INSIGHTS INTO NORTH MESOPOTAMIAN ‘METALLIC WARE’*

With the aim of shedding new light on the still poorly understood North Mesopotamian metallic ware, ceramic and soil samples from Tell Beydar (northeastern Syria, third millennium bc ) were investigated using a range of analytical techniques, including optical microscopy, SR–XRD and SEM–EDX. The objective of this work was to differentiate calcareous metallic ware from non‐calcareous ware without the aid of chemical analyses and to find further validation of the existing hypothesis that the former group is an imitation of the latter. A third group of metallic wares from Tell Beydar is believed to be of non‐local, still regional origin.     

THE APPLICATION OF TIME‐OF‐FLIGHT SECONDARY ION MASS SPECTROMETRY (ToF‐SIMS) TO THE CHARACTERIZATION OF OPAQUE ANCIENT GLASSES*

Time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS) has been used, for the first time, for the characterization of opaque ancient glasses. Isotope‐specific chemical imaging with sub‐micron resolution enabled the separate analysis of opacifiying inclusions and the surrounding glass matrix. Phase identification has been demonstrated and quantification of the matrix composition has been investigated by use of Corning Glass Standard B as a model. Trace element detection limits are typically in the range 0.5–5.0 ppm atomic—in favourable cases down to 0.01 ppm. For the analysis of inclusions in particular, this has the potential to provide new information of use in establishing provenance and trade routes by ‘fingerprinting’ as well as the investigation of manufacturing techniques, as demonstrated by comparisons between glasses and with EDX data from the same samples.     

CHEMICAL–MINERALOGICAL ANALYSES AND MICROSTRUCTURAL STUDIES OF PREHISTORIC POTTERY FROM RAHMATABAD,SOUTH‐WEST IRAN*

A series of prehistoric pottery samples excavated from Rahmatabad, south‐west Iran, were investigated using XRF and XRD analyses to determine their chemical and mineralogical compositions. The sample microstructures were also studied by SEM/EDX. The relative similarity of compositions, the fine, dense and homogeneous microstructures and the presence of high‐temperature phases such as diopside and mullite showed the use of high firing temperatures, in the range 950–1050°C. This, along with the homogeneity in shape, decoration and size ranges of the ware, all indicate the adoption of specialized pottery‐making techniques by the potters of Rahmatabad in the fifth to fourth millennia bc .     

Post‐Depositional Elemental Alterations in Pottery: Neutron Activation Analyses of Surface and Core Samples*

From 38 sherds with ‘corroded’ surfaces, two samples per sherd were examined using Neutron Activation Analysis, one from the surface and one from the core of each sherd, in order to analyse post‐depositional alterations of minor and trace elements. The most striking effect was that a leaching of Ca could be found at the surface. Another group of elements that is severely affected are the alkali metals, with Cs and Rb showing the strongest changes. A third conspicuous group of elements are the Rare Earth Elements. Finally, the effect of such alterations on a statistical data evaluation to classify pottery according to provenance is investigated.     

Inductively coupled plasma emission spectroscopy and Postclassic Petén slipped pottery: an examination of pottery wares,social identity and trade*

ICP–ES analysis of the clay pastes of Postclassic (c. ad 850–1524) slipped pottery from the central Petén lakes region establishes chemical composition groups that provide information concerning manufacturing traditions and trading patterns. These data demonstrate that manufacturing traditions and trading patterns change throughout the Postclassic period, reflecting possible socio‐political alliances as different ethnic groups migrated to and from the Yucatán peninsula into the central Petén lakes region. The chemical composition groups also demonstrate that some manufacturing traditions imitate those from the Late Classic period and that some clay sources were used throughout the Postclassic period for multiple ceramic groups.     

INVESTIGATION ON ROMAN LEAD GLAZE FROM CANOSA: RESULTS OF CHEMICAL ANALYSES*

Five sherds of green glazed pottery excavated at Canosa (Apulia) in Italy have been analysed by scanning electron microscopy. The aim of the investigation was to determine the chemical composition of the glazes and thus obtain information on the methods used in their production. The glazes were all of the high‐lead type, coloured green by the addition of copper. Intermediate layers, observed at the interface between the glaze and body and giving the appearance of an applied white slip, were the result of the crystallization of lead feldspar from the molten glaze. Non‐calcareous clays were used in the production of the pottery bodies. Concentration profiles from the glaze exterior to the body suggested that the glazes were produced by applying a suspension consisting of lead oxide plus silica to the bodies. On the basis of the glaze and body compositions, it is suggested that the Canosa glazed pottery was produced locally.     

NON‐DESTRUCTIVE ANALYTIC METHOD USING XRF FOR DETERMINATION OF PROVENANCE OF ARCHAEOLOGICAL OBSIDIANS FROM THE MEDITERRANEAN AREA: A COMPARISON WITH TRADITIONAL XRF METHODS*

A non‐destructive analytical method using wavelength‐dispersive X‐ray fluorescence (WDXRF) that allows the establishment of the provenance of archaeological obsidians was developed and a comparison with the classical XRF method on powders is discussed. Representative obsidian samples of all the geological outcrops of archaeological interest of the Mediterranean area (Lipari, Pantelleria, Sardinia, Palmarola and the Greek islands of Melos and Gyali), were analysed with the normal procedures used in rock analysis by XRF (crushing, powdering and pelletizing). The non‐destructive XRF analysis was instead conducted on splinters taken from the original geological pieces, with the shape deliberately worked to be similar to the refuse usually found at archaeological sites. Since the analysis was conducted on the raw geological fragment, intensity ratios of the suitably selected chemical elements were used, instead of their absolute concentrations, to avoid surface effects due to the irregular shape. The comparison between concentration ratios (obtained by traditional XRF methods) and the intensity ratios of the selected trace elements (obtained from the non‐destructive methodology) show that the different domains of the chemical composition, corresponding to the geological obsidians of the source areas, are perfectly equivalent. In the same way, together with the geological splinters, complete archaeological obsidians, from Neolithic sites, may be analysed and their provenance may be determined. The proposed non‐destructive method uses the XRF method. Due to its sensitivity, low cost and high speed, it is surely an extremely valid instrument for the attribution of the provenance of the archaeological obsidian from Neolithic sites.     

THE HISTORY OF THE LAWRENCE BERKELEY NATIONAL LABORATORY INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS PROGRAMME FOR ARCHAEOLOGICAL AND GEOLOGICAL MATERIALS

The Lawrence Berkeley National Laboratory pottery provenance group developed standards and instrumental neutron activation analysis (INAA) methods that are used at many archaeometry laboratories around the world. The background and development of ‘Standard Pottery’ and of methods for INAA are described. Early pottery provenance studies are described, and other research programmes, involving obsidian and magmatic mixing, the origin of the stone used for the Colossi of Memnon, and the ‘Plate of Brass’, are mentioned. Research work by the Laboratory included the discovery of the world‐wide iridium anomaly and extensive subsequent research on what has come to be known as the ‘Asteroid Impact Theory’. Characteristics of the analytical programme for pottery provenance work, including overall aims, precision and accuracy, intercalibration, and irradiation and measurement protocols, are discussed. New research areas developed in the past 15 years, to broaden the usefulness of chemical compositional data for archaeological investigation, and examples of recent work, are described. This research, which makes use of high‐precision X‐ray fluorescence analysis in addition to INAA measurements on sample splits, includes distinguishing the products of different workshops located at the same production site, studies on the significance of the distribution of silver in archaeological pottery and the use of high‐precision chemical compositional data as an aid for making chronological distinctions.     

THE SMITHSONIAN–NIST PARTNERSHIP: THE APPLICATION OF INSTRUMENTAL NEUTRON ACTIVATION ANALYSIS TO ARCHAEOLOGY

The history and procedures of the Smithsonian–NIST programme in the application of instrumental neutron activation to the study of archaeological materials are reviewed. Statistical processing of the resulting analytical data is a major focus of the programme, with attention called to processes of initial group formation. Specific areas of current research emphasis are presented, which build upon the strength of accumulated databases.     

TRACING THE RESOURCES OF IRON WORKING AT ANCIENT SAGALASSOS (SOUTH‐WEST TURKEY): A COMBINED LEAD AND STRONTIUM ISOTOPE STUDY ON IRON ARTEFACTS AND ORES*

Lead and strontium isotope analyses were performed by thermal ionization mass spectrometry (TIMS) on Roman to Byzantine iron artefacts and iron ores from the territory of ancient Sagalassos (south‐west Turkey), to evaluate Pb and Sr isotopes for provenance determination of ores for local iron production. It can be demonstrated that for early Roman artefacts and hematite iron ore processed in early Roman times from Sagalassos proper, as well as for magnetite placer sands and early Byzantine raw iron from the territory of the city, Sr isotopes are much less ambiguous than Pb isotopes in providing clearly coherent signatures for ore and related iron objects. Late Roman iron objects were produced from iron ores that as yet remain unidentified. Early Byzantine iron artefacts display more scatter in both their Pb and Sr isotope signatures, indicating that many different ore sources may have been used. Our study demonstrates that iron objects can be precisely analysed for their Sr isotopic composition, which, compared to Pb isotopes, appears to be a much more powerful tool for distinguishing between chronological groups and determining the provenance of raw materials.