The rock shelter of Qillqatani is at 4400 masl along the Río Chila to the southwest of Mazo Cruz, and it is 221 km or 50.3 hours walking time, by the hiking model, across the puna from the Chivay obsidian source. Qillqatani lies on the southwestern perimeter of the Lake Titicaca Basin in the headwaters of the ríoHuenque drainage in the Department of Puno, and it is not far from the headwaters of the Osmore drainage on the western slope in the Department of Moquegua. The shelter has a strong pastoral component, but excavations revealed occupations dating back to the Middle Archaic. The shelter is also known for elaborate rock art panels. Qillqatani was excavated in 1990 by Aldenderfer in two adjacent blocks, labeled East Block and West Block (1999;2005;in prep.). The East Block measured 20 m²in horizontal extent, while the West Block measured 60 m².

Table 3-5. Qillqatani excavation levels, radiocarbon dates, and obsidian samples. (a) Titicaca chronology, (b-c) levels and¹⁴C dates from Qillqatani, all dates are on charcoal and were analyzed by Beta Analytic, from Aldenderfer (1999). (d-f) Obsidian from Qillqatani chemically provenienced at MURR from data presented by Frye, Aldenderfer, and Glascock (1998), with "Tumuku" type replacing reference to "possible Alca-2", and Aconcahua type abbreviated to "Aconc."

Figure 3-7. Qillqatani data showing percentage of bifacially flaked tools and percentages of debris made from obsidian per assemblage by count (Aldenderfer 1999;Aldenderfer in prep.).

Table 3-6. Qillqatani periods by tools (bifacially flaked) and debitage (all other lithics), in obsidian and non-obsidian categories.

Excavations in the two blocks at Qillqatani revealed a switch from hunting and gathering to a predominantly pastoral economy between the occupation in level 25, and that of level 24 that was stratigraphically superior (Aldenderfer 2005: 20;). The occupation in Level 24 appears to have been the first residential occupation, and it is considerably thicker than were previous levels that appeared to have been logistical in nature. The ovoid structures of Level 24 are slightly larger and are free standing, while in the preceding levels the structures are against the rear wall of the rock shelter. Level 24 is the first level with ceramics, but it is being considered Terminal Archaic in this analysis due to economic evidence and the exceptionally early ceramics at Qillqatani.

Table 3-7. Counts of obsidian debitage at Qillqatani by weight (g).

The earliest obsidian at Qillqatani is a Middle Archaic sample from an unknown source. In the Late Archaic, Chivay obsidian begins to appear at the rock shelter. Subsequently, during the Terminal Archaic obsidian from Chivay occurs in relatively large numbers and it persists until the end of the Early Formative (the Qillqatani Formative Cperiod) where chemical testing of ten obsidian samples reveals there is greater heterogeneity in obsidian procurement. In this period, Chivay obsidian makes up 60% of the obsidian tested by the Missouri University Research Reactor (MURR), the Tumuku type makes up 20%, and the Aconcahua type and Alca type make up the remaining 10% (one sample of each).

Three obsidian artifacts from two proveniences at Qillqatani, West level XI and East level XIV, were found to belong to the Tumuku chemical group, a group that derives from an as-yet-unlocated source that probably lies in the southern department of Puno. This chemical group has not yet been well characterized, as no source samples are available and the samples analyzed by NAA in the 1970s at Lawrence Berkeley Labs (Browman 1998: 309-311; Burger and Asaro 1977) are not easily comparable with more recent NAA results from MURR. As a consequence, in initial studies of these three Qillqatani artifacts it was proposed that the artifacts belong to a subgroup from the Alca obsidian source in northern Arequipa, a subgroup that was referred to as "Alca-2" (Frye, et al. 1998) and "Alca-Z" (Jennings and Glascock 2002: 111). More recently, Michael Glascock at MURR has stated that these three Qillqatani samples probably derive from the Tumuku source (M. Glascock, March 2006, pers. comm.).

Flake sizes at Qillqatani indicate that relatively large flakes were being discarded (Table 3-7), particularly during the Terminal Archaic and Early to Middle Formative. A central question concerning obsidian circulation is to what degree were flakes used for shearing and butchering tasks? Were flakes sufficiently large to be hand-held for these activities? Length measurements from these flakes from Qillqatani are not available, but an estimate of the size of those flakes based on their weight is provided by comparing similar obsidian flakes from the Chivay source dataset. An obsidian flake weighing 4g from the Chivay dataset had the following dimensions: 45 x 13 x 7mm. A smaller obsidian flake weighing 3g measured 31 x 14 x 6mm. These flakes appear to have been sufficiently large for shearing and butchering tasks. Further technical studies, as well as use wear and residue analysis, may shed more light on the use of large obsidian flakes in the regional consumption zone.