Methodology

The Quijos Valley Project chipped stone assemblage was classified into 21 individual artifact types (Table) representing informal bipolar and expedient flake technologies. Two examples of formalized bifacial retouching flakes were recovered, but in light of the entire assemblage these were likely produced randomly during expedient reduction as no formal bifacial or unifacial tools were found. In addition, three types of blade artifacts were recovered, but these do not represent formal prismatic blade technology. Rather, they represent simple blades. Analysis of the entire lithic assemblage was carried out in 2002. In 2007, the survey assemblage and those from excavations at Bermejo, Vega, and Oritoyacu were reanalyzed after a better understanding of bipolar reduction technology had been acquired. Due to time constraints, the remaining excavation assemblages (Sardinas Grande, Borja, San José, Sardinas Chico, Pituro, La Palma, Pucalpa, Vinueza, Santa Lucía del Bermejo, Logmapampa, Cumandá) could not be reanalyzed. As a result, any discussion on artifact type and frequency from excavated contexts is limited.

Obsidian artifacts also were classified by color and phynocrystic inclusions when observed, as well as any other macroscopically identifiable attributes like fracture quality and surface texture. Three base colors were distinguished (black, clear, and grey). Color categories also were divided into twelve “subcolors” that refer to secondary visual characteristics and account for the full range encountered in the analysis. These subcolor attributes are black, grey, green, clear, clear with clouds, cloudy, banded, clear polarized, clear polarized with specks, grey-green, black webbed and mottled. Black obsidian was completely opaque, even along the margins of the artifact. This category of obsidian correlates to the presence of inclusions, often having greater amounts of larger inclusions than other colors of obsidian. The clear category of obsidian was broader, including completely translucent examples (e.g. clear-clear) to those opaque in the center and only translucent along the margins (e.g. clear-cloudy). In those cases opacity was due to the thickness of the artifact rather than the density of the color. One result of this however, is that thinner artifacts may be classified as clear, whereas a thicker example of the same material may have been classified as black. This is one short-coming of visual classification. Clear obsidian accounted for the majority of the 12 subcolors also identified. Grey obsidian artifacts were uncommon and exhibited a dense, opaque light grey color. The presence and size of inclusions, type of surface texture, and other distinctive characteristics also were noted.

Finally, each artifact was analyzed for edge use wear in order to determine the types of activities that it may have been used for. Use wear was determined macroscopically and with the aid of a 10x hand-lens. This macroscopic approach undoubtedly missed many microscopic indicators of use that could be observed at higher magnification. The categories of use wear included in the analysis derive from Clark’s (1988) use wear replications on obsidian prismatic blades. These categories are descriptive of the type of use wear observed: contiguous microflaking; overlapping microflaking; truncated microflaking; irregularly spaced microflaking; crushing; abrasion; continuous slicing; rounded and dull; very acute flake removals (chopping/bashing); whittled; deep scallops; grinding abrasion. In addition, 12 examples of specialized obsidian tool types (Illustration) were recovered. These include end scrapers (Illustration), thumbnail scrapers, gravers, burins, and at least one spokeshave, used to scrape, grave, drill, incise and whittle. These morphologically distinct tool types were not restricted in their distribution across the survey zone.

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