ELECTRON SPIN RESONANCE THERMOMETRY APPLIED TO QUARTZITE COBBLES FROM VERGELEGEN SLAVE LODGE,SOMERSET WEST,SOUTH AFRICA

This paper describes the use of electron spin resonance spectroscopy to estimate the degree of heating of quartzite cobbles from hearths on the floor of the archaeological remains of an eighteenth-century Dutch colonial slave lodge. A novel technique based on the comparison of line intensities for the E’and O^-₂ centres in quartz distinguished successfully between cobbles which had been heated to estimated temperatures ranging from 300 °C to 450° C and controls from an adjacent stream bed. This inexpensive and simple technique could be applied to a wide range of archaeological problems involving the thermal history of objects consisting of or containing quartz.     

ON THE USE OF COLOUR COORDINATES TO EVALUATE FIRING TEMPERATURES OF ANCIENT POTTERY*

Colour measurement was investigated as a means to evaluate equivalent firing temperatures of ancient pottery. Colour coordinates were determined on samples of six clays previously fired, and then refired, in the temperature range 600–1100°C. Under the adopted conditions, significant variations of colour hue and saturation were normally observed on refired samples only after the original firing temperature had been exceeded; less reliable information was provided by luminosity. Original firing temperatures of clay samples were correctly recognized in most cases by projecting the points representing samples’ colour on to the a*b* plane of the ClEL*a*b* colour space.     

Technology Transfer at the Periphery of the Mycenaean World: The Cases of Mycenaean Pottery Found in Central Macedonia (Greece) and the Plain of Sybaris (Italy)*

The study of technology transfer in pottery production to the periphery of the Mycenaean world has been addressed by considering two different areas, southern Italy and central Macedonia. Technological features such as ceramic paste, decoration and firing have been determined for different ceramic groups established according to provenance criteria. The studies of technology and provenance have been performed following an archaeometric approach, using neutron activation analysis, petrographic analysis, X‐ray diffraction and scanning electron microscopy. The results have revealed the existence of two different models. On the one hand, southern Italy seems to exhibit a more organized pottery production, which follows a Mycenaean‐like technology, while in central Macedonia production is probably more varied, being based in part on the technology of the local tradition.     

RELATIONSHIP BETWEEN THE COLORATION AND THE FIRING TECHNOLOGY USED TO PRODUCE SUSA GLAZED CERAMICS OF THE END OF THE NEOLITHIC PERIOD*

Ancient decorated potteries from Susa (Mesopotamia) dating from 4200 to 3700 bc , were studied in order to determine the origin and the nature of the raw materials used, and to identify the technological processes applied to make the ceramic bodies and their decorations. Bulk compositions were determined by particle induced X‐ray emission (PIXE), while the microstructure and the mineralogical phases were studied using scanning electron microscopy (SEM), energy dispersive X‐ray analyses (EDX) and X‐ray powder diffraction (XRD). The results showed that the raw materials used to elaborate these potteries were similar for all the ceramic bodies (carbonates and iron and magnesium‐rich clays containing sand), and for all the decorations (iron oxides, silica, potassic and alumina sources). The variations of coloration of the ceramics and of their decorations were due to different firing temperatures. The ranges of firing temperatures used by potters were evaluated on the basis of mineral stability domains.     

THE STUCCO TECHNIQUE OF THE MAGISTRI COMACINI: THE CASE STUDY OF SANTA MARIA DEI GHIRLI IN CAMPIONE D'ITALIA (COMO,ITALY)

This paper is aimed at defining the artistic technique performed by the outstanding artist Isidoro Bianchi for the Baroque stucco decorations in the church of Santa Maria dei Ghirli (Campione d'Italia, Italy). Samples of stucco were examined by means of optical microscopy, scanning electron microscopy with a microprobe, X‐ray powder diffraction, Fourier transform infrared spectroscopy, gas chromatography–mass spectrometry and laser ablation mass spectrometry equipped with plasma source spectrometry. On the basis of the results obtained, art historians have made new hypotheses on the biography of the artist and on the historical location of his birthplace.     

DUNG BY PREFERENCE: THE CHOICE OF FUEL AS AN EXAMPLE OF HOW ANDEAN POTTERY PRODUCTION IS EMBEDDED WITHIN WIDER TECHNICAL,SOCIAL, AND ECONOMIC PRACTICES*

A discussion of how Andean potters acquire and use their fuels is used to demonstrate the ‘embedded’nature of ceramic technology. The most common choice of fuel in the highlands of Peru and Bolivia is animal dung (mainly cow, sheep, and llama). This technological choice is related to wider social and economic practices (particularly in relation to animal husbandry) which has further repercussions that affect other technologies (such as agriculture practices). Such a succession of interrelated activities is not unique to pottery; it is fundamental to all technologies and should be considered within archaeological analysis.     

MODELLING CHANGES IN MOLLUSC SHELL INTERNAL MICROSTRUCTURE DURING FIRING: IMPLICATIONS FOR TEMPERATURE ESTIMATION IN SHELL‐BEARING POTTERY*

Firing experiments have been carried out on a clay containing naturally occurring fragments of mollusc shell. The transformation and/or decomposition of mineral phases with temperature was monitored by thermal analysis on the starting material and compared with X‐ray diffraction data on the fired specimens. Scanning electron microscopy revealed systematic changes in the internal microstructure of the shell fragments. Micrometer‐sized intra‐ and inter‐layer pores formed in the shells before the complete decomposition of calcite. The shape, dimension and location of the pores within the shell microstructure were found to be directly related to the firing temperature. The analysis of these microstructural features in archaeometric studies offers a good constraint on the estimation of the firing temperature in shell‐bearing pottery.     

Characterization of Late Prehistoric Plasters and Mortars from Erimi – Laonin tou Porakou (Limassol,Cyprus)

Several plasters and mortars from the Middle Bronze Age site of Erimi – Laonin tou Porakou (Cyprus) were analysed in order to perform a technological characterization. Morphological (SEM), elemental (EDX), mineralogical (XRPD), petrographic (polarized OM, SEM–EDX), thermal (TGA) and spectroscopic (FT–IR) techniques were applied. Plasters and mortars were identified as pyrotechnological lime products, obtained using local raw materials and containing a moderate amount of spathic calcite fragments. The use of organic fibres was ascertained and a seminal use of a crumbled ceramic as additive was evidenced.     

AN APPRAISAL OF THE PROBLEMS INVOLVED IN THREE-DIMENSIONAL GROUND PENETRATING RADAR IMAGING OF ARCHAEOLOGICAL FEATURES

There are a number of problems that are due to the physics involved in the ground penetrating radar (GPR) technique which result in the recorded data giving a distorted representation of the true subsurface structure. Many of these problems are reduced by the experience of the person interpreting the data. This paper is an attempt to remove some of the subjectivity from this process by considering how the distortion in the data could be reduced by applying a migration routine. The amount of data, and the time needed to collect it, place a restriction on the use of the migration process to two dimensions only and result in a compromise approach to the use of GPR. This compromise may, however, result in better integration of GPR with the other geophysical techniques available.