5.8.2. Sampling during excavation

Test excavations at A02-26 and A02-39 involved screening all collections through 1/4" mesh and 1/16" window screen with the exception of material from level 1 (plow zone) that was only coarse screened. Furthermore, the excavation at A02-26 (Taukamayo) was into a landslide margin and therefore a profile was available revealing that the unit was effectively sterile until level 3. Thus, a coarse 1/4" screen was used in level 2, except for one quad in levels 1 and 2 that were fine screened.

At Q02-2, the obsidian source, more stringent sampling was required for three reasons. First, at a raw material source researchers will inevitably find a great abundance of material and sampling is the preferred means of reducing that abundance to a manageable quantity. Second, fieldwork while camping at high altitude at the Chivay source was constrained by available time. Finally, collections were constrained because they had to be hauled out on the backs of mules, including all artifacts and soil samples, limiting the quantity that could be transported.

At Q02-2u2 (quarry pit) and Q02-2u3 (workshop) the units were virtually all flaked obsidian, although at the quarry pit much of the material was non-culturally fractured obsidian. The solution devised was to excavate a standard 1x1m test unit, as described in this chapter, however collection would include non-diagnostic flakes from one quad of the unit, resulting in collection of 25% of the flakes from u2 and u3. The remaining three quads (75%) of non-diagnostic material were used as backfill. This allowed the recovery of diagnostic artifacts, retouched artifacts, cores, and organic materials such as charcoal, from throughout the 1x1m unit.