Characterised by the extensive use of obsidian, a blade-based tool inventory and microblade technology, the late Upper Palaeolithic lithic assemblages of the Changbaishan Mountains are associated with the increasingly cold climatic conditions of Marine Isotope Stage 2, yet most remain poorly dated. Here, the authors present new radiocarbon dates associated with evolving blade and microblade toolkits at Helong Dadong, north-east China. At 27 300–24 100 BP, the lower cultural layers contain some of the earliest microblade technology in north-east Asia and highlight the importance of the Changbaishan Mountains in understanding changing hunter-gatherer lifeways in this region during MIS 2.

The typological, technological, and use-wear analyses of obsidian artifacts from Terminal Classic Pook's Hill (AD 830–950+) provide opportunities to better reconstruct socioeconomic activities in this plazuela group, including long-distance trade, tool production, subsistence practices, domestic tasks, and the organization of craft production. Based on visual sourcing, most of the obsidian originated from highland Guatemala, specifically El Chayal. The majority of obsidian artifacts were prismatic blades, although both casual and bipolar reduction of blade cores and the recycling of blades from earlier occupations occurred at the site. Use-wear analysis reveals that obsidian tools were mainly used for subsistence and domestic household activities; however, the concentrations of tools with specific wear patterns (bone, ceramic, plants, and shell) at some locations in the plazuela provide evidence for local craft production among the population. Further support for craft production is provided by comparable use-wear on chert/chalcedony tools from these same locations. The products of low-level craft production were used within Pook's Hill itself and may have been distributed to neighboring communities within the Roaring Creek and Upper Belize River Valleys. Despite the sociopolitical and socioeconomic disruptions to lifeways that accompanied the Terminal Classic period, the Pook's Hill Maya seem to have experienced minimal upheaval in their daily lives and continued local low-level craft production. However, one important change in the Terminal Classic appears to be the increased difficulty in obtaining obsidian at Pook's Hill and the growing need for tool recycling and raw material conservation.

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.

We describe an analysis of the flaked stone tools recovered from households in the Postclassic central Mexican city of Calixtlahuaca (a.d. 1130–1530). Most artifacts are obsidian and represent the blade-core technology, but biface and bipolar artifacts are also represented. Even though household residents were involved in limited biface and bipolar reduction, it appears that the city did not have any resident blade producers. This finding is at odds with the views of many archaeologists, who tend to associate craft production with the emergence of complex Mesoamerican urban centers. We examine the technologies from temporally distinct Calixtlahuacan household assemblages. We discuss why the quantity and quality artifacts associated with blade production are not consistent with resident blade making in the city. Finally, we examine four models for blade provisioning: (1) whole-blade trade, (2) processed-blade trade, (3) long-distance itinerant craftsmen, and (4) local, hinterland-based craftsmen. Evaluating how the Calixtlahuacans got their flaked stone tools has important implications for the comparative understanding of the organization and scale of economic provisioning systems in Postclassic central Mexico. This analysis supports new inferences about the nature of commercial networks that supplied the Toluca Valley prior to the arrival of the Spanish in the sixteenth century.

Experimental alteration of obsidian with HCl solution was performed to elucidate dissolution mechanism and formation process of clay minerals in acid solution. Reactions were carried out using 0.1, 0.5, and 4.0 g of obsidian to 100 ml of 0.01 N HCl solution at 150° and 200°C for 1 to 60 days. The reaction products were examined by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy (TEM), and energy dispersive X-ray analysis. The surface composition of obsidian before and after alteration was investigated by X-ray photoelectron spectroscopy (XPS). TEM showed that boehmite precipitated at early stage and spherical kaolinite appeared subsequently by 200°C reactions. However, spherical halloysite occurred predominantly with small amounts of allophane, boehmite, and kaolinite by 150°C reaction in which formation process of the halloysite from allophane passing through an intermediate phase of small size rounded aggregate that consists of fine particles of allophane was observed. A boehmite exhibiting hexagonal platy habit with higher degree of crystallinity was formed by 200°C reaction as a stable phase in solution containing lower Si concentration at which the solution composition coincides with the stability field of boehmite on activity diagram for the system Na2O-Al2O3-SiO2-H2O. The fibrous boehmite having lower crystallinity appeared with increasing Si concentration, considered as a metastable phase in the stability field of kaolinite. XPS indicated that dissolution of obsidian in acid solution proceeded initially by cation exchange between Na ions and hydronium ions in solution and subsequently by preferential release of Al ions relative to Si from the Na depleted surface.

Experimental alteration of obsidian was performed in 0.001 to 0.5 N NaOH and KOH solutions at 150 and 200 °C for 1 to 30 d. The products were examined by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive X-ray analysis (EDX). Changes in chemical composition and pH value of solutions during the reactions were also measured. As the pH of reacting solutions was increased, smectite, phillipsite and rhodesite crystallized progressively in NaOH solutions, while smectite, merlinoite and sanidine grew successively in KOH solutions. In addition, a small amount of less-soluble, poorly ordered boehmite was present as products of all the experiments. Smectite mainly appeared at slightly high pH, Si/Al and Na/K conditions, whereas rhodesite should be produced in extremely high pH, Na/K and Si/Al conditions. Sanidine was also formed in conditions of very high pH and Si/Al and very low Na/K. In intermediate conditions of pH and Si/Al, crystallization of phillipsite was stimulated in solutions of Na/K > 10, while formation of merlinoite was favored in conditions of Na/K < 1.

Experimental alteration of obsidian in distilled-deionized water at 150°, 175°, 200°, and 225°C was studied. The alteration products were examined by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy (TEM), and energy dispersive X-ray analysis (EDX) to evaluate the formation process of clay minerals. The surface composition of obsidian before and after alteration was examined by X-ray photoelectron spectroscopy (XPS), and concentrations of released elements in solution were measured to elucidate alteration and dissolution processes. TEM clearly showed that allophane appeared as the first reaction product in each experiment. With increasing reaction length, noncrystalline straight fibrous material was formed in the aggregates of allophane particles as a metastable transitional phase, and tended to form curled or wavy bundles of fibers with longer reaction. The non-crystalline fibers were transformed into highly curled smectite exhibiting small circular forms less than 1.0 µm in diameter as reaction progressed. EDX confirmed that the smectite consisted mainly of Si, Al, and small amounts of Ca, K, and Fe. XPS revealed the formation of a dealkalized leached layer on the surface of obsidian during the reaction. The concentration of released elements suggested that nonstoichiometric dissolution proceeded during the reaction.

We present the first geochemical data of archaeological obsidian for Isla Victoria, Nahuel Huapi National Park in Patagonia. XRF analyses were performed on 15 samples of obsidian-like rocks from the Puerto Tranquilo 1 site. Only five of the artifacts—all of which come from upper levels of the site—correspond to obsidian as a raw material. The provenance analysis indicates the use of obsidian sources located in the Andean Forest area of southern Neuquen Province. Based on these preliminary results, we propose a north–south circulation axis for this raw material. These geographic results are discussed in relation to the information available regionally.

Este trabajo busca conocer las estrategias tecnológicas, los rangos de acción y la conectividad en las estrategias humanas de ambientes marginales. Se discute, para el caso del sur de Mendoza, el modelo clásico de trashumancia cazadora recolectora entre tierras bajas y altas. El estudio se centra específicamente en El Payén y en el uso de la obsidiana andina Laguna del Maule. En El Payén, esta obsidiana ocupa el primer lugar entre las variedades conocidas y su uso se vinculó a circuitos de movilidad estacional que involucraban tierras bajas y altas. La obsidiana Laguna del Maule posee dos subtipos geoquímicos, el Subtipo 1 registrado en cordillera, y el Subtipo 2 localizado en depósitos fluviales distales. En este trabajo modelamos las estrategias de interacción de tierras altas con tierras bajas, enfocándonos en modelos propuestos para La Payunia, que ponen énfasis en la tecnología lítica y se articulan con análisis geoquímicos y geoarqueológicos. Los resultados sostienen que las poblaciones de El Payén obtenían este recurso mediante distintas estrategias tecnológicas: un aprovisionamiento serial del Subtipo 2, con circuitos de movilidad centrados en tierras bajas; diferente al Subtipo 1 de aprovisionamiento cíclico, que habría involucrado la interacción entre tierras altas y tierras bajas.

The Andes offers a particularly effective focus for an archaeology of mobility because their extreme topography compresses enormous vertical resource diversity across short horizontal distances. In this article, the authors combine findings from two large-scale archaeological studies of adjacent watersheds—the Nasca-Palpa Project and One River Project—to provide the necessary context in which to explore changing mobilities from the Archaic Period to the Inca Empire, and from the Pacific coast to the high Andes. Analyses of obsidian lithics and stable isotopes in human hair are used to argue that changing patterns of mobility offer a new way of defining the ‘Horizons’ that have long dominated concepts of periodisation here.

Excavations conducted by Beloit College in 1958 and 1960 identified the site of La Magdalena in the Bajío of Mexico. Investigators have since highlighted three primary phases of occupation at La Magdalena, two of which were proposed to have been culturally influenced by Teotihuacan or Tula. Modern research in the Bajío mostly diverges from those postulations of distant connections, supplanting them with local patterns that hold much more explanatory power. Archaeometric studies are pivotal in this regard but have thus far been infrequently used. This research analyzes the obsidian assemblage from La Magdalena and finds a nearly ubiquitous utilization of a local obsidian source known as Ojo Zarco. These findings merit a reevaluation of obsidian in the eastern Bajío and argue for more archaeometric studies that elucidate local procurement patterns.

Economic directness is a new model of socioeconomic organization for the Paracas culture (800–200 BC) in southern Peru, with wider implications for economic theory of the prehispanic Andean past. Using an archaeoeconomic approach to analyze settlement patterns, obsidian artifacts, malacological material, and camelid skeletal remains, this study reconstructs the Paracas economy by using primary archaeological data from the northern Nasca Drainage. Its results force reconsideration of existing socioeconomic models for the ancient Andes such as verticality, circuit mobility, llama caravan mobility, transhumance, and market concepts. Whereas components typical of these models are often absent in the case of the Paracas economy, our new proposal of economic directness integrates their relevant aspects. Economic directness is defined essentially by direct access to important resources from diverse ecological tiers, direct and down-the-line exchanges, reduced transaction costs, llama caravan transport, unbalanced commodity flows across the western Andes, and forces of supply and demand with major consumption on the coast. These features formed under conditions of population growth, generating a continuous and dense settlement pattern from the Pacific coast to the highland puna zone.

Se presentan los resultados del análisis químico de artefactos de obsidiana del sitio Villa JMC-1 Labranza, cuenca media del Río Cautín, valles centrales del centro sur de Chile, datado aproximadamente 1000 años aP (período Alfarero temprano). Se postula que la interpretación sobre la representación de grupos químicos de obsidiana en sitios arqueológicos del área centro sur de Chile se encuentra sesgada por muestreo y limitaciones de las técnicas analíticas. Eso implicó una escasa visibilidad de grupos químicos orientales en el sector centro sur chileno que fue interpretado como evidencia del carácter limitante de la cordillera de los Andes, en disonancia con otras evidencias. La ampliación de la muestra y el uso de técnicas no destructivas sobre el total de la colección del sitio permitieron reconocer que tres de los cinco artefactos de obsidiana provienen de dos grupos químicos del sector oriental cordillerano. Algunos aspectos tecnológicos de las propiedades de las materias primas y sus modificaciones superficiales sugieren la explotación y aprovisionamiento selectivo de variedades cromáticas que posiblemente requirieron el acceso a fuentes primarias. Finalmente, se amplía la distribución espacial del grupo químico CP-LL1 y al mismo tiempo se describe su primer registro para la República de Chile.

The province of Van in north-eastern Turkey served as a land bridge between Africa and Eurasia during the Palaeolithic. The region is of particular relevance for understanding the movement of hominins between these continents. This study concerns the lithic remains from a locality at Gürgürbaba Hill, named Locality 010, north of the village of Ulupamir (Erciş district). Locality 010 was dated to 311±32 kya by terrestrial cosmogenic nuclides method, which coincides with Marine Isotope Stage 9 (MIS 9), a Middle Pleistocene interglacial period. The assemblage from this site is attributed to the Late Acheulean and resembles that of the southern Caucasus. This similarity indicates that the artefacts from Locality 010 were probably produced by late Lower Palaeolithic technology in a broad sense. These findings suggest local adaptations of late Middle Pleistocene hominins to high plateau environments.

To describe the structure of production and the organization of exchange of obsidian chipped stone during the Middle Postclassic period (AD 1200–1350) in south-central Veracruz, Mexico, I analyzed 65 residential inventories from the center of Sauce and its hinterland. Previous research on obsidian production found a spatial association with Sauce, which could support the political administration of exchange, or alternatively, identify market exchange nearby. I argue that reliance on spatially based models alone for identifying exchange mechanisms is not advisable because of potential equifinality, in which different forms of exchange appear alike. Local obsidian artifacts have additional interpretive complications: they come from a single geological source, there was universal access to them, and they were employed in potentially specialized activities. I used the articulation of production combined with spatial distribution and residential contextual information to distinguish between redistribution and market exchange. Results indicate that market exchange is the main mechanism. The largest concentrations of primary production indicators and the highest quantities of blade segments were found near the Sauce center, which suggest that political elites at Sauce encouraged market exchange, although they did not direct it to the extent that they were controlling significant amounts of obsidian.

The obsidian mirror associated with the Elizabethan polymath and magus John Dee (1527–1608/1609) has been an object of fascination for centuries. The mirror, however, has a deeper history as an Aztec artefact brought to Europe soon after the Spanish conquest. The authors present the results of new geochemical analysis, and explore its history and changing cultural context to provide insights into its meaning during a period in which entirely new world views were emerging. The biography of the mirror demonstrates how a complex cultural history underpins an iconic object. The study highlights the value of new compositional analyses of museum objects for the reinterpretation of historically significant material culture.

The connection between people in the prehispanic U.S. Southwest / Northwest Mexico (SW/NW) and Mesoamerica is one of the most debated research topics in American archaeology. SW/NW groups used objects from Mesoamerica, but did they also trade for obsidian? Archaeologists have yet to find Mesoamerican obsidian from confirmed prehispanic SW/NW contexts, but here we discuss four green obsidian prismatic blades from New Mexico and Arizona. Using EDXRF spectrometry, we demonstrate that the blades are from the Pachuca source in Mesoamerica. The blades were found at four sites that the Spanish and their Mexican Indian allies used or potentially visited beginning in AD 1540. Using lithic technological organization and historical narratives, we assess the credibility of the different hypothesized models of prehispanic SW/NW-Mesoamerican interaction and obsidian use by the Mexican Indian allies. We suggest that green Pachuca blades would have been traded into the SW/NW if interaction with Mesoamerica had occurred more frequently. We also offer reasons why archaeologists have found so few Mesoamerican obsidian blades at post-1540 sites. This research is relevant because it expands our knowledge about SW/NW-Mesoamerican connections and the Mexican Indian allies of the Spanish, who are an underrepresented group in the archaeological and historical records.