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In North America, it is critical for archaeologists to differentiate between American native copper and European smelted copper. Indeed, native copper, a rather pure metal, was not smelted in this region, unlike European copper objects that later became available to Native Americans during trading encounters. Until now, archaeologists with a low budget wishing to use a totally non-invasive approach have relied on visual inspection and archaeological contextualization of the objects to distinguish American native copper from European smelted copper. This paper assesses the reliability of portable x-ray fluorescence (pXRF) as a fast, effective, and completely non-destructive method of differentiating the two types of copper present at Northern American sites through a case study of two sites from the Upper Great Lakes region. To establish group attribution with pXRF, results obtained on a subset of objects with LA-ICP-MS are used. Results indicate that for the specific purpose of differentiation between native and European copper types, pXRF can be used reliably, without sample preparation and despite surface corrosion. Therefore, pXRF provides a non-destructive way to clarify European trade item distribution and continuity of native copper object use among Indigenous peoples of North America during the colonial period. [ABSTRACT FROM AUTHOR]

Evidence supporting the hypothesis that Neanderthals developed cultural adaptations comparable to those associated with the Upper Palaeolithic is controversial, and come from a handful of sites, mainly attributed to the Châtelperronian. Pigments play a growing role in this debate. We present a critical review of available information on Châtelperronian pigment use, and submit pigment lumps from three Châtelperronian sites, Roc-de-Combe (Lot), Le Basté, and Bidart (Pyrénées Atlantiques) to a microscopic, elemental and mineralogical analysis using multifocus optical microscopy, SEM-EDS, XRF, Raman, and μXRD techniques. The thirty-nine pigment lumps from Roc-de-Combe consist of a great variety of red and black iron and manganese oxide rich rocks, probably collected at close and relatively distant sources. A third of the pieces from Roc-de-Combe and one piece from Bidart and Le Basté bear percussion marks and facets produced by grinding. Our results demonstrate that a consistent use of pigments, interpreted as reflecting site function, occurs at sites located in the South-western area of the known distribution of the Châtelperronian. Considering that this area is distant from the location of the earliest Proto-Aurignacian and Early Aurignacian sites from Germany and Austria, and that available radiocarbon dating indicate a chronological anteriority of Roc-de-Combe Châtelperronian, we argue that the hypothesis that Châtelperronian pigment use results from Neanderthal ‘acculturation’ is improbable. [ABSTRACT FROM AUTHOR]

Abstract: 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. [Copyright &y& Elsevier]

Abstract: The response from Speakman and Shackley to my paper highlights a number of important issues currently facing archaeological sourcing research. Many of these issues, however, have little to do with HHpXRF itself and more to do with an artificial crisis triggered by specialists'' concerns about a hitherto restricted technique becoming available to a wider community. Despite their mantra of “validity and reliability,” Speakman and Shackley erroneously equate these two concepts with the accuracy of an instrument''s measurements. Additionally, they mischaracterise a self-contained test, conducted with specific parameters (i.e., “off-the-shelf” operation), as an endeavour to facilitate or endorse poor-quality data. Paradoxically, their disparagement of experimental internal consistency as “silliness” is incongruous with their own data. Furthermore, a discussion focused on handheld instruments is obfuscated by their inclusion of desktop instruments that are “portable” only in the sense of luggable to an electrical outlet in a laboratory context. Most troubling is that they envision themselves as the arbiters of science vs. “playing scientist.” Contrary to their claims, HHpXRF proliferation will improve reproducibility and archaeological results. [Copyright &y& Elsevier]

Provenance studies of archaeological ceramics based on their elemental composition illuminate the production and distribution of pottery vessels and, in the case of transport containers, of the commodities that they contained. A basic assumption is that the elemental composition of ceramics from a specific workshop or production area can be distinguished from other production groups, mainly because of the use of geochemically different clays, either singly or in combination. In some cases, however, the compositional differences between production groups are quite small. Thus, laboratory methods with high performance, in terms of precision and accuracy, such as neutron activation analysis (NAA) or wavelength dispersive X-ray fluorescence (WDXRF), are often preferred for analyzing archaeological ceramics, especially for effective comparison with reference groups and published data from other studies. Handheld portable energy dispersive XRF systems (pXRF), although increasingly used during recent years, offer lesser analytical performance, which may obscure compositional differences and currently do not offer the same potential for comparison to known reference groups. However, due to their potential for fast and non-invasive measurements, considerably larger numbers of samples can be analysed by pXRF, offering an array of advantages. We argue that pXRF offers the opportunity for an initial analytical survey of a large ceramic assemblage as the basis for efficient sample selection for laboratory analysis, covering a large number of samples and avoiding for the generation of redundant measurements. We present the application of such a stepped analytical approach to a well-studied assemblage of amphorae of the Hellenistic period at Nea Paphos, Cyprus. The analysis of 287 amphora fragments by pXRF, the grouping of that data to select samples for further analysis of 97 individuals by NAA, and the comparison of the grouping of data from both chemical techniques is presented. This leads not only to archaeological insights on the production and circulation of amphorae, but tests an innovative methodology that offers the chance to maximize and extend the application of geochemical techniques of high accuracy and precision on an assemblage-wide scale. • pXRF as survey tool for sample selection. • assessment of analytical performance of pXRF. • Comparison of pXRF and NAA for discriminating archaeological ceramics. • Study of amphorae from a marketplace. • Assignment of compositional patterns to reference patterns. [ABSTRACT FROM AUTHOR]