding process in medieval Syria and Egypt (13th–14th century)

Twelve gilded and enamelled Islamic glass fragments, produced in Syria or Egypt during the Ayyubid or Mamluk period, were provided by the Louvre museum for complete non-destructive analysis. The enamelling process of similar objects has been extensively studied in the last decades, but the gilding process has never been investigated in details. This paper focuses on the understanding of both the gilding process and the gold/glass adhesion mechanism. The structure, composition and thickness of the gold flakes forming the gilding decoration are measured. The complete process combining gilding and enamelling is described and the local mechanism of adhesion of gold flakes on the glass body is discussed.     

A brackish water aquatic foodweb: trophic levels and salinity gradients in the Schlei fjord, Northern Germany, in Viking and medieval times

This study serves for the definition of baseline isotopic signatures of vertebrates living in the Schlei fjord, a brackish water inlet in the north German plain, where the salinity decreases from its mouth at the Baltic Sea towards the inland locations. The Viking trade centre Haithabu and its immediate successor, the town of Schleswig, are located at opposite banks of the Schlei and constitute a settlement continuum from the 9th until the 13th century. This development not only includes a relocation of the settlement site, but also a change in economy and social structure, and witnesses the metamorphosis from an international trading locality to the rise and decline of a prototypical medieval town with town charter. In this paper, stable isotope ratios of bone collagen and bone structural carbonate of 141 vertebrate bone finds mainly of fish, birds, and sea mammals from both sites are reported to provide the baseline food web in this brackish water environment, which is the prerequisite for our ongoing studies aiming at the reconstruction of human subsistence strategies as well as the geographic origin of humans, animals, food stuffs, and raw materials in order to complete the historical picture of emerging medieval towns in a complex palaeoecosystem. In particular, we are able to show how a combination of stable isotopes from bone collagen and carbonate is capable of defining the salinity gradients in the aquatic environment.     

Developmental defects and postmortem changes in archaeological pig teeth from Fais Island,Micronesia

The study investigated developmental defects of the dental hard tissues and postmortem changes in archaeological pig molars from Fais Island, Micronesia. The developmental defects of enamel were indicative of a disturbance of the secretory stage (accentuation of the incremental pattern, occurrence of Wilson bands and of hypoplastic defects) and the maturation stage of amelogenesis (hypomineralisation). Presence of coronal cementum in an M₃ indicated a partial premature breakdown of the reduced enamel epithelium or a partial demise of the enamel organ earlier during tooth development. Developmental defects of dentine presented as accentuated Andresen lines and areas of interglobular dentine. The pattern of developmental defects in the studied molars and the fact that deciduous premolars of the pigs from Fais did not exhibit developmental defects on macroscopic inspection are consistent with the hypothesis that the tooth defects were caused by periods of severe nutritional stress occurring after weaning. Postmortem changes caused by microbial infiltration were recorded in dentine and cementum. A presumed case of soft tissue preservation in the form of presence of odontoblast processes was observed in an M¹.     

Method-dependent variations in stable isotope results for structural carbonate in bone bioapatite

Stable carbon and oxygen isotope values (δ¹³C, δ¹⁸O) were obtained for structural carbonate in the bioapatite of archaeological bones from Guatemala and Sudan using several common analytical methods. For the Sudan samples, the different methods produced δ¹³C values within ±0.1‰ and δ¹⁸O values within ±0.7‰, on average. The isotopic results for the Guatemala samples were similar in reproducibility to the Sudan samples when obtained using methods that employed lower reaction temperatures and reactions in sealed vessels. However, many Guatemala samples had highly variable and extremely low δ¹⁸O values when reacted at higher temperatures in vessels that remained open to cryogenic traps. The latter arrangement caused reaction products to be removed immediately upon their production. The anomalously low δ¹⁸O values are related to the production of a contaminant gas that causes the m/z 46/44 ratio to be lowered, either by adding to the m/z 44 peak or subtracting from the m/z 46 peak. That said, potential contaminant materials were not detectable in “anomalous” bones using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, or inductively-coupled plasma atomic emission spectroscopy. However, subtle structural and chemical differences between “normal” and “anomalous” samples were observed, most notably in the FTIR ν₂ CO₃ domain. We suggest that these changes promote volatilization of an oxyphosphorus compound and oxygen isotope fractionation between PO⁻ derived from this compound and CO₂ derived from bone carbonate. Production of the contaminant gas and the related “anomalous” δ¹⁸O values is reversible if the reaction occurs within a sealed vessel for a sufficient period of time, which allows a “back-reaction” to occur.     

Isotopic analysis of the ecology of herbivores and carnivores from the Middle Pleistocene deposits of the Sierra De Atapuerca,northern Spain

Carbon and oxygen isotope values reveal resource partitioning among the large mammal fauna from three contemporaneous Middle Pleistocene hominid-bearing localities within the Sierra de Atapuerca (northern Spain). Carbon isotope values sampled from the tooth enamel of fauna present during Atapuerca Faunal Unit 6 show that a C₃-dominated ecosystem surrounded the area where fossils were preserved during this time. For the herbivores, Fallow deer isotope values are significantly different from Red deer and horses and show that this species did not forage in open environments at this locality. Red deer and horses show similar feeding strategies with less negative carbon values implying use of more open environments for these taxa. For the carnivores, carbon isotope values for Ursus deningeri are significantly different from either lions (Panthera leo) or foxes (Vulpes vulpes) and support the contention that this species is herbivorous. Special metabolic mechanisms involved in hibernation in U. deningeri might also have influenced its isotope values. The carbon isotope values of remaining carnivores were similar and suggest that each was typically a generalist carnivore, eating a wide variety of prey items. While the isotopic results generally correspond to ecology indicated by previous techniques, this study shows that isotope analyses can provide further insights that alternate techniques do not provide. Isotope analyses can help elucidate the ancient ecology of taxa present in the Sierra de Atapuerca during the Middle Pleistocene allowing for an accurate portrayal of the setting in which humans lived.     

Accessing Hunter-Gatherer site structures using Fourier transform infrared spectroscopy: applications at a Taltheilei settlement in the Canadian Sub-Arctic

The results of Fourier transform infrared spectroscopy on soils and caribou bone from a Taltheilei culture settlement in northern Canada contribute to developing micro-archaeological approaches suitable for locating and characterizing hearth and midden features on hunter-gatherer sites. A weak yet pervasive signal for montgomeryite was developed from the diagenesis of dispersed ash and caribou processing residues. Disordered calcite, carbonate hydroxylapatite, charcoal, and burned bone in two pit-house hearth deposits indicate that both wood and bone were used for fuel. Crystallinity indices and carbonate/phosphate ratios for bone indicate high intensity burning. These data, in tandem with the presence of semi-subterranean dwellings, demonstrate that this particular tundra-based encampment was occupied during cold seasons, a type of settlement behaviour previously unrecognized in the Taltheilei archaeological record. Our results confirm that Fourier transform infrared spectroscopy is an accessible, rapid, and cost effective means of discovering micro-archaeological evidence valuable for reconstructing hunter-gatherer site structures.     

Pedogenetic dating of loess strata

Loess is an aeolian Pleistocene sediment of periglacial or arid origins, deposited without internal stratification in parcels representing geological periods. The contents of total as well as individual carbonates are comparatively uniform within a specific stratum, but the relative carbonate contents differ significantly between the various glacials as represented by loess facies. There is a consistent increase in the content of dolomite with decreasing age of stratigraphic units, which has traditionally been attributed to postdepositional alteration, notably the gradual removal of the calcite fraction by weathering. The explanation of pedogenetic enrichment in the course of aeolian recycling of glacial and glacio-fluvial deposits could convincingly account for the stepped profile of the dolomite's depth functions. The implication is that such recycled sediments can be attributed to specific cryocratic phases simply by their characteristic dolomite fraction, i.e. they can be dated. In order to test this hypothesis against the competing weathering hypothesis, strata of the Gudenus Cave in Lower Austria were subjected to carbonate differentiation analysis. The results are presented, analyzed and discussed. It is shown that the dolomite contents of the unweathered strata provide a clear trend that is even more pronounced than that found at open-air sites.     

故宫博物院藏一件景泰款掐丝珐琅器的科学分析

本工作以X射线计算机断层扫描(X-CT)成像技术为主要研究手段对故宫博物院藏一件景泰款掐丝珐琅器进行了结构工艺上的研究,结合X射线荧光光谱仪的元素分析和拉曼光谱仪的特征拉曼光谱佐证,发现此件珐琅器不同部位如口沿、耳部、颈部、腹部、底足均来自不同的器物。结果显示釉层厚度、釉料颜色、结构关系以及元素成分含量趋势之间的对应关系可互相验证并吻合,明确了此件珐琅器为后期拼配的改制器。本工作应用X-CT成像技术和X射线荧光(XRF)光谱技术对景泰款珐琅器的研究结果科学化、可视化地证实了以前专家学者靠观测得出的推论。