In lieu of the traditional preceramic / ceramic divide in archaeology, the "Early Agropastoralist" time block was defined for this project because, in many ways, the conditions during the final millennium of the Archaic had more in common with events in the Formative than with the preceding Archaic Periods. Differentiating sites as "Early Agropastoralist" beginning in the Terminal Archaic requires that one delimits a firm boundary on a process that was millennia in the making. Considering the Terminal Archaic as the beginnings of agropastoralism, and thereby linking it to the attendant settlement distribution that includes series 5 projectile points, connects cultural and economic evidence from throughout the region with a generalized estimate of when food production took hold in terms of scheduling, mobility, and prioritizing the needs of agricultural planting and herding. As mentioned, the term "Early Pastoral" is not meant to imply that no food production occurred before this date and hunting and gathering did not persist after this date. Indeed the current evidence suggests that camelids were first domesticated sometime during the Middle or Late Archaic, probably after 5000 BCE (Browman 1989;Kadwell, et al. 2001;Wheeler 1983;Wing 1986). The "Early Agropastoralist" period refers to a period after 3300 BCE that features a predominantly food producing economy in the highlands including intensive pastoralism, as well as seed-plant and tuber cultivation. These changes in food production may have been linked to the accumulating evidence of increased rainfall and shortening of the dry season beginning circa 2500 cal BCE (Baker, et al. 2001;Marchant and Hooghiemstra 2004;Mourguiart 2000). These changes in economy are joined by evidence of increased sedentism, widening stylistic distributions pointing to long distance cultural integration, and the beginnings of social differentiation apparent in architecture and grave goods. The circulation of obsidian was linked to these phenomena because increased regional interaction was perhaps articulated through camelid caravans, although the presence of caravans in the Terminal Archaic is being explored, not assumed, in this study.
In the Titicaca Basin, the changes incurred between the Terminal Archaic and the Late Formative are monumental. However, from the perspective of the Chivay source the intensification revealed archaeologically, both at the source and in the consumption zone, is notable beginning in the Terminal Archaic, and the intensification does not change notably throughout the Formative Period. Defining the ending of the "Early Agropastoralist" period as the end of the Late Formative is similarly problematic. By the Late Formative, the economic influence of Pukara and other regional centers probably impacted the peoples of the Upper Colca, but direct evidence returning from Pukara, only 140 km away, is scarce in the Colca. In contrast, during the Tiwanaku times, regional states with socio-economic impacts over hundreds of kilometers dominated both the circulation of goods like obsidian, and regional settlement organization.