EMPA and EDXA analysis of slag from the multicomponent site of Pirque Alto, Bolivia

Abstract

In June 2007 the UW-L Bolivian Archaeological Field School uncovered two features consisting of rings of standing stones at the multicomponent agricultural site of Pirque Alto near Cochabamba, Bolivia. These features contain a form of unidentified slag within the ring, indicating that the features served as reduction furnaces. This paper demonstrates, by means of electron microprobe analysis, the composition of the slag sample as well as the nature and purpose of the forge features, and their probable date. EMPA indicates that the slag itself is the result of copper smelting occurring at very high temperatures indicating that the features served as the bases of huayrachina furnaces. This paper utilizes information from past research on the site of Pirque Alto as well as ethnographic accounts of huayrachina use to imply a Middle Horizon (C.E. 500-1000) date to the smelting activities of Pirque Alto, as well as technological influence from the site of Tiwanaku.