INDUCTIVELY COUPLED PLASMA-MASS SPECTROMETRY FOR THE ANALYSIS OF ANCIENT METALS*

Inductively coupled plasma-mass spectrometry (ICP-MS) is a relatively new analytical technique, growing in popularity, that offers many advantages over previously available instrumentation for the measurement of both the elemental and isotopic composition of metallic antiquities. The application of this method of analysis to archaeological metalwork is discussed and the technique compared with other methods of analysis commonly used in archaeometallurgy. Particular attention is drawn to the potential pitfalls and difficulties associated with ICP-MS and the need for extremely careful sample preparation and instrument operation.     

ACCESSORY MINERALS AS TRACERS IN THE PROVENANCING OF ARCHAEOLOGICAL MARBLES,USED IN COMBINATION WITH ISOTOPIC AND PETROGRAPHIC DATA*

Thirty‐eight archaeological marbles (Roman and medieval) from Modena and Reggio Emilia (northern Italy) were provenanced using the accessory minerals as tracers and the results were compared with those inferred for the same artefacts using isotope composition and MGS (maximum grain size of calcite grains). The number of inferred possible sources is generally lower when using the mineralogical method, which therefore seems to be suited to marble provenancing.     

ESTIMATION OF THE AGE OF A PRE‐INDUSTRIAL IRON SITE IN KOREA*

A pre‐industrial iron‐smelting site in Korea, whose period of active use is placed on typological grounds between the eighth and 18th centuries ad , has been dated using accelerator mass spectrometry and thermoluminescence. The ages of two charcoal samples were 77 ± 25 and 81 ± 25 years bp , with the calibrated date for both ranging from ad 1700 to ad 1955, while a clay fragment dated to ad 1650 ± 50. The results from typology and radiocarbon seem insignificant due to the considerable uncertainties involved, but in combination with the thermoluminescence result they place the most probable date of the site at around ad 1700.     

SERIPHOS SURFACES: A STUDY OF COPPER SLAG HEAPS AND COPPER SOURCES IN THE CONTEXT OF EARLY BRONZE AGE AEGEAN METAL PRODUCTION

Kephala and Phournoi, on the island of Seriphos, add to a growing number of EBA metal production sites identified in the south‐central Aegean. Analytical examination of samples from the two sites addressed the technological parameters of the copper smelting process, indicating the use of mixed oxidic and sulphidic copper–iron ores to produce unalloyed copper with minute copper sulphide inclusions. A preliminary geological reconnaissance of the island identified several small copper mineralizations, one of them close to the site of Kephala. Nevertheless, the ore sources used remain unclear. Comparisons are made with other contemporaneous neighbouring smelting sites.     

COPPER AND BRONZE DURING THE ENEOLITHIC AND EARLY BRONZE AGE: A METALLOGRAPHIC EXAMINATION OF AXES FROM THE NORTHALPINE REGION*

This paper presents the results of a metallographic examination of Eneolithic and Early Bronze Age axes from the Northalpine region of central Europe. During this period, different types of copper were in use: arsenical copper, Fahlerz copper and tin bronze. We examine if and to what extent the different properties of the metals used were known to prehistoric metalworkers and actively manipulated in the production of the axes. The development of methods of casting and smithing is discussed. Both aspects contribute to our understanding of the nature of prehistoric technological change. During the Early Bronze Age of the Northalpine region, different traditions of early metallurgy can be identified, which differ in their use of Fahlerz copper, their attitude towards tin alloying and the use made of tin bronze in the production of the axes. These traditions can only be adequately described by reference to both composition—that is, access to different types of copper as well as tin—and knowledge of the production techniques provided by metallographic data.     

OBSIDIAN IN THE MEDITERRANEAN AND THE NEAR EAST: A PROVENANCING SUCCESS STORY

Obsidian provenancing studies comprise one of the most productive and successful research programmes of archaeological science. Obsidian characterization has been successful because workable obsidian is homogeneous on a small scale, analysable by a large number of methods, and is restricted to a small number of mainly readily distinguishable geological sources. Analytical, dating, source, and trade studies within the western Mediterranean, central and eastern Europe, the Aegean, and Anatolia and the Near East during the last 30 years or so are reviewed. Research has shown that distributions are mainly separate in the four regions examined, and that obsidian was traded up to 900km in the prehistoric period. Publications on obsidian in the areas under review reached a peak of frequency in the later 1970s and 1980s, but have now decreased in number. This may reflect changing fashions in archaeometric studies, and a current lack of routine application of the provenancing methods developed.     

THE COMPOSITION OF COPPER-BASED SMALL FINDS FROM A WEST PHOENICIAN SETTLEMENT SITE AND FROM NIMRUD COMPARED WITH THAT OF CONTEMPORARY MEDITERRANEAN SMALL FINDS

About 100 Phoenician copper alloy artefacts from Morro de Mezquitilla (Spain) have been analysed by inductively coupled plasma spectrometry and atomic unpublished analyses of contemporary material from Nimrud and with small finds of the same period from several Mediterranean areas. There are no published large-scale analyses of Phonenician metalwork and few analyses of the copper-based, very minor objects of the sort typically recovered from excavation and the comparisons show both similarities and differences in techniques and alloys of the various civilizations and classes of objects.     

LEAD ISOTOPE ANALYSES OF BRONZE AGE COPPER‐BASE ARTEFACTS FROM AL‐MIDAMMAN,YEMEN: TOWARDS THE IDENTIFICATION OF AN INDIGENOUS METAL PRODUCTION AND EXCHANGE SYSTEM IN THE SOUTHERN RED SEA REGION*

The results of the lead isotope analysis (LIA) of 15 copper‐base artefacts from the Bronze Age site of al‐Midamman, Yemen, are reported. The LIA data suggest the existence of an indigenous Bronze Age metal production and exchange system centred on the southern Red Sea region, distinct from those in neighbouring regions of Arabia and the Levant. These preliminary results are highly significant for the archaeology of the region, suggesting that local prehistoric copper extraction sites have thus far gone unrecorded, and highlighting the need for systematic archaeometallurgical fieldwork programmes in the countries surrounding the southern Red Sea.     

COMPOSITIONAL VARIATIONS IN AGED AND HEATED PISTACIA RESIN FOUND IN LATE BRONZE AGE CANAANITE AMPHORAE AND BOWLS FROM AMARNA,EGYPT*

This study examines resinous deposits from the interior surfaces of sherds of imported Canaanite amphorae and locally produced bowls from the 18th Dynasty site of Tell el‐Amarna, Egypt. Archaeological evidence indicates that the Canaanite amphorae were used for resin transport, whilst the bowls are associated with burning resin as incense. A number of characteristic triterpenoids identify all the resinous deposits from both vessel types as Pistacia spp. No other resins were observed and there was no evidence of mixing with oils or fats. The composition of the archaeological resins is more complex than that of modern pistacia resin, due to degradation and generation of new components. Experimental heating alters the relative abundance of the triterpenoid composition of modern pistacia resin. One component, the triterpenoid 28‐norolean‐17‐en‐3‐one, is produced by such heating; however, an increase in its relative abundance in ancient samples is not matched by the archaeological evidence for heating. It is therefore not possible to use this component reliably to identify heated resin. However, additional unidentified components with a mass spectral base peak at m/z 453 have been associated with seven (out of 10) bowls and are not observed in resins associated with Canaanite amphorae. It is proposed that these components are more reliable molecular indicators of heating.     

REGIONAL VARIATIONS IN BLOOMERY SMELTING SLAG OF THE IRON AGE AND ROMANO‐BRITISH PERIODS*

This study highlights regional variation in the composition of iron‐smelting slag produced in England prior to the medieval period and attempts to link slag composition to the type of ore smelted. For many sites, the slag compositions were consistent with the use of limonite ore, but there is evidence that siderite ore was smelted at sites in Sussex in the late Iron Age/Romano‐British periods. A compositional comparison of smelting slags and slag inclusions in Iron Age currency bars, using data from Hedges and Salter (1979 ), illustrates the potential of smelting slag compositional data in provenance studies of early iron objects.     

EVIDENCE FOR THE MIXING OF FATS AND WAXES IN ARCHAEOLOGICAL CERAMICS

Lipid residues from two Late Saxon/early medieval ceramic vessels recovered from excavations at West Cotton, Raunds, Northamptonshire, U.K., have been investigated by high-temperature gas chromatography (GC) and GC/mass spectrometry (GC/MS). The solvent extracts of sherds sampled from different points on each vessel (i.e., base, body and rim) were analysed quantitatively and qualitatively and compounds were identified which were characteristic of beeswax and animal fat. Furthermore, by determining the sites of accumulation of the specific lipid types and their concentrations in different parts of the vessels it can be inferred that the beeswax was added to the vessels prior to the addition of the fat. It was concluded that the two vessels performed different functions in antiquity.     

QUANTIFICATION AND DISTRIBUTION OF LIPID IN ARCHAEOLOGICAL CERAMICS: IMPLICATIONS FOR SAMPLING POTSHERDS FOR ORGANIC RESIDUE ANALYSIS AND THE CLASSIFICATION OF VESSEL USE

Organic residue analysis has been performed on 62 reconstructed vessels from a single archaeological site (Rounds, Northamptonshire, U.K.). In order to establish regions of lipid accumulation within a vessel, sherds were sampled from different parts of a vessel, for example base, body and rim, and submitted to lipid extraction procedures. The techniques of high-temperature gas chromatography (GC) and GC/mass spectrometry (GC/MS) were then used to analyse the sherd lipid extracts. The quantitative results obtained show differential accumulation and preservation of lipid in various parts of the same vessel. This latter observation has serious implications for the sampling of potsherds for organic residue analysis. Furthermore, the amount of absorbed lipid varies quite considerably between vessel types. On this basis, a new method is proposed for classifying vessel use by comparing the concentration of lipid present in different parts of individual vessels.     

LEAD ISOTOPE AND TRACE ELEMENT ANALYSIS IN THE STUDY OF OVER A HUNDRED SOUTH INDIAN METAL ICONS*

Technical investigations were made on 130 South Indian statuary images and a few miscellaneous artefacts mostly sampled from the Government Museum, Madras, India, and from the Victoria and Albert Museum and the British Museum, UK. Lead isotope investigations were attempted on 60 of these, and compositional analysis for 18 elements on 115, using inductively coupled plasma optical emission spectroscopy; thus, for 40 objects both lead isotope and trace element analysis was done. From the isotopic and elemental framework, insights are obtained into some art-historical problems of images and artefacts of the Pre-Pallava, Pallava, Chola (i.e., Vijayalaya Chola), Later Chola (i.e., Chalukya-Chola and Later Pandya), Vijayanagara (and Early Nayaka) and Later Nayaka (and Maratha) dynasties, spanning the Early Christian era to the nineteenth century, along with a few other regional styles. Inferences are also made regarding provenance of the lead and the early use of zinc and brass in the early historic period (c. fourth century BC—fourth century AD).     

THE STUDY OF NABATAEAN ORGANIC RESIDUES FROM MADÂ’IN SÂLIH,ANCIENT HEGRA,BY GAS CHROMATOGRAPHY – MASS SPECTROMETRY*

Four Nabataean samples collected in some of the monumental tombs of Madâ’in Sâlih, ancient Hegra, in Saudi Arabia, have been studied by gas chromatography coupled with mass spectrometry. These samples are textile fragments that are either covered with a black layer or bound together with some black amorphous substance. Fatty acids and triterpenoic compounds were detected. Eight triterpenic compounds were identified: ursa‐9(11),12‐dien‐3‐ol, ursa‐9(11),12‐dien‐3‐one, olean‐9(11),12‐dien‐3β‐ol, β‐amyrone, β‐amyrin, α‐amyrone, α‐amyrin and lupeol. The resinous chemical composition and these pentacyclic alcohols, in considerable proportion, indicate a resin of the Burseraceae family, possibly of the genus Canarium.