• Cuello: Resolving the Chronology Through Direct Dating of Conserved and Low-Collagen Bone by AMS

      Law, I. A.; Housley, R. A.; Hammond, Norman; Hedges, R. E. M. (Department of Geosciences, The University of Arizona, 1991-01-01)
      It is well known that 14C dating of fossil bone with seriously depleted protein levels, or bone that has been consolidated with preservatives, can produce erroneous results. In the tropics, warm and moist soil conditions lead to constant reworking of organic matter and add to the danger of bone contamination. Because of this, 14C dating of preservative-impregnated bone from such areas has rarely been successful. We report here a set of AMS dates on both unconsolidated animal bone and polyvinyl acetate/polyvinyl alcohol (PVA/PV-OH) impregnated human burials from the Maya site of Cuello, Belize. The steps needed to purify the samples are described, together with details on the use of qualitative infra-red (IR) spectra as a means of assessing sample purity.
    • A Radiocarbon Chronology for Human-Induced Environmental Change on Mangaia, Southern Cook Islands, Polynesia

      Kirch, P. V.; Flenley, J. R.; Steadman, D. W. (Department of Geosciences, The University of Arizona, 1991-01-01)
      A suite of 23 14C age determinations, from a well-stratified rockshelter and from 3 pollen cores on Mangaia Island is reported. The rockshelter has yielded significant evidence for avifaunal extinctions during the period cal. A.D. 1000-1600. The Lake Tiriara pollen cores span a period from ca. 6500 cal. b.p. to the present, and palynological analysis of the TIR 1 core indicates major anthropogenic disturbance on the island's vegetation after ca. 1600 cal. B.P. These sites, and the radiocarbon ages associated with them, provide the first chronologically secure evidence for human impacts on the island ecosystems of the southern Cook Islands.