Varvarco obsidian: a new source in northwestern Patagonia (Neuquén, Argentina)

En el norte neuquino existen depósitos piroclásticos que contienen nódulos de obsidianas. Las investigaciones en la región dieron a conocer las principales fuentes utilizadas por las poblaciones que allí habitaron. Para profundizar el conocimiento de cada fuente de obsidiana se adoptó un programa de estudio geoarqueológico y geoquímico. Así, se han descubierto nuevas ocurrencias de obsidianas, la más destacable de las cuales es la obsidiana Varvarco que aquí se presenta. Se dan a conocer los muestreos realizados en el valle del río Varvarco, su contexto geológico y geomorfológico, la presencia de obsidiana, el tipo de yacimiento, forma de presentación, distribución y abundancia. Luego, se describen las principales características observadas bajo microscopio petrográfico. Por último, se presentan los resultados de análisis geoquímicos de fluorescencia de rayos X y activación neutrónica. A partir de los primeros la obsidiana Varvarco se diferencia de la de Cerro Huenul, pero no de la obsidiana Maule 1 y 2. Los segundos análisis discriminan bien esta nueva obsidiana de las ya conocidas para Neuquén. Los resultados obtenidos permiten reinterpretar la disponibilidad de recursos líticos de buena calidad para la talla y revisar las interpretaciones de movilidad e interacción de poblaciones en esta región.In northern Neuquén there are pyroclastic deposits containing obsidian nodules. The researches in the region revealed the main sources used by the people that lived there. A program of geoarchaeological and geochemical study was adopted to extend the knowledge of each source of obsidian. Thus, new occurrences of obsidian have been discovered, the most notable of which is the Varvarco obsidian presented here. We present the samples points conducted in the valley of Varvarco river, its geological and geomorphological context, the presence of obsidian, the type of deposit, presentation form, distribution and abundance. Then, we described the main characteristics observed under a petrographic microscope. Finally, we present the results of X-ray fluorescence and neutron activation geochemical analysis. The Varvarco obsidian differs from that of Cerro Huenul, but not from the obsidian Maule 1 and 2 from the XRF. NAA discriminates well this new obsidian from those already known in Neuquén. The results obtained allow to reinterpret the availability of good quality lithic resources and to revise the interpretations of mobility and interaction of populations in this region.Fil: Fernández, María Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Diversidad Cultural y Procesos de Cambio. Universidad Nacional de Río Negro. Instituto de Investigaciones en Diversidad Cultural y Procesos de Cambio; ArgentinaFil: Leal, Pablo Rodrigo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Geociencias Básicas, Aplicadas y Ambientales de Buenos Aires; ArgentinaFil: Della Negra, Claudia. No especifíca;Fil: Klesner, Catherine. University of Arizona; Estados UnidosFil: MacDonald, Brandi L.. University of Missouri; Estados UnidosFil: Glascock, Michael D.. University of Missouri; Estados UnidosFil: Barberena, Ramiro. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales. Laboratorio de Paleoecología Humana; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Interdisciplinario de Ciencias Básicas. - Universidad Nacional de Cuyo. Instituto Interdisciplinario de Ciencias Básicas; Argentin

The Regional Production, Consumption, and Trade of Glazed Ceramics in Medieval Central Asia

Central Asia has long been the connecting bridge facilitating the long-distance trade of goods across Eurasia. While Central Asian communities have served as trading centers, they were also producers of specialty goods and centers of technological innovation themselves. In the 9th-12th c. CE glazed ceramics were introduced and began to be produced in the region. The characterization of ceramic provenance and technology of these first glazed ceramics from southern Kazakhstan helps reveal the physical trade networks in place in northern Central Asia during the Medieval Period, as well as how technologies were transmitted and adapted. A total of 200 ceramics dating from the 9-15th c. CE from eleven sites in southern Kazakhstan were analyzed as part of three studies, which are presented in this dissertation. They detail the compositional analysis of the ceramic pastes, the reconstruction of local lead glazed ceramic production technology, and the compositional and lead isotopic analysis of the lead glazes on the ceramics. The compositional analysis by neutron activation analysis (NAA) of the ceramic pastes characterized the extent of local production and trade in the region during the Early Islamic period. Compositional analysis of the ceramic pastes demonstrates that there are seven distinct compositional groups for the glazed ceramics from the region. Comparison of the glazed ceramic NAA data to a large database of previously analyzed ceramics from across Asia indicates local production of lead-glazed ceramics at one site, Aktobe, and the concurrent presence of imported ceramics from Southwest Asia. A representative group of lead-glazed ceramics excavated from the site of Aktobe were analyzed to reconstruct their production technology. The ceramics were examined by scanning electron microscopy (SEM) and electron microprobe analysis (EMPA) to establish the variability of local artisans’ use of raw materials, glazing methods, and decorative techniques. The results demonstrate that the ceramics were introduced by skilled craftspeople who knew the production technology that was being used in Islamic centers in southwest and Central Asia. Chemical analysis of the glazes by laser ablation–inductively coupled plasma mass spectrometry (LA-ICP-MS) and EMPA revealed that there were several distinct glaze types present in the ceramics from southern Kazakhstan. These include transparent high-lead glaze and opaque high-lead glaze, of which tin-opacified glazes, tin- and antimony-opacified glazes, and antimony-opacified glazes were all identified. The occurrence of antimony-opacified glazes, and tin- and antimony-opacified glazes is unattested in this region in the period and indicates that the local craftsmen in southern Kazakhstan are innovating in their production of opaque glazed ceramics using local raw materials. Lead isotope analysis was employed to identify potential sources of lead, and the results indicate that the craftsmen were obtaining lead from at least two different sources for their glazed production. Using a large comparative database and through the application of Euclidean distance, potential ore deposits were identified, including deposits that were active silver mines during the Medieval Period. These ore sources were local and suggest that potters were obtaining lead for glaze production from within larger acquisition networks. One cluster of samples had a distinct isotopic signature that matched a unique deposit in Xinjiang, China, which indicates craftsmen were not strictly using local sources, but also obtaining lead through long-distance trade networks. This systematic analysis of glazed ceramics demonstrates how examining a technology at the microscale can inform us about larger changes in cultural identity and cross-cultural contact. The three studies deepen the understanding of the role glazed ceramics played in northern Central Asia in the Medieval period, as well as demonstrating the strength of integrating chemical, isotopic, and microscopic analyses into a single research program

Reverse Engineering of Corinthian Pigment Processing and Firing Technologies on Archaic Polychrome Ceramics

Decorative, polychrome ceramics from Corinth, Greece, produced during the 8th-6th centuries B.C.E. are luxury goods that were widely traded throughout Greece and the Mediterranean. The decorated ceramics were produced in a variety of shapes, including aryballos, alabastron, and olpe. They were decorated with slip-glazes in distinctive white, black, red, yellow, and purple colors, and in a variety of surface finishes, matte, semi-matte and glossy. Artisans in Corinthian workshops experimented to change the colors of the slips by varying the type and amount of iron-rich raw materials. They also varied the composition of the clay used as a binder and the amount of flux used as a sintering aid to promote glass formation. This research reconstructs the technology used by the Corinthian craftsmen to produce the Archaic polychrome ceramics, and shows how these technologies differed from the production of better known, more prestigious Athenian black-figure and red-figure ceramics. Through microstructural examination of archaeological samples and replication experiments, this thesis proposes that the purple iron oxide pigment is the result of acid treatment and oxidation of iron metal. The firing temperature range of the Corinthian polychrome ceramics was determined experimentally to be 925-1025° C, which is higher than previously reported and similar to that reported for Corinthian transport amphoras. The firing range is higher by 50-150° C than the Athenian black-figure and red-figure ceramics. Samples of Corinthian polychrome and Athenian black-figure ceramics from the Marie Farnsworth collection at the University of Arizona were tested and compared to Corinthian clay collections. Analytical techniques included Fourier-transform infrared spectroscopy (FTIR), scanning-electron microscopy with energy-dispersive spectroscopy (SEM-EDS), micro-Raman spectroscopy, and wavelength-dispersive electron microprobe (EPMA with BSE-SEM)

Las elecciones mexicanas de 2006, ¿manifestación de una sociedad dividida?

The 2006 Mexican elections did not reveal significant social cleavages. Voters did not base their political choices on their class, gender, age, or ethnic characteristics to any important extent. Region did emerge as a major difference among the bases of the three principal candidates, but regional cleavages are more complex than the conventional blue (PAN) and yellow (PRD) division frequently discussed by the press and political analysts. Followers of Felipe Calderón tended to support the status quo, to believe that Vicente Fox had been a president who brought change to Mexico and to worry that Andrés Manuel López Obrador would threaten the advances made under Fox. In contrast, López Obrador’s supporters considered Fox to have been a failure, particularly in bringing substantive change to their nation. Las elecciones mexicanas de 2006 no revelaron diferendos sociales significativos. Los votantes no basaron sus preferencias partidarias en su clase, género, edad o características ét- nicas. La región emergió como una diferencia mayor entre las bases de los tres candidatos principales, pero las disparidades regionales son más complejas que la convencional división azul (PAN) y amarillo (PRD) a menudo discutida por la prensa y los analistas políticos. Los partidarios de Felipe Calderón tendieron a apoyar el statu quo al creer que Vicente Fox trajo el cambio a México, el cual se vería amenazado por Andrés Manuel López Obrador; en contraste, los adeptos de éste consideraron a Fox un fracaso, en particular por no generar cambios sustantivos en la nación.