Previous studies of the Hohokam have suggested that obsidian procurement and distribution practices were conducted differently between two subsequent intervals, the Sedentary and Classic periods. In ...the Sedentary period, obsidian may have changed hands at events associated with the ballcourt ritual. By the Classic period, obsidian is argued to have moved either through an elite-sponsored or kinship-based economy. However, the Sedentary and Classic periods are long temporal intervals, which, when used to describe changes in time, can mask short-term but significant temporal variation. Our research employs a refined dating scheme, standard lithic analysis, and X-ray fluorescence spectrometry on a sample of obsidian from the Hohokam village of Las Colinas to determine: (1) when the change in obsidian exchange patterns actually began, (2) if the transition was an immediate shift or a gradual trend, and more generally (3) the behavioral changes related to the Sedentary to Classic transition. The results of our study suggest that there was not one decisive transition in the obsidian exchange system, but rather changes in the procurement patterns (i.e., frequency and sources) at two different points in time. These shifts in the movement of obsidian were felt at Las Colinas, and perhaps across much of the Hohokam region, and were seemingly related to the demise of the ballcourt network at the end of the middle Sedentary and the later rise of platform mounds during the early Classic period.
Estudios previos de la cultura Hohokam sugieren que la procuración y prácticas de distribución de obsidiana fueron realizadas de manera diferente entre dos intervalos subsecuentes, los periodos Sedentario y Clásico. En el periodo Sedentario el intercambio de obsidiana puede haber ocurrido en eventos asociados con el ritual del juego de pelota. Se argumenta que para el periodo Clásico la obsidiana se movía a través de una economía auspiciada por la élite o basada en parentesco. Sin embargo, los periodos Sedentario y Clásico son intervalos temporales largos, que al ser utilizados para describir cambios en tiempo pueden ocultar variaciones significativas pero de corto plazo. Nuestra investigación emplea un esquema de cronología refinada, análisis lítico estándar, y espectrometría fluorescente de rayos X, en una muestra de obsidiana de la aldea Hohokam de Las Colinas para determinar: (1) cuándo realmente comenzó el cambio en los patrones de intercambio de, (2) si la transición fue un cambio inmediato o una tendencia gradual, y de manera más general (3) los cambios en comportamiento relacionados a la transición del Sedentario al Clásico. Los resultados de nuestro estudio sugieren que no hubo una transición decisiva en el sistema de intercambio de obsidiana, sino cambios en los patrones de procuración (i.e., frecuencia y fuentes) en dos diferentes momentos. Estos cambios en el movimiento de obsidiana fueron experimentados en Las Colinas, y tal vez a través de gran parte de la región del Hohokam, y parecen estar relacionados con el desaparición del sistema del juego de pelota al final del Sedentario medio, y con el surgimiento más tarde de los montículos-plataforma durante el periodo Clásico temprano.
Recently, due to an increasing number of analyses of archaeological obsidian worldwide, the reporting of chemically differentiated and compositionally zoned, obsidian producing rhyolite domes has ...increased. While these studies have been important, and furthered our knowledge of the potential chemical variability of rhyolite magmas as they relate to archaeological obsidians, they are rarely made relevant to archaeological issues. In northwestern New Mexico the “Grants Ridge” source in the Mount Taylor Volcanic Field exhibits two compositionally differing glasses derived from the same magma source that also exhibit significant megascopic variability correlating with raw material quality. While Grants Ridge was previously seen as a single source, this study suggests that one of the localities was considered a more viable raw material in prehistory, at least in the local area. The Grants Ridge study indicates the value of more intensive investigations of archaeological obsidian sources in the Southwest including systematic geoprospection and chemical analysis. The wavelength and energy-dispersive X-ray fluorescence analysis reported here provides the first systematic study of this high-silica archaeological obsidian source in the Mount Taylor Volcanic Field.
An energy-dispersive X-ray fluorescence (EDXRF) analysis of nineteen obsidian source rocks from a mid-Tertiary rhyolite/perlite flow in the upper Río Bavispe basin of northeastern Sonora, Mexico ...solves the location of "Sonora Unknown B" as reported by
) for recent archaeological projects in northeastern Sonora and southeastern Arizona. This newly discovered source, called Selene, is a relatively large marekanite source consisting of a very high-silica rhyolite with regionally distinct high barium (Ba) and strontium (Sr) values, and low zirconium (Zr) elemental concentrations. The Selene nodules are relatively large compared to nodules from other northern Sonoran and Chihuahuan obsidian sources, and have excellent knapping qualities. We believe these attributes contributed to the transport, trade, and use of Selene obsidian hundreds of kilometers from the source. This is in contrast to marekanites from some other sources in northwestern Mexico, which were at most transported and used a few tens of kilometers from their sources (
;
:77).
The social and economic organization of obsidian procurement has been a topic of particular interest in southwestern archaeology as a result of recent work identifying and characterizing a number of ...sources throughout Arizona, New Mexico, and northern Mexico. Recent studies have attempted to explain temporal and spatial variability of obsidian distribution in the larger contexts of regional exchange networks, socially bounded territories, and elite redistributive efforts. This study reviews the current state of research as reflected in three models. Patterns in obsidian source diversity and reduction stage data are assessed relative to model expectations and an analysis of obsidian acquisition and distribution. The likelihood of elite members of an increasingly formalized socioeconomic system playing a role in these processes should be considered, while at the same time noting that kin-based raw material procurement and ritual item mobilization may explain many of the obsidian patterns. The emerging perspective suggests that obsidian moved in a variety of spheres, concurrently serving a number of social and economic purposes. This study highlights the importance of modeling individual, nonlocal commodities before attempting to generate monolithic exchange models.
For the first time, we have identified evidence that the disappearance of Neanderthals in the Caucasus coincides with a volcanic eruption at about 40,000 BP. Our data support the hypothesis that the ...Middle to Upper Paleolithic transition in western Eurasia correlates with a global volcanogenic catastrophe. The coeval volcanic eruptions (from a large Campanian Ignimbrite eruption to a smaller eruption in the Central Caucasus) had an unusually sudden and devastating effect on the ecology and forced the fast and extreme climate deterioration ("volcanic winter") of the Northern Hemisphere in the beginning of Heinrich Event 4. Given the data from Mezmaiskaya Cave and supporting evidence from other sites across the Europe, we guess that the Neanderthal lineage truncated abruptly after this catastrophe in most of its range. We also propose that the most significant advantage of early modern humans over contemporary Neanderthals was geographic localization in the more southern parts of western Eurasia and Africa. Thus, modern humans avoided much of the direct impact of the European volcanic crisis. They may have further benefited from the Neanderthal population vacuum in Europe and major technological and social innovations, whose revolutionary appearance shortly after 40,000 BP documents the beginning of Upper Paleolithic. PUBLICATION ABSTRACT
Comprehensive geochemical studies of archaeological obsidian sources in the Southwest typically have lagged behind other regions of North American and Mesoamerica. Current archaeological and ...petrological research indicates four previously unreported sources in Arizona, Sonora, and western New Mexico. This initial semiquantitative X-ray fluorescence (XRF) examination of archaeological silicic-glass sources in this region focuses on current technical problems in southwestern obsidian studies. The chemical variability within some regional obsidian sources appears to be relatively extensive and new data from the San Francisco volcanic field in northern Arizona modifies the results of earlier researchers.
The end of the Pleistocene era brought dramatic environmental changes to small bands of humans living in North America: changes that affected subsistence, mobility, demography, technology, and social ...relations. The transition they made from Paleoindian (Pleistocene) to Archaic (Early Holocene) societies represents the first major cultural shift that took place solely in the Americas. From the Pleistocene to the Holocene: Human Organization and Cultural Transformations in Prehistoric North America provides an overview of the present state of knowledge regarding this crucial transformative period in Native North America.
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