MATCHING PAST AND PRESENT CERAMIC PRODUCTION IN THE BANDA AREA (GHANA): IMPROVING THE ANALYTICAL PERFORMANCE OF NEUTRON ACTIVATION ANALYSIS IN ARCHAEOLOGY USING MULTIVARIATE ANALYSIS TECHNIQUES*

The transfer of advances in chemometrics into archaeometric research opens up a wide range of new application possibilities in this rapidly developing field. Neutron activation analysis (NAA) of ceramic samples from the Banda Traditional Area (west‐central Ghana) combined with chemometrics allowed us to establish a link between current and ancient systems of ceramics production in the historic settlements of Kuulo Kataa and Makala Kataa. Principal component analysis (PCA) and the soft independent modelling of class analogy (SIMCA) method were applied to the Das Dores Cruz data set in order to unequivocally determine the geographical origin of the diverse archaeological samples. After global autoscaling pretreatment, PCA analysis showed a clear difference between samples from different locations. The classification models obtained by SIMCA showed a classification ability of 100% and a prediction ability of 97.7%, with a mean sensitivity of 84% and a specificity of 100% for the three categories. The application of SIMCA showed that some NAA variables (elements) were more important than others in terms of geographical classification. With the class models that we obtained, we were able to determine the origin of the ancient remains. SIMCA has proved to be a powerful technique for the class modelling of archaeological data.     

THE USE OF TRACE ELEMENT ANALYSIS OF ENTRAPPED SLAG INCLUSIONS TO ESTABLISH ORE – BAR IRON LINKS: EXAMPLES FROM TWO GALLO‐ROMAN IRON‐MAKING SITES IN FRANCE (LES MARTYS,MONTAGNE NOIRE,AND LES FERRYS,LOIRET)*

Knowledge of the iron trade in ancient times rests on determining the source of the objects recovered during archaeological excavations. Unfortunately, attributing the origin is not always possible using archaeological tools alone. Trace element data of the ore and the archaeological material (reduction and reheating slags, entrapped slag inclusions from the bloom, bar iron and iron blades) from two Gallo‐Roman iron‐making centres, Les Martys (Montagne Noire) and Les Ferrys (Loiret), were determined using ICP–AES/MS and LA–ICP–MS. The results highlight a continuity of composition that makes it possible to establish a link between the initial ore and the semi‐finished iron products.     

A REVIEW OF SUPERVISED AND UNSUPERVISED PATTERN RECOGNITION IN ARCHAEOMETRY*

Principal component, cluster and discriminant analysis are multivariate statistical methods that are widely used in archaeometry. They are examples of what are known in some literatures as unsupervised and supervised learning methods. Over the past 20 years or so, a wide variety of other learning methods have been developed that take advantage of modern computing power and, in some cases, have been designed to handle data sets more complex than those often used in archaeometric data analysis. To date, these methods have had little impact on archaeometry. This paper reviews, in a largely non‐technical manner, the ideas behind these newer methods; illustrates their use on a variety of data sets; and attempts to assess their potential for future archaeometric use.     

SAND FOR ROMAN GLASS PRODUCTION: AN EXPERIMENTAL AND PHILOLOGICAL STUDY ON SOURCE OF SUPPLY*

This paper reports the results of an experimental study performed on Campanian littoral sand, together with a careful philological analysis of Pliny's text concerning the production of glass using the above sand in order to verify its suitability. Accurate chemical and mineralogical characterization of sand samples and experimental glasses was carried out, proving the unsuitability of sand for glass production in its original state. Taking into account both the results of the philological analysis of Pliny's text and the mineralogical assemblage of the sand, a new hypothesis regarding Roman glass‐making technology is proposed and tested here. The technology implies the production of ‘quartz‐enriched’ sand by means of selective grindings according to the different degrees of hardness and cleavage of the mineralogical phases. Melting experiments, carried out on treated sand and in the temperature range compatible with Roman technology, yielded a glass with composition similar to those of typical Roman glasses. Therefore, new perspectives on the sources of supply of raw materials, hitherto debated, are opened up.     

LUSTRE-DECORATED CERAMICS FROM A 15TH TO 16TH CENTURY PRODUCTION IN SEVILLE*

A set of 17 fragments of ceramics have been uncovered on the occasion of excavations of a workshop in Triana near Seville. These ceramics are typical of objects that are not commonly encountered in present collections in spite of intensive production during the 15th–16th centuries. Chemical and mineralogical analyses have been performed using various techniques (X-ray fluorescence and diffraction, SEM, ion beam analyses). The majority of the ceramic sherds represent the diversity of the Seville production; three fragments recovered in the same archaeological context were not locally produced and belong to the production of eastern Spain (Valence area). The ceramic bodies of the Seville sherds are compatible with the use of clays from the Guadalquivir valley. The glaze and the lustre decoration are comparable to those produced in eastern Spain. These conclusions are based on data that represent the production of a single workshop in Seville; the scatter of the data is due to variations in the processing and/or to alterations during the five centuries of burial of the ceramic fragments.     

MATHEMATICAL MODELLING OF THE RELATIONSHIP BETWEEN NEOLITHIC SITES AND THE RIVERS IN XI’AN (SHAANXI PROVINCE,CHINA)*

Based on analyses of the ecological environments of the Neolithic sites along the Chan and Ba Rivers in the Xi’an area (Shaanxi Province, China), it was found that the characteristic factors of the sites had a very close relationship with the nearby river. The characteristic factors of Neolithic sites have been analysed and defined as mathematical parameters by statistical methods. A mathematical model of the human–land relationship between Neolithic sites and rivers has been established using the stepwise regression procedure REGRESS in SPSS^®. The mathematical model is Y = 496.153 – 4.833X₁ + 113.692X3 + 725.097X₅ – 27.683X₃X₄. It shows that the distance (Y) from a site to a river has a marked relationship with the site area (X₁), the river flux (X₃), the site location (X₅) and river ratio drop (X₄). The model shows that the relationship between the sites and the river is in accordance with the conclusions of archaeological research. The mathematical model not only offers theoretical guidance for the archaeological excavation of Neolithic sites in Xi’an, but also contributes to the archaeological environmental research of Xi’an Neolithic sites.      

WHERE DID THE LUSTRE TILES OF THE SIDI OQBA MOSQUE (ad 836–63) IN KAIROUAN COME FROM?*

Metallic lustre decoration of glazed ceramics is a very special kind of ornament, because its colours change with the observational conditions. In diffused light, they can be green, brown or ochre–yellow. In specular reflection, they show an associated coloured metallic shine (blue, golden‐yellow or orange). The lustre tiles at the Sidi Oqba Mosque in Kairouan still have no defined origin (possibly Kairouan and/or Mesopotamia). Physicochemical analyses of eight Kairouan lustre tile samples and four Mesopotamian lustre pottery samples show that the Kairouan tiles probably came from Mesopotamia, from a major production centre, possibly Baghdad, Samarra or Basra.