• Age Structure of Holocene Coastal Sediments: Gulf of Carpentaria, Australia

      Rhodes, E. G.; Polach, H. A.; Thom, B. G.; Wilson, S. R. (American Journal of Science, 1980-01-01)
      Shells in beach-ridge and chenier Holocene deposits from the Gulf of Carpentaria, Queensland, have been dated by radiocarbon. Possible contamination of carbonate by post-depositional diagenetic processes, isotopic fractionation, ocean reservoir environmental effect, and association of biological age of sample material with depositional event have been examined in order to validate dating of samples from this environment. A numerical methodology used for comparing 'groups' of 14C dates strongly supports morphostratigraphic evidence that time discontinuities occur within both chenier and beach-ridge sequences. Four episodes are recognized in each area, all younger than ca 5800 years ago, the time when sea level reached its postglacial maximum in the Gulf of Carpentaria. To some extent, these episodes are out of phase, reflecting different modes of strandline accumulation.
    • Exploratory Analysis of the International Radiocarbon Cross-Calibration Data: Consensus Values and Interlaboratory Error: Preliminary Note

      Currie, L. A.; Polach, H. A. (American Journal of Science, 1980-01-01)
      A preliminary review is given of the evaluation of the International Cross-Calibration Radiocarbon Data. Consensus values and standard errors are D14C = 508.1 +/- 2.0 per mil (ANU Sucrose) and Delta = -2.5 +/- 1.5 per mil, (1850 Wood). Reporting format follows recornmendations of Stuiver and Polach (1977).