Preliminary neutron diffraction study of two fenestrated axes from the ‘Enot Shuni' Bronze Age cemetery (Israel)

Neutron diffraction (ND) analyses of ancient metals show that this method is capable of detecting differences in the inner composition and microstructure of ancient metal objects. Here, ND measurements were conducted on two ‘eye shaped’ axes from the end of the 3rd-beginning of the 2nd millennium BC. The objects were excavated from the ancient cemetery of ‘Enot Shuni' Israel; one is made of bronze and the other of silver. Both artefacts are rare finds, with the silver axe unique in the archaeology of Israel, and therefore had to be analysed locally. For that purpose, a newly assembled diffractometer (KARL) at the IRR-1 of the Nuclear Research Centre (Soreq, Israel) was used. ND measurement on the bronze axe revealed the existence of an α-phase with a range of Cu/Sn ratios (Cu–Sn solid solutions) and some amount of a δ-phase (intermetallic compound of Cu and Sn). The silver axe ND pattern shows the existence of an α-phase (Ag–Cu solid solution) and some amount of copper metal. Our ND data are discussed in comparison with XRF surface measurements and thermal neutron radiography. The results are shedding more light on the in-depth material composition profile, as well as on the objects’ structural and compositional affinities, and help to better understand the production processes and assist in conservation decisions.     

Soil geochemistry and detection of early Roman precious metal and copper alloy working at the Roman town of Calleva Atrebatum (Silchester,Hampshire, UK)

A geochemical soil survey was carried out over 500 m² of a first and second century AD house complex in insula IX of the Roman town of Calleva Atrebatum (Silchester, Hampshire, UK) where there was little prima facie evidence for non-ferrous metalworking. Preliminary analyses were made by XRF of lead, zinc and copper. These were followed by analysis for Au, Ag and Sn by ICP-MS of the samples with the highest concentrations of Pb, Zn and Cu. Certain of the Pb, Zn and Cu concentrations suggest the working of copper alloy including brass, and could be associated with archaeological evidence of hearths and burnt areas of second century AD date. Other samples have concentrations of the above metals and of gold and silver which do not appear to be associated with any physical remains of hearths and burnt areas. These concentrations date to the mid-first century AD.     

The Context and Significance of Copper Artifacts in Postclassic and Early Historic Lamanai,Belize

Abstract

We consider the archaeological contexts in which copper objects have been recovered at the ancient Maya site of Lamanai in northern Belize and the significance these objects had for the residents of the community during Postclassic (ca. A.D. 950–1544) and Spanish colonial (post 1544) times. More copper objects have been recovered from controlled archaeological contexts at Lamanai than any other site in the southern Maya lowlands area. Bells make up the majority of the assemblage during the centuries just prior to and during historical times, but high status objects such as rings and clothing ornaments found in elite burials dominate in the Early Postclassic period. All of these objects were imported from outside the Maya area. Utilitarian objects, including needles, axes, and fish books, are found in a variety of contexts during Late Postclassic and Spanish colonial times, as are bells and rings. Production materials, including prills, blanks, and pigs/ingots, in addition to mis-cast objects that are production failures, also appear during this time. Nearly all of the copper objects found at Lamanai are distinctly Mesoamerican in form and design, and based on metallurgical analyses it appears that manufacturing technologies were distinctly Mesoamerican as well. The presence of production materials and mis-cast piecesy along with the results of chemical compositional and microstructural analyses, support the idea that the Maya at Lamanai were engaged in the on-site production of copper objects by late precolumbian times.     

Technology,chronology and the role of crucible steel as inferred from iron objects of the ancient site at Junnar,India

Ordinary iron objects from an ancient habitation site at Junnar in India, dating to the 2nd BC to AD 2nd century, were examined for their microstructure, chemical composition and age. The objects were mostly made of high carbon steel with a homogeneous microstructure consisting of fine spherical particles of carbide in the ferrite background, free of non-metallic inclusions. Their carbon concentration ranged from 0.7% to over 1.6% with one exception at 0.2%. Some of them contained trace amounts of silicon, manganese and sulfur while one object retained cavities due to volume contraction during solidification reactions. These features indicate that the objects examined constitute an early example of Indian steel making in crucibles. Evidence was found that basic techniques needed for the success of crucible steel technology were mostly available at Junnar at the time. The radiocarbon measurement on carbon samples extracted from one of the iron objects placed its date between 176 BC and AD 20, in agreement with the radiocarbon dates of three charcoal samples from the same site. The forgoing results support that crucible steel was produced in India at a much earlier date than previously supposed, to serve as a material for specific needs arising in daily life.     

Morphological reconstruction of Roman <Emphasis Type="Italic">styli</Emphasis> from <Emphasis Type="Italic">Iulia Concordia</Emphasis>—Italy

Iulia Concordia is an important Roman settlement known for the production of iron objects and weapons during the Roman Empire. A huge number of well-preserved styli were found in the bed of the main channel of the city. In order to shed light on the production processes used by Roman for stylus manufacturing and the conservation state of the finds, a neutron tomography analysis was performed on NEUTRA beamline in Switzerland. SEM-EDS analyses were performed on few selected objects in order to identify the composition of metal decorations. Here, we present results from our investigation conducted on 91 styli, disclosing, in a non-invasive way, the morphological characterization related to the ancient Roman working techniques.     

中国古墨与现代墨元素成分研究

对中国古墨（汉墨、明墨与清墨）与不同产地的现代墨元素成分作了对比分析。用离子背散射测定墨中常量元素C、N、O的含量,用质子激发X荧光法测定微量元素K、Ca、Ti、Cu、Fe等10种元素的含量。实验结果表明,古墨中微量元素K、Ca的含量比现代徽墨、沪墨高10倍以上,而现代徽墨与沪墨中元素N和An的含量也有明显的差别。     

A Better Shade of Black: Effects of Manufacturing Parameters on the Development of Ancient Black Bronzes*

Copper alloys with controlled contents of Sn, Ag and Au were treated with methods and solutions that mimic those used in ancient and traditional procedures for the production of black bronze. Examination of the resulting patinas with colorimetry, SEM–EDS, TEM, Raman spectroscopy and XRD revealed no systematic differences according to the fabrication method, whereas patina homogeneity and colour in those alloys that did not contain precious metal were affected by superficial work. Patina microstructure determines adherence and coverage, and depends upon the solution used irrespective of the alloy composition, but the colour of the patina is mainly related to the alloy composition. Gold promotes the development of cuprite, slowing the oxidation to tenorite in the corrosion process. Gold additions produce a more uniform patina as well as a desirable blue–black tone, which is likely to have been a factor in alloy selection.     

Late horizon silver,copper, and tin from Machu Picchu,Peru

Analyses of silver–copper alloy artifacts from Machu Picchu show silver contents ranging from 24 to 81%. The tin present, ranging up to 3%, originated with the copper, perhaps from admixture of recycled bronze. The presence of 0.4–0.9% lead in the silver-rich phase indicates use of silver prepared by cupellation. All the objects had been forged after casting, some extensively. All have surface enhancement of the silver arising from depletion of the copper-rich phase. Some of the tin found at the site contains inclusions of hardhead (FeSn₂) and of a nickel–arsenic–copper compound. Forming trials with duplicate silver–copper alloys show that intermediate anneals at temperatures between 500 and 600 °C facilitate making thin sheet artifacts. Mechanical tests show that the most commonly used alloys, containing 25–30% silver, are particularly well adapted to forging because of their uniform work hardening during plastic deformation. Annealing of the laboratory-made alloys in air followed by boiling in salty weak acid creates a silver-rich surface layer comparable to that found in the artifacts. Depletion forms a dense silver surface on the alloy containing more silver than the eutectic composition, but a porous surface layer on the 25% silver alloys.     

Was Lacquer the Key Ingredient for Luxurious Jinyin Pingtuo Products in the Tang Dynasty of China (AD 618–907)?

Jinyin pingtuo is one of the most sumptuous decorative methods applied on ‘lacquered' objects described in Tang dynasty literatures. Two Tang dynasty objects, a silver bowl and a bronze mirror, in the British Museum collection said to be made by this technique, were scientifically examined to confirm the application of the technique. Although the metal décors levelled with the rest of the surfaces on these objects suggested the application of the pingtuo method, lacquer, a major ingredient of this technique, was not identified by Py (HMDS)-GC–MS in any of the four samples analysed. The results question the use of lacquer in the pingtuo technique as usually described. The detection of shellac and oil in the bronze mirror aligns with other studies on similar objects, whereas proteinaceous materials as main ingredient of the decorative layers of the silver bowl, appear less usual. Further comparative study by scientific analysis of similar objects in other museum collections or from excavations is required to help better understand the use of lacquer in ancient China.     

Optical Coherence Tomography for the non-invasive investigation of the microstructure of ancient Egyptian faience

Optical Coherence Tomography (OCT) is a non-invasive subsurface 3D imaging technique based on the Michelson interferometer. The non-invasive nature of OCT and its speed of acquisition makes it possible to image large volumes of intact objects to yield a complete overview of the microstructure. The production methods for ancient Egyptian faience were first investigated using scanning electron microscopy (SEM) imaging of the microstructure in polished sections and microprobe analysis of the composition of the glass phases. These studies were based on original Egyptian faience objects and laboratory reproductions of faience beads made using three different production methods. The microstructure of the same laboratory samples and the Egyptian faience objects from the British Museum Research Laboratory Collection are re-examined using OCT. It is found that OCT virtual cross-section images can be used to group ancient faience objects into three categories on the basis of the morphology of the surface glaze layer and the glaze/core interaction layer. The OCT images correspond well with SEM images of polished sections of ancient faience objects and laboratory reproductions. The virtual cross-sections produced by OCT are somewhat limited by the penetration depth, which is affected by the high absorption coefficient of the material and, therefore, cannot always provide information on the presence or absence of interparticle glass that binds together the quartz particles in the core. Nevertheless, the top two layers are well imaged and since OCT images can be obtained rapidly and without the necessity of removing a sample, the method can be applied to a very much wider range of ancient faience objects than is possible by SEM examination of polished cross-sections. In summary, this paper examines to what extent OCT can assist the investigation of the production techniques of ancient Egyptian faience.     

Early Cambodian gold and silver from Prohear: composition,trace elements and gilding

Rescue excavations in Prohear, southeast Cambodia, recently saved the last untouched graves of one of the richest prehistoric sites in Southeast Asia. Many Iron Age burials dating from the 2nd century BC to the 1st century AD contained gold and silver ornaments so far unknown from archaeological contexts together with indications for the presence of an immigrated elite. A first selection of 59 objects were analysed by LA-ICP-MS to obtain detailed information about the composition, as well as minor and trace elements. The majority of the ornaments consist of electrum and auriferous silver with low copper concentrations, and two main groups indicating different alluvial gold sources can be distinguished by different concentrations of Pt, Ir, Bi and different Pd/Pt ratios, one group being related to rich burials with non-local features. The SEM and EDX analyses of four objects revealed two different gilding techniques observed for the first time in Southeast Asian artefacts: foil-fusion gilding, related to special Ag–Au–(Cu)–Sn alloys containing up to 4% tin, and depletion gilding.     

The Cape Gelidonya Shipwreck and the Bronze Age Metals Trade in the Eastern Mediterranean

Abstract

Controversy has surrounded the identification of the home port of the ship wrecked off Cape Gelidonya, Turkey. In an attempt to contribute further information pertinent to the solution of this problem, samples for metallurgical study were taken from eight of the copper ingots that were carried on the ship: four oxhide-shaped, two plano-convex, and two slab-shaped. Analysis of these samples shows that, with a single exception, the structure and composition of the ingots are little different from ingots found in Cyprus, Crete, Greece, and Sardinia. The inferences to be drawn from the metallurgical research are 1) that the ingots represented typical items of international trade and 2) that the home port of the ship and lading port of the ingots cannot be determined since the ship and crew were operating in the international sphere. It may also be surmised that at least a part of the Bronze Age trade was in the hands of private entrepreneurs.     

Pre-Hispanic gold pieces of an enigmatic archaeological finding in Medellín,Colombia: A glance at an archaeometric analysis

The study analysed pre-Hispanic gold objects found within a surprising archaeological finding of a structure that likely served as a funeral pyre in Medellín, Colombia. ¹⁴C analyses of the site's organic materials dated the structure to the fifth century ce . The metal objects were subjected to X-ray diffraction (XRD), energy-dispersive X-ray fluorescence (EDXRF), scanning electron microscopy-energy dispersive X-ray (SEM-EDX), density measurement by the Archimedes method, and metallographic analysis. The measurements by EDXRF and SEM-EDX showed that the pieces were composed mostly gold and silver. The XRD results indicated that the microstructure of the objects corresponded to a single phase of gold and silver. The images obtained by the metallographic microscope showed equiaxial grains with some twins, a structure consistent with annealed metals. The different colours observed correspond to different grain orientations. Pre-Hispanic objects from a second archaeological site in the municipality of Amalfi (Department of Antioquia) were also analysed for comparative purposes. The results showed that the gold objects were not subjected to any alloying process, but were instead manipulated in their original form (native gold). The shape of the objects and their microstructural results suggested that the pieces were manufactured by casting, mechanical deformation and then annealing.     

First Evidence Of The Use Of Freshwater Pearls As A Cosmetic In Ancient China: Analysis Of White Makeup Powder From A Northern Song Dynasty Lv Tomb (Lantian,Shaanxi Province,China)

The Lv family tombs in Lantian, Shaanxi Province are one of the most important archaeological sites of China in recent years, providing numerous objects and a wealth of information for the study of the history of the Northern Song dynasty. There were a large number of exquisite cultural relics unearthed from the tombs, including one porcelain box containing white powder, which was identified as women's makeup. The phase composition, microstructure, thermal properties and characteristics of the trace elements in the unearthed white cosmetic powder were comprehensively analysed by X‐ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry – thermogravimetry (DSC–TG), Fourier transform infrared (FT–IR) microscopy and inductively coupled plasma atomic emission spectroscopy (ICP–AES). The white makeup powder was determined to be a product made from high‐quality freshwater pearls. These results, for the first time, showed evidence that freshwater pearl powder was used as a cosmetic in ancient China using archaeological objects, providing scientific evidence and new clues to enrich and expand research into the ancient Chinese cosmetic materials.     

Identifying a Roman Casting Pit at Tel Dor,Israel: Integrating Field and Laboratory Research

Abstract

The functional identification of industrial features is difficult when few characteristic artifacts are preserved. We studied a Roman-period pyrotechnological feature at Tel Dor, Israel, where the only possibly diagnostic ceramic artifacts were found in fill between the walls and above the floor, rendering their association with the feature itself uncertain. The ceramic artifacts included coarse slabs and fragments of utilitarian vessels, some vitrified with adhering bronze droplets or slag-like residues. Analysis of the sediments within and around the industrial feature, using an X-ray fluorescence spectrometer on-site, revealed high concentrations of copper and lead, indicating metallurgical activity. Lead isotope analyses showed that the slag-like residue adhering to a ceramic fragment had the same isotopic values as the sediments, implying that the fragment was associated with the activities carried out in the feature. Microscopic and chemical analyses of the slag-like residue demonstrated that it was produced from melting leaded bronze. Some of the ceramic fragments contained elongated impressions on their inner surfaces, similar to those of casting molds found at other sites. We propose that the feature was used as a casting pit for bronze objects.     

Trace element fingerprinting of ancient Chinese gold with femtosecond laser ablation-inductively coupled mass spectrometry

In this collaborative investigation, femtosecond laser ablation-inductively coupled mass spectrometry (LA-ICP-MS) was applied to the study of a remarkable group of ancient Chinese gold objects in the Smithsonian's Freer Gallery of Art and Arthur M. Sackler Gallery. Taking advantage of the superior ablation characteristics and high precision of a femtosecond 266 nm Ti:sapphire laser at Lawrence Berkeley National Laboratory, major, minor and trace element concentrations in the gold fragments were quantified. Results validate use of femtosecond LA-ICP-MS for revealing “fingerprints” in minute gold samples. These fingerprints allow us to establish patterns based on the association of silver, palladium and platinum that support historical, technical and stylistic relationships, and shed new light on these ancient objects.     

Identification of ancient textiles from Yingpan,Xinjiang, by multiple analytical techniques

Various extraordinary textiles were excavated from a graveyard at Yingpan, Xinjiang, on the middle route of the ancient Silk Road. Applications of western motifs and designs to traditional Chinese textiles led to the emergence of compound woven textiles with central Asian characters. For a better understanding of the cultural exchanges and textile trade between the West and the East in ancient times, identifications of archaeological fibres and dyes were carried out for various funerary textile objects by using multiple analytical techniques, such as high performance liquid chromatography with photodiode detection, optical microscopy, scanning electronic microscopy (SEM), and Fourier transform infrared spectroscopy (FT-IR). Fibre identifications were performed for 35 archaeological textile samples, and the results showed that the ancient textiles were mostly made from Bombyx mori silk and wool. The SEM and FT-IR experimental results revealed that these ancient textiles remained morphologically intact due to the special (very dry) climate in Xinjiang, but noticeably degraded at the molecular level due to long time thermo-ageing and/or biodegradation. The principal colouring matters, such as alizarin, purpurin, indigotin and luteolin, were respectively characterised for nine archaeological textile samples. The yellow dyestuffs derived from luteolin-based plants were assumed to have been imported to China from the Middle East and Western Asia through the Silk Road.     

MICROANALYTICAL METAL TECHNOLOGY STUDY OF ANCIENT NEAR EASTERN BRONZES FROM TELL BEYDAR*

Forty‐six bronze objects have been investigated to assess their composition and microstructure, using SEM–EDX and optical microscopy. The bronzes originate from Tell Beydar, a site in the northeastern part of Syria that was mainly occupied during the third millennium bc . The compositional results of the metals show a clear chronological sequence in the use of the alloying elements arsenic and tin. In addition, the microstructure indicates advancement in the metalworking techniques that were used.     

Phytolith-rich layers from the Late Bronze and Iron Ages at Tel Dor (Israel): mode of formation and archaeological significance

The presence of many phytolith-rich layers in late Bronze and Iron Age deposits at Tel Dor, Israel, are indicative of specific locations where plants were concentrated. Detailed studies of six of these phytolith-rich layers and associated sediments from Tel Dor show that the phytoliths were derived mainly from wild and domestic grasses. The most common domestic grass was the cereal Triticum aestivum (bread wheat). Three of these layers have a microlaminated microstructure, associated dung spherulites and phosphate nodules; characteristics that all point to the phytolith-rich layers having formed from dung in animal enclosures. In two of the layers, the microlaminated structure is absent while dung spherulites and phosphate nodules are present, suggesting that these too originate from dung that was not deposited in an enclosure. The sixth layer is microlaminated but does not contain spherulites. We thus cannot suggest a parsimonious explanation of its observed properties. Concentrations of burnt phytoliths are present in three locations, implying that dung was either burnt in situ or the ashes from burnt dung were redeposited. The transformation of dung accumulations into phytolith-rich layers involves a loss of organic material and hence a significant reduction in sediment volume, which is clearly apparent in the stratigraphy of some of the locations examined. The volume reduction can be observed in the macrostratigraphy and has important implications with regard to macrostratigraphic interpretation. The presence of abundant phytolith-rich layers on the tell has significant implications for the concept of ‘urbanism’ during these periods.     

The potential of stable Cu isotopes for the identification of Bronze Age ore mineral sources from Cyprus and Faynan: results from Uluburun and Khirbat Hamra Ifdan

Copper isotope ratios differ between hypogene sulfidic, supergene sulfidic and oxidized ore sources. Traditional lead isotope signatures of ancient metals are specific to deposits, while Cu isotope signatures are specific to the types of ore minerals used for metal production in ancient times. Two methodological case studies are presented: First, the mining district of Faynan (Jordan) was investigated. Here, mainly oxidized copper ores occur in the deposits. The production of copper from Fayan’s ore sources is confirmed by the measurement of the Cu isotope signature of ingots from the Early Bronze Age metal workshop from Khirbat Hamra Ifdan. Based on our results illustrating differences in the Cu isotope composition between the ore mineralizations from Timna (Israel) and Faynan, it is now possible to determine these prehistoric mining districts from which copper artifacts originated by combining trace elements and Pb isotopes with Cu isotopes. The second case study presents data on Late Bronze Age copper production in Cyprus. Oxhide ingots from the shipwreck of Uluburun (Turkey) were tested for their lead isotope signatures and assigned to Cypriot deposits in the recent decades. The oxhide ingots from Uluburun show a Cu isotope signature which we also found for oxidized copper ores from Cyprus, while younger oxhide ingots as well as metallurgical slag from the Cypriot settlements Kition and Enkomi show a different signature which might be due to the use of sulfidic ore sources from a greater depth of deposits. We assert that there could be a chronological shift from oxidized to sulfidic ore sources for the copper production in Cyprus, requiring different technologies. Therefore, Cu isotopes can be used as a proxy to reconstruct mining and induced smelting activities in ancient times.