Evidence from regional consumption patterns indicate that while Chivay obsidian was in wide circulation within the Tiwanaku economic sphere, the regional distribution and quantity consumed declined during the subsequent LIP and Late Horizon. As one of the research questions motivating this study at the Chivay source, evidence was specifically sought to explain the economic circumstances around obsidian production in Late Prehispanic contexts. New evidence will be reviewed that was acquired from fieldwork in 2003, and later in this chapter contrasting models of production will be explored in more detail.
No direct evidence of Tiwanaku was encountered at the Chivay source or in the immediate vicinity during fieldwork in 2003. A single obsidian preform was encountered that appears to have been an early stage of a type 4E (Tiwanaku stemmed) projectile point in Block 2, but the identification is not definitive. Titicaca Basin materials were encountered deriving from particular time periods in the form of non-local decorated ceramics, such as sherds of possible Qaluyu and Pukara (Formative) styles, and Colla and Chucuito (LIP and Late Horizon) ceramic styles, but no Tiwanaku pottery was encountered any where in the Upper Colca research area. In Block 3, a calibrated radiocarbon date of A.D. 650 - A.D. 780 (Figure 7-3) from Taukamayo places the occupation in the Tiwanaku period, but no Tiwanaku or Wari evidence was found at the site. Rather, pottery akin to the local Chiquero material was encountered that is diagnostic to the Formative in the main Colca valley (Wernke, 2003). The asymmetrical relationship between Chivay obsidian consumption in the Tiwanaku economic sphere, and the lack of Tiwanaku diagnostic materials in the Chivay source area will be discussed in more detail below.
Local Middle Horizon patterns are of particular interest because regional distributions of these ceramics may shed light on the nature of the frontier relationship between Tiwanaku and Wari that appears to have been occurring in the upper Colca valley during the latter half of the first millennium AD. Ceramics in the local Middle Horizon style (Wernke 2003: 466-478) were encountered in Block 2, but these sherds were confined to the northern half of Block 2. Middle Horizon pottery was found scattered throughout Block 3. A single local Middle Horizon sherd was found mid-way between the Chivay source and the town of Chivay, and one sherd was found in Block 6 upstream of Tuti. In short, the Colca Middle Horizon type defined by Wernke was encountered throughout the Upper Colca study area although, as discussed in Chapter 6, there is a distinct zone in Block 2 south of which the local MH pottery is not found.
Ceramics of the local Collagua style dominate the decorated ceramics found throughout the Upper Colca survey area. Pastoral facilities are rich in decorated ceramics resembling the main Colca Valley styles described by Wernke and others and underscoring the close links between Collagua polity in the Colca valley, and their expanding herding sector on the adjacent puna. Sherds of the Colla type, the Lake Titicaca Basin LIP style, were found in the northern part of Block 2 and also along the trail leading from Block 2 towards Block 1 and the Colca valley. Relatively close economic and cultural links are expected between LIP groups in the Colca and the Titicaca Basin as these groups shared a number of traits including the Aymara language, chulpamortuary architecture, and the defensive pukarahilltop settlements. Yet, interestingly, no Colla sherds were encountered in Block 3, the upper Colca valley, although the ceramics and architectural evidence shows that the Collagua presence was relatively strong in this area. This may be explained in terms of ecological complementarity, as one might expect the Colla to have been actively trading with the lower Colca valley agriculturalists, but the upper Colca valley is at the same elevation as the Titicaca Basin and thus it had relatively little to complement the goods available in the Titicaca Basin.
The LIP occupation of Block 3 appears to have been focused around agricultural plots and pastoralism in the adjacent high puna. Evidence of abandoned agricultural plots was noted both upstream and downstream of Callalli (3,900 masl) with furrowed areas that were likely planted in frost resistant crops like quinoa or tubers.
During the Late Horizon the reorganization that took place under Inka rule is evident in settlement pattern changes and ceramics distributions. At the Chivay obsidian source, the highest quantity of diagnostic ceramics were those in Late Horizon styles. These ceramics may be derived from the mortuary structures that were encountered in the Maymeja source area, or the LH ceramics may be a reflection of the increased investment in water control projects and expanded herding. A possible extension to the Huarancante canal capturing water from Quebrada de los Molinos would have had its origins precisely at the Maymeja workshop at the Chivay source.
Elsewhere in the survey area the Inka period introduced a number of changes including distinctive differences in long-distance interaction. In Block 2, the Late Horizon component appears to have been consolidated around a few larger sites. The presence of Titicaca Basin pottery is notably lower in the Late Horizon in Block 2, and Cusco Inka styles are introduced in that area. Fourteen sherds of Colla style pottery (Titicaca Basin LIP) were found in Block 2, and these were primarily scattered in the northern half of the block. By the subsequent Late Horizon only two Chucuito style sherds (Titicaca Basin LH) were found in Block 2. The most common decorated pottery was the local LH Collagua-Inka and the Collagua-3 style. In Block 3, settlement became concentrated at agricultural plots along natural river terraces near the confluence of the Río Colca and Río Llapa in an area known as Callalli Antiguo. A concentration of structures with non-local Inka pottery along the principal road system on the south side of the Colca suggests that this site may have had administrative functions in the Late Horizon settlement pattern.