Sourcing of sanukite implements by X-ray fluorescence analysis II

Non-destructive analysis of sanukite stones of known source and sanukite implements was carried out by means of energy-dispersive X-ray fluorescence spectrometry. Attention was focussed on areas in middle-western Japan. Stone taken from four source districts was classified into nine different groups. More than a hundred implements obtained from thirty-six archaeological sites were allocated to their sources by means of Hotelling's T² test.     

青铜器的X-荧光不破坏分析方法研究

不破坏分析法是文物保护和考古研究中最有希望的一种方法。X-荧光不破坏分析法已广泛用于多种合金的分析,但在国内把这种技术应用在古青铜的分析还不多,已发表的工作还是以放射源激发为主。由于放射源强度的限制,对小含量组分(例如含量为千分之一以下)分析还存在一定困难。X 射线管激发可进行小岔量组分的分析.但由于轫致辐射引起的高本底.影响了灵敏度的提高.采用 X-射线结合二次靶激发,通过对青铜标样的研究.以降低本底.提高方法灵敏度.并与放射源激发的结果进行了比较。     

Precision in the X-ray fluorescence analysis of sixty-one Augustan quadrantes

Sixty-one Augustan quadrantes were analysed for calcium, iron, nickel, copper, silver, tin, antimony, and lead by X-ray fluorescence. Most coins contained about 99·7% copper with the other seven elements present as trace impurities. Significant differences in composition were found for the three different issues of quadrantes minted in c. 9 BC indicating that these issues were not minted exactly contemporaneously. Quadrantes minted in c. 4 BC have trace element concentrations in ranges that differ from those of the 9 BC quadrantes. The precision is very good for all trace elements (the precision of calcium was not calculated): average standard deviations are 0·0021% for Fe, 0·0026% for Ni, 0·0038% for Ag, 0·0014% for Sn, 0·0031% for Sb, and 0·015 for Pb.     

X-ray fluorescence analysis of late Roman and Sassanian silver plate

About 200 analyses have been made on late Roman and Sassanian silver objects using energy-dispersive X-ray fluorescence. This has shown that the main feature of the composition of the silver throughout the period and across the geographical area studied was towards high fineness (average silver percentage about 95%). Compositional differences are found between Roman and Sassanian silversmiths' products for the elements copper and lead. Much of the material analysed came from hoards, and using a statistical technique on the analytical data (Discriminant Analysis) broad compositional differences between hoards were found to emerge. The use of different compositions of silver for different joined parts of a single object are discussed.     

X-ray fluorescence survey of tikal ceramics

X-ray fluorescence measurements of Ca, Fe, Rb, Sr, Y and Zr were made on 362 ceramic sherds excavated from the lowland Maya centre at Tikal, Guatemala. Twelve sample categories include unslipped, polychrome and red slipped ceramics from three cultural periods, the Manik, Imix and Eznab. Also represented are Manik black, Ik polychrome and Imix Tinaja pink. Results of analyses show two prevalent paste compositions, a calcite-tempered type characteristic of unslipped ceramics and a calcium- poor, rubidium-rich type typical of Late Classic slipped wares. Within these broad types, we observe strong overlap in the compositional data among the different ceramic categories. However, despite the similarities, there are measurable differences in the scatter (or variabilities) of these data and in their degrees of overlap. In general, the variabilities observed in the ceramic composition correlate with the population of the site and the expected number of production centres.     

Energy dispersive X-ray fluorescence analysis of 1st millennium ad glass from Britain

A series of energy dispersive X-ray fluorescence analyses has been undertaken in response to archaeological problems relating to 1st millennium AD glass excavated in Britain. The aim of the work was to furnish a set of comparable analytical results to be used in assessing hypotheses concerning the general state and development of glass technology through this period. Within this framework, however, it has also been possible to attempt answers to specific archaeological questions relating to material from particular sites. The paper discusses the background to, and the interpretation of such results, particulars of the analytical technique used, a general overview of approximately 200 analyses and three examples of the use of this data in relation to specific archaeological problems.     

X-ray and neutron-based non-invasive analysis of prehistoric stone artefacts: a contribution to understand mobility and interaction networks

Carbonate-rich archaeological artefacts are difficult to identify and correlate between them and with raw materials of such heterogeneous geological sources, especially when only non-invasive analysis is possible. A novel combination of X-ray and neutron-based non-invasive analysis is implemented and used for the first time to study prehistoric stone idols and vessels, contributing to culture identity, mobility and interaction in the recent Prehistory of Southern Iberia. Elemental composition was obtained by prompt gamma activation analysis (PGAA) and external beam particle-induced x-ray emission (PIXE); homogeneity of the stone artefacts and the presence/absence of internal fractures were obtained by neutron radiography (NR). These atomic and nuclear techniques, simultaneously used for complementary chemical information, have been demonstrated to be of great value as they provide non-destructive compositional information avoiding sample preparation, crucial in so singular and rare objects. The obtained results, especially of PGAA, are very promising and useful in general assessments of provenance. The stone artefacts show signs of both nearby and long-distance procurement, as well as of unknown attribution.     

Potentialities of X-ray fluorescence analysis in numismatics: the case study of pre-Roman coins from Cisalpine Gaul

X-ray fluorescence (XRF) is a well-known technique for the analysis of ancient metals. Thanks to the availability of portable instruments (p-XRF), it is extensively used for the chemical characterization of coins directly in museums. In this work, the potentialities of the technique have been investigated, through its application to a case study concerning the Cisalpine Gaul coinage. More than 200 drachmas have been analysed to discriminate different productions on the base of minor elements. Major elements, on the other hand, have been used to trace alloy changes through the centuries. As concerns the quantification of the silver content (fineness), XRF and neutron diffraction results have been compared, in order to check the presence of surface-enriched layers.     

X-ray fluorescence analysis and intra-island exchange in the Society Island archipelago (Central Eastern Polynesia)

We apply X-ray fluorescence (XRF) geochemical analysis to a collection of 'Opunohu Valley lithic artifacts from Mo'orea island to investigate the local scale of raw material procurement, adze production, use, and exchange within the Society Island archipelago. We use these data to document the distribution of non-local versus local volcanic artifacts in 'Opunohu Valley house sites, ritual sites, and specialized sites, as a means for establishing intra-site production and consumption patterns, and access to exotic, possibly superior, stone resources, and how these two themes correlate with site function or household wealth and status. Overall, 30% of the artifacts analyzed via WDXRF derive from non-local sources, notably two other islands in the archipelago outside of the political boundaries of Moorean chiefdoms. Our case study thus provides the first direct material evidence of intra-archipelago trade and exchange in the Society Islands. Intra-archipelago trade in adzes was certainly in place by as early as A.D. 1350, if not earlier, and continued up until the time of European contact. In addition, our analyses have identified a local adze production locale in the Afareaitu district of Mo'orea island. The patterns of local versus non-local adze production and exchange strongly suggest that dual interaction spheres were involved. The correlation between adzes and adze-related debris produced from off-island sources and sites with specialized use, which were often reserved for the social, ritual, and political elites in Ma'ohi society suggests that some of the exotic adzes derived from gift exchange between Mo'orea and ruling elites in Tahiti and the Leeward Islands. These adzes from afar would have solidified socio-political and ideological alliances between elites in the Windward and Leeward sectors of the archipelago.     

基于广域X射线荧光扫描成像技术(MA-XRF)的文物科学分析

本工作主要介绍了基于一种新型的X射线荧光分析技术——广域X射线荧光扫描成像技术(MA-XRF)的文物科学分析案例。对MA-XRF技术的发展历史做了简要的概述,结合不同类型文物的特点阐述了该方法的优势,并介绍了故宫博物院利用该方法对其文物藏品完成的多个研究案例。该研究的目的及意义在于为该新型技术在国内文物保护领域内的研究提供适用的案例介绍,指明该技术的优势所在,为今后的进一步发展和应用提供参考。     

古陶瓷元素成分分析技术定量方法的探讨

随着古陶瓷科学技术分析研究的不断深入,不同分析技术间数据的交流和借鉴成为必然。本工作主要从技术角度分析目前国内用于古陶瓷分析研究常见的几种科学分析技术的测量偏差来源,并对测量分析中的相关问题进行了探讨。在针对古陶瓷样品不均匀性要求方面,比较了几种分析技术实验条件的选择,指出适合于古陶瓷分析测量束斑的大小为φ2-3mm。结合上博实验室ED-XRF技术用于古陶瓷胎样品定量分析方法工作,详尽探讨了古陶瓷胎样品的原始样和粉末压片样的定量分析,指出古陶瓷中的“气孔效应”是造成两类样品不能公用标准样品的原因。     

Provenance of prehistoric obsidian artefacts from Kul Tepe,northwestern Iran using X-ray fluorescence (XRF) analysis

Analysis by X-ray fluorescence of 53 obsidian artifacts the main source of obsidian for the workshops in Kul Tepe was Syunik but obsidian sources as far as west as the Lake Van region (Nemrut Da? and Meydan Da?) and as far north as Gutansar were also utilized. These new results indicate a broad network of trade and exchange.     

Application of X-ray fluorescence imaging to ceramics from the American Southwest

We have used synchrotron-based X-ray fluorescence imaging (XRFI) to examine sherds of painted ceramics from prehistoric cultures of the American Southwest. These sherds are very well suited to XRFI analysis. Paints can generally be detected and distinguished by the fluorescence intensities of their constituent elements. Spatial maps of element distributions yield the spatial distribution of pigments. Pigments can be distinguished that are (or have become) visually similar; layers that have been obscured by overpainting can be examined; and pigment residues can be distinguished from surface contaminants deposited after painting and firing. As a result, XRFI allows the painted motifs to be clarified and hidden features to be revealed. Furthermore, the very rapid scanning and high sensitivity elemental detection possible with synchrotron-based XRFI facilitate measurements on large collections of sherds, allowing an integrative rather than anecdotal analysis.     

Using portable energy dispersive X-ray fluorescence (EDXRF) analysis for on-site study of ceramic sherds at El Hibeh,Egypt

As part of its geoarchaeological research program, the El Hibeh Project of the University of California, Berkeley field-tested at the site of El Hibeh, northern Middle Egypt, the utility of a portable EDXRF unit for obtaining geochemical analyses of pottery suitable for provenance and other ceramic classification studies. When the geochemical ceramic data from the field test are combined with basic petrographic analysis for the pottery sample set, compelling results are generated. In particular, a triangular scattergram using elemental iron, strontium and rubidium data, in parts per million, provides excellent temporal and spatial separation of ceramic fabrics type, origin and date. The geochemical behavior of iron, strontium and rubidium is discussed in relation to geological source materials utilized for pottery manufacture.     

Experimental analysis of rubble stone masonry walls strengthened by transverse confinement under compression and compression-shear loadings

Stone masonry walls of ancient buildings have reasonable resistance to vertical loads but lower resistance to shear forces and reduced tensile strength. However, to achieve such compressive strength the masonry must not disaggregate when subjected to loading. This can be achieved if during the construction of the walls larger stones, usually referred as “through stones”, are used, spanning the thickness of the wall, making it possible to improve the transverse confinement of the masonry. For rehabilitation projects and structural reinforcement of such buildings, the transverse confinement can be achieved by fixing steel elements perpendicular to the wall. This confinement technique is often part of a more comprehensive rehabilitation solution, which includes the application of mortar or concrete reinforced layers applied to the wall surface.

This article presents results of an experimental research on material properties and mechanical characterisation of stone masonry specimens strengthened by two transverse confinement solutions (independent steel reinforcing rods and continuous steel ribbons wrapping the specimen). Specimens were tested under compression and compression and shear loadings.

This experimental work is part of a major research project to study the mechanical behavior of URM and strengthened walls, and the characteristics of the building materials of such specimens.     

Non-destructive provenance study of cuneiform tablets using portable X-ray fluorescence (pXRF)

Portable X-Ray Fluorescence (pXRF) apparatus of the last generation was tested to determine its potential for routine provenance determination of clay cuneiform tablets, which cannot be analyzed by “classical” intrusive methods. A group of tablets from Hattuša (Bo?azköy) and from el Amarna, which were previously provenanced using optical mineralogy (OM) and instrumental neutron activation analysis (INAA), was analyzed by pXRF and the results were used to establish the grouping according to their elemental concentrations. These groups were compared with the previous results retrieved by OM and INAA in order to confirm their validity. The results corroborate the high potential of the pXRF for non-destructive study of well-defined, ‘closed’ assemblages of clay-derived, delicate artifacts, such as cuneiform tablets, bullae, and fine-ware pottery. Consequently, a group of previously unexamined tablets from Hattuša was analyzed by pXRF and the results are discussed with implications on future research.     

Non-invasive characterization through X-ray fluorescence and neutron radiography of an ancient Japanese lacquer

Oriental lacquer artefacts represent very interesting objects of investigation, involving a huge variety of materials and manufacturing techniques. Lacquers are very attractive not only for their stylistic features but also for understanding the variety of production processes, time evolution, use and artistic applications involved in their manufacturing. Till recently, the research activity on these materials has been mainly based on standard, more or less invasive, analytical methods. With the aim to characterise a nineteenth century Japanese lacquer in a totally non-invasive and non-destructive way, in situ X-ray fluorescence (XRF) and neutron radiography (NR) have been employed. While XRF suggested an identification of the pigments embedded into superficial layers, NR allowed revealing, in a single measurement, the average bulk properties of the sample.