CYPRIOT BYZANTINE GLAZED POTTERY: A STUDY OF THE PAPHOS WORKSHOPS

Twenty‐five samples of Byzantine glazed pottery from two archaeological sites between Limassol and Paphos region (Cyprus), dated between the 12th and 15th century ad were studied using micro X‐ray fluorescence spectroscopy, scanning electron microscopy and X‐ray diffraction analysis. It was found that all the glazes contain lead, following the main manufacturing process of medieval pottery in the Mediterranean territory, while some of them contain tin, possibly for better opacity. Furthermore, it is shown that copper, iron and cobalt with nickel are responsible for the decoration colours. Finally, the application of principal component analysis revealed significant differentiation for some of the samples.     

THE SCIENTIFIC IDENTIFICATION OF ARCHAEOLOGICAL JET-LIKE ARTEFACTS

Jet has been widely used in the past for jewellery but was just one of a range of black lithic materials employed. When worked into small objects these materials can be visually indistinguishable, yet discrimination is important because of the restricted occurrence of jet. X-ray fluorescence (XRF) is a rapid non-destructive discriminatory technique, but not all samples are clearly classified, and inhomogeneity may pose problems. A reassessment of the use of XRF is reported. Other techniques considered include electron spin resonance, infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis, scanning electron microscopy and X-radiography. These were tested on geological materials to define an effective methodology for archaeological material. The recommended approach is a combination of XRF and X-radiography, although preliminary Fourier transform infrared results showed promise. The X-ray techniques were tested on Romano-British assemblages from Catterick and Stanwick.     

NEW EVIDENCE FOR THE NATURE OF THE ATTIC BLACK GLOSS

New evidence is reported here using transmission electron microscopy, scanning electron microscopy, and laser reflectance for the nature of the black glossy decoration layer present on the Attic black or red figure vases of the sixth to fourth century BC. The black layer, of total thickness about 20 μm, consists mainly of poly crystalline magnetite (Fe₃O₄) particles of dimensions from 0.2 μm down to extremely fine sizes embodied in an amorphous vitreous matrix. On the outer surface of the black paint we discovered for the first time a thin clear glassy film of approximate thickness 0.1 μm which is rich in Al and Fe and poor in Si. This film must be responsible for the characteristic sheen of the surface. This is verified with the reflection of laser light mostly in specular direction, a unique property compared with black paints of other areas and other periods.     

CHARACTERIZATION AND PROVENANCE OF LIME PLASTERS FROM THE TEMPLO MAYOR OF TENOCHTITLAN (MEXICO CITY)

In this work, we present the results of the analyses of 20 lime plaster samples taken from the Templo Mayor (Great Temple), the main pyramid of Tenochtitlan (Mexico), the ancient capital of the Mexicas. The samples were analysed to recover information on the mixtures used in the fabrication of the plasters and for the provenance of the raw materials (in particular, limestone) used to make the plasters. The characterization of the samples was done by OM, SEM/EDS, XRF and LA–ICP–MS analyses, while the identification of the provenance of raw materials was done by studying the lumps present in the samples with LA–ICP–MS. The objective of the study was to establish if there was a relationship between changes in the construction techniques employed in the pyramid over time and if there were changes in the provenance of the raw materials. Six different construction phases of this pyramid are analysed, showing the similarities and differences among them, mainly based on differences in the sieving of the aggregates and in the raw materials employed. The provenance studies of the limestone used to make the plasters demonstrated that all the limestone comes from the Tula region.     

ALTERATION PROCESSES OF POTTERY IN LAGOON‐LIKE ENVIRONMENTS

Post‐depositional processes in pottery can give rise to chemical and mineralogical alterations, the extent of which is closely related not only to the microstructure and composition of the potsherds, but also to the chemical–physical conditions of the burial environment. The present paper describes the characterization of post‐depositional alterations and identification of processes involving pottery buried in lagoon‐like environments. A set of various types of Roman transport amphorae and African Red Slip ware (ARS), collected from two archaeological sites characterized by a lagoon‐like depositional environment and showing evident changes in the original colours, was analysed by a combination of microstructural, mineralogical and microchemical approaches. The formation of pyrite after hematite, jarosite after pyrite and microstructural substitution features are interpreted here in terms of the chemico‐physical conditions of the burial environment and their evolution in time.     

CLAY RESOURCES AND TECHNICAL CHOICES FOR NEOLITHIC POTTERY (CHALAIN,JURA, FRANCE): CHEMICAL,MINERALOGICAL AND GRAIN‐SIZE ANALYSES*

Many authors have considered pottery manufacturing constraints and sociocultural elements as factors in change in past civilizations over time. The main issue of this research is to better understand the reasons for changes, or choices, in pottery raw materials. The very precise and detailed stratigraphy and cultural succession of occupations is based on dendrochronological data from the lake‐dwelling sites of Chalain (Jura, France). Petrographic, palaeontological and chemical analyses were used to determine the nature and origins of the raw materials used by the Neolithic potters. Stratigraphy and dendrochronological data were used to reconstruct in detail the evolution dynamics of fabric changes. Several raw material sources were identified for many of the pottery groups. Each of them was sampled for qualitative experimental tests of pottery forming. The experimental results show a high variability between the sediments tested. This variability was quantitatively estimated by XRF, XRD, the Rietveld method, calcium carbonate quantification and laser grain‐size analyses of matrices, indirect measures of plasticity. These analytical results allow a better understanding of the differences observed in the experimental tests. On the basis of these experimental and analytical results, changing parameters such as pottery manufacturing constraints, mineralogical characteristics of raw materials and sociocultural factors are considered. In conclusion, all the social and technical parameters, in each archaeological context, must be taken into account for a better understanding of the changes occurring throughout the chronological sequence.     

The production technology of Iznik pottery—a reassessment*

Previous research has established that Iznik pottery differs from other Islamic stonepaste pottery in that its stonepaste bodies contain lead oxide as well as soda and lime, and that a significant proportion of the tin oxide in its glaze is present in solution rather than as tin oxide particles. In order to better understand these distinguishing features, the chemical compositions and microstructures of Iznik pottery and tile samples, together with those of lumps of glass found in association, were investigated using both scanning electron and optical microscopy. These data have been supplemented by the study of replicate lead–alkali glazes produced in the laboratory with a range of different compositions. The results demonstrate that separate soda–lime and high‐lead glasses were used in the production of Iznik stonepaste bodies, and that the total glass contents of the bodies were significantly higher than those quoted by Abū’l‐Qāsim, who was writing in about ad 1300. The very high purity of the lead–soda Iznik glazes indicated that the alkali flux used was either a purified plant ash or an as yet unidentified mineral source of soda. Replication experiments established that the high solubility of tin oxide in the glaze was due to the high purity of the glaze constituents. Furthermore, it is suggested that tin oxide was added to the glaze in order to give it a very slight opacity and thus obscure any blemishes in the underlying body.     

TECHNOLOGICAL STUDY OF PTOLEMAIC – EARLY ROMAN FAIENCE FROM MEMPHIS,EGYPT*

Fourteen fragments of faience vessels from the Ptolemaic/Roman period found at the Egyptian site of Memphis, near Cairo, were analysed by SEM. The fragments included high‐relief polychrome vessels, which are first produced in numbers in this period. Analysis allowed the composition and microstructure of the vessels to be assessed and conclusions drawn as to the raw materials of manufacture. Combining this information with archaeological evidence from excavation of the kilns and associated finds, it was possible to reconstruct the production technology of the vessels.     

QUANTIFICATION AND DISCRIMINATION OF LITHIC USE‐WEAR: SURFACE PROFILE MEASUREMENTS AND LENGTH‐SCALE FRACTAL ANALYSIS*

This experimental programme employs length‐scale analysis of measured profiles to quantitatively discriminate the surface textures of stone flakes manufactured from East Anglian chalk flint used on four contact materials (shell, wood, dry hide and soaked antler). It presents a method for evaluating texture characterization parameters based on their ability to discriminate wear types, and to determine a level of confidence to the discrimination, using the F‐test. The results of this experimental work demonstrate that relative lengths, over certain scale ranges, can discriminate the stone tool surface wear profiles produced by the different contact materials.     

SCANNING ELECTRON MICROSCOPY-ENERGY DISPERSIVE SPECTROMETRY AND PROTON INDUCED X-RAY EMISSION ANALYSES OF MEDIEVAL GLASS FROM KOROINEN (FINLAND)*

Thirteenth- to fourteenth-century ecclesiastical window glass, excavated from the administrative centre of Koroinen, Finland, represents the earliest window glass in the country and includes the only emerald green window glass known from Finland at this time. This was examined, together with some excavated vessel glass. X-ray analysis, using scanning electron microscopy-energy dispersive spectrometry and proton induced X-ray emission, reveals that while the vessels are made from potash-lime, soda-lime, mixed alkali and lead-silica glasses, the window glasses are lead-silica and wood ash-lead-silica glasses; they resemble similar glasses from central Europe and suggest that Koroinen shared the trading network of other European religious centres.