The Andes present a valuable opportunity for examining anthropological models of economy and exchange in prehistory. Distinctive historical aspects of Andean development, including the emergence of pristine states at high altitude, the administration of vast empires without a formal system of writing, and the wealth of ethnohistoric data provided by Spanish chroniclers, offer important research problems for economic anthropology. This study investigates the procurement and circulation of obsidian from the Chivay source in the south-central Andes during a broad time period that includes major shifts in the economy and in socio-political organization.

Throughout prehistory, the long, narrow Andean cordillera presented distinctive challenges to human groups that were addressed through a variety of technological and social strategies. Here, a focus on lithic raw material procurement and exchange permits obsidian circulation to serve as an indicator for particular types of regional interaction.

Exchange has a complex role in mediating human relationships over distance (see Section2.2.2), and in the south-central Andes, obsidian appears to have served as both a political tool and relatively ordinary aspect of economic activity. In part, the persistence of exchange in herding regions reflects lack of autarky among the dedicated pastoralists; they require vegetative and agricultural products, and such items are widely available in the sierra and foothills. In reference to the early development of long distance caravan networks in the altiplano, David Browman (1981: 413) notes "[t]he trade in consumables is less spectacular than the trade in luxury items, and more difficult to detect archaeologically, but it was much more important to the average altiplano inhabitant." In other words, due to the environmental contrasts in the Andes, relatively mundane consumables like salt, ajipeppers, and even coca leaf could precipitate a low-level but persistent demand for exchange of goods between adjacent ecological zones and, in some cases, across larger distances.

A central point of the following discussion is that wide-ranging exchange networks, apparently organized at the level of the household and facilitated by caravan transport, are a persistent theme in the south-central Andean highlands. These networks do not integrate easily with the exchange typologies presented above (Section 2.2.4), and this form of articulation is sometimes seen as irrelevant "background" reciprocity in models of early competitive leadership. However, this distributed mode of integration may have served as an early foundation for subsequent political organization in the region. This study focuses on obsidian procurement and distribution and infers that other goods were also being transferred along these networks. While the simple assumption that evidence of obsidian circulation is analogous to prehistoric trade in a multitude of other more perishable goods is problematic, the persistence of obsidian exchange in the south-central Andes is compelling evidence of generalized contact over distance.Andean approaches to regional economy are reviewed here in order to examine the distribution of obsidian and other goods through diverse mechanisms of procurement and exchange.