APPLICATIONS OF PETROGRAPHY AND ELECTRON MICROPROBE ANALYSIS TO THE STUDY OF INDIAN STONE SCULPTURE*

Examples of research on ancient Indian stone artefacts utilizing petrographic examination coupled with qualitative and quantitative electron beam microprobe analysis of specific minerals are described. Types of artefacts discussed include Gandharan schist sculptures. Pala dynasty phyllite and schist objects from eastern India, Hoysala sculptures from Karnataka state (southern India), and sandstone objects from northern India. In spite of the rich history of stone sculpture in the Indian subcontinent, characterization studies to date have been limited in scope, typically involving unprovenanced artefacts. The examples described point to areas in which more extensive research could produce useful information for the provenancing of artefacts.     

CHEMICAL COMPOSITION OF A BOG BODY ADIPOCERE

Chemical analyses were carried out on adipocere obtained from a bog body recovered from a peat bog at Meenybradden, County Donegal, Ireland. Chromatographic (thin-layer chromatography and gas chromatography) and mass spectrometric analyses, combined with microanalytical chemical transformations, have yielded detailed compositional information. An absence of intact triacylglycerols, diacylglycerols and monoacylglycerols indicates that hydrolysis is complete. Consequently the adipocere is composed mainly of fatty carboxylic acids. The high proportion of palmitic and stearic acids, together with depleted oleic acid content, indicates that extensive reduction and, possibly, β-oxidation have occurred during burial in the peat bog. Hydration of the double-bond in oleic acid has also occurred, as is shown by the formation of 10-hydroxystearic acid. The monoenoic fatty carboxylic acids that are present, composed mainly of C₁₈ and C₁₆ compounds, comprise a mixture of positional isomers. The results are compared and contrasted with those obtained from previous studies of the lipid composition of other adipoceres and cadavers of archaeological interest.     

CYPRIOT BLACK-ON-RED WARE: TOWARDS A CHARACTERIZATION

Chemical analysis of Early Iron Age sherds from Cyprus and the Levant using atomic absorption spectrometry shows that Black-on-Red ware was manufactured only in Cyprus. Two types of fabric are isolated, calcareous and non-calcareous, and their technological significance discussed. The presence of trade links between the Cypriot sites of Kition and Amathus and sites in the Levant is suggested.     

ENERGY DISPERSIVE X-RAY FLUORESCENCE ANALYSIS OF ANCIENT COPPER ALLOYS: EMPIRICAL VALUES FOR PRECISION AND ACCURACY

Energy dispersive X-ray fluorescence (EDXRF) analyses are compared with neutron activation as well as atomic absorption analyses of ancient copper-based alloys in order to examine their accuracy and to estimate realistic values for precision and sensitivity of EDXRF. The results show that it is possible to obtain reliable data of the surface composition of objects non-destructively. Better results for bulk composition are usually obtained with drill samples where the sensitivity of the method is at least competitive with atomic absorption spectroscopy with flame atomization.     

THE USE OF IMAGE ANALYSIS TO DETERMINE YARN TWIST LEVEL IN ARCHAEOLOGICAL TEXTILES

An analysis of the structure of archaeological textiles can give an insight into different traditions, geographic origins or technologies associated with the textile production. An important parameter in this context is the level and direction of yarn twist. In this paper a new quantitative method of yarn twist measurement is described. Using image analysis techniques a measure of the mean twist level and the variation in twist can be determined. The technique is applied to a selection of woven woollen textiles from the first-century Roman fort at Vindolanda in northern England.     

LEAD ISOTOPE CHARACTERISTICS OF THE CYPRUS COPPER ORE DEPOSITS APPLIED TO PROVENANCE STUDIES OF COPPER OXHIDE INGOTS

Nearly 200 new lead isotope analyses of sulphidic and oxidized ores from 26 copper mines on Cyprus show that the mines from different geological regions group in five distinctive isotopic groups, each with a substructure, related to the geological history of the ore formation. Comparison of lead isotope compositions of Bronze Age artefacts with these data can in many cases reveal the actual mines from which the copper for particular artefacts was obtained. The particular case of the provenance of the copper for 78 Late Bronze Age copper ‘oxhide ingots’found in Cyprus, Crete, Greece, Sardinia, Turkey and Bulgaria is discussed. The data show that all oxhide ingots so far analysed, dating to the fourteenth century BC and later, were made of copper consistent isotopically with only one mining region in the geographical north of Cyprus, and especially the Apliki mine. The study provides further evidence which supports the validity of the conventional approach to the use of lead isotope analysis for provenancing metals; this evidence is antithetical to recent suggestions of a model for the production of copper oxhide ingots which involved widespread mixing of copper from a number of ore sources throughout the Mediterranean.     

THE ESTABLISHMENT OF A DATA BASE OF NEUTRON ACTIVATION ANALYSES OF WHITE MARBLE*

The establishment of a data base of trace element analysis results obtained by neutron activation analysis of 183 marble samples, each weighing about 200 mg, from eight different quarrying localities for use in provenance studies is described and a summary of the results presented. The problems of sampling museum artefacts are discussed, and details of tests of the reproducibility of the technique are given together with those obtained from multiple-samples from single museum objects. Replicate analyses of a marble standard are also discussed. Thus these data are a measure of the accuracy and precision of the technique, as well as allowing an assessment of the variation in trace element composition within quarry sources and single blocks of marble, as used for artefacts.     

AN INVESTIGATION OF THE PROVENANCE OF THE ROMAN AMPHORA CARGO FROM THE PLEMMIRIO B SHIPWRECK

Eighty-six Roman amphora sherds from the Plemmirio B shipwreck, off Sicily, have been analysed by neutron activation analysis. A large group representative of the amphora cargo, mainly of forms Africana 1 and Africana 2A (from the area of modern Tunisia), was subsequently defined. No differences between Africana 1 and Africana 2A samples were observed, thus implying a similar origin for both forms. The provenance of this cargo group was then investigated by comparison with a Roman amphora kiln data base. After elimination of the more mobile elements it was shown that the cargo amphorae were more likely to have been manufactured at kilns around Sullecthum rather than Leptis Minor. The analytical conclusions are thoroughly consistent with the known archaeological information.     

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.     

PRODUCTION TECHNOLOGY OF ROMAN LEAD‐GLAZED POTTERY AND ITS CONTINUANCE INTO LATE ANTIQUITY

A broad selection of Roman lead‐glazed pottery dating from the first century ad through the fifth century ad was studied to establish locations of workshops and to address their technology of production. The ceramic bodies were analysed by ICP–AES. In addition, lead isotope analysis was undertaken on a selection of glazes. These findings suggested that there were several regions responsible for the production of lead‐glazed ceramics in the western Roman world, including central Gaul, Italy and, probably, Serbia and Romania. Using the body compositions as a starting point, the glazing techniques employed by each of the potential workshops were examined using electron probe microanalysis. It was determined that there were two primary methods of glazing. The first method used lead oxide by itself applied to non‐calcareous clay bodies, and the second method used a lead oxide‐plus‐quartz mixture applied to calcareous clay bodies. Based on these data for clay composition and glazing method, transfer of technology from the Hellenistic east to the western Roman world was proposed. Likewise, the inheritance of lead‐glazing technology into late antiquity was established by making comparisons to lead‐glazed ceramics dating to the seventh to ninth centuries from Italy, the Byzantine world and Tang Dynasty China.