During the Middle Horizon (AD 600–1000), obsidian was transported in greater quantities and distances than ever before identified in the Andes, in part by the expansionary Wari state. Two of the three major obsidian sources used in the south-central Andes are located in the modern department of Arequipa, Peru. Arequipa was a region of intense Wari influence and intrusive presence; however, little is known about regional obsidian use. Portable X-ray fluorescence (pXRF) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) were used to analyze 383 obsidian artifacts recovered from 10 archaeological sites in Arequipa. Results highlight diachronic and spatial patterning related to obsidian procurement strategies, state versus bottom-up exchange networks, and local participation within the Wari realm. A wide variety of geological obsidian sources, including nonlocal obsidians originating from Wari's Ayacucho heartland, were used. By the late Middle Horizon, the Wari had consolidated regional resources with the sole use of Alca-1 and Alca-4 bedrock obsidians, the largest-sized and highest-quality sources in the area. We assess related models of obsidian procurement and exchange related to state political economy, long-distance caravan activity, and the role of local ceremonial/waystation centers that facilitated the flow of ideas, goods, and people across Arequipa.

This is the first comprehensive publication of the Knaresborough 1864 hoard of copper-alloy vessels and tools. A consideration of the circumstances of the hoard’s discovery, along with a biographical account of Thomas Gott (the man who deposited the hoard in the Yorkshire Museum), for the first time enables a case to be made for a findspot. A consideration of the vessels and other objects establishes the hoard as one of the most unusual assemblages of its kind from late Roman Britain. pXRF analysis of the vessels sheds light on their composition. Finally, a discussion of the hoard places it within the international context of late Roman deposition practices.

Se caracterizó mediante análisis de fluorescencia de rayos X portable (pXRF) un conjunto de obsidianas (n = 142) del sitio San Gregorio Atlapulco, en Xochimilco, Ciudad de México, procedentes de los niveles precerámicos, a través del análisis de 10 elementos químicos (Mn, Fe, Zn, Ga, Th, Rb, Sr, Y, Zr, Nb); esto nos permitió conocer la composición elemental de cada uno de los artefactos para posteriormente efectuar comparaciones con obsidianas de yacimientos sistemáticamente muestreados. Los resultados indican una amplia dominancia de la subfuente de Soltepec en Otumba (94%), además de otras dos fuentes menores que incluyen a Pachuca. Lo anterior tiene implicaciones importantes sobre los procesos de interacción de los grupos precerámicos del Holoceno medio en la Cuenca de México, y permite vislumbrar la importancia de la obsidiana de Otumba para el período denominado Arcaico, y la formación de redes de intercambio tempranas que continuarían durante el período Formativo.

Often understudied by archaeologists, ground stone tools (GST) were ubiquitous in the ancient Maya world. Their applications ranged from household tools to ceremonial equipment and beyond. Little attention has been focused on chemically sourcing the raw stone material used in GST production, largely because these tools were fashioned out of igneous or sedimentary rock, which can present characterization challenges. And, although portable X-ray fluorescence (pXRF) has been applied widely to source obsidian, the utility of pXRF for geochemically sourcing other kinds of stone remains underexplored. We present a small-scale application of pXRF for determining granite provenance within a section of the Middle Belize Valley in Belize, Central America. Belize is an ideal location to test chemical sourcing studies of granite because there are only three tightly restricted and chemically distinct sources of granite in the country, from which the overwhelming majority of granite for ancient tool production derived. The method described here demonstrates that successful and accurate geological characterizations can be made on granite GST. This cutting-edge sourcing technique has the potential to be more widely applied in other regions to reveal deeper connections between the sources of GST production and sites of consumption across space and through time.

Portable X-ray fluorescence (pXRF) spectroscopy is commonly used for testing toxic levels of heavy metals in modern industrial waste sites, and it has seen growing applicability in the context of archaeological survey and soils. In this study, we present the results of our pXRF analysis of surface soils at a historic silver refinery located near Puno, Peru, in the western Lake Titicaca Basin. The results of our analysis identified hazardous levels of antimony (Sb), arsenic (As), mercury (Hg), and lead (Pb) in excavation soils, necessitating the relocation of planned excavation units and the use of personal protective equipment. This study highlights the advantages of rapid, in situ pXRF analysis of surface soils in contaminated industrial archaeology sites to assess potential harm to human health.

Reconstructing routes of ancient long-distance voyaging, long a topic of speculation, has become possible thanks to advances in the geochemical sourcing of archaeological artifacts. Of particular interest are islands classified as Polynesian Outliers, where people speak Polynesian languages and have distinctly Polynesian cultural traits, but are located within the Melanesian or Micronesian cultural areas. While the classification of these groups as Polynesian is not in dispute, the material evidence for the movement between Polynesia and the Polynesian Outliers is exceedingly rare, unconfirmed, and in most cases, nonexistent. We report on the first comprehensive sourcing (using a portable X-ray fluorescence spectrometer) of obsidian and volcanic glass artifacts recovered from excavations on the Polynesian Outlier island of Tikopia. We find evidence for: (1) initial settlement followed by continued voyages between Tikopia and an island Melanesian homeland; (2) long-distance voyaging becoming much less frequent and continuing to decline; and (3) later voyaging from Polynesia marked by imports of volcanic glass from Tonga beginning at 765 cal yr BP (±54 yr). Later long-distance voyages from Polynesia were surprisingly rare, given the strong cultural and linguistic influences of Polynesia, and we suggest, may indicate that Tikopia was targeted by Tongans for political expansion.

The glass bead trade in southern Africa provides important evidence of interregional contact during the early modern period. Compositional analysis of a large assemblage of imported glass beads from the sixteenth- to seventeenth-century AD trading site of Baranda in northern Zimbabwe reveals a south Asian origin of the majority of the beads. Combining stratigraphic data and morphological analysis with innovative compositional XRF and Raman spectroscopy approaches, the research was able to assign the Baranda beads accurately to their correct chronological range. This coincides with the period of Portuguese dominance of Indian Ocean trade.

Over 40 years of archaeological investigations along the south coast of Papua New Guinea has identified a rapid succession of cultural changes during the late Holocene. The so-called ‘Papuan Hiccup’ (c. 1200–800 cal bp) is a poorly understood period of socio-economic upheaval along the coast, identified mainly from changes in archaeological ceramic styles and settlement patterns. During this period, the region-wide Early Papuan Pottery (EPP) tradition diverges into separate, localised ceramic sequences that have generic associations with local ethnographic wares. A correspondence between the timing of the Papuan Hiccup and a period of peak El Niño-Southern Oscillation (ENSO) activity implies a link between cultural and climate change. This paper explores this relationship further by examining changes in interaction networks along the south coast of Papua New Guinea, specifically focusing on chert artefacts. Chemical characterisation (portable X-Ray Fluorescence; pXRF) and technological analysis are used to map changes in lithic technology over time, including access to raw materials and technological organisation, at the site of Taurama, a prehistoric coastal village site that was occupied both prior to and after the Papuan Hiccup. Although the sample sizes are small and the interpretations necessarily circumscribed, it is argued that changes in the number of chert sources being exploited and in the intensity of core reduction at Taurama may be related to climate change in the region.

An unexpected new source of tin was recently located at Hisarcık, in the foothills of the Mount Erciyes volcano in the Kayseri Plain, close to the Bronze Age town of Kültepe, ancient Kanesh and home to a colony of Assyrian traders. Volcanoes in Turkey have always been associated with obsidian sources but were not known to be a major source of heavy metals, much less tin. X-ray fluorescence analyses of the Hisarcık ores revealed the presence of minerals suitable for the production of complex copper alloys, and sufficient tin and arsenic content to produce tin-bronze. These findings revise our understanding of bronze production in Anatolia in the third millennium BC and demand a re-evaluation of Assyrian trade routes and the position of the Early Bronze Age societies of Anatolia within that network.