MODIFIED MAHALANOBIS FILTERS FOR GROUPING POTTERY BY CHEMICAL COMPOSITION*

A statistical procedure for grouping pottery in provenance studies by chemical data is presented, which now is routinely in use in our laboratory. It is based on the Mahalanobis filter method and X² -statistics, and can be used for both establishing groups and assigning single sherds to already known groups, thus replacing principal components analysis or cluster analysis and avoiding their problems in grouping pottery. The new method is able to consider correlations, uncertainties of measurement and constant shifts of the data in case of dilution. In particular, considering dilution effects results in both a better assignment to and separation of reference groups and is also equivalent to the compositional data approach, if log-transformed data are used. Other distortions of data (e.g., mixing of clays) can also be considered.     

LEAD ISOTOPIC EVIDENCE FOR A MIXED PROVENANCE FOR ROMAN WATER PIPES FROM POMPEII*

Lead isotope analysis has been applied to the investigation of some Roman objects found in the town of Pompeii, consisting mostly of fistulae from the Augustan water supply system. The results of the analyses have produced ratios between 18.10 and 18.66 for ²⁰⁶Pb/²⁰⁴Pb, between 15.63 and 15.72 for ²⁰⁷Pb/²⁰⁴Pb and between 38.21 and 38.98 for ²⁰⁸Pb/²⁰⁴Pb. These data point to a fairly complex origin for the lead artefacts, probably involving several successive meltings and recyclings of a rather heterogeneous lead supply. The spread of lead isotope ratios can only be reconciled with a multiplicity of end‐members, at least three, but very probably more. There is one certain Sardinian ore, other indistinguishable Hercynian ores of Sardinia and/or Spain, and several different Alpine Mesozoic‐Tertiary mineralizations of the Mediterranean basin (Spain, Greece, Tuscany).     

MULTI‐METHOD MARBLE PROVENANCE DETERMINATIONS: THE CARRARA MARBLES AS A CASE STUDY FOR THE COMBINED USE OF ISOTOPIC,ELECTRON SPIN RESONANCE AND PETROGRAPHIC DATA*

A multi‐method approach, based on petrography, stable isotope data and electron spin resonance spectroscopy for assigning the provenance of white marbles, is presented. A total of 11 experimental variables has been used, including the quantitative measurement of the sample colour and its homogeneity. On this basis we attempt to distinguish the three main quarrying basins of the Carrara district, that is, Torano, Miseglia and Colonnata. Such discrimination, extremely uncertain on the basis of the single techniques, may be performed with acceptable confidence’ using a properly selected subset of six petrographic, isotopic and spectroscopic variables. The final resubstitution and jackknifed re‐assignment rates are, respectively, 85% and 81%. Inclusion of the remaining five variables into the classification rule does not improve the results, but simply increases data overinterpretation. The practical possibility of using such an approach for more general provenancing problems is considered.     

RAW MATERIALS OF GLASS FROM AMARNA AND IMPLICATIONS FOR THE ORIGINS OF EGYPTIAN GLASS*

Analysis has been conducted on 19 blue glasses from Amarna in Middle Egypt dated to around 1350 BC. The results suggest that these glasses fall into two distinct types: cobalt coloured glasses with a natron based alkali made from local Egyptian materials, and copper coloured glasses with a plant ash alkali, which follow a Mesopotamian tradition of glass making. It is suggested that at least some of this copper/plant ash glass is imported into Egypt during the Amarna period despite extensive local production of cobalt/natron glass. Existing analyses (Lilyquist and Brill 1995) of the earliest glass from the reign of Tuthmosis III (c. 1450 BC) suggest that during this period the same two types of glass are present. Local Egyptian cobalt and natron in these early glasses implies that, despite the lack of archaeological evidence for production sites, glass was produced from its raw materials in Egypt as early as the reign of Tuthmosis III.     

SHAFT‐HOLE AXES FROM CAPUT ADRIAE: MINERALOGICAL AND CHEMICAL CONSTRAINTS ABOUT THE PROVENANCE OF SERPENTINITIC ARTEFACTS*

The change of raw materials used to produce stone axes during the Neolithic to Copper Age transition in northeastern Italy, central and western Slovenia and northwestern Croatia (Caput Adriae) has been recently linked to the development of early European metallurgy. Serpentinite shaft‐hole axes occur commonly in the archaeological context of this region and their rounded irregular shape suggests that the raw material was mainly sourced from secondary deposits. The aim of the present study is to characterize with multiple analytical methods, including synchrotron radiation, the axes and locate the primary outcrop(s) of raw materials and related secondary exploitation areas. All the analysed artefacts are manufactured from peridotites and probably pyroxenites completely metamorphosed in greenschist facies and characterized by antigorite, diopside and magnetite, sometimes rimmed by penninite. Mineralogical and petrographic data exclude most Eastern Alps outcrops as possible raw material sources, thus limiting the research to the Hohe Tauern. Chemical data reveal a close homogeneity for the peridotite‐derived axes and therefore demonstrate a selection of the most suitable raw material for axe production. Provenance from Hohe Tauern and related secondary deposits of the Drava River hydrographical system agrees with previous studies, as this region is rich in copper ore deposits, which have been exploited since prehistory.     

CHARACTERIZATION AND PROVENANCE OF LIME PLASTERS FROM THE TEMPLO MAYOR OF TENOCHTITLAN (MEXICO CITY)

In this work, we present the results of the analyses of 20 lime plaster samples taken from the Templo Mayor (Great Temple), the main pyramid of Tenochtitlan (Mexico), the ancient capital of the Mexicas. The samples were analysed to recover information on the mixtures used in the fabrication of the plasters and for the provenance of the raw materials (in particular, limestone) used to make the plasters. The characterization of the samples was done by OM, SEM/EDS, XRF and LA–ICP–MS analyses, while the identification of the provenance of raw materials was done by studying the lumps present in the samples with LA–ICP–MS. The objective of the study was to establish if there was a relationship between changes in the construction techniques employed in the pyramid over time and if there were changes in the provenance of the raw materials. Six different construction phases of this pyramid are analysed, showing the similarities and differences among them, mainly based on differences in the sieving of the aggregates and in the raw materials employed. The provenance studies of the limestone used to make the plasters demonstrated that all the limestone comes from the Tula region.     

PROVENANCING FLINT ARTEFACTS WITH ICP–MS USING REE SIGNATURES AND Pb ISOTOPES AS DISCRIMINANTS: PRELIMINARY RESULTS OF A CASE STUDY FROM NORTHERN SWEDEN

Archaeological flint artefacts from the late Mesolithic/early Neolithic site of Vuollerim, northern Sweden, have been geochemically investigated with ICP–SFMS and MC–ICP–MS in search for the geological/geographical origin of the non‐local flint. The Vuollerim flints were compared with reference samples from Denmark (Cretaceous/Tertiary flint) and Russia (Carboniferous flint). Elemental concentrations as well as elemental ratios for REEs and isotopic ratios for Pb and Sr are presented. Significant differences were found between different geological/geographical contexts. Two of the Vuollerim samples can be ascribed a South Scandinavian origin. Possibly also eastern flint is present, although the results are not conclusive in this case.     

THE TECHNOLOGY OF GLAZED ISLAMIC CERAMICS USING DATA COLLECTED BY THE LATE ALEXANDER KACZMARCZYK

During the 1980s, the late Alexander Kaczmarczyk undertook the analysis of some 1200 glazed Islamic ceramics from Egypt, Iran, Iraq and Syria spanning the period from the eighth to the 14th centuries ad , using a combination of XRF for the glazes, and AAS or PIXE for the bodies. The aim of the present paper is, first, to bring to the attention of researchers into Islamic ceramics the fact that these analytical data are available on the Research Laboratory for Archaeology and the History of Art website, and also that some 400 of the analysed sherds are held in the Research Laboratory. Second, the paper provides a preliminary interpretation of the analytical data in terms of the choice of glaze type (i.e., alkali–lime, lead–alkali and high‐lead), tin‐opacification, body type (i.e., quartz or stonepaste, calcareous clay, and non‐calcareous clay), and colorants.     

ALTERATION PROCESSES OF POTTERY IN LAGOON‐LIKE ENVIRONMENTS

Post‐depositional processes in pottery can give rise to chemical and mineralogical alterations, the extent of which is closely related not only to the microstructure and composition of the potsherds, but also to the chemical–physical conditions of the burial environment. The present paper describes the characterization of post‐depositional alterations and identification of processes involving pottery buried in lagoon‐like environments. A set of various types of Roman transport amphorae and African Red Slip ware (ARS), collected from two archaeological sites characterized by a lagoon‐like depositional environment and showing evident changes in the original colours, was analysed by a combination of microstructural, mineralogical and microchemical approaches. The formation of pyrite after hematite, jarosite after pyrite and microstructural substitution features are interpreted here in terms of the chemico‐physical conditions of the burial environment and their evolution in time.     

INSTRUMENTAL NEUTRON ACTIVATION BASED PROVENANCE STUDIES AT THE HEBREW UNIVERSITY OF JERUSALEM,WITH A CASE STUDY ON MYCENAEAN POTTERY FROM CYPRUS

A neutron activation programme aimed at archaeological provenance research operated at The Hebrew University of Jerusalem between the years 1974 and 1997. The history and accomplishments of that laboratory are presented. Endeavours to preserve unpublished results are described. Results on Cypriote pottery are presented.