Abstract

In the pre-Columbian Andes, ceremonial centres were places for large-scale periodic celebrations that facilitated interaction and the reproduction of social life; however, little is known about their role and emergence in early periods. In order to explore the nature and scale of social aggregations, we study the circulation of obsidian artefacts from two early ceremonial centres: Tulan-52 (5300 to 4200 cal. BP) and Tulan-54 (3200 to 2400 cal. BP). Compositional analyses indicate the exploitation of local obsidian, but with a significant contribution from several extra-local sources in the north of the Salar de Atacama (Chile), the Andes highlands (4000 masl) and the northwest of Argentina. According to technological studies and other complementary data, obsidian was employed mainly for the production of bifacial projectile points used in collective hunts and ritual feasts. Our data supports the existence of wide, decentralised inter-community networks fostered by inclusive access to these periodic congregations. We argue that early ceremonial centres were intended to maintain social cohesion and cooperative labour between trans-egalitarian groups in the face of the profound socio-economic changes introduced by the adoption of a more sedentary, pastoralist way of life.