Non-destructive pXRF Research Articles

Selecting reproducible elements in non-destructive portable X-ray fluorescence analysis of prehistoric and early historical ceramics from Korea

The use of non-destructive portable X-ray Fluorescence (pXRF) analysis for provenance studies of ceramics requires careful evaluation of the quality of data and selection of reliably measured elements. In this study, we report pXRF data on prehistoric and early historical ceramics from South Korea and compare the results with those obtained by destructive conventional geochemical techniques to evaluate the reproducibility of pXRF-measured elemental concentrations. A total of 92 ceramic sherds from the Mumun Period (15-1C BCE), Proto-Three Kingdoms and Three Kingdoms periods (1C BCE – 7C CE), and Unified Silla Period (7C – 10C CE) were analyzed. The results show that for ceramics of the Mumun and Three Kingdoms periods, Si, K, Ti, Mn, Fe, Rb, Sr, Zr, and Ba are elements whose concentrations are reliably measured by non-destructive pXRF. However, for the Unified Silla ceramics, only Fe, Sr, and Ba showed high reproducibility, while Si, K, Ti, Rb, and Zr did not, possibly due to different surface treatments applied. It is suggested that reproducible elements vary depending on context, even in the same area. Since it is difficult to globally determine reliably meausred elements, pilot studies and the development of local protocols to select reproducible elements in given contexts are recommended prior to provenance studies.

Ancient Ceramic Casting Molds from the Southern Russian Far East: Identification of Alloy Traces via Application of Nondestructive SEM-EDS and pXRF Methods

The investigation presented in this paper is a unique assemblage of ceramic casting molds discovered at one of the sites from the Bohai period (698–926) in the territory of the southern Russian Far East. The main research aim is to recognize probable traces of metal alloys cast in ceramic molds. Nondestructive pXRF and SEM-EDS methods were used as the research instruments for detecting the expected alloys’ chemical components. As a result, the elements Pb, Sn, Cu, and As were indicated at the surfaces of the molds’ cavities with evidence of carbonization caused by the casting process. Preliminarily, two groups of alloys were distinguished: lead-bearing alloys and lead-free alloys. Our new insights are in good accordance with the results of previous investigations on chemical compositions of bronzes from the Bohai period archaeological sites of the southern Russian Far East. In particular, data on the examination of ceramic molds confirm the conclusion that various kinds of copper alloys were known and used in the bronze casting craft of the Bohai period.

Non-Destructive pXRF on Prehistoric Obsidian Artifacts from the Central Mediterranean

Volcanic obsidian was widely used in ancient times for stone tools, with its highly glassy nature making it sharper than other lithics for cutting purposes. In Europe and the Mediterranean, there are just several island sources, and a few in one inland region, all having been used since the beginning of the Neolithic period, ca. 6000 BCE. Maritime transport was necessary for access to the Italian and Greek island sources, with the distribution of artifacts over distances up to 1000 km. While elemental analyses were used for identifying specific sources starting in the 1960s, the development of non-destructive and especially portable X-ray fluorescence spectrometers has revolutionized the number of artifacts tested since 2010, allowing statistically significant numbers for potential comparisons based on variables including time period, open-water distance, visual and physical properties, and cultural contexts. One overall accomplishment is the documentation of long-distance travel routes in the Tyrrhenian and Adriatic Seas of the central Mediterranean, based on the distribution proportions and quantity of obsidian artifacts from different geological sources, apparently following a down-the-line prehistoric exchange system. The spread of Palmarola obsidian is much greater than previously thought, while in Malta, Pantelleria obsidian was specifically selected for burial accompaniments on Gozo.

Geochemical characterisation of carnelian beads from Aceramic Neolithic Cyprus using portable X-ray Fluorescence Spectrometry (pXRF)

This paper presents the results of the compositional analysis conducted on carnelian beads from Aceramic Neolithic sites on the island of Cyprus. Carnelian is a rare raw material with alleged geological sources in the broader eastern Mediterranean–western Asia region. Most of these sources remain little explored and no detailed data concerning their geochemical signatures and elemental composition are available. Carnelian, albeit an exogenous material, is found in small quantities in lithic assemblages from Cypriot sites dating to 8500–5200 Cal BCE. The paper discusses these occurrences and uses non-destructive pXRF technology to (a) attempt to identify distinct geochemical groups (i.e. exploited sources) within these assemblages, and (b) use this information to infer the role of Cyprus within the broader eastern Mediterranean social landscape and exchange networks of the Early Holocene. Our analyses suggest multiple origins for the carnelian raw material and, more significantly, demonstrate that occasionally other materials, visually indistinguishable from carnelian, were used in bead manufacture. We consider the symbolic role of these raw material choices and propose that these early island communities engaged in a system of linked values with their mainland counterparts dependent on the materials exchanged objects were made of.

Obsidian from the Bronze Age Village of San Vincenzo, Stromboli, Aeolian Islands: A Preliminary Investigation

Abstract We present the preliminary results of the ongoing investigation of the obsidian from the Bronze Age village of San Vincenzo, Stromboli, Aeolian Islands, for the purpose of providing technological and typological characterization, and also provenance of the raw material, the latter with non-destructive p-XRF. Regarding provenance, the source of the raw material is likely to be neighbouring Lipari. It was transported to Stromboli and used mostly in a highly opportunistic manner and for the production of blade(let), non-bladelike tools (mainly scrapers) and micro bladelets. The obsidian distribution around the site shows concentration in both domestic and production areas.

Origins of obsidian at the “Pompeii of the Syrian Desert:” Sourcing lithic artifacts from the Yale-French excavations at Dura-Europos

The Hellenistic, Parthian, and Roman site of Dura–Europos (or simply “Dura”), dubbed the “Pompeii of the Syrian Desert” by Yale historian and archaeologist Michael Rostovtzeff, was jointly excavated by Yale University and the French Academy of Inscriptions and Letters from 1928 to 1937. Given the outstanding preservation of art and architecture at Dura, it is not surprising that four obsidian artifacts have escaped attention, despite evidence that stone tools – including obsidian ones – continued to be used into and after the Iron Age in the Eastern Mediterranean. After more than eight decades, the character of Dura's connections to the Classical world remains a matter of debate. Pottery includes not only local ceramic wares but also North African and Aegean ones. Our nondestructive pXRF testing establish that the Dura artifacts match the three most widely used Eastern Anatolian obsidian sources: Nemrut Dağ volcano as well as the Bingöl A and B sources. If indeed obsidian arrived at Dura via long-standing mechanisms of Mesopotamian exchange, these Eastern Anatolian obsidians would be expected. Unfortunately, the artifacts' precise locations at Dura are unclear, the excavations lacked stratigraphic constraints, and Near Eastern obsidian distribution patterns have been rarely studied beyond the Early Bronze Age. Keeping in mind these limitations, our findings are most consistent with past suggestions regarding the importance of local Mesopotamian influences and resources at the site.

Destructive and nondestructive geochemical analysis of vesicular basalt from bedrock outcrops in the Salt-Gila Basin, Arizona: Evaluating the potential of nondestructive portable X-ray fluorescence spectroscopy for archaeological provenance analyses

Researchers have long been interested in tracing the movement of vesicular basalt from natural source areas to archaeological contexts in the Salt-Gila Basin of southern Arizona. However, this effort has been hampered by the lack of a reliable and practical analytical technique for characterizing the composition of individual artifacts and specimens from geological sources. This paper summarizes an assessment of the efficacy of nondestructive portable X-ray fluorescence spectrometry (pXRF) for vesicular basalt provenance analyses. Specifically, the nondestructive technique was evaluated by comparing its performance in the analysis of 100 geological samples to an independent study that utilized destructive XRF and Neutron Activation Analysis (NAA). Additionally, nondestructive pXRF was used to analyze 900 vesicular basalt samples from 18 different volcanic outcrops in the study region. The results of these analyses indicated that nondestructive pXRF is capable of generating sufficiently reliable data for select elements and also that there is considerable geochemical variability among the material source areas. Therefore, pXRF may be both a reliable and practical analytical technique for vesicular basalt provenance studies in the Salt-Gila Basin.

Eneolithic menhirs of Laconi (central Sardinia, Italy): from provenance to technological properties

A multi-technique approach was carried out to investigate the provenance and technological properties of 34 anthropomorphic menhirs from Laconi (central Sardinia, Italy) dated back to the local Copper Age (III millennium BC). After visual inspection, geological materials coming from local ignimbritic outcrops were characterized by elemental and mineralogical analyses: portable X-Ray Fluorescence (pXRF), Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES), Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) and Powder X-Ray Diffraction (PXRD). Conversely, the menhirs were studied only by visual examination and non-destructive pXRF measurements. By means of a comparison between pXRF data collected on the menhirs and the lithological outcrops, it was possible to assign the prehistoric artifacts of Laconi to local geo-sources, taking into account geochemical intra- and inter-source variabilities. pXRF was demonstrated to be a useful tool for provenance studies while mineralogical analysis resulted fundamental for the technological aspects. The latter technique pointed out the main use of hardstones, probably owing to the durability they give to the menhirs.To the best of our knowledge, this is the first archaeometric study on Sardinian menhirs and one of the few recently developed on European megaliths.

Sourcing Rapa Nui mata‘a from the collections of Bishop Museum using non-destructive pXRF

On Rapa Nui (Easter Island), four geological sources of rhyolitic obsidian were utilised to manufacture obsidian artefacts, including tanged implements known as mata‘a . In the present study, a total of 332 mata‘a from the collections of Bishop Museum were analysed using portable X-ray fluorescence (pXRF). Two analytical methods, Discriminant Function Analysis and Support Vector Machines Classification, were used to assign geographical provenance to these artefacts. These appear to be manufactured using obsidians predominantly from Orito, one of four geological sources on the island. This study demonstrates how non-destructive analyses of museum collections can contribute to our understanding of obsidian procurement and production on Rapa Nui.

Archaeological Fingerprinting and Fremont Figurines

AbstractAfter the anonymous 2011 return of a long-missing Pilling Fremont figurine, a multi-disciplinary research team conducted “fingerprint” analyses in an effort to match it to 10 mates with intact provenance. The Pilling figurines, crafted 1,000 years ago and cached in a remote sandstone niche in eastern Utah, are the most significant find of Fremont portable art ever documented because they occurred in situ and are unparalleled in detail and completeness. Most of the other 400-plus known Fremont figurines derive from secondary contexts, limiting inferences archaeologists might otherwise draw in domains ranging from Fremont exchange to inter- and intra-cultural ideology. Basketry-imprint analysis, scanning electron microscopy, and portable X-ray fluorescence suggest that the returned specimen is the original Pilling. After a 40-year absence, it is now permanently curated with the rest of the collection at the Prehistoric Museum, USU Eastern, in Price, Utah, and can contribute to research of a rare artifact class. The techniques reported can also be applied to finds of fragmentary Fremont figurines in secondary contexts to assess relationships among specimens and sites. Most broadly, the successful application of nondestructive pXRF may inspire confidence in scientists studying rare and delicate specimens traditionally profiled using destructive methods such as INAA.

Geochemical characterisation of north Asian glazed stonewares: a comparative analysis of NAA, ICP-OES and non-destructive pXRF

The analytical performance of non-destructive portable X-ray fluorescence (pXRF) is compared with that of Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) and Neutron Activation Analysis (NAA) for the elemental characterisation of a group of glazed stonewares from North-East Asia. As a non-destructive technique pXRF is potentially well suited to the elemental analysis of high value archaeological and museum collections but has yet to be critically evaluated for the analysis of archaeological stonewares. In this study we use multivariate evaluation to compare results from non-destructive pXRF in relation to ICP-OES and NAA analysis for the same group of samples. We conclude that, although pXRF is comparatively limited to a small number of major, minor and trace elements, these are sufficient to identify the same compositional groups as high dimensional ICP-OES and NAA datasets for this assemblage.

Non-destructive pXRF of mafic stone tools

Archaeological use of non-destructive pXRF has been most systematically applied to the classification and provenancing of volcanic glass (obsidian) artefacts. Comparable work has yet to be developed for non-vitreous artefacts. We report results of pXRF analysis for a sample of grey to black (mafic) aboriginal hatchets from Sydney and adjacent coastal regions to the north and south. The study shows both broad and detailed classification is achievable depending on rock type and degree of elemental depletion or enrichment of the samples. PXRF analysis reveals not only distinct patterns of resource use between the three regions of this study but also enables a high degree of geographic resolution in the case of the basalt artefacts of our sample. We conclude that non-destructive pXRF is effective for reliable characterisation of non-vitreous stone artefacts that have a sufficiently complex and enriched compositional signature (i.e., unaltered basalts); with ∼50% of the basalt hatchets in our sample matched with spatially and geologically specific sources.

Non-destructive PXRF analysis of museum-curated obsidian from the Near East

Non-destructive pXRF has the potential to expand sample populations of archaeological provenancing studies by facilitating access to museum collections of artefacts. In this study, we use museum-curated obsidian for the sites of Tell Brak, Mersin-Yümüktepe and Tell Arpachiyah and geological obsidian samples from central Turkey to demonstrate that non-destructive pXRF is comparable to other techniques in differentiating between Near Eastern obsidian sources. Secondly, we use multivariate analysis to evaluate whether non-destructive pXRF is sufficiently accurate and precise to enable comparison with legacy datasets from previous analysis using PIXE and ICP-MS. Multivariate analyses show that instrumental offsets between the results from pXRF and other analytic techniques are less than source-to-source variation typical for most Anatolian obsidian outcrops and pXRF-identified geochemical groups are directly comparable to legacy datasets. Non-destructive pXRF analysis indicates that during the Chalcolithic, East Göllü dağ and Nenezi dağ continued to be the major sources of obsidian to communities in central Anatolia and the Bingöl range and mountains surrounding Lake Van supplied sites east of the Levant. Variations in the analysed assemblages suggest a number of obsidian exchange networks existed during this period.