Obsidiana Varvarco: una nueva fuente en el noroeste de Patagonia (Neuquén, Argentina)

In northern Neuquen 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 Neuquen. 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.