• Differentiating Bone Osteonal Turnover Rates by Density Fractionation; Validation Using the Bomb 14C Atmospheric Pulse

      Shin, Ji Young; O'Connell, Tamsin; Black, Stuart; Hedges, Robert (Department of Geosciences, The University of Arizona, 2004-01-01)
      The density (BSG) of bone increases, at the osteon scale, during lifetime aging within the bone. In addition, post-mortem diagenetic change due to microbial attack produces denser bioapatite. Thus, fractionation of finely powdered bone on the basis of density should not only enable younger and older populations of osteons to be separated but also make it possible to separate out a less diagenetically altered component. We show that the density fractionation method can be used as a tool to investigate the isotopic history within an individual's lifetime, both in recent and archaeological contexts, and we use the bomb 14C atmospheric pulse for validating the method.
    • The End of Empire: New Radiocarbon Dates from the Ayacucho Valley, Peru, and Their Implications for the Collapse of the Wari State

      Finucane, Brian Clifton; Valdez, J. Ernesto; Pérez Calderon, Ismael; Vivanco Pomacanchari, Cirilo; Valdez, Lidio M.; O'Connell, Tamsin (Department of Geosciences, The University of Arizona, 2007-01-01)
      This paper presents a suite of new accelerator mass spectrometry (AMS) radiocarbon measurements from the Ayacucho Valley of Peru and discusses their implications for the timing and nature of the collapse of the Wari Empire. Analysis of these and previously published dates from the region indicate that there is little evidence for state political authority in Ayacucho prior to the end of the 7th century. Dated human remains from the politys eponymous capital indicate that the authority of the states rulers persisted at least as late as the mid-11th century. Dates from rural sites in the Ayacucho Valley suggest continuity of occupation and folk material culture following Waris disintegration. Finally, AMS measurements of bone from 2 large extramural ossuaries represent the first absolute dates associated with Chanca ceramics and suggest that this archaeological/ethnohistoric culture appeared in the valley at about AD 1300.