• Radiocarbon Age Anomalies in Shell Carbonate of Land Snails from Semi-Arid Areas

      Goodfriend, Glenn A. (American Journal of Science, 1987-01-01)
      Radiocarbon age anomalies, resulting from ingestion of old carbonate, were measured in shell carbonate of live-collected snails from arid and semi-arid areas of Israel and the West Bank. The age anomalies were found to be similar to those in land snails from other climatic regions and averaged ca 1600 yr in Trochoidea seetzeni, 2200 yr in Sphincterochila spp, 800 yr in Levantina sp, and 1700 yr in coastal dune species. The differences are associated with ecological differences among taxa. The uncertainties of the age anomalies average several hundred years within each group. This renders radiocarbon dates of late Holecene snails relatively imprecise, whereas it has almost no effect on the age uncertainties of relatively old samples (ie, those with large errors of measurement). Procedures for correction for fractionation are discussed.
    • Radiocarbon, Volume 29, Number 2 (1987)

      American Journal of Science, 1987-01-01
    • Southern Methodist University Radiocarbon Date List III

      Haas, Herbert (American Journal of Science, 1987-01-01)
    • Tbilisi Radiocarbon Dates IV

      Burchuladze, A. A.; Togonidze, G. I. (American Journal of Science, 1987-01-01)
    • The Impact of Bioturbation on a AMS 14C Dates on Handpicked Foraminifera: A Statistical Model

      Andree, Michael (American Journal of Science, 1987-01-01)
      When single species of foraminifera picked from marine sediments are 14C dated with Accelerator Mass Spectrometry (AMS), bioturbation puts limits on the minimal sample size to be used, as uncertainty is added to the result by statistics of the picking process. The model presented here simulates the additional statistical uncertainty introduced into the measurement by the coupling of bioturbation and small sample amounts. As there is no general solution for this problem, we present two simple cases only. The model can also be used to simulate more complicated situations occurring in sediments.
    • University of Waikato Radiocarbon Dates I

      Hogg, Alan G.; Lowe, David J.; Hendy, Chris H. (American Journal of Science, 1987-01-01)