Characterisation of archaeological mortars from Pompeii (Campania,Italy) and identification of construction phases by compositional data analysis

This work describes the compositional characterisation of coccciopesto and natural pozzolanic mortars sampled in the Regio VI area of the archaeological site of Pompeii, with particular reference to the Casa di Pansa in Insula 6 and Casa 17 in Insula 2. Samples were studied by optical microscopy and analysed by XRF, SEM-EDS, LA-ICP-MS and XRPD. The XRF and SEM-EDS data, subjected to multivariate analysis (cluster analysis), identified the three main construction phases involved in building the Casa di Pansa. In addition, mineralogical and petrographic characteristics of the aggregate were determined and found to be compatible with pyroclastic deposits from the volcano Vesuvius. Study revealed C–S–H phases in the binder, due to pozzolanic hydration phemomena of hydrated lime with cocciopesto and natural pozzalana.     

ROMAN WINDOW GLASS: A COMPARISON OF FINDINGS FROM THREE DIFFERENT ITALIAN SITES

Thirty‐three samples of window glass and five glass lumps coming from three Italian archaeological sites—the Suasa excavations (Ancona, settled from the third century bc to the fifth to sixth centuries ad ), the Roman town of Mevaniola (Forlì‐Cesena, settled from the Imperial Age up to the fourth century ad ) and Theodoric's Villa of Galeata (Forlì‐Cesena, settled from the sixth century ad onwards)—were analysed to track the changes in the chemical composition and manufacturing technology of window glass through the centuries. The aims of this study were: (1) to establish the origin of the raw materials; (2) to verify the chemical homogeneity among samples coming from different sites and/or produced using different techniques; and (3) to sort the samples into the compositional groups of ancient glass. The analysis of all the chemical variables allowed two groups to be distinguished: (a) finds from Mevaniola and Suasa; and (b) finds from Galeata. All the samples had a silica–soda–lime composition, but the analysis of minor elements—in particular, of Fe, Mn, and Ti—made it possible to split the samples into two groups, with the higher levels of these elements always found in the Galeata samples (HIMT glass). In conclusion, it can be asserted that the main differences between the samples are related to their chronology.     

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.     

pXRF: a study of inter-instrument performance

Integrating portable X-ray fluorescence (pXRF) instrumentation into archaeological investigations has generated as much interest as skepticism because several characteristics of the technique limit analytical accuracy and precision. This paper seeks to explore inter-instrument performance in order to assess the potential pXRF instrumentation has in examining the elemental composition of lithic raw materials. Two pXRF instruments, Delta and Omega models both manufactured by Olympus Innov-X Systems, were utilized to obtain the trace element signatures of five fine-grained volcanic sources and four obsidian sources in the Great Basin. We compared the two portable instruments to a wavelength-dispersive instrument extensively calibrated with geologic standards and to a commercial benchtop energy-dispersive system. Our results suggest that the relationships between the data produced by these different instruments are complex, and as we look to the future of pXRF use in archaeological analysis we argue that that the same strict protocols applied in laboratory-based XRF analyses, involving instrument calibration, evaluation of inter-instrument performance, and comparison to accepted geologic standards, need to be applied in pXRF analysis.     

Transition in the use of cobalt-blue colorant in the New Kingdom of Egypt

Cobalt-blue colorant was first used in the 18th Dynasty in the New Kingdom of Egypt. The source of this cobalt was cobaltiferous alum from the Western Oases of Egypt. The use of this alum, especially in glass, was suddenly limited at the end of the 18th Dynasty. There is little evidence of the production of cobalt-blue glass in the Ramesside Period (the 19th–20th Dynasties) in the New Kingdom of Egypt. In this study, we brought a portable X-ray fluorescence spectrometer to two archaeological sites located in the Memphite region and used it for onsite analyses of Ramesside cobalt blue-colored glasses and faiences. This method revealed that the compositional characteristics of the cobalt-blue colorant in these Ramesside glasses and faiences is different from the colorant derived from cobaltiferous alum used in the 18th Dynasty, based on the comparison of transition metal composition and alumina content with those of the cobalt blue-colored artifacts from the 18th Dynasty. This result suggests that a new cobalt source other than cobaltiferous alum from the Western Oases was utilized in Egypt during the Ramesside Period.     

A COMBINED MULTI‐ANALYTICAL APPROACH FOR THE STUDY OF ROMAN GLASS FROM SOUTH‐WEST IBERIA: SYNCHROTRON μ‐XRF,EXTERNAL‐PIXE/PIGE AND BSEM–EDS

An integrated, multi‐analytical approach combining the high sensitivity of SR‐μXRF, the light element capability of PIXE/PIGE under a helium flux and the spatial resolution of BSEM + EDS was used to characterize chemical composition and corrosion of glass samples (first to fourth centuries ad ) from an important, but scarcely investigated, Roman region of south‐west Iberia (southern Portugal). The geochemical trends and associations of major, minor and trace elements were investigated to shed light on production techniques, the provenance of raw materials and decay mechanisms. The results, while confirming a production technique common to Roman glasses throughout the Empire—that is, a silica‐soda‐lime low‐Mg, low‐K composition, with glass additives as colouring and/or decolouring agents (Fe, Cu, Mn, Sb)—show at one site high Zr–Ti contents, suggesting a more precise dating for these glasses to the second half of the fourth century. The Ti–Fe–Zr–Nb geochemical correlations in the pristine glass indicate the presence of minerals such as ilmenite, zircon, Ti‐rich Fe oxides and columbite in the sands used as raw materials for the glass former: these minerals are typical of granitic‐type source rocks. The unusually high K content in the corrosion layers is consistent with burial conditions in K‐rich soils derived from the alteration of 2:1 clays in K‐bearing rock sequences.     

MATERIAL CHARACTERIZATION OF CERAMIC TILE MOSAIC FROM TWO 17TH‐CENTURY ISLAMIC MONUMENTS IN NORTHERN INDIA

Coloured tiles from two northern Indian monuments were analysed for their body and glaze composition. The results suggest that three different groups of tiles were used, all comprising a stonepaste body with alkali glaze. One group has strong similarities to a major Indian glass group, known as high alumina mineral natron glass, while the other two are similar to Western and Central Asian plant ash glazes, although with much lower lime content. The colorants conform with those usually employed in pre‐modern glazes, with lead‐tin yellow Type I and Type II for opaque yellow, copper blue‐turquoise, cobalt blue, manganese purple, and green through mixing of lead‐tin yellow and copper blue.     

Evaluating effects of chemical weathering and surface contamination on the in situ provenance analysis of building stones in the Cuzco region of Peru with portable XRF

As the only type of instrument capable of determining artifact geochemistry in a wide variety of settings, portable X-Ray Fluorescence (PXRF) may be frequently utilized as probably the best option for collecting data when removal of objects in part or in whole is unfeasible. However, using PXRF in circumstances where sample selection and preparation diverge from standards developed for lab-based instrumentation requires assessing the impact of new and potentially limiting factors to establish the validity of the method in these new contexts. Here we examine the effects of surface contamination and chemical weathering on the ability to assess provenance of igneous building stones used in the Cuzco region of Peru. Surface contamination was assessed through comparing low-impact cleaning methods on diorite and andesite blocks, and weathering was examined by comparing weathered vs. fresh surfaces of samples from two andesite quarries. In general, the lightest elements were most impacted by contamination and weathering while measurements of many of the heavier elements commonly used in provenance studies were relatively unaffected. Concentrations of Pb and Zn were problematic in the urban context of Cuzco because of pollution. Ability to determine provenance of building stones within those limitations (i.e., the validity of this application of PXRF) was demonstrated in a preliminary study by comparing measurements from uncleaned, exposed building stones in the region to fresh quarry samples.     

古陶瓷完整器元素成分无损分析的实现（二）——设备改建和定量分析方法

为了真正实现古陶瓷完整器的元素成分无损分析,就要建造能容纳常规大小古陶瓷样品的真空靶室,以及建立弯曲表面古陶瓷的定量分析方法。本文报道了本实验室QuanX型能谱仪真空靶室改造的整体设计和加工,以及针对弯曲表面古陶瓷样品定量分析的处理方法。大量的测量工作表明所改装的能谱仪完全适应古陶瓷完整器的元素成分无损分析的需要,同时证明古陶瓷样品在较低真空条件下的测量分析是完全无损的;所提出表面弯曲古陶瓷的定量分析处理方法具有简便易行,精确度较高的特点。     

Late Pleistocene Lithic Procurement and Geochemical Characterization of the Cerro Kaskio Obsidian Source in South‐western Bolivia

Primary questions regarding the foraging behaviour of the first hunter–gatherers who colonized the New World are how they found, procured and utilized high‐quality raw materials for manufacturing stone tools. In this paper, we present evidence from the late Pleistocene site of Cueva Bautista in the highlands of south‐western Bolivia, which demonstrates that a substantial portion of the recovered stone tool assemblage originated in Cerro Kaskio, a recently discovered obsidian source located 15 km south‐west of the site. In addition to describing the geological and geochronological setting, we provide the first geochemical characterization of the Cerro Kaskio source by means of instrumental neutron activation analysis and energy‐dispersive X‐ray fluorescence. Supported on the technological analysis and archaeometric sourcing of the obsidian lithics found in Cueva Bautista, we discuss the nature of the procurement strategies practised by the earliest mobile hunter–gatherers who explored and colonized the Andean highlands. We conclude that opportunistic lithic resource procurement was probably an important component of the first foraging societies that explored the highland Andes.