Dyes from the Tumilaca and Chiribaya Cultures, South Coast of Peru

During the terminal stages of the Tiwanaku state at the end of Middle Horizon, at least two new cultural groups appeared in the archaeological record of the coastal Osmore valley in southern Peru. The cultures are now known as Tumilaca and Chiribaya. Radiocarbon dating, as well as stylistic and technological comparison of textile remains, established the coexistence and close relationship between both cultures. Chemical and physical examination of textiles from both cultures was undertaken to gain a better understanding of the dyestuffs and techniques used. Attempts were made to identify dyestuff mordants by energy dispersive analysis of X-rays (EDXRF). Dyestuffs were analysed by the complementary use of UV-vis absorption spectrophotometry (UVAS), thin-layer chromatography (TLC) and a number of microchemical tests.Distinct differences were found in the dyestuffs and textile techniques used in both cultures.     

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.     

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.     

MECHANICAL PROPERTIES OF STONE ARTEFACT MATERIALS AND THE EFFECT OF HEAT TREATMENT*

Mechanical testing of lithologies used for stone tool manufacture has shown that fracture toughness is the most objective measure of the quality of raw materials shaped by either flaking or pecking/grinding. Materials amenable to pressure flaking and blade manufacture have low values of fracture toughness, whereas those shaped by pecking/grinding have high values. The fracture toughness test is also the most definitive for quantifying the improvement in flaking properties of materials subjected to intentional heat treatment. Cryptocrystalline and macrocrystalline siliceous lithologies demonstrate a well-defined, gradual reduction in fracture toughness with increased temperature. When heated to optimum temperatures, their fracture toughness approaches that of obsidian, the lithology generally regarded as having the best flaking properties.     

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.     

FIRING ANALYSIS OF SOUTH-EASTERN MISSOURI INDIAN POTTERY USING IRON MÖSSBAUER SPECTROSCOPY*

The Mössbauer spectra of prehistoric pottery and clay from the Malden Plain of south-eastern Missouri, USA, were examined. The pottery dates from AD 500 to 1400. The earlier sherds were tempered with sand and the later ones with shell. The sherds and clay contain a mixture of illite, smectite, and kaolinite. Most samples of clay and sherds contained both ferric and ferrous species. The spectral parameters for the ferric species were %DLE_Q～0. 7—1.1 mms^-1 and δ～0.0–0.3 mms^-1 for the ferrous species, ΔE_Q～2.1–2.7mms^-1 and δ～0.7–1.0mms^-1. The ferric to ferrous ratio is more accurately determined from the spectra than from consideration of the colour or the firing core of the sherds, which are not always related to the iron species ratio. Differences among sherds in the ferrous ΔE_Q can be related to original temperature of heating but with low precision.