Non‐Destructive Survey of Early Roman Copper‐Alloy Brooches using Portable X‐ray Fluorescence Spectrometry

This paper argues that portable X‐ray fluorescence spectrometry (pXRF) is a suitable elemental measurement technique to study the production of copper‐alloy artefacts. However, rather than try to imitate the accuracy and precision of laboratory techniques, it is more beneficial to deploy it in a survey role, one that attempts to model chronological and geographical changes within large quantities of artefacts. To achieve this, it was investigated to what extent corrosion and the issues surrounding surface measurements affect the potential of this type of research. Analyses on early Roman period brooches gathered in the Nijmegen region of the Netherlands were subsequently compared with published data.     

Geochemical Methods for Sourcing Lava Paving Stones from the Roman Roads of Central Italy

This paper documents the results of in situ analysis of 306 lava paving stones and 74 possible source rocks using pXRF. Data were collected from sites both in the city of Rome—on major roads beyond the city (including the Viae Flaminia, Cassia, Clodia, Praenestina and Appia)—and in the city of Ostia. Comparison of the pXRF data with lava compositional data from the geological literature allows broad identification of possible sources. The results point to quite distinctive patterns of exploitation for the city of Rome and Ostia, utilizing the Alban Hills lava flows, and the roads of the middle Tiber Valley, drawing on lava flows associated with the Vico and Sabatini volcanoes. The results show the potential of pXRF to produce data to elucidate the exploitation of lava flows for paving the Roman roads.     

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.     

Parameters in the use of pXRF for archaeological site prospection: a case study at the Reaume Fort Site,Central Minnesota

Field portable/hand-held x-ray fluorescence (pXRF) analyzers have been characterized as potentially useful for archaeological site prospection, but little has been published on the parameters of their use in this manner. The purpose of this study is to explore whether the variability of surface geochemistry as characterized with a pXRF analyzer corresponds with subsurface archaeological features at a site subsequently excavated, and what conditions influence the success of this endeavor, including feature depths, soil moisture, and sample processing. A 520 m² within-site area was systematically surveyed on a 2 m interval, within which several types of archaeological features were excavated (chimney bases, wall trenches, and a bonebed of faunal waste), taking readings in situ and collecting samples for ex situ testing (undried, dried but not powdered, and dried/powdered). The four different tests of each grid location, analyzed through univariate and multivariate tests, showed that the pXRF surface data does correspond with some types of subsurface features when those features are very shallow (within 5 cm of surface level) and are associated with clayey fills. Further, the data from the subsurface samples provides excellent distinction of feature fills from other sediments, regardless of sample preparation. In situ surface survey with pXRF analyzers may however be adequate for sites with a thorough baseline geochemical database.     

祥云地区出土铜器pXRF成分分析——昆明夷铜器工艺类型初探

为探究滇西地区青铜文化及相关铜器的制作技术,本研究使用便携式X射线荧光光谱(p XRF)对滇西祥云县大波那墓地、检村石棺墓和红土坡古墓群出土357件铜器进行了成分分析。结果表明,p XRF可在无损、原位的情况下,基本做到铜器合金成分的定量分析。铜器材质均以红铜和锡青铜为主,铅锡青铜和砷铜居少量。三处墓地铜器Sn、Pb配比模式高度一致。铜矛、铜剑等兵器中出现少量高锡青铜。这些现象反映出祥云地区各时期铜器的制作工艺高度一致,可称之为昆明夷铜器工艺类型。大波那墓地铜器基本不含铁,其余墓地存在较多高铁铜器,大波那地区的先民应该采用了不同的冶炼技术。砷铜全部出自红土坡古墓群,初步推测晚期墓葬出现的砷铜乃至砷铜工艺很可能是沿着"半月形文化传播带"由西北地区传入祥云地区的。     

Determining the Provenance of Cayo Pottery from Grenada,Lesser Antilles,Using Portable X‐Ray Fluorescence Spectrometry

Portable XRF was used to analyse the chemical composition of 52 indigenous Cayo ceramics from excavations and from private collections on Grenada, Lesser Antilles. Initially, a comparative baseline of data representing three different islands (Grenada, St Vincent and Trinidad) was created by analysing with pXRF ceramic material that had previously been analysed both chemically and petrographically. The field data, when compared to the laboratory baseline data, indicated that the majority of the ceramics were made with clay local to Grenada. Four samples were potentially made with clay from another, as yet unidentified, source.     

Investigating ancient technology and ceramic composition at Al-Khidr site (Failaka Island,Kuwait): Geochemical analyses of Bronze Age pottery by pXRF and thin-section petrographic analyses

Pottery assemblages from the site of Al-Khidr on Failaka Island, Kuwait, were analysed in order to reconstruct the chemical composition of Bronze Age wares and to build a mineralogical database of Bronze Age pottery dated from Failaka Periods 1–3B (2000–1650 BCE). A total of 145 ceramic sherds from Al-Khidr, as well as reference groups, were analysed by non-destructive portable X-ray fluorescence (pXRF) spectrometry. Preliminarily petrographic thin-section analysis was applied to four samples to reconstruct possible clay paste recipes and to identify raw materials. The results indicate that geochemical analyses can successfully distinguish subgroups within a typological category of ceramic assemblages. The results identified two subgroups within the Al-Khidr typological category: the Dilmun Barbar tradition and the Mesopotamian tradition. Future comparative compositional studies can be conducted to explore other aspects of craft specialisation, such as ceramic technological choices and possibly the influence of sociopolitical units.     

Handheld Portable X‐Ray Fluorescence of Aegean Obsidians

We tested two portable XRF instruments (with different technologies) using two correction schemes (‘soils’ and ‘mining’) with both factory‐set calibrations and linear regression calibrations derived from published data. All four Aegean obsidian sources, including Sta Nychia and Dhemenegaki on Melos, were distinguished in each case. The newer instrument provided better ‘off‐the‐shelf’ accuracy than the older instrument, but calibrations negated these differences. The newer model also offered superior precision for most elements, despite measuring specimens for shorter times. Both correction schemes for the newer instrument resulted in almost equal precision, meaning that either may be used for successful Aegean obsidian sourcing.     

Trade,tribute, and neutron activation: The colonial political economy of Xaltocan,Mexico

In Trade, Tribute, and Transportation, Ross Hassig argues that indigenous towns in the northern Basin of Mexico during the colonial period were largely self-sufficient. They traded with Mexico City mostly in elite goods, but for the most part they produced for their own subsistence or traded with nearby towns. Chemical characterization by instrumental neutron activation analysis (INAA) and portable X-ray fluorescence (pXRF) of ceramics and obsidian from post-conquest contexts in Xaltocan, a site in the northern Basin of Mexico, reveals that Hassig’s model is partly correct for describing Xaltocan. The town focused on trade with nearby towns and it produced some ceramics for local consumption. However, Xaltocan was hardly isolated and self-sufficient in the post-conquest period. Instead, the data suggest that the people of Xaltocan also obtained ceramics and obsidian from a greater variety of sources than under Aztec domination. Rather than being an isolated rural site, Xaltocan either increased its external connections and number of trading partners after the Spanish conquest, or it managed to obtain a greater variety of products than before through a bustling market system.     

Portable XRF analysis of zoomorphic figurines, “tokens,” and sling bullets from Chogha Gavaneh,Iran

This study examines small finds from the site of Chogha Gavaneh, Iran, including zoomorphic clay figurines, geometric-shaped objects (often referred to as “tokens”), and sling bullets in order to investigate the possible social and economic functions of these artifacts. While Chogha Gavaneh has been occupied from the Pre-Pottery Neolithic A (PPNA) (ca. 9000 B.C.E) period to the present, we focus on 87 small finds from the Early Chalcolithic period (ca. 5000–4000 B.C.E.). We explore how portable X-ray fluorescence spectrometry (pXRF) provides a new line of data with which to test the conventional wisdom about the uses of these small finds. Our findings suggest that local production is unlikely to account for the diversity in the elemental composition of the small finds. We argue that this supports claims that Neolithic and Chalcolithic people exchanged “tokens”. The presence of non-local zoomorphic figurines also raises interesting questions regarding their possible role in past societies.