Conclusions

The most striking feature of the Quijos Valley Project chipped stone assemblage is its uniformity across space and through time. The occupants of the Quijos Valley employed only informal reduction technologies during the Early and Late Periods. Whether this was due to a lack of the requisite knowledge to create bifacially flaked artifacts or blades, or simply because formal technologies weren’t necessary cannot be determined from the data. While there is a long history of both informal and formal lithic technology use in other parts of Ecuador (Burger et al. 1994; Mayer-Oaks 1986; Salazar 1992), there is no known antecedent use of formal technologies in the Quijos Valley (Porras 1975). Parry and Kelly (1987) have observed a correspondence between reduction technology and degree of mobility/sedentism. They argue that bifacial reduction technologies are better suited to migratory populations who do not have ready access to raw material, but move across the landscape obtaining suitable stone. Since they are always on the move, they require multipurpose formal tools that can be easily reduced to suit varying needs. They contrast this to sedentary populations where a guaranteed and relatively easily accessible supply of raw material is available, thus little need for high investments of time and effort in the production of serviceable stone tools. The Quijos Valley was supplied with a steady source of obsidian, albeit in varying degrees of quality, from the Aliso-Pumayacu source.

In the southern subregion of the survey zone, artifacts of both poor quality black obsidian and high quality clear obsidian were, on average, heavier, and thus larger, than artifacts from any other area of the survey zone. The farther away from the southern subregion, the smaller the artifacts became, especially those made from the higher quality clear obsidian. In addition, clear obsidian material was being reduced further than black obsidian material, which corresponded to a switch in reduction technologies from expedient flake to bipolar. On average, fewer casual flake cores of clear obsidian were recovered than of black obsidian. When clear causal flakes cores were recovered, they tended to be smaller than those of black. In addition, flakes of clear obsidian were, on average, smaller than those of black. As such, this general pattern of extended use life of clear obsidian and relative wastefulness of black obsidian conforms to Renfrew’s (1977) Law of Monotonic Decrement, which describes the correlation between amount of material and distance from source. In general, the further from the source area one is, the less source material will be recovered, and by extension the increase in the methods used to extend the use life of that material through reduction techniques and artifact recycling. The closest known obsidian source to the Quijos Valley is the Aliso-Pumayacu source, located just south of the southern limits of the survey.

For the most part, all artifacts were used principally for the scraping and cutting of hard materials. However, this pattern is likely biased by the fact that the scraping and cutting of hard materials leaves the most noticeable use wear on obsidian artifacts. It is very possible that other activities on soft materials, like flesh and fiber, were more common. The use wear patterns for these types of activities were not readily visible, especially considering that each artifact was only analyzed with the aid of a 10x hand lens. Microscopic analysis of the assemblage for use wear may identify many additional activities.

Beyond the general activities of scraping and cutting of hard materials, differences in use wear between the heaviest artifacts, which were mostly of black obsidian, and the lightest artifacts, most of which were of clear obsidian, was prevelant. Rounded and dull edges, indicative of cutting of hard surface like ceramics or shell, were more prevalent on larger black obsidian artifacts, while some specialized scraping activity that resulted in truncated edge flaking was more prevalent on small clear flakes. The preference of a larger obsidian tool for cutting of a very hard material is expected, as obsidian is quite brittle and the force placed on a smaller tool might crush it altogether. Additional use wear experiments are needed to clarify the types of scraping activities that produced the patterns observed on the smaller clear obsidian artifacts.

Finally, this discussion of the distribution of obsidian artifacts in the Quijos Valley Project survey zone is based on the assumption that the vast majority, if not all of the raw material used in the survey zone came from the Aliso-Pumayacu source in the south. High quality clear obsidian is known from the Mullumica source in the Cordillera Real approximately 30 km to the west, northwest of the survey zone. In addition, several obsidian flows of low quality are known just west of the town of Papallacta, 12 km west of the western limits of the survey zone (Bigazzi et al. 1992). It is possible that some of the obsidian artifacts recovered in the Quijos Valley were made from obsidian from one or more of these sources. This, of course, would alter the interpretations and conclusion of raw material distribution presented here. Chemical analysis of a sample that represents a diversity of artifacts and raw materials from the survey is in preparation to characterize obsidian distribution throughout the valley.

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