THE PROVENANCE OF IRON ARTEFACTS FROM MANCHING: A MULTI‐TECHNIQUE APPROACH*

Iron finds from the Celtic oppidum of Manching in southern Bavaria (Germany) are analysed in view of their possible provenance. The exceptional size and the location of Manching are usually attributed to the presence of abundant iron ores in its vicinity. After a review of previous approaches for source determination of iron artefacts, we introduce lead isotope analysis as a new approach. However, only by combining the trace element patterns of slag inclusions and iron metal with lead isotope ratios in the metal is it possible to distinguish various iron ore formations near Manching. As a result, it turns out that, indeed, the most obvious ones—namely, bog ores near the Danube—constituted the main resources for iron production at Manching. It was even possible to select one occurrence as the most likely ore source.     

Investigating the production provenance of iron artifacts with multivariate methods

The quest for suitable data, data treatments and statistical methods for identifying the provenance of iron artifacts has led to a variety of analytical strategies. Researchers working on the problem have been slow to develop or adopt the use of multivariate statistical techniques, despite their successful implementation in other archaeomaterials sourcing frameworks. This paper explores the analytical potential of a comprehensive multivariate statistical strategy for identifying the primary production origins of bloomery iron artifacts using bulk chemical analyses of bloomery smelting slag and slag inclusions in iron artifacts. This strategy includes a multivariate model for identifying distinct slag inclusion types introduced during smelting and refining. Principal component analysis and linear discriminant analysis are then applied to smelting slag training sets to create multivariate provenance fields, the chemical distributions of which are defined by kernel density estimation. Single and multi-group evaluation methods are examined. Appropriate data transformations are discussed to facilitate the projection of the chemistry of “unknown” slag inclusions into the multidimensional space generated by the smelting slag groups of known provenance. The efficacy of this strategy is demonstrated through its application to a previously examined data set derived from three iron production experiments and a published archaeological example. Results indicate that an appropriately designed multivariate strategy can be an effective tool for evaluating provenance hypotheses for bloomery iron artifacts.     

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.     

Slag inclusions in iron objects and the quest for provenance: an experiment and a case study

Slag inclusions are found within most archaeological bloomery iron artefacts and are remainders of slag created during the smelting and smithing processes. Although they are widely believed to provide data with the potential for provenancing iron artefacts, previous slag inclusion studies have mostly proven inconclusive. The main aim of the work reported here is to analyse experimental smelting and smithing assemblages (including ore, furnace lining, fuel and slag), to compare these to slag inclusions in the resulting bloom and worked objects, and then explore the relationships between ore, slag and slag inclusions. This study has revealed that the composition of slag inclusions most closely relates to the smelting slag produced, whereas provenance to a specific ore would be difficult due to the chemical variability derived from furnace lining, fuel and any fluxes used. Some compounds in the slag inclusions are particularly affected during smithing of the artefact, i.e. those present in the sand flux and fuel used. However, trends are observed in the K₂O/MgO, MnO/SiO₂, Al₂O₃/SiO₂, Al₂O₃/MgO, Al₂O₃/K₂O and Al₂O₃/CaO ratios that allow comparison between slag inclusions and smelting slag in these experiments, and may therefore be used during other provenancing attempts. The knowledge gained from the experimental assemblages was subsequently applied to an archaeological case study, examining objects from the 900 Cal BC smithing site of Tel Beth-Shemesh, Israel and the 930 Cal BC smelting site of Tell Hammeh, Jordan. The analyses suggest that none of the artefacts examined derived from the Hammeh smelting system.     

Microstructural and elemental analyses of slags excavated from Xuxiebian iron‐smelting site,Sichuan, China

Xuxiebian is an iron‐smelting site located in Pujiang county of Sichuan province, China. Two excavations were carried out in 2007 and 2011, and four bowl‐shaped furnaces were excavated. Ten slag samples from the site were prepared and analysed. The present paper reports the results of metallographic and elemental examination of the specimens. It is concluded that both pig‐iron‐smelting and refining process were applied at the Xuxiebian site, and the bowl‐shaped furnaces are possibly refining furnaces. The function of the site was probably to produce pig iron and refine the pig iron into wrought iron.     

Strontium isotope analysis in ancient glass from South Asia using portable laser ablation sampling

In order to carry out strontium (Sr) isotope analysis, glass artefacts from South Asia were sampled with portable laser ablation (pLA), a relatively novel sampling technique that leaves damage invisible to the naked eye. Subsequently, thermal ionization mass spectrometry (TIMS) was used to obtain Sr isotope ratios after sample dissolution and separation. In this study, the goal was twofold: to determine whether the measurements of Sr isotope ratios were impacted by using a portable laser as a sample tool; and to assess the pertinence of using Sr isotope ratios to provenance Indian glass. Despite a deterioration in the precision of the measurement of the Sr isotope ratios for artefacts sampled with pLA compared with the traditional sampling method, the Sr isotope ratios of certain Indian glass are so different that this does not affect their separation but a comparison of data sets obtained using standard methods and pLA might be challenging.     

Non-ferrous metallurgy from the Phoenician site of La Fonteta (Alicante, Spain): a study of provenance

The lead isotope composition of 22 samples from the excavation of the Phoenician site of La Fonteta (Guardamar del Segura, Alicante, Spain) has been analysed in a preliminary study of their provenance. These materials span chronologically from the first half of the 8th century BC to the middle of the 6th century BC.The samples have been selected to include materials used in lead and silver production, as well as in copper-based metallurgy. Therefore, lead droplets, galena nodules and fragments of litharge have been analysed, together with a fragment of a copper ingot, an object, a melting waste composed of a Cu–Pb alloy, and two fragments of a material that we have provisionally labelled ‘Pb–Cu cupellation debris’.All these materials have been initially analysed by X-Ray Fluorescence-Spectrometry to identify their bulk compositions. Some of them have been also analysed by SEM–EDX and ICP–OES. Subsequently, lead isotope analyses (LIA) have been performed using Thermal Ionization Mass Spectrometry (TIMS). The new LIA data obtained has been compared with published lead isotope data from the Mediterranean area. The identification of different groups suggests a significant complexity of the internal and external trade routes during the Orientalising period. For this reason, the provenance study of these materials is especially important in shedding light on the commercial dynamics that the Phoenicians established with native people to control the raw materials and to commercialise finished products.     

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.     

THE ORIGIN of METAL OBJECTS FROM the EARLY BRONZE AGE SITE of THERMI ON the ISLAND of LESBOS

Summary: Lead isotope analysis of metal are deposits in the Mediterranean provides an important database for provenance studies of ancient metal artefacts. the Isotrace laboratory at Oxford has accumulated during the past decade well over 2000 lead isotope data on copper and lead ores and these data (in addition to analyses published by other groups) can be used for comparisons with lead isotope compositions of ancient metal objects. In a search for the roots of Early Bronze Age metallurgy in Europe we have analysed 34 copper-based objects from the Early Bronze Age strata of the town of Thermi on the Aegean island of Lesbos. the results of lead isotope analysis show that the metal objects on this site have a quite varied origin. Some of the objects are made of copper consistent with an origin from the mineral deposits of the Troad whilst others might be made of copper from the Cyclades. However, there are also some objects which are not made of copper from any of the Aegean deposits. These imports have later parallels on the site of Kastri on Syros and amongst the objects excavated by Schliemann at Troy.     

TIN ISOTOPY—A NEW METHOD FOR SOLVING OLD QUESTIONS

Tin was a vital commodity in times past. In central Europe, the earliest finds of tin‐bronze date to about 2200 bc , while in Greece they are c. 400–500 years earlier. While there is evidence for prehistoric copper mining—for example, in the Alps or mainland Greece, among other places—the provenance of the contemporary tin is still an unsolved problem. This work deals with a new approach for tracing the ancient tin via tin isotope signatures. The tin isotope ratios of 50 tin ores from the Erzgebirge region (D) and 30 tin ores from Cornwall (GB) were measured by MC–ICP–MS. Most ore deposits were found to be quite homogeneous regarding their tin isotope composition, but significant differences were observed between several deposits. This fact may be used to distinguish different tin deposits and thus form the basis for the investigation of the provenance of ancient tin that has been sought for more than a century. Furthermore, the tin‐isotope ratio of the ‘Himmelsscheibe von Nebra’ will be presented: the value fits well with the bulk of investigated tin ores from Cornwall.     

New data of 87Sr/86Sr ratio in classical marble: an initial database for marble provenance determination

⁸⁷Sr/⁸⁶Sr ratios are presented for white marbles collected from some of the most famous classical quarry areas of the Mediterranean: Carrara, Paros, Naxos, Pentelikon, Dokimeion, Hymettus, Thasos, and Proconnesus. These ratios range from 0.7071 to 0.7092. The ranges of the different quarry areas are notably superimposed; this prevents a common adoption of this parameter in distinguishing the quarry locations for the classification of the provenance of marbles used during classical times for architectural and sculptural artefacts. However some quarry areas show peculiar distributions of their isotopic values, which could help to assign the provenance to an unknown marble artefact.Adding these new data to the scarce number of strontium isotopic compositions measured on white marbles and available in the relevant literature, permits the creation of an initial database of 11 classical quarry locations. This database confirms that the strontium isotope ratio could be used in marble provenance determination, together with petrographic and geochemical methods, as an ancillary technique.     

Iron isotope analysis of red and black pigments on pottery in Nasca,Peru

The Nasca culture of the south coast of Peru developed during the first millennium ad and is known internationally for its elaborately decorated polychrome pots. Despite decades of iconographic analysis, little is known about the more technological aspects of Nasca pigment production and application. We present results from a pilot study on iron isotopes as a potential line of inquiry into the differences between red and black pigments in Nasca pigments. As well, we conduct a small firing experiment to examine potential changes in isotope composition. Our analyses show three significant results. First, firing does not change the isotopic ratios of Fe in pigments. Second, red and black pigments show differences in their iron isotope composition, which relate to differences in the minerals used to make the different colors. Third, naturally available hematite samples show greater isotopic variation than pigment samples, suggesting that people selected a limited range of iron oxides to produce pigments.     

A Rock‐Magnetic Quest for Possible Ore Sources for the Ancient Iron‐Smelting Industry in the Olkhon Region (Lake Baikal,Siberia)

Rock‐magnetic techniques were used to examine the topsoil layer of Kurma archaeological site (in the Olkhon region, on the north‐western coast of Lake Baikal, Siberia) in an effort to determine the possible sources of iron ores for iron‐smelting centres (at about the bc /ad boundary). Measurements have shown a magnetic enhancement of the topsoil due to magnetite grains resulting from weathering of strongly magnetic crystalline rocks. They have also revealed a preliminary picture of the distribution of strongly magnetic topsoils around the ancient iron‐smelting centres. Perhaps, in addition to traditional sources of raw materials, the ancient metallurgists used black sand talus as an ore deposit.     

GIS在北京延庆大庄科辽代冶铁遗址群景观考古研究中的初步应用

以北京延庆县大庄科乡冶铁遗址群为例,对空间结构及其与资源、环境间的关系通过GIS工具进行分析。根据对冶炼活动有显著关系的影响因子,建立遗址分布之间的定量关系,进而模拟小区域范围内的遗址预测。研究发现,该区冶铁遗址群对地理位置中的坡度和高程因素展现出较强的依赖性,主要表现为遗址的坡度(7°以下)和高程(650m以下)数值均相对较小;遗址与水系间联系明显,冶铁遗址主要集中在河流交汇处,方便冶炼过程及相关活动水源的供应;而随着冶炉容积(即冶铁产量)的增加,小范围内的冶铁遗址选择,并未以铁矿资源距离就近为最佳选取原则,表明了人类生产活动中对资源的依赖程度有所减低。     

济南运署街汉代铁工场遗址的相关问题探讨

为探讨济南运署街汉代铁工场遗址的性质和冶炼技术,应用X-射线荧光、X-射线衍射、热膨胀测温等方法,对遗址出土的部分遗物进行了相关分析。结合出土实物和测试结果,可以推断运署街遗址是汉代一处兼有冶炼和铸造的铁作坊。陶范、耐火砖、铁渣及矿石原料等冶铸遗物的分析指出,当时的矿石分选、加工、冶炼、铸造技术已经十分成熟,在一定程度上反映了汉代冶铁业的工艺水平。     

A study of the glazing techniques and provenances of Tang sancai glazes using elemental and lead isotope analyses

This study discusses the elemental compositions and lead isotope ratios of Tang sancai glazes unearthed from the Huangpu kiln, Huangye kiln and two Tang sancai tomb sites. The various glazes feature distinct lead isotope ratios and trace element characteristics, which can be interpreted as evidence for the use of different lead ore deposits and siliceous raw materials in the glazes. This is a strong indication that lead isotopes combined with trace element analysis could be used as a viable approach for identifying the provenance of Tang sancai of unknown origin by linking them to kiln sites, This provenance technique could be significant in the interpretation of ancient ceramic trade and communication patterns. In this study, the provenance of several Tang sancai glazes of uncertain origin were determined using this method: some Tang sancai wares unearthed in Xi'an City were produced in the kiln near Luoyang City and then traded to Xi'an City, providing an idea of ancient Tang sancai ceramic trade routes.     

PROVENANCE OF ANCIENT TEXTILES—A PILOT STUDY EVALUATING THE STRONTIUM ISOTOPE SYSTEM IN WOOL*

Strontium isotopes are used in archaeology to reconstruct human and animal migration routes. We present results of a pilot study applying strontium isotope analyses to modern sheep hair as a basis for its potential use as a provenance tracer for ancient woollen textiles. Our hydrofluoric acid‐based, lipid soluble analytical protocol, also tested on a number of ancient textile fibres, allows for contamination‐free, low blank strontium isotope analysis of minimal amounts of archaeological material. ⁸⁷Sr/⁸⁶Sr ratios of decontaminated sheep hair agree well with the compositions of biologically available (soluble) strontium fractions from the respective feeding ground soils, a translatable requirement for any potentially successful provenance tracing applied to wool textiles.     

On the origins of extractive metallurgy: new evidence from Europe

The beginnings of extractive metallurgy in Eurasia are contentious. The first cast copper objects in this region emerge c. 7000 years ago, and their production has been tentatively linked to centres in the Near East. This assumption, however, is not substantiated by evidence for copper smelting in those centres. Here, we present results from recent excavations from Belovode, a Vin?a culture site in Eastern Serbia, which has provided the earliest direct evidence for copper smelting to date. The earliest copper smelting activities there took place c. 7000 years ago, contemporary with the emergence of the first cast copper objects. Through optical, chemical and provenance analyses of copper slag, minerals, ores and artefacts, we demonstrate the presence of an established metallurgical technology during this period, exploiting multiple sources for raw materials. These results extend the known record of copper smelting by more than half a millennium, with substantial implications. Extractive metallurgy occurs at a location far away from the Near East, challenging the traditional model of a single origin of metallurgy and reviving the possibility of multiple, independent inventions.     

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.