Sources of obsidian artefacts, exchange networks and landscape use in Auca Mahuida (Neuquén, northwestern Patagonia)

Abstract

We present the results of XRF analysis for 59 obsidian samples from 11 archaeological sites in Auca Mahuida region, Northeastern Neuquén, Argentina. The results indicate that several obsidian sources were utilized; however, the intensities of their exploitation were variable. Strong differences appear between the Colorado river basin, characterised by a low variability of obsidian groups from northern Neuquén, the Auca volcano, with a low variability of obsidian groups but from local sources located north and southwards from the study area; and along Bajo del Añelo, which presents a high variability of obsidian groups from several local and non-local sources. The pattern recorded fit different mechanisms of access to the sources and conveyance of obsidian across the landscape. Two distinct paths of direct access are suggested for obsidian available along the Colorado river in northern Neuquén and for Portada Covunco obsidian in central Neuquén. Additionally, we suggest the presence of obsidian from sources in southern Neuquén Province (Cerro Las Planicies-Lago Lolog), located ca. 350 km from the study area. While not conclusive yet, this possibility parsimoniously integrates available geochemical and spatial information, allowing us to propose the existence of either long-distance transport or indirect access by exchange or similar mechanisms.