THE ISOTOPIC COMPOSITION OF TIN IN SOME ANCIENT METALS AND THE RECYCLING PROBLEM IN METAL PROVENANCING

A recent suggestion that some ancient metallurgical processes might give rise to large changes (> 0.5%) in the isotopic composition of tin gave hope that it might be possible to identify ancient bronze samples which had undergone recycling and mixing processes. This paper describes a method for the analysis of the isotopic composition of tin by thermal ionization mass spectrometry and applies it to analyse a number of ancient bronzes and tin metal objects from the Bronze Age Mediterranean. No observable isotopic fractionation of tin was found above $0.1% in the ratio¹²² Sn/¹¹⁶. Consequently, either recycling of bronze in the Late Bronze Age Mediterranean was not so common as supposed, or the isotopic composition of tin is not fractionated by anthropogenic metallurgical processes to the extent predicted by the Bradford group.     

SEM and electrochemical characterization of bronze artifacts from the Francavilla archaeological site

The excavations in the necropolis of the Francavilla Marittima archaeological area, in Calabria, have brought to light the rich burial artifacts and materials, dated between the end of the ninth and sixth centuries BCE. SEM/EDS analysis was conducted on some sections taken from a bronze artifact classifiable as an armilla or fibula fragment. Our aim was to elucidate the nature of the corrosion processes acting on the specimen. SEM investigation detected the segregation of tin towards the outer layer and a depletion of the copper content in the same region. Furthermore, the elemental distribution maps of the sections analyzed evidenced the presence of chloride ions in the border area between the corrosion patina and the metal alloy. Such anion migration of chloride ions into the interior of the alloy leads to a particular variant of the type of corrosion of structure that in the literature has been identified as structure I.A cavity electrode designed for electrochemical measurements of powders was used to perform cyclic voltammetry experiments devoted to explore the activity of the patina covering the surface of the bronze fragment. The surface layer consists mainly of tin and tin oxides; the layer immediately beneath it contains copper oxides. An increase of reactivity was shown in an acidic environment. The activity of the patina is greatly reduced at pH 5 and appears to be zero at neutral pH.     

Studying the Cannons of Punta Santa Anna,Spain: In Situ Conservation,Promoting Public Access,and Monitoring Iron Corrosion

The 2001 UNESCO convention for the Protection of Underwater Cultural Heritage (UCH) encourages and supports projects that would make accessible to the general public underwater cultural sites. Since 2010 the Catalonian Federation of the World Underwater Federation (FECDAS), have been developing outreach activities with the objective of promoting the protection of the UCH among recreational scuba divers. The purpose of this paper is to introduce one such project, the Punta Santa Anna in Blanes, Spain. This project has three objectives: the promotion of UCH to the general public, the in situ protection of this underwater archaeological site, and a case study on iron corrosion processes. FECDAS/CMAS will create an underwater archaeological park where recreational scuba divers will be able to visit some purposely selected archaeological iron cannons. To expose UCH to the general public will potentially affect the integrity of these artefacts. This risks potential damage and so, with the objective of minimizing potential threats, a series of protective measures and a systematic monitoring programme have been planned. The programme is designed to study the relationship between the underwater environment and the artefacts. The aim is to acquire a better understanding of the corrosion processes of iron objects present in marine underwater sites.     

BUILDING AN IDENTITY: ARISTOCRATIC LANDSCAPE AND CONSPICUOUS CONSUMPTION AT THE 16TH‐CENTURY BISHOP'S PALACE IN ODENSE

In the 16^th century, establishing and maintaining one's status and position in society was an important social factor and motivator. This article examines to what extent such efforts can be deduced from archaeological material. The subject is the 16^th‐century bishop's palace in Odense, Denmark. This case study has been encouraged by the unprecedented large‐scale archaeological excavations that have taken place in the Odense city centre in recent years. The new archaeological data allows for a contextual analysis in which the finds and structures are considered as evidence for negotiated identity expressed through materiality. The main conclusion is that a unique socioeconomic identity is expressed in the building structure, while evidence from the portable objects is more ambiguous.     

An Analytical Methodology for the Study of the Corrosion of Ferrous Archaeological Remains in Soils

Abstract

In the context of the cultural heritage, a methodology based on ?eld and laboratory approaches is developed for studying the long-term corrosion of iron. Moreover it has been adapted to the study of archaeological artefacts buried in anoxic soils in the speci?c case of in situ preservation. The environmental parameters are determined on the archaeological sites and artefacts are collected and characterized using complementary multi-scale techniques. Moreover, laboratory experiments are performed to locate the reaction sites inside the corrosion layer and to identify its electronic properties. The results allow estimation of a low corrosion rate for iron buried in an anoxic soil (under 2 μm/year) and the proposal of a mechanism based on a decoupling of the anodic and the cathodic sites. Then a diagnosis of the alteration state of the samples is established.     

Iron Age tin bronze metallurgy at Marlik,Northern Iran: an analytical investigation

The archaeological excavations performed in 1961 and 1962 at the necropolis of Marlik (Gilan District, northern Iran) revealed important archaeological remains dating to Iron Age I and II periods (late second/early first millennium BCE). While the metal collection from Marlik includes various gold, silver and bronze objects and is considered one of the most significant finds of metal objects from the prehistoric Iran, the technological investigations discussed in this paper provide information on tin bronze objects only from Marlik. Both the composition and the microstructure of 25 copper alloy objects have been determined in order to achieve a better understanding of the metallurgical processes used in northern Iran from the second to the first millennium BCE. Experimental analyses were carried out using inductively coupled plasma mass spectrometry (ICP-MS), scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS) and optical microscopy. The results demonstrated that the copper-base objects were made of the binary copper–tin alloy with variable tin contents. Other elements such as As, Ni, Pb, Zn and Sb were detected in minor/trace amounts. Variable tin content may be due to the application of an uncontrolled procedure to produce bronze alloy (e.g. co-smelting or cementation). Microscopic observations and microanalyses revealed the presence of numerous copper sulphide inclusions, lead globules and intermetallic phases scattered in the bronze solid solution. The microstructures seen in the bronze objects under study were varied and included worked/annealed or dendritic grain structures.     

X射线显微CT成像技术在金属文物制作工艺研究与腐蚀状态评估中的应用

金属腐蚀过程不仅受环境等外部因素的影响,制作工艺、合金组成及缺陷等内部因素同样起着重要作用。为实现金属文物制作工艺和内部腐蚀状态的可视化研究,运用X射线显微CT对铜镜文物碎片以及出土、海洋出水铁质文物样品进行扫描探测,并结合X射线荧光、X射线衍射等检测手段,开展金属文物材质、工艺及矿化程度的综合分析。结果表明,在显微CT影像重建基础上,通过设定不同的阈值,可实现文物内部缺陷、腐蚀矿化程度等内部信息的测量统计。该方法可为金属文物材质、制作工艺研究和腐蚀状态评估提供无损的研究手段。     

甘肃张家川马家塬战国墓地M4出土料珠研究

甘肃马家塬墓地是战国晚期至秦初的西戎墓地,本研究以该墓地M4出土的料珠为研究对象,以期通过分析其成分和结构特征,讨论其工艺特征,以丰富对战国时期费昂斯的相关认识。研究使用扫描电子显微镜-能谱和激光拉曼光谱仪,分析结果显示料珠为费昂斯制品,其釉层玻璃化程度很高,经历腐蚀后熔剂流失严重,明显区别于西周时期的费昂斯制品。同时确定釉层中的一些高锡颗粒物为SnO_2,表明当时在釉层制作中加入锡石或锡粉末。该费昂斯制品应采取了直接施釉或包埋施釉工艺。研究结果可为我国费昂斯发展历程演变提供信息。     

The Importance of Multiple 14C Dates from Significant Archaeological Contexts

Radiocarbon (¹⁴C) dates are the most important means for determining the age of Holocene archaeological deposits. The theoretical physical basis of this method is by now unassailable, having been consistently tested and refined over two generations. However, the means by which this method has been applied and the interpretation of these results remain as key issues, particularly for complex archaeological discoveries that substantially affect our understanding of world prehistory and social evolution. Many factors can produce uncertainty or variation in the ¹⁴C concentrations of samples, even those that have been selected from the same archaeological context or event. A number of recent studies have also addressed the ways in which ambiguities and irregularities in the ¹⁴C calibration curve can affect the interpretation of archaeological dates and temporal patterns. Of greatest concern, however, is a growing practice of using only one or two samples to date a significant prehistoric context or event. The date of these events, usually relative to other human activities, often holds important theoretical implications for evolutionary anthropology and related disciplines. In this article, we demonstrate that such a practice is rarely adequate or acceptable. Rather, proper procedure requires a suite of dates that permit statistical verification that the deposit or event itself is being correctly dated. We present a detailed case study that highlights the importance of analyzing multiple samples of ¹⁴C from significant archaeological contexts.     

BRITTLE ARCHAEOLOGICAL SILVER: A FRACTURE MECHANISMS AND MECHANICS ASSESSMENT*

Some archaeological silver objects are found to be brittle. The brittleness is a consequence of long‐term corrosion and microstructural changes. The types and mechanisms of embrittlement are defined and explained. The severity of embrittlement is increased by a larger grain size and by synergistic action of corrosion‐induced and microstructurally induced embrittlement. Micromechanical models of fracture that incorporate the grain size provide an insight into these effects and help to explain why severely embrittled objects are frangible or even friable.     

The meaning of 1970 for the acquisition of archaeological objects

Abstract

Many museum and professional associations, particularly in the United States, have adopted a 1970 standard for the acquisition of archaeological materials–that is, in recognition of the 1970 UNESCO Convention on the Means of Prohibiting and Preventing the Illicit Import, Export and Transfer of Ownership of Cultural Property, archaeological objects should be documented has outside of their country of origin before 1970 or have been exported legally after 1970. This article explores the extent to which this standard has been adopted, its influence on restitutions and claims for restitution of archaeological objects, and the policies that this standard attempts to promote.     

巴蜀带斑纹兵器的锈蚀产物分析及机理探讨

带斑纹兵器是巴蜀兵器的一大特色。由于表面有斑纹的青铜兵器锈蚀与一般青铜器锈蚀有所不同,必须针对其特殊性进行锈蚀机理的研究,才能对症下药,达到有效保护的目的。应用矿相分析、SEM EDS、XRD等分析手段对几件巴蜀带斑纹兵器表面与截面锈蚀产物进行分析,并与非斑纹锈蚀进行比较;对斑纹与非斑纹的锈蚀机理进行探讨。分析结果表明,斑纹的锈蚀产物主要是SnO2,其在兵器斑纹表面形成钝性保护膜,防止其进一步腐蚀,对斑纹下面的基体有一定的保护作用。非斑纹层锈蚀向斑纹层下面的基体扩展,膨胀是造成斑纹层凸起甚至脱落的主要原因,对斑纹兵器保护的关键是控制非斑纹层锈蚀的进一步发展。     

Contribution of strontium to the human diet from querns and millstones: an experiment in digestive strontium isotope uptake

The question of whether rock grit ingested unintentionally from querns, metates or millstones, or deliberately through pica or geophagy, is bioaccessible in the human gut has not been addressed in archaeological strontium (Sr) isotope studies. This study employed the unified bioaccessibility method and determined that ingested rock grit can provide bioaccessible ⁸⁷Sr/⁸⁶Sr, but that unintentional consumption is unlikely to constitute > 1% of the diet (by mass) and will not significantly change, that is, by > 0.001, human skeletal ⁸⁷Sr/⁸⁶Sr. The use of locally or non‐locally sourced querns or millstones will not affect the interpretation of archaeological human ⁸⁷Sr/⁸⁶Sr values in Britain.     

Strontium isotope analysis of Neolithic and Copper Age populations on the Great Hungarian Plain

The strontium isotope ratio (⁸⁷Sr/⁸⁶Sr) is used in archaeological studies to identify major events of population movement in prehistory such as migration, conquest, and inter-marriage. This study shows that the strontium isotope method can be expanded to identify more subtle shifts in prehistoric human mobility. ⁸⁷Sr/⁸⁶Sr isotope ratios were analyzed in dental enamel from human and faunal specimens from the Late Neolithic and Copper Age on the Great Hungarian Plain. The archaeological record indicates that several aspects of life changed during the transition from the Late Neolithic to the Copper Age (ca. 4500 BC) in Hungary; evidence for increased interaction over a wide geographical area, less resource pooling and the use of secondary products has been used to support the idea that local populations became more mobile, perhaps due to the adoption of an agro-pastoral economy. Results from this study identify a change in the range of strontium isotope values from the Late Neolithic to the Copper Age from a very narrow range of values to a much broader range of values, which suggests that changes in how land and resources were utilized on the Great Hungarian Plain affected incorporation of strontium into the skeletal system. This study indicates that the strontium isotope ratio is a valuable tool for identifying more subtle changes in prehistoric behavior such as a shift to a more pastoral economy.     

Provenancing East Mediterranean cedar wood with the <Superscript>87</Superscript>Sr/<Superscript>86</Superscript>Sr strontium isotope ratio

⁸⁷Sr/⁸⁶Sr isotope ratios of cedar wood from forests in the East Mediterranean have been compiled in order to investigate the feasibility of provenancing archaeological cedar wood finds. Cedrus sp. forests furnished a great amount of wood in antiquity, for purposes ranging from ship to temple construction, and for fashioning cult statues and sarcophagi. The ⁸⁷Sr/⁸⁶Sr signatures of archaeological cedar samples may be compared with the preliminary dataset presented here to help determine the geographic origin of wooden artifacts. Sample sites include two forest areas in the Troodos Massif of Cyprus, five in the Lebanon, and two in Turkey’s Taurus Mountains. Sr ratios for wood varieties (i.e., early heartwood, late heartwood, sapwood, and twig wood) demonstrate relative uniformity between the xylem types frequently recovered from archaeological contexts. As such, this pilot study also assesses important issues of archaeological sampling and the geographical factors that influence Sr uptake in cedar trees of this region. While the regional signatures are distinct in most cases, small sample sizes and range overlap indicate the need for additional methods to make a case for a certain source forest. Alone, this method continues to be best used to disprove assumed wood provenances.     

TECHNOLOGY AND PROVENANCE OF A COLLECTION OF ISLAMIC COPPER‐BASED OBJECTS AS FOUND BY CHEMICAL AND LEAD ISOTOPE ANALYSIS*

Chemical and lead isotope analyses were utilized to determine the composition, technology and origin of a collection of Islamic copper‐based objects found in Jordan. The atomic absorption spectrometry results show that the objects were made of different types of copper‐base alloys that contain various amounts of zinc, tin and lead. The use of brass, highly leaded brass and quaternary alloys of Cu‐Zn‐Sn‐Pb in the manufacture of everyday, household objects strongly points to Islamic traditions. The lead isotope compositions of the objects match very well that of the copper ore mined from the Dolomite‐Limestone‐Shale unit of the Arabah copper mines.     

Contexts for Conflict: Conceptual Tools for Interpreting Archaeological Reflections of Warfare

Abstract

There has been a long history of interest in the material remains of conflict, but in the last two and a half decades archaeologists have made strides in the study of war and warfare. Techniques have been developed, refined, and borrowed to expose the material record of combat. Sites associated with other military undertakings have been discovered and the material culture of conflict has been documented. This growth has expanded an understanding of past conflicts and challenged previously held ideas about warfare. Although archaeologists do not currently have interpretive frameworks to link the diverse sites and objects that form the archaeological record of war, modern military planners have developed such models. This paper uses sites from the North American Great Plains to suggest that military models of conflict analysis can contribute to a synthetic archaeological interpretation of conflict.     

Palaeolithic radiocarbon chronology: quantifying our confidence beyond two half-lives

It is now three decades since Waterbolk introduced evaluation criteria to ¹⁴C chronology. Despite this, and other subsequent attempts to introduce quality control in the use of ¹⁴C data, no systematic procedure has been adopted by the archaeological community. As a result, our databases may be significantly weakened by questionable dates and/or questionable associations between dated samples and the archaeological phenomena they are intended to represent. As the use of chronometric data in general becomes more ambitious, we must pause and assess how reliable these data are. Here, we forward a set of evaluation criteria which take into account archaeological (e.g. associational, stratigraphic) and chronometric (e.g. pre-treatment and measurement) criteria. We intend to use such criteria to evaluate a large ¹⁴C dataset we have assembled to investigate Late Glacial settlement in Europe, the Near East and North Africa, supported by the Leverhulme Trust. We suggest that the procedure presented here may at least form the basis of the development of more rigorous, scientific use of ¹⁴C dates.     

The Medieval and Early Modern Cornish Stamping Mill

Abstract

The exhaustion of the richest alluvial tin deposits led to development of lode tin. Stamping mills were developed to crush the ore and although considerable archaeological and documentary work had been carried out in neighbouring Devon, little research had been undertaken in Cornwall. The excavation of two mills at Colliford, the survey of further examples at Retallack and an extensive search of documentary evidence has allowed an appraisal of this aspect of the early Cornish tin industry. Much work still remains, but now it is possible to be much more positive about the character of the surviving field evidence, the potential for excavation and the need to develop a research strategy.     

Making sense out of cents: compositional variations in European coins as a control model for archaeometallurgy

Archaeometallurgy frequently seeks to correlate between the temporal and spatial distribution of ancient metal objects and their chemical composition. In this study, we examined whether and to what extent local or temporal deviations in the content of modern artifacts can be identified as a proxy for archaeological material that is typically less controlled and therefore more difficult to cluster. For this purpose, Euro coins of 10, 20 and 50 cents from Germany, France, Spain, Italy and Belgium, which are made of copper (Cu) with 5% aluminum (Al), 5% zinc (Zn) and 1% tin (Sn), were analyzed using a simple XRF analyzer. The mass ratios Sn/Cu and Zn/Cu were measured with a relative precision c.a. of 5%. The mean content of the coins from each country was then determined for 20–39 of them. The difference of the mass ratio Sn/Cu observed – from 0.0101 to 0.0111. One coin from Luxemburg shows differences in various areas of its surface of up to a factor of 1.5. Thus, the results of this small pilot research show that even in modern metal artifacts we can detect differences in metal content, which can be correlated to their production and utilization places. Therefore, this study can serve as a model for evaluating compositional variations noted in archaeometallurgical studies where the standard deviations are greater and the differences can be linked more readily to spatial and temporal differences.