Obsidian localization and circulation in northwestern Patagonia (Argentina): sources and archaeological record

Abstract

AbstractThe objectives of the current research are to characterize obsidian sources and lithic archaeological remains in two areas of NW Patagonia, so as to establish spatial distribution and network circulation patterns. Obsidian tools and remains were found in archaeological contexts dated back 3200 years and up to the 16th–18th centuries. Geological and artefact sample rocks were analysed by instrumental neutron activation analysis and inductively coupled plasma emission mass spectrometry. Four potential sources were detected (Sacanana, Angostura Blanca, Portada Covunco and Laguna La Larga). Obsidians in the region appear to be related to two petrotectonic associations: (1) an arc source, located in the western part of Argentina and Chile, of Plio-Pleistocene age; (2) an intraplate and back-arc source, located in the North Patagonian Massif, east of the studied area, of Miocene age. The latter, because of the higher frequency of tools and remains that appear in archaeological context, seems to be more intensively used. Some hypotheses about obsidian circulation patterns, the mobility of northern Patagonia hunter-gatherers, and landscape occupation throughout the last 3200 years are outlined based on the results obtained in this work.