Archaeometric Investigations Research Articles

LIBS and XRF analysis for a stratigraphic study of pictorial multilayer surfaces

The study of painting materials is a primary goal for the historical and artistic characterization of works of artbecause it provides useful information about the original materials and their degradation products, the paintingstechnique and any conservation treatments. However, the archaeometric investigations are very complex because theneed to safeguard the Cultural Heritage makes necessary the use of non or micro invasive techniques. Among thepossible analytical approaches, Laser-Induced Breakdown Spectroscopy, supported by X-ray Fluorescencespectroscopy for a faster elements identification, allows stratigraphic analysis with high spatial resolution enough todiscriminate different layers. Moreover, an integrated approach based on XRF and LIBS investigation is particularlyuseful for the complementarities of the outcomes in terms, both of investigated thicknesses and detectable elementalcontent.This paper aims to validate, in the archaeometry field, the use of LIBS for stratigraphic investigation of paintedsurfaces/objects by means of analytical results obtained from original fragments of mural paintings originating fromdifferent sites and artistic eras. Indeed the focus of this work is to determine the optimum parameters for bothtechniques in order to acquire the maximum information with the least damage to the works of art.The results have demonstrated the usefulness of the LIBS investigation, through that it has been possible toreveal chemical elements undetectable by XRF and to analyse the stratigraphic sequence of paint layers from thesurface up to the support layer. Furthermore they have provided good insight into the different painting layers byconfirming the potential of the LIBS to carried out stratigraphic analyses in a micro destructive way.

Provenancing of VI–VII century terra sigillata coming from Matera burial area by X-ray photoelectron spectroscopy

Abstract One of the most important aspects of archaeometric investigations regards provenance. There are numerous studies on pottery in which the origin is investigated employing NAA, XRF or ICPMS. “Terra Sigillata” productions have been widely studied from the point of view of the composition as well. This work represents the first analytical application of the XPS technique in pottery provenancing and in particular of three Terra Sigillata wares exhibited in the Matera National Archaeological museum and dating back to the sixth-seventh century AD. XPS permitted to ascertain the samples were imported and among the different known ateliers the samples match the composition of Sigillata A/D, specifically the one produced in the factory of Henchir el-Guellal at Djilma, central Tunisia. The analyses also definitely excluded the possibility that a local production, imitating the shapes of African Terra Sigillata in accordance with the tendency of production typical of the sixth and seventh centuries AD, occurred.

TIN AND TINNED DRESS ACCESSORIES FROM MEDIEVAL WROCŁAW (SW POLAND). X-RAY FLUORESCENCE INVESTIGATIONS

Introduction Most of what we know about medieval clothing elements and jewellery is from portraits, pictures in manuscripts and artefacts from museum collections. However, this knowledge is focused on precious accessories (and jewellery) that adorned knights and nobles. It was nevertheless important for all social groups to look fashionable and to wear jewellery. To the women and men of the Middle Ages dress elements were not only the determinant of social status, but had a religious context as well. The jewellery motifs were often devotional, e.g. crosses and pilgrims' badges (often worn by men on their hats). Women wore pendants, finger rings, belts and brooches, which were often wedding gifts (Kupstas 2000). Clothing accessories were made from very different metals; noble metals (gold and silver) were intended for wealthy men and cheaper metals for the others. The raw material used to produce the latter ones was bronze, tin, lead and/or lead-tin alloy (Kocka-Krenz 1982; Egan & Pritchard 2008). The imitation of noble jewellery is quite intriguing and will be discussed in this paper. After their conservation, several artefacts were selected for detailed studies: jewellery, dress accessories and tools. They were found during an archaeological excavation in the New Market Square in Wroclaw, SW Poland. The excavation was connected with the construction of an underground car park, which covered nearly 4000 [m.sub.2] in the southern part of the square. The research team, composed of staff and graduate students of several Polish universities (mainly the University of Wroclaw) was led by Professor Jerzy Piekalski. The main excavation took place from September 2010 to December 2012. The New Market Square is located in the eastern part of the Old Town of Wroclaw. It has a long and varied history, bursting with the rich remains of the past in the form of cultural strata. Previous studies of medieval archaeology in Wroclaw indicate that the beginnings of settlement land use are related to the 11th-12th century and were in the close vicinity of the castle on Cathedral Island. The archaeological and architectural study aimed to determine the true nature of craft production, as well as the layout of the New Market Square in the context of medieval Wroclaw. The huge collection of artefacts (11,838 in total, some compact groups of or single ones) is useful in the study of the material culture of medieval Wroclaw, as well as its external contacts (Bonar et al. 2013). The condition of the selected artefacts retrieved from archaeological layers was different (specimens covered by corrosion and layers of impurities, sometimes without metallic cores), which made the identification of tin/tinned artefacts difficult. The state of preservation of metal artefacts is a well recognized topic in archaeology and has been the subject of previous papers discussing soil effects on metal objects, e.g. Gerwin & Baumhauer (2000) and Neff et al. (2005). Therefore, artefact conservation prior to archaeometric investigations is very important. Because of the great historical value of the objects in these and previous investigations, there is a need to use non-destructive analytical methods (Bugoi et al. 1999; Janssens et al. 2000). There are many suitable methods that may be applied in archaeometry: neutron activation analysis (NAA), proton-inducted x-ray emission (PIXE), laser induced breakdown spectroscopy (LIBS) or many types of X-ray spectrometry (X-ray fluorescence (XRF) or scanning electron microscopy with energy dispersive X-ray detection (SEM-EDX)). Many research groups use such analytical techniques, e.g. Linke & Schreiner 2000; Lazic et al. 2005; Smit & Semrov 2006; VlachouMogire et al. 2007. The appropriate techniques should be universal, rapid and not too expensive for the institutions that take care of artefacts and store them (e.g. museums, universities and institutes). X-ray fluorescence is one of the aforementioned methods that are often applied in archaeometry projects (Milazzo 2004; Giumlia-Mair 2005). …

Extracting phosphoric iron under laboratorial conditions smelting bog iron ores

In recent years it has been indicated by archaeometric investigations that phosphoric-iron (P-iron, low carbon steel with 0,5-1,5wt% P), which is an unknown and unused kind of steel in the modern industry, was widely used in different parts of the world in medieval times. In this study we try to explore the role of phosphorus in the arhaeometallurgy of iron and answer some questions regarding the smelting bog iron ores with high P-content. XRF analyses were performed on bog iron ores collected in Somogy county. Smelting experiments were carried out on bog iron ores using a laboratory model built on the basis of previously conducted reconstructed smelting experiments in copies of excavated furnaces. The effect of technological parameters on P-content of the resulted iron bloom was studied. OM and SEM-EDS analyses were carried out on the extracted iron and slag samples. On the basis of the material analyses it can be stated that P-iron is usually extracted but the P-content is highly affected by technological parameters. Typical microstructures of P-iron and of slag could also be identified. It could also be established that arsenic usually solved in high content in iron as well.

Contrasting diagenetic pathways of higher plant triterpenoids in buried wood as a function of tree species

Terpenoid biomarkers with high chemotaxonomic value, which can be used for the identification of an angiosperm input to sedimentary organic matter are desirable for studies devoted to the reconstitution of past environmental change. There is also a need, in the framework of archaeometric investigations, for reliable biomarkers to allow wood species determination from archaeological remains. In this context, we report the analysis of the triterpene content of buried wood and bark from oak, alder and birch, and comparison with that of the corresponding fresh material. Identification of new biomarkers led us to elucidate the diagenetic transformations undergone by triterpenoids in buried wood. A large set of triterpenoid biomarkers characterized by the presence of an oxygenated functionality in ring A at C-2 only could be exclusively evidenced in buried oak wood. An overall diagenetic pathway leading from the predominant polyfunctionalized triterpenoids in fresh oak wood (oxygenated functionalities at C-2/C-3/C-19/C-23/C-24/C-28) via numerous C-2 and C-2,C-3 functionalized intermediates to C-2 oxygenated aromatic triterpenoids is proposed. The evolution of the triterpenoid assemblage with respect to the level of diagenetic alteration could be followed. In contrast, the predominant triterpenoids in fresh alder and birch are common C-3 functionalized compounds. Their degradation follows the classical degradation/aromatization pathways reported for C-3 oxygenated triterpenes, ring A degradation appearing to represent only a minor process. In addition, the formation of phenolic triterpenoids, which have only been reported from brown coal, was observed.

The history of the “Virgin with Child” sculpture (Ottaviano, Naples, southern Italy): Hypotheses from archaeometric multi-technique investigations

Abstract A life-size whitish marble statue of a “Virgin with Child” has been recently rediscovered in the St. Rosario church located in Ottaviano, a small town near Naples (southern Italy). This artwork shows stylistic features of the Tuscan-Roman school of the 16th century, and is framed in an intriguing historical context. Historical documents testify that the sculpture was a property of the cadet branch of noble Tuscan family of the Medici, the Medici of Ottaviano. A multianalytical approach has been used to try to indicate the supply area of the white marble of the studied sculpture. Considering the whole mineralogical, petrographic and geochemical data, the source rock can be possibly limited to the main classical white marbles of the Mediterranean district, as the classical marble of Aphrodisias. A reuse practice of a former artwork can be also hypothesized.

Archaeometric investigations on naturally and thermally-aged iron-gall inks using different tannin sources

Abstract This paper investigates the behavior of paper strips containing iron-gall inks prepared with tannins from different sources, subjected to natural and thermally-induced aging. Results indicate that inks containing initial concentrations of ferrous sulphate ranging from 0.2 to 10.0 g are amenable to treatment with calcium phytate, and thata good correlation exists between the recovery of excess iron and the initial concentration. Infrared spectra showed an absorption band at 1,750 cm−1, typical of esther, solely in the samples prepared with a condensed tannin. The condensed nature of this tannin produced a different oxidation pattern, with iron removal inferior to those observed from inks produced with hydrolisable tannins. When tannic acid was used ferrous iron removals ranged from 0.050 to 1.800 g, decreasing to 0.5 g in the presence of copper; the same behavior was observed for the remaining hydrolisable tannins, with a lower recovery from the condensed tannin. The adopted natural aging procedure released a higher amount of ferrous iron compared to ASTM thermal aging. This was probably due to the marked effect of humidity, not considered in the thermal procedure. A series of archaeometric possibilities were used to help elucidate the degradation of cellulose strips impregnated with iron-gall inks.

The Frankfurt University's Southeast Anatolia Project (SOAP): Archaeometric investigations on Early Bronze Age pottery

This paper is a first report on the chemical analyses carried out on samples of North-Mesopotamian Metallic Ware from Southeast Anatolia and on clay samples from the Pütürge Massif area, southeast of Malatya (Turkey), collected in the framework of the Southeast Anatolia Project (SOAP) of the Goethe University of Frankfurt/M. The chemical data obtained by applying wavelength dispersive X-ray fluorescence (WD-XRF) spectrometer were used to locate the provenance area of the raw clay source of non-calcareous North-Mesopotamian Metallic Ware, which is a characteristic major feature of the population groups settling in Southeast Anatolia and Northeast Syria in the 3rd millennium B.C. The analytical results show that the raw clay source of the pottery derived from metamorphic rocks with felsic affinity (e.g., schist/slate or similar parent rocks). It is suggested that the similar metamorphic rocks exposed in the Pütürge Massif area may be the source for the non-calcareous clay of the North-Mesopotamian Metallic Ware.

Sampling strategy and analysis of trace element concentrations by inductively coupled plasma mass spectrometry on medieval human bones – the concept of chemical life history

Medieval human bones have the potential to reveal diet, mobility and treatment of diseases in the past. During the last two decades trace element chemistry has been used extensively in archaeometric investigations revealing such data. Many studies have reported the trace element inventory in only one sample from each skeleton - usually from the femur or a tooth. It cannot a priori be assumed that all bones or teeth in a skeleton will have the same trace element concentrations. Six different bone and teeth samples from each individual were carefully decontaminated by mechanical means. Following dissolution of ca. 20 mg sample in nitric acid and hydrogen peroxide the assays were performed using inductively coupled plasma mass spectrometry (ICPMS) with quadropole detection. We describe the precise sampling technique as well as the analytical methods and parameters used for the ICPMS analysis. The places of sampling in the human skeleton did exhibit varying trace element concentrations. Although the samples are contaminated by Fe, Mn and Al from the surrounding soil where the bones have been residing for more than 500 years, other trace elements are intact within the bones. It is shown that the elemental ratios Sr/Ca and Ba/Ca can be used as indicators of provenance. The differences in trace element concentrations can be interpreted as indications of varying diet and provenance as a function of time in the life of the individual - a concept which can be termed chemical life history. A few examples of the results of such analyses are shown, which contains information about provenance and diagenesis.

The Transition from the Bronze to the Iron Age in Northern Palestine. Archaeological and Archaeometric Investigations on Tall Zirā‘a

The Transition from the Bronze to the Iron Age in Northern Palestine. Archaeological and Archaeometric Investigations on Tall Zirā‘a

Analytical techniques in art, archaeology and conservation science

This special issue of Analytical and Bioanalytical Chemistry is dedicated to the use of analytical techniques in the field of cultural heritage. It contains a selection from the contributions presented in Berlin during the TECHNART 2011 conference on non-destructive and microanalytical techniques in art and cultural heritage. The contributions to the conference covered a wide range of advanced X-ray, ion and neutron beam techniques with special emphasis on microanalysis [X-ray fluorescence (XRF), particle-induced X-ray emission (PIXE), X-ray diffraction, scanning electron microscopy–energy-dispersive X-ray analysis] and confocal microscopy (3D micro-XRF, 3D micro-PIXE). Other contributions focussed on Fourier transform IR and Raman microscopy, UV–Vis and near-IR absorption, reflectance and fluorescence methods and other laser-based analytical techniques. Finally, contributions on the use of magnetic resonance spectroscopy, highperformance liquid chromatography and gas chromatography coupled with mass spectrometry, and optical imaging in addition to coherence techniques were also presented. As usual, mobile spectrometry played a major role in the TECHNART conference. Studies of cultural objects often comprise questions on their origin and dating and attribution to artists or workshops. Sometimes stylistic and art-historical examination coupled with information from contemporary technological treatises and secondary literature may be sufficient to answer such questions. However, in many cases the missing information can be deduced from the physical and chemical properties of the artefacts. In its individual materiality, each cultural asset is the result of a wide variety of influences (e.g. production, storage, restoration, preservation). So investigations of physical properties and chemical composition generate important input for answering cultural-historical questions that cannot be solved by historical and philological methods alone. Because of recent technological developments, instrumental diagnostics in art and culture are winning recognition in such fields of transdisciplinary research. Intimately connected with archaeometric investigations are conservation and restoration studies: the development of reversible restoration or conservation concepts requires knowledge of the material compositions and ageing phenomena of the artefacts. The growing importance of physical and chemical diagnostics in the field of cultural heritage is reflected in a variety of conferences, workshops and journals. Hence, the dissemination of new developments in analytical technologies is an important prerequisite for further progresses in such a field of transdisciplinary research. All in all, this special issue represents the state of the art, illustrating how different techniques and different methods can be successfully applied to analytical investigations in the field of cultural heritage. I would like to thank all authors for submitting convincing and newsworthy contributions, all referees for constructive and conducive comments, and finally the central editorial office and the editors for their friendly cooperation.

Thermal behaviour of ‘metamorphic vermiculite’ in Ca-rich ancient ceramic sherds and experimental ceramics

AbstractA ‘metamorphic vermiculite’-like phase was identified in Ca-rich ancient ceramic sherds from excavations in NW Peloponnese, Greece. Archaeometric investigations have shown that the raw materials used in the production of ancient ceramics were derived from local Plio-Pleistocene sediments. Analysis by X-ray diffraction and scanning electron microscopy-energy dispersive spectroscopy showed that ‘metamorphic vermiculite’ is a common constituent phase of these sediments occurring in three texturally different types: as interstratified white mica-chlorite and chlorite-vermiculite, and white mica-(white mica-chlorite) stacks. In an attempt to elucidate the thermal transformation of ‘metamorphic vermiculite’ present in the calcareous raw materials, we produced experimental ceramics made from these local raw materials and fired them at 700, 750, 850, 950 and 1050°C in a static air furnace. The mixed-layered chlorite-vermiculite was transformed completely at ∼800°C contributing to the formation of new high-T minerals. The two other types of ‘metamorphic vermiculite’ retain their original lath-like shape up to 1050°C and only a few crystals show that they have undergone complete transformation at this temperature. In the latter crystals, numerous nanocrystals were formed sub-parallel to the former cleavages of ‘metamorphic vermiculite’ pseudomorphs, suggesting their contribution to the nucleation of high-T minerals (i.e. ferrian aluminian diopside, spinel, Fe oxides) by reactions with the available CaO. It is suggested that the firing conditions (i.e. maximum reaction temperature of 1050°C, reaction time of 1 h, oxygen atmosphere) which promote disequilibrium reactions, and the greater contribution of the white mica constituent against chlorite in some of the initial structures of ‘metamorphic vermiculite’ may be responsible for the delay of its thermal decomposition at 1050°C.

Archaeometric analyses of Early and Middle Neolithic pottery from the Pian del Ciliegio rock shelter (Finale Ligure, NW Italy)

The Neolithic site of Pian del Ciliegio is a rock shelter located in the Ponci Valley, at 220 m asl, in the Finalese (Liguria, NW Italy), a well-known karstic area characterised by the existence of several caves with prehistoric occupation. Archaeometric investigations (by optical microscopy and XRPD) were carried out on pottery samples mostly belonging to the Square-Mouthed Pottery Culture and the Impressed Ware Culture found out in the recent excavations of this site. Several fabrics were distinguished among the Square-Mouthed Pottery Culture pottery, suggesting different raw materials sources and production techniques. However, the nature of the mineral inclusions indicates in all cases local or circum-local production (e.g. within a range of a maximum of a few ten kilometres). All Square-Mouthed Pottery fabrics, in fact, contain elements that can be referred to the Palaeozoic metamorphic rocks outcropping in the area. In most cases they are associated with angular sparry calcite inclusions, possibly added as temper, which is a typical feature of other Neolithic pottery production from cave contexts studied in the area. On the contrary the Impressed Ware, although represented by a few sherds, shows a great variability both in fabrics and raw material provenance. Together with different local fabrics (with metamorphites ± calcite), fabrics with ophiolitic inclusions (possibly from Tuscany) and volcanic temper (from Central Italy) were found too. These data confirm and integrate those resulting from the investigation of the neighbouring Arene Candide cave site: a long-distance movement by sea of people and goods, pottery included, during the Early Neolithic is now clearly demonstrated.

Electrochemical lead separation from copper, copper alloy, silver and silver alloy for isotope ratio determination in archaeometric investigations

The possibility of electrochemical oxidation of Pb 2+ to PbO 2 as a method of isolation of lead in low concentrations in copper and silver matrixes was studied. Suitable electrolysis cell was developed and the influence of various factors (electrode surface and state, reaction time, temperature, electrolyte volume, acidity, concentration of indifferent electrolyte, stirring rate and current density) on the efficiency of the process was evaluated. The accuracy and reproducibility of the method were estimated by determination of the quantity of lead in SRMs by inductively coupled plasma atomic emission spectrometry (ICP-AES) and atomic absorption spectroscopy (AAS). By means of ICP-mass spectrometry (MS), the lead isotopic ratios in SRMs were determined.

INAA of some geological standard reference materials

INAA results of 11 standard reference materials used in archaeometric investigations of pottery as well as in environmental analysis are presented. The values obtained for 24 elements are compared with the certificate values as well as with the analytical data of other investigators. The accuracy of analysis is discussed.

Mean concentration of elements determined in Ohio Red Clay

Mean values for 42 elements in Ohio Red Clay, a reference material in archaeometric investigations of pottery, are calculated using results published by 10 laboratories. The dependence of the analytical results for Ba, Sc, and Ta on the standard used in the analysis is established.

Instrumental neutron activation analysis of native copper: Some methodological considerations

A scheme for INAA of native copper, which permits the determination of 22–24 elements is proposed. The possible error source in INAA of native copper and other types of more or less pure copper are evaluated quantitatively. The accuracy and precision of the analyses are tested by comparison with NIST-SRM's. The applicability of the proposed method for archaeometric investigations is demonstrated by the analysis of two samples of native copper and two eneolithic archaeological artifacts from Bulgaria.

Archeomaterials ed. by Tamara Stech

546 Book Reviews TECHNOLOGY AND CULTURE of materials. A pair of his articles on the history of materials appears in Pergamon’s Encyclopedia ofMaterials Science and Engineering. Archeomaterials. Vol. 1, no. 1 (Fall 1986), no. 2 (Spring 1987); vol. 2, no. 1 (Fall 1987), no. 2 (Spring 1988); vol. 3, no. 1 (Winter 1989). Edited by Tamara Stech. Philadelphia: Department of Materials Science and Engineering, University of Pennsylvania. Pp. 172/211/96; illustrations, tables, references. $45.00 (individual subscription); $60.00 (institution subscription); $60.00 (back vol­ ume) (paper). The journal Archeomaterials is a recent manifestation of the efforts of scholars to spread the printed word across the library shelves faster than the speed of light, but in this case the sacrifice of woodland is justified. The birth of this journal reflects lively activity in the field of archaeometry—the discipline that is concerned with the application of the physical and life sciences to studies of the past. Archaeometric research has grown steadily over the past decades, attracting not only archaeologists who are profiting by the scientific analysis of excavated material, but also practitioners of the “hard” sciences who are interested in the histories of their original disciplines and their relations to cultural development. Furthermore, there are now some archaeometrists who have received formal training in both archaeology and one of the hard sciences. Archaeometric techniques are used for such purposes as dating, prospection (the location and identification of buried structures), the determination of palaeodiet and palaeopathology, the provenancing (sourcing) of materials, and the reconstruction of ancient technolo­ gies. The museums and the universities are of course the institutions most involved in such research. Archeomaterials serves one of the major areas of specialization within this discipline. As the editor, Tamara Stech, states in the debut issue, it “is intended to provide an outlet for scholars studying a broad range of pre-industrial materials and processes. The topics include all materials altered by man in the past—minerals, metals, plant and animal products, clays, vitreous materials—and the ways in which they were manipulated.” The study of materials, ancient and modern, is generally founded on the characterization of their structures, using a spectrum of techniques and equipment. Structure, in this case, means structure at many levels, ranging from the fine-scale atomic, or even subatomic, to macroscopic or coarser levels such as provenance. All levels of structure are important. As W. D. Kingery states in volume 1, number 2, “Each of these levels of structure provides information necessary for complete evaluation and interpretation of the object as it is related to material culture” as well as enhancing our appreciation of the aesthetics of the material. TECHNOLOGY AND CULTURE Book Reviews 547 This reference to the relationship between object and material culture is of crucial importance in archaeometry. It is vital that the archaeometrist constantly bear in mind the ultimate aim of archaeometric investigations: a better understanding of the past. This is stated clearly in editor Stech’s admonition to prospective contributors to the journal: “The topic of research should always be placed in broader context than the laboratory or site. It is therefore important that the cultural background of each situation be clearly presented and that the relevance of the materials or processes to their social milieu be emphasized. An artifact without proper context has no scientific value and hence should not be the subject of scientific investigation.” While there can be exceptions to this latter statement, in general it is sound. The importance of the human element is stressed in Cyril Stanley Smith’s lead article in the debut issue (and there is no one more appropriate than Smith to provide such leadership). Smith makes the point that sensory and emotional factors, as well as intellectual ones, are at the heart of understanding and interpreting the material record; hence it is necessary to experience the feelings of the assayers and artisans of the past: “It is only if we gain a feeling for the experience of our predecessors while actually manipulating matter to make things that we can aid the archaeologist’s understanding.” It is encouraging to see that this point is reinforced frequently in articles that have appeared to...

Instrumental neutron activation analysis of reference materials for archaeometric investigations of pottery

The results from INAA of 3 of the standard materials /Perlman and Asaro standard pottery, Ohio Red Clay and Lefkandy Brick/ used in archaeometric investigations of pottery are presented. The values obtained for 32 determined elements are compared with the analytical data of other investigators. The accuracy of analysis and applicability of the standards are discussed.