Discussion and Conclusions

Discussion & Conclusions

The combination of GPR and magnetometry has proven to be a very effective and reliable approach at Tiwanaku. One major advantage is the import and selective use of andesite at Tiwanaku, which can be distinguished from other common building materials because of its strong remnant magnetic field. This combined with GPR, which reveals the majority of architecture in the upper meter, allows delineation of much of the buried landscape in the northeast monumental core. These interpretations admittedly suffer from a lack testing, but limited excavations presented above show the geophysical data to be very reliable. Aerial photos, conductivity, and magnetic susceptibility data also greatly aided interpretation. The northeastern monumental core area at one time may have been constructed in a series of terraces stepping down east of the Semisubterranean Temple and north from the Akapana and Kantatayita. East-facing “revetments” probably included large blocks of andesite, while north-facing “revetments” did not. This is consistent with findings elsewhere at Tiwanaku, where east and west facing facades include much andesite, but north and south facing portions are constructed with little or no andesite and are clearly not meant to impress pilgrims (Isbell and Vranich 2004; Vranich 2006). If our interpretations are correct this suggests that the east-facing revetments were constructed with andesite to impress pilgrims entering the city from the east.

In addition to the possible terraces and revetments in the northeast, several other features have been identified and some verified by excavation. A possible square structure was identified in the northernmost portion of the survey area. A series of “pools” may have been constructed east of Akapana, perhaps for ritual bathing or other ceremonial activities. In addition, two possible residential compounds were identified (one of them shown in Figure 9). Many other anomalies suggest additional archaeological features, but we chose to focus on a few key features for this paper. The geophysical data serve as an immense database of information for future excavation and interpretation.