Sources and distribution of different types of obsidian from archaeological sites in Central-South Chile (38-44°s)

Resumen:
Thirty-five samples of obsidian from two coastal sites (Chan Chan-18 north of Valdivia and Puente Quilo in Chiloé) and six inland terrestrial-hunter gatherer sites (Alero Cabeza de Indio-1, Fundo Tres Arroyos-1, Flor del Lago-1, Los Riscos-1, Quillen-1 and Granaderos-2) in south-central Chile were analyzed, by ICP-MS techniques, to determine their trace-element chemistry for comparison with obsidian from know source in the area. The obsidian samples differ in color and include black (23 samples), grey (3 samples), translucent (5 samples) and red (4 samples) types. For the 23 black samples, 3 have chemistry that does not correspond to any know source, while the other 20, including 2 samples from Chan Chan-18 and all 3 from Puente Quilo, are chemically similar to black obsidian (MEL) from a source in the Nevados de Sollipulli. Three grey samples from Chan Chan-18 are similar to obsidian from Chaitén volcano (CH). The 5 translucent and 4 red samples are all similar to each other and to type PC1 obsidian that occurs as uvial transported cobbles along Arroyo Covunco east of the Andean Cordillera in central Neuquén, Argentina. However, this obsidian may have its primary source closer to the Andean drainage divide in the volcanic belt that extend southwest from Copahue caldera through Pino Hachado to Palao Mahuida caldera and Queli Mahuida cone just north of Paso de Icalma. This is the lowest elevation pass (1,298 m) in this area and the probable path for the entrance of this obsidian form Argentina into Chile. The fact that all the samples derived from the relatively remote PC1 obsidian source (>70 km) are visually distinctive translucent and red suggest that this distinctly colored obsidian may have had some aesthetic value relative to the more local (<30 km) and more easily accessible black MEL obsidian from Nevados de Sollipulli.

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