COMPOSITIONAL CHARACTERIZATION OF FRENCH LIMESTONE: A NEW TOOL FOR ART HISTORIANS*

Limestone from quarries known to medieval craftsmen and from the monuments they built and embellished, as well as from carvings now in museum collections, has been characterized by neutron activation analysis. Specimens from 38 quarries in the Lutetian and Jurassic limestone formations of France and from sculptures in American and French museums have been tested, and the results have been compiled in a data base to which art historians may refer when attempting to determine provenance for sculptures. Multivariate statistical analysis of concentration data shows stone from a particular quarry in the Paris basin to be compositionally homogeneous and distinguishable from other quarries in the same formation. The same approach to data related to quarries near the Burgundian abbey of Cluny finds general agreement between classifications based on compositional and on petrographic data, but the number of samples available for analysis at the time of writing was insufficient to achieve the finer distinctions reported for the Paris basin.     

THE POSSIBLE FRACTIONATION OF LEAD ISOTOPES IN ANCIENT METALLURGICAL PROCESSES

The possibility of lead isotope fractionation in ancient lead production is examined. Kinetic theory relating to isotopic fractionation in non-equilibrium evaporation is considered and the feasibility of the alteration of lead isotope abundance ratios in ore roasting and smelting is assessed. Previous experimental work is shown to have been inconclusive and conclusions are drawn on the need for further research to quantify the possible extent of fractionation in practice.     

ELECTRON SPIN RESONANCE STUDY OF WHITE MARBLES FROM THARROS (SARDINIA): A REAPPRAISAL OF THE TECHNIQUE,POSSIBILITIES AND LIMITATIONS*

The characterization of various samples of white marble from the archaeological site of Tharros (Sardinia) is the starting point for the reexamination of the capabilities of electron spin resonance (ESR) spectroscopy as a tool for identifying the quarries of origin of ancient marble artefacts. Existing methods and data bases are employed for the assignment of our samples, but also reviewed to see if a more extensive use of the technique is feasible. It turns out that ESR spectroscopy, coupled with other available methods, may readily provide valuable information, often yielding the final answer to the problem of marble provenance. However, it is also clear that much work has still to be done to standardize the data collection and analysis procedures and to expand the available data base.     

CALCAREOUS MICROFOSSILS IN BRONZE AGE AEGEAN CERAMICS: ILLUMINATING TECHNOLOGY AND PROVENANCE*

The calcareous skeletal remains of various microscopic organisms such as foraminifera and ostracods are a striking feature of thin sections of many archaeological ceramics from the Aegean Bronze Age. While the presence of these calcareous microfossils in pottery has been noted for some time, attempts to utilize them to further the aims of ceramic compositional analysis have been few in number. In the following paper, we take a first detailed look at the occurrence and utility of calcareous microfossils in archaeological ceramics. By presenting selected case studies from the Bronze Age of Crete, we demonstrate the potential of calcareous microfossils, especially the extremely small ‘nannofossils’ and the highly contextual geological information that they contain, in terms of the characterization and grouping of ceramics, the determination of their provenance and the reconstruction of ancient technology.     

THE PROVENANCE AND TECHNOLOGY OF NEAR EASTERN GLASS: OXYGEN ISOTOPES BY LASER FLUORINATION AS A COMPLEMENT TO STRONTIUM*

The ability to make rapid measurements on small samples using laser fluorination enhances the potential of oxygen isotopes in the investigation of early inorganic materials and technologies. δ¹⁸O and ⁸⁷Sr/⁸⁶Sr values are presented for glass from two primary production sites, four secondary production sites and a consumer site in the Near East, dating from Late Antiquity to the medieval period. δ¹⁸O is in general slightly less effective than ⁸⁷Sr/⁸⁶Sr in discriminating between sources, as the spread of measured values from a single source is somewhat broader relative to the available range. However, while ⁸⁷Sr/⁸⁶Sr is derived predominantly from either the lime‐bearing fraction of the glass‐making sand or the plant ash used as a source of alkali, δ¹⁸O derives mainly from the silica. Thus the two measurements can provide complementary information. A comparison of δ¹⁸O for late Roman – Islamic glasses made on the coast of Syria–Palestine with those of previously analysed glasses from Roman Europe suggests that the European glasses are relatively enriched in ¹⁸O. This appears to contradict the view that most Roman glass was made using Levantine sand and possible interpretations are discussed.     

ARCHAEOMETRIC ANALYSES ON ‘CORINTHIAN B’ TRANSPORT AMPHORAE FOUND AT GELA (SICILY,ITALY)*

The aim of this work is to throw light on the archaic production of ‘Corinthian B’ amphorae, which are widely diffused in the Western Mediterranean basin and are also present in Greece, but whose geographical provenance is still under discussion. We analysed a group of 37 samples belonging to different ceramic classes dated to the sixth and fifth centuries bc . In particular, there were 19 sherds of trade amphorae of the so‐called archaic ‘Corinthian B’ type, from archaeological excavations in Gela (Sicily, Italy). As a comparison, we also investigated 18 samples of tiles and local coarse pottery from Sibari (Calabria, Italy). The samples were analysed using different techniques, such as optical analysis with a polarized‐light microscope (OM), X‐ray diffraction (XRD), Fourier transform–infrared absorption (FT–IR) and inductively coupled plasma–optical emission spectroscopy (ICP–OES). The combination of these complementary analytical methods allowed us to characterize the samples, determine their firing temperatures and identify the probable provenance. The study of thin sections of sherds by OM allowed us to divide the investigated amphorae into two main groups: the first was characterized by a composition that suggested a Western provenance, in particular from the Calabrian–Peloritan region; the second one was very similar to the ‘Corinthian B’ amphorae that come from Corinth and have been classified as ‘fabric class 1’ by Whitbread (1995 ). The XRD and FT–IR results permitted us to determine the mineral composition of the findings and to estimate their firing temperature. The ICP–OES technique was particularly useful in identifying the production centres. In fact, in the studied pottery, this analysis revealed Ni and Cr values that were noticeably different between Greek and southern Italian production.     

GEOCHEMICAL CHARACTERIZATION OF ARCHAEOLOGICAL LIME MORTARS: PROVENANCE INPUTS*

Chemical and mineralogical analyses were carried out on historical lime mortars from the parish church of Santa María La Real (Guipúzcoa). The study included various periods ranging from Roman to modern times and allowed the identification of various types of raw materials. In order to obtain pure binder, free of carbonate aggregates and charcoal particles, an innovative binder separation method was implemented. The chemical composition of the binder allows discrimination of different provenance areas for the raw materials, although those areas do not correlate with specific historical periods. In addition, the influence of burial processes on the primeval chemical features has been assessed and reveals that modern mortars display greater chemical modification than the Roman mortars.     

THE PROPERTIES AND IDENTIFICATION OF MARBLE FROM PROCONNESOS (MARMARA ISLAND,TURKEY): A NEW DATABASE INCLUDING ISOTOPIC,EPR AND PETROGRAPHIC DATA*

This paper reports an updated and enlarged archaeometric database of Proconnesos marbles with the aim of attaining more reliable inter‐ and intra‐site identification. Quarry and artefact samples (n = 397) from 23 different quarrying areas were characterized using petrographic, isotopic and EPR results. The most distinct property of Proconnesos marbles is their extremely weak EPR intensity, associated with the low concentration of Mn²⁺impurities. This feature, supported by the contribution of other important isotopic and petrographic variables, forms the basis for the correct identification of Proconnesos marbles. Within the site the distribution of properties is relatively homogeneous; only limited intra‐site discrimination is possible. All the experimental results, as well as the quarry samples are made available to other researchers willing to measure additional experimental properties, thus increasing the rate of within the site discrimination. Extensive survey has proved that, although about 10% of the samples exhibit maximum grain size below 1.0 mm, no locations exist where fine grained marbles could be intentionally quarried. The historical aspects of Proconnesos marble quarrying and usage are also discussed.     

THE SECTILIA PANELS OF FARAGOLA (ASCOLI SATRIANO,SOUTHERN ITALY): A MULTI‐ANALYTICAL STUDY OF THE RED,ORANGE AND YELLOW GLASS SLABS*

SEM–EDS, EMPA, ICP–MS and ICP–OES were applied to the study of three sectilia panels made of red, orange and yellow glass slabs. In order to determine the chemical state of Cu, XAS was also performed. The results indicate that, with the exception of the red samples, all slabs were made by mixing a siliceous sand with natron. The red slabs show significant compositional differences with respect to K₂O and MgO contents, probably linked to the use of plant ashes as a source of alkali. The red, orange and yellow slabs are coloured by metallic copper, cuprite and Pb antimonates, respectively. The comparison between the chemical composition of the Faragola samples and several glass reference groups did not provide conclusive evidence of provenance.