Akapana Pyramid: August 3, 2004
Most of our excavation units on the west side of the Akapana Pyramid were placed in a specific location according to the ground-penetrating radar data and correspond to subsurface anomalies of particular interest to us based on their form and location. Units L-5, L-6, and L-7, however, were not put in based on the GPR. With these units, we were attempting to locate a plaza floor or walls not apparent in the data. Our reason for their placement was the way the grass grew in over the past two years since we cleared it for the GPR collection. A rectangular depression was visible from above, and we thought that this could possibly indicate the presence of a plaza.
The rest of our excavation west of the Akapana is based on the results of the ground-penetrating radar. We began unit L-8 over a linear north-south running feature that appears in multiple slices of the GPR data. We determined that this reflection source was a wall, probably either colonial or republican, and is likely unrelated to the Tiwanaku culture. Another deeper anomaly corresponds to a domestic floor and a pile of rocks that are not in situ.
Unit L-9 was placed over an area believed to correspond to a monumental structure south of the Putuni. A rectangular depression is visible from the surface, and the radar showed very strong reflections in a rectangular shape roughly 50 by 70 meters. The unit was approximately in the center of what would be the eastern wall of this structure. Tiwanaku architecture, such as the Kalasasaya and the Putuni, has a history of having entrances in the center of the eastern wall. We put L-9 here with the hope that an entrance to this previously unexcavated structure could be uncovered. This unit yielded monumental architecture in situ and construction fill that may be associated with a platform. We encountered a tile floor in the southwest corner of L-9, and we started unit L-11 in an attempt to follow this feature. Unit L-14 was put in an area we believe is the northwest corner of this monumental feature. We've uncovered construction fill in this unit, and there are interesting soil changes that are possibly associated with the GPR data. We need more investigation to confirm the exact origin of the radar reflections.
The GPR data shows an intersection of two linear features in the southeast corner of the monumental structure associated with units L-9 and L-11. We positioned L-10 to investigate the source of this reflection. It contains a large amount of cobbles, pebbles, llama bones, and ceramics. This feature is very thick and dense, which we can see in the radar data. There is possibly more of this feature or another unrelated feature below this level, and we'll see which in the coming weeks. A portion of what was originally believed to be the same feature was excavated during the 2002 season. If this is part of the same, we expect based on the radar data to find another feature at a greater depth.
We placed L-12 to investigate what appeared to be a smaller, possible domestic structure southwest of the Akapana. This unit has yielded linear walls and a tile floor that correspond nicely with the GPR data. L-12 has since been expanded to the north to follow the reflections and to find the end of the walls.
L-15 was started after the success of L-12. So far this unit has what appears to be later architecture not associated with Tiwanaku. Even so, the walls are in the exact location we expected them to be.