Provisioning of the Inka army in wartime: obsidian procurement in Pambamarca, Ecuador

Ninety-nine obsidian artifacts from fortified and non-fortified sites in the Pambamarca region of northern Ecuador were analyzed with XRF to examine patterns of procurement of obsidian by soldiers in the Inka army and by the local Cayambes who were resisting Inka conquest. The results show that the Inkas acquired material from several different sources, a pattern consistent with provisioning by subject peoples in partial fulfillment of labor obligations. The Cayambes also acquired material from multiple sources, although they may not have directly procured material from all of the sources because the external boundary of Inka territory bisected the region of obsidian sources. That frontier may have prevented the Inkas from accessing one source, Callejones, from which the Cayambes acquired some of their obsidian. In addition, the Inkas were acquiring some obsidian from the Yanaurco-Quiscatola source, which had been previously abandoned around AD 1000.