Quest for ancient routes: obsidian sourcing research in Northwestern Argentina

Abstract

This paper presents data regarding the provenance of obsidian artefacts in several NW Argentina archaeological sites as well as the geochemical characteristics and geologic ages of the different sources. The goal of our project was to gain knowledge about ancient trade routes through the study of the networks constructed around obsidian procurement and distribution at the onset of an agropastoral economy. The time span considered goes from 2200 years BP to 400 years BP, which also encompasses the time of consolidation of long distance exchange contacts. The objective was accomplished by (1) locating, geochemically characterizing, and dating ten potential sources (seven of which were actually used in the past) in several sectors of the Puna region (between 3500 and 4200 masl) in Northwestern Argentina, and (2) to determine the provenance of 176 obsidian artefacts from 37 sites, not only in the Puna but also in neighboring environments, such as the temperate valleys (between 900 and 3500 masl) and the western border of the subandean forest ( yungas) (between 300 and 1500 masl). The methodology employed for source identification was instrumental neutron activation analysis (INAA) to measure the trace elements in every source specimen and archaeological artefact. This has enabled accurate identification of the geographical origins and main distribution areas for several sources, while discovering changes in source utilization over time.