GEOARCHAEOLOGY OF EARTHEN ARCHITECTURE, TARACO ARCHAEOLOGICAL PROJECT, BOLIVIA

The advent of communal earthen architecture during the Formative on the Taraco Peninsula, Lake Titicaca, Bolivia marks the onset of socio-political complexity in this region. We employ geoarchaeology, including geochemistry, to aid in reconstructing architectural forms, the logic their construction and the impacts of time and use on these structures. In this way, we treat archaeological building sediments as artifacts. Our study includes results from three major Formative sites: Chiripa, Kala Uyuni and Sonaji. Chiripa is a well-preserved tell site of superimposed adobe structures with a presumed ritual use. Kala Uyuni and Sonaji are both highly complex sites that include well- preserved stratified occupational and architectural deposits as well as areas with a high degree of pitting and bioturbation. As a result the stratigraphy of these sites is discontinuous and highly complex. We combine geochemistry with physical and micromorphological analyses to characterize the archaeological sediments from these sites.

Our results indicate that sediments are most clearly identifiable as flooring and walling when they are imported sediments, thick (over 3cm) or burned in situ. In contrast, surfaces and mudbricks that are thin, uncovered and of local sediments leave little geochemical trace unless they are preserved as above-ground tells, are burned or are in deeply buried deposits. Soil micromorphology helps differentiate thin floor deposits and small patches of different soil fabrics, once discrete stratigraphy, which would otherwise be obscured in bulk analyses by mixing. This study thus shows both the utility and limitations of geochemical studies for earthen architecture in this semi-arid highland setting.