Obsidian provenance during the transition to food production in Antofagasta de La Sierra (Southern Argentinean Puna, South-Central Andes), 4500-1100 BP

Abstract

This study attempts to produce a close understanding of obsidian procurement and distribution during the transition from hunter-gatherer to agro-pastoralist societies (ca.4500- 1100 BP) in Southern Argentinean Puna. Obsidian regional circulation in a high elevation desert environment, emphasizing differential distribution and use of this raw material, is discussed. Additionally, this obsidian research supports the occurrence of exchange networks based on use of different extra-regional obsidian sources located in Northern Argentinean Puna. The Argentinean Puna is a natural continuation of the Peruvian–Bolivian high mountain plateau and is part of the Atacama Puna. From an environmental point of view, the Puna is a high desert biome characterized by an arid and cold climate, intense solar radiation due to the altitude, an ample day and night thermal range, poor summer rains, low atmospheric pressure and marked seasonality. For this study, non-destructive elemental analysis of obsidian artifacts was conducted using two different X-ray fluorescence spectrometers (ED-XRF). All obsidian samples (112) come from archaeological sites, locatedin the Argentinean Puna at the Antofagasta de la Sierra Basin (Catamarca, Argentina), with stratified archaeological remains. Sixty obsidian samples are, on one hand, from four rock-shelters which are residential bases with late hunter-gatherer occupations dated to ca. 4500-3000 BP. On the other hand, fifty-two obsidian samples come from two open air sites which also are residential bases but with consolidated agro-pastoral contexts dated to ca.2100-1100 BP. The results obtained indicate differential patterns of procurement and use of obsidian during the time span considered. First, between 4500-3000 BP, all five regional obsidian sources were used by hunter-gatherers in transition to food production but with differential use intensity and showing a preferential utilization of the northern regional sources, 60 to 100 km distance from the sites. Second, between 2100-1100 BP, a different pattern in the use of the different types of obsidian is clearly noted. Specifically, the data show that one of the northern sources was the most utilized, with small proportions of obsidian supplied by two sources located 75 km south and 30 km east of the sites. Third, both late hunter-gatherer and agro-pastoralist societies maintained extra-regional contacts evidenced by the presence of obsidian from far-distant sources between 200 and 360 km away. Finally, the mobility, territoriality and exchange developed by humans in high elevation desert environments are considered.