THE COMPLEMENTARY USE OF NEUTRONS AND X‐RAYS FOR THE NON‐DESTRUCTIVE INVESTIGATION OF ARCHAEOLOGICAL OBJECTS FROM SWISS COLLECTIONS*

This paper shows the possibilities offered by the combined use of non‐destructive neutron and X‐ray beams in archaeological research on metallic finds. The following five artefacts from Swiss excavations were submitted to investigation, each with dedicated aims: a Roman sword, a Roman dagger, an Iron Age bucket, Iron Age spearheads and a Roman finger ring. The images obtained with both methods—neutrons and X‐rays—are discussed in length in this paper. The investigations took place at the Paul Scherrer Institute and the archaeologists who studied the objects come from the Universities of Lausanne and Zurich.     

PROVENANCE OF MEDIEVAL PIETRA OLLARE ARTEFACTS FOUND IN ARCHAEOLOGICAL SITES OF CENTRAL–EASTERN ITALY: INSIGHTS INTO THE ALPINE SOAPSTONE TRADE*

Medieval archaeological findings made of pietra ollare (basic and ultrabasic metamorphic rocks belonging to the greenschist facies) and coming from central–eastern Italy have been characterized through a petrological study (modal mineralogy, whole‐rock geochemistry, XRD and SEM–EDS analyses). The pietra ollare artefacts considered in this work consist of fine‐grained, grey to pale‐grey, magnesite‐bearing talc‐schists (i.e., soapstones). In order to determine their production centres, Alpine soapstones quarried in ancient times were selected on the basis of their mineralogical and textural compatibility with the archaeological findings. The mineralogy and chemistry (major and trace elements) contributed to establishing the ancient quarries of the Valchiavenna (central Alps) as the probable provenance area. This archaeometric investigation proves that Alpine artefacts made of pietra ollare spread to the south of the Po Plain during the Middle Ages. It can be inferred that the Alpine soapstone trade towards the Marche and Abruzzo regions was addressed through the main waterways: Lake Como, the Adda and Po Rivers and finally the Adriatic Sea.     

REPRODUCIBILITY OF ELEMENTAL ANALYSES OF BASALTIC STONE ARTEFACTS BY QUADRUPLE ICP–MS USING DIFFERENT SAMPLE SIZES AND DIGESTION METHODS,WITH IMPLICATIONS FOR ARCHAEOLOGICAL RESEARCH

Using high‐precision inductively coupled plasma mass spectrometry (ICP–MS), we measured >40 elements in basalts sampled by diamond micro‐drills to evaluate the effectiveness of different digestion methods and the reproducibility of elemental analysis for different sample sizes from 5 mg to 100 mg. The results indicate that those elements that are most suitable for geochemical characterization, such as rare earth elements (REE), high‐field strength elements (HFSE) and certain mobile elements (Rb, Sr, Th, U), show excellent reproducibility with an average relative standard deviation (RSD) of 3% between open‐beaker and pressured ‘bomb’ digestion methods. This observation rules out the presence of refractory phases such as zircon, which can only dissolve in pressured ‘bombs’, and suggests that the results from open‐beaker digestion are reliable. The ICP–MS data for powders of different weights ranging from 10 to 100 mg collected from two fine‐grained basalt artefacts display excellent reproducibility, with a RSD of <5% for the most important elements. The reproducibility is reduced when including the 5 mg weight fraction (RSD of ～2–9%), which is still sufficient for archaeological applications. Our results demonstrate the usefulness of 10 mg samples for elemental measurement, which is valuable for geochemical characterization and sourcing of fine‐grained basalt artefacts from museum collections that require minimal destructive sampling.     

MINERALOGICAL AND PETROLOGICAL INVESTIGATIONS OF EARLY BRONZE AGE COPPER‐SMELTING REMAINS FROM THE KIECHLBERG (TYROL,AUSTRIA)

The prehistoric settlement on the Kiechlberg hilltop is located a few kilometres to the north‐east of Innsbruck, in the Tyrolean Inn Valley. Despite its rather isolated location, a multiphase settlement between the fifth and the second millennium bc was confirmed by archaeological investigations in 2007 and 2008. Metallurgical artefacts, such as copper ore fragments, copper slag and raw copper, as well as finished copper and bronze artefacts, are concentrated mainly in Late Copper Age to Middle Bronze Age layers. The chemical compositions of the slag and raw metals confirm Fe—Zn tetrahedrite–tennantite (fahlore) smelting. The ore was most probably imported from the 30–50 km distant copper ore deposits (mainly fahlore) of Schwaz–Brixlegg, in the Lower Inn Valley. The small amount of slag and the presence of slagged and thermally altered ceramic fragments suggest copper production in small‐scale workshops. Most probably, sulphide‐rich ores were smelted in crucibles in a hearth fire. The process was relatively reducing below the 2Sb + 1.5O₂ → Sb₂O₃ reaction (?8.5 log fO₂ at 1100°C), producing Sb‐rich (>10 wt% Sb in metal) raw copper. Inhomogeneous slag remains containing high amounts of sulphide and metal inclusions suggest a poor separation of the metal, matte (copper sulphide) and silicate/oxide melt during the smelting process.     

CHARACTERIZATION OF ARCHAEOLOGICAL AND IN SITU SCOTTISH WINDOW GLASS

Scottish window glass from both archaeological sites and historic buildings was examined using portable X‐ray fluorescence (pXRF) and scanning electron microscopy – energy‐dispersive X‐ray micro‐analysis (SEM–EDX). The elemental composition of the glass provides information regarding the materials used and, subsequently, an approximate range of dates of manufacture. pXRF is shown to be more vulnerable than SEM–EDX to the effects of surface corrosion and matrix effects in archaeological samples. The study showed that the production of window glass in Scotland from the 17th century onwards appears to closely parallel that in England. It also demonstrated the potential of pXRF for in situ studies of window glass in historic buildings. pXRF was used to assess two Scottish buildings; one in state care and one in private ownership. The building in state care, the Abbot's House at Arbroath Abbey, showed a uniform glass type, suggesting that the building was re‐glazed completely at some point during the late 19th or early 20th century. The building in private ownership, Traquair House, had a range of glass types and ages, demonstrating a different maintenance and repair regime. This type of data can be useful in understanding historic buildings in the future, particularly if re‐glazing is being considered.     

A NEW DATING METHOD FOR HIGH‐CALCIUM ARCHAEOLOGICAL GLASSES BASED UPON SURFACE‐WATER DIFFUSION: PRELIMINARY CALIBRATIONS AND PROCEDURES*

The first European settlers came to North America in the early 17th century using glass in the form of containers and decorative objects. Thus, glass is a horizon marker for all historic period settlements and a potential source of chronometric dates at archaeological sites belonging to the historic period in the Americas. We have developed a new absolute dating method based upon water diffusion into the surface of manufactured glasses that predicts diffusion coefficients based upon variation in glass chemical constituents. Low‐temperature (< 190°C) hydration experiments have been performed on a set of five high‐calcium (21.7–28.3%) glasses that were used to manufacture wine bottles from the 17th?19th centuries. Infrared spectroscopy and secondary ion mass spectrometry was used to model the water diffusion/alkali exchange process. The ability of the model to accurately predict archaeological ages was evaluated with artefacts recovered from ceramic‐dated contexts at Thomas Jefferson's plantation known as Monticello.     

THERMAL ALTERATIONS IN ARCHAEOLOGICAL BONES*

Archaeological bones, found close to Mexico City (Tlatelcomila), with alterations due to probable thermal exposure attributed to a possible case of cannibalism, have been characterized by XRD, SAXS and SEM. It is shown how these non‐destructive techniques, which are not conventionally used in archaeological research, may provide useful information. The deterioration degree of the bone structure is quantified through parameters such as gyration radius or fractal dimension. As some of the reported modifications could be attributed to diagenesis, a discussion is presented in terms of bone crystallinity and ionic exchange. Furthermore, the hydroxyapatite crystallite size increased depending on colour: this feature is not explained by diagenesis—it can only be attributed to temperature. We conclude that the samples were thermally treated. Indeed, thermal treatment alters the structure and morphology of bone at a very fine level (microscopic and nanometric), while morphology follows the structural modifications. It is determined that the studied human bones were treated at three different temperatures close to 100, 250 and 600°C. Therefore, they were either boiled (barbacoa) or grilled.     

THE AMBER OF EL DORADO: CLASS IB ARCHAEOLOGICAL AMBERS ASSOCIATED WITH LAGUNA GUATAVITA*

Laguna Guatavita, a crater‐like lake located in central Colombia, was used by pre‐Columbian Muisca people for a variety of socio‐religious ceremonies, many of which involved casting offerings into the lake. Of these, the installation of a new ‘king’ became the basis of the El Dorado myth that was carried back to Europe by 16th century conquistadores. In the present study, beads collected from Laguna Guatavita during a late 19th/early 20th century attempt to recover valuables from the lake bed, have been subjected to geochemical analysis. Results establish that these artefacts have been fabricated from Class Ib amber. Class Ib ambers have not previously been reported in either the geological or archaeological records of Central or South America, and their existence in this context implies that the Muisca people had access to a unique local or regional source of amber, knowledge of which has subsequently been lost.     

FIXED‐FREQUENCY RADIO‐WAVE IMAGING OF SUBSURFACE ARCHAEOLOGICAL FEATURES: A MINIMALLY INVASIVE TECHNIQUE FOR STUDYING ARCHAEOLOGICAL SITES*

In memoriam Tony Clark Sadly, this research marked the last field visit to the test site that the authors were able to share with their colleague Tony Clark. His enthusiasm, experience and encouragement inspired us to complete this project that, to many, must have appeared as grown men at play in a sand pit. A new approach to subsurface exploration has been developed, based on fixed‐frequency radio‐wave illumination from a buried transmitter. Data are collected from a buried, continuous wave source with a phase‐coherent surface‐scanning receiver and recorded in a digital archive from which images of the archaeological features are subsequently produced. An important feature of this approach is the opportunity to separate the data collection and archive functions, which form an uncompromised record of the site, from the more subjective image formation function. This paper reports the results of a feasibility assessment programme and discusses the future application of the method to real archaeological sites.     

ARCHAEOLOGICAL VOLCANIC GLASS FROM THE SITE OF ROCCHICELLA (SICILY,ITALY)*

The site of Rocchicella, near Catania, in eastern Sicily, has yielded important archaeological evidence from prehistoric times to the Middle Ages. Extensive archaeological investigations of cultural layers dating from the Palaeo‐Mesolithic to the Copper Age have recently been undertaken, and volcanic glass, mainly obsidian, has been collected in the course of excavation. To determine the provenance of this volcanic glass, a non‐destructive elemental analysis was carried out to measure the concentration of characteristic trace elements. The analysis was carried out using a new XRF spectrometer equipped with a beam stability controller and a quantitative method developed at the LANDIS laboratory of the INFN–CNR Institutes of Catania. In addition to the obsidian, it was demonstrated for the first time that a local vitreous material similar to obsidian, but displaying a completely different composition, was used during all the investigated periods. This material was identified as a basaltic glass, characterized by a superficial product of devitrification called palagonite. Analysis of the obsidians has led to the identification of the island of Lipari as the provenance source. High‐ and low‐power microscopic use‐wear analysis on obsidian and basaltic glass artefacts indicated that soft wood and plant matter might have been processed at the site.     

ceraDAT—PROTOTYPE OF A WEB‐BASED RELATIONAL DATABASE FOR ARCHAEOLOGICAL CERAMICS

The prototype of a relational database for archaeological ceramics is presented. At this stage, the ceraDAT database contains the elemental compositions of several thousand ceramic artefacts from the Eastern Mediterranean, analysed by neutron activation analysis (NAA) at different laboratories. The data have been calibrated on the basis of the analytical routine and can be accessed via a web application. Apart from the elemental compositions, the database contains reference patterns of specific sites, metadata concerning archaeological information, the geographical distribution, literature references and former statistical evaluations. Due to the database design, the structure can be extended in future towards petrographical and mineralogical information.     

1H‐NMR AND 31P‐NMR CHARACTERIZATION OF THE LIPID FRACTION IN ARCHAEOLOGICAL OINTMENTS

Lipids are a broad group of naturally occurring molecules, which includes fats, oils, waxes, sterols, terpenes, fat‐soluble vitamins, monoglycerides, diglycerides, phospholipids and others. Lipids have been widely used in human history and they are often present in archaeological finds. In particular, in the field of medicine and cosmetics, lipids have been employed as base in the preparation of unguents, salves and balms. The characterization of these products and their degradation products induced by ageing is important for an understanding of the ancient pharmaceutical techniques and to assess the state of conservation. ¹H‐NMR and, for the first time, ³¹P‐NMR spectroscopy have been applied to the characterization of such compounds. By derivatization of the samples with 2‐chloro‐4,4,5,5‐tetramethyl‐1,3,2‐dioxaphospholane, it is possible to recognize, quantify and evaluate the degradation degree of lipids in archaeological unguent samples. With this new approach, lipids have been recognized in 17th‐century archaeological ointments from the Aboca Museum. Moreover, severe hydrolysis and oxidation markers have been detected.     

ANALYSING ARCHAEOLOGICAL BASALT USING NON‐DESTRUCTIVE ENERGY‐DISPERSIVE X‐RAY FLUORESCENCE (EDXRF): EFFECTS OF POST‐DEPOSITIONAL CHEMICAL WEATHERING AND SAMPLE SIZE ON ANALYTICAL PRECISION*

Energy‐dispersive X‐ray fluorescence (EDXRF) has been commonly used to determine geological sources of volcanic glass artefacts, but its ability to discriminate between basaltic sources is less developed. We examine the precision and accuracy of non‐destructive EDXRF for basalt artefacts by analysing varying size and weathering characteristics. The experiments identified no appreciable effect in reproducibility or measured composition due to thickness (down to 1 mm) or natural weathering of pre‐contact flake scars for the 17 elements measured in this study. Samples with surface area less than 100 mm², however, show significant variability in measured composition and reproducibility.     

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.     

Vegetation,land, and wood use at the sites of Bat and Al‐Khashbah in Oman (fourth–third millennium BC)

About 4200 charcoal fragments have been identified from the fourth‐ to third‐millennium BC archaeological sites of Bat and Al‐Khashbah in order to gain an understanding of plant resources available at the sites. Acacia sp., Ziziphus sp., and Tamarix sp. were the main taxa identified at both sites and indicate a similar vegetation composition as today. Phoenix sp. (date palm) charcoal also has been found at both sites. Whereas the cultivation of date palm for the 2700–2300 BC layers from Bat was likely, given other circumstantial evidence (i.e. local cereal cultivation and floodwater irrigation), it is unclear whether date palm was cultivated at Al‐Khashbah. Especially for the older periods (3300–2700 BC) it is possible that nomadic pastoralists were exploiting and/or managing wild date palms. The find of Avicennia marina at Al‐Khashbah indicates long‐distance contacts with the coast.     

A NEW SETTING FOR THE NORTHERN BORDER OF THE VENETI: METALLIC FINDS FROM THE VENETIC SITE OF MONTE CALVARIO,AURONZO DI CADORE*

In 2000 several bronze and lead objects were discovered at the Venetic‐Roman site (200 bc –ad 200) of Monte Calvario di Auronzo, in the Italian eastern Alps. They were mostly finished artefacts plus semi‐worked products. Analysis included SEM–EDS, EMPA, XRPD, TMS and AMS spectrometry. The compositional results of the finished artefacts suggest that the choice of the alloy had been made according to the decorative techniques to be used. A semi‐worked high‐leaded bronze object indicates the existence of a metallurgical production of cast artefacts at the site. TMS analyses of a lead ingot exclude local provenance, proving the existence of important trade routes.     

ORGANIC RESIDUE ANALYSIS IN ARCHAEOLOGY: THE ARCHAEOLOGICAL BIOMARKER REVOLUTION*

Organic residue analysis utilizes analytical organic chemical techniques to identify the nature and origins of organic remains that cannot be characterized using traditional techniques of archaeological investigation (because they are either amorphous or invisible). The field is founded upon the principle that the biomolecular, or biochemical, components of organic materials associated with human activity survive in a wide variety of locations and deposits at archaeological sites. The archaeological information contained in organic residues is represented by the biomolecular components of the natural products that contribute to the formation of a given residue. By applying appropriate separation (chromatographic) and identification (mass spectrometric) techniques, the preserved, and altered, biomolecular components of such residues can be revealed. Once identified, the Archaeological Biomarker Concept can be applied, wherein the structure and even isotopic composition(s) of a given biomolecule or suite of biomolecules (the ‘chemical fingerprint’) can be related to the compositions of organisms exploited by humans in the past. As the organic residue field emerges from its pre‐paradigmatic phase, and the organic residue revolution gathers pace, the way is open for challenging many long‐held archaeological hypotheses and offering new perspectives on the study of human activity in the past.     

MICROSCOPIC IDENTIFICATION AND SOURCING OF ANCIENT EGYPTIAN PLANT FIBRES USING LONGITUDINAL THIN SECTIONING*

Plant fibres and the artefacts constructed from them often remain overlooked in the archaeological record because of their poor survival and the problems related to the precise identification of the species to which the fibres belong. The goal of this study was to design a simple and accurate method of identifying archaeological plant fibre sources. Twenty‐two fibre samples from two sets of ancient Egyptian botanical artefacts were examined under both a stereomicroscope and a compound microscope, and compared to a large reference collection and to previously published research. By examining longitudinal thin sections of the ancient plant specimens, we identified plant fibres from the following species: Hyphaene thebeica, Cyperus papyrus, Desmostachya bipinnata, Imperata cylindrica, Phragmites australis and Linum usitatissimum. Our identification of these plant fibres reveals essential information about the materials used for producing ropes, baskets, sandals, mats and fabric. The results of this study demonstrate the value of longitudinal thin sectioning and light microscopy as a major means of identifying the source material of botanical artefacts, and advance our knowledge of ancient Egyptian plant exploitation as well as the associated technologies involved in constructing these types of artefacts.     

NON‐DESTRUCTIVE INVESTIGATION OF BRONZE ARTEFACTS FROM THE MARCHES NATIONAL MUSEUM OF ARCHAEOLOGY USING NEUTRON DIFFRACTION*

Non‐destructive neutron diffraction techniques were applied to determine composition and microstructure data, and hence to derive information on manufacturing techniques of Picenum bronze artefacts. Furthermore, texture analyses were carried out on standards and suitable ancient artefacts to investigate their potential role in archaeometallurgical studies. This is a first step towards an overall characterization of the bronze collection of the Marches National Museum of Archaeology, Italy, and the analytical demonstration of relations with and differences compared to Etruscan metallurgy. The work is also an example application of the powerful non‐destructive archaeometrical approaches provided by time‐of‐flight neutron diffraction.