• 14C Wiggle Matching of the 'Floating' Tree-Ring Chronology from the Altai Mountains, Southern Siberia: The Ulkandryk-4 Case Study

      Slusarenko, I. Y.; Christen, J. A.; Orlova, L. A.; Kuzmin, Yaroslav V.; Burr, George S. (Department of Geosciences, The University of Arizona, 2001-01-01)
      The Bayesian approach to calibration of radiocarbon dates was used to wiggle-match the "floating" tree-ring chronology from a Pazyryk culture (Scythian-type complex from Sayan-Altai Mountain system, southern Siberia) burial ground in order to estimate the calendar age of its construction. Seventeen bidecadal tree-ring samples were 14C dated with high precision (+/20-30 yr). The results of wiggle-matching show that the Pazyryk-type burial mounds in the southern Altai Mountains were created in the first part of 3rd century BC.
    • A Fresh Water Diet-Derived 14C Reservoir Effect at the Stone Age Sites in the Iron Gates Gorge

      Cook, Gordon T.; Bonsall, C.; Hedges, Robert E. M.; McSweeney, K.; Boronean, V.; Pettitt, Paul B. (Department of Geosciences, The University of Arizona, 2001-01-01)
      Human bones from single inhumation burials and artifacts made from terrestrial mammal (ungulate) bone found in direct association with the skeletons were obtained from the Stone Age site of Schela Cladovei situated just below the Iron Gates Gorge of the River Danube. The results of stable isotope analyses of the human bone collagen are consistent with a heavy dependence on aquatic protein while radiocarbon dating of the samples reveals an offset of 300-500 years between the two sample types, indicating a freshwater reservoir effect in the human bone samples. Since protein consumption is by far the major source of nitrogen in the human diet we have assumed a linear relationship between delta-15N and the level of aquatic protein in each individual's diet and derived a calibration for 14C age offset versus delta-15N which has been applied to a series of results from the site at Lepenski Vir within the gorge. The corrected 14C ages (7310-6720 BP) are now consistent with the previous 14C age measurements made on charcoal from related contexts (7360-6560 BP). In addition, the data indicate a change from a primarily aquatic to a mixed terrestrial/aquatic diet around 7100 BP and this may be argued as supporting a shift from Mesolithic to Neolithic. This study also has wider implications for the accurate dating of human bone samples when the possibility exists of an aquatic component in the dietary protein and strongly implies that delta-15N analysis should be undertaken routinely when dating human bones.
    • Marine Radiocarbon Reservoir Effect in the Western North Pacific Observed in Archaeological Fauna

      Yoneda, Minoru; Hirota, Masashi; Uchida, Masao; Uzawa, Kazuhiro; Tanaka, Atsushi; Shibata, Yasuyui; Morita, Masatoshi (Department of Geosciences, The University of Arizona, 2001-01-01)
      Faunal remains originating from terrestrial and marine mammals, and belonging to the same archaeological deposits were compared to evaluate the marine radiocarbon reservoir ages around the Hokkaido island, Japan. From five shell middens of different ages from the Jomon period (4900 BP) to the Ainu cultural period (800 BP), 107 animal bone samples were selected for radiocarbon measurements. The apparent age differences between Japanese deer and northern fur seal showed the clear effect of deep-water upwelling in this region. Our data showed relatively stable age differences from 4500 BP to 800 BP, with an estimated Delta-R values around 380 14C yr. Results are consistent with previous estimation based on simulation models and oceanographic properties.
    • New Methods and Critical Aspects in Bayesian Mathematics for 14C Calibration

      Steier, Peter; Rom, Werner; Puchegger, Stephan (Department of Geosciences, The University of Arizona, 2001-01-01)
      The probabilistic radiocarbon calibration approach, which largely has replaced the intercept method in 14C dating, is based on the so-called Bayes' theorem (Bayes 1763). Besides single-sample calibration, Bayesian mathematics also supplies tools for combining 14C results of many samples with independent archaeological information such as typology or stratigraphy (Buck et al. 1996). However, specific assumptions in the "prior probabilities", used to transform the archaeological information into mathematical probability distributions, may bias the results (Steier and Rom 2000). A general technique for guarding against such a bias is "sensitivity analysis", in which a range of possible prior probabilities is tested. Only results that prove robust in this analysis should be used. We demonstrate the impact of this method for an assumed, yet realistic case of stratigraphically ordered samples from the Hallstatt period, i.e. The Early Iron Age in Central Europe.
    • Radiocarbon and Dendrochronological Dating of Logboats from Poland

      Pazdur, Anna; Krąpiec, Marek; Michczyński, Adam; Ossowski, Waldemar (Department of Geosciences, The University of Arizona, 2001-01-01)
      The earliest dating of samples taken from logboats found in the area of Poland was done at the Gliwice Radiocarbon Laboratory in the late 1970s and early 1980s. After a 10-year break, the study of their chronology was renewed. The 14C dates (56) include all previously published and new, unpublished results obtained during last several years. Here, we discuss and provide probabilistic interpretation of the calendar age of the dated boats. The calibration of 14C dates was done with the OxCal program for dates less than 300 BP, and with the GdCALIB program for all remaining dates. In distribution of calibrated dates we find a lack of samples between the ages of around 800 BC and 300 AD. This result is surprising and differs from results observed for Central Europe. The remaining age ranges, with high frequency of dates, are in good coincidence with similar periods obtained for Central Europe. Tree-ring dating of oak logboats was carried out on 60 growth sequences, dated against standard chronologies defined for the area of Poland. The results of 14C dating and tree-ring analyses give consistent chronologies.
    • Radiocarbon Dating of Single Compounds Isolated from Pottery Cooking Vessel Residues

      Stott, A. W.; Berstan, R.; Evershed, P.; Hedges, Robert E. M.; Bronk Ramsey, Christopher; Humm, M. J. (Department of Geosciences, The University of Arizona, 2001-01-01)
      We have developed and demonstrated a practical methodology for dating specific compounds (and octadecanoic or stearic acid—C18:0—in particular) from the lipid material surviving in archaeological cooking pots. Such compounds may be extracted from about 10 g of cooking potsherd, and, after derivatization, can be purified by gas chromatography. To obtain sufficient material for precise dating repetitive, accumulating, GC separation is necessary. Throughout the 6000-year period studied, and over a variety of site environments within England, dates on C18:0 show no apparent systematic error, but do have a greater variability than can be explained by the errors due to the separation chemistry and measurement process alone. This variability is as yet unexplained. Dates on C16:0 show greater variability and a systematic error of approximately 100-150 years too young, and it is possible that this is due to contamination from the burial environment. Further work should clarify this.
    • The Chemical and Enzymatic Hydrolysis of Archaeological Wood Cellulose and Monosaccharide Purification by High pH Anion Exchange Chromatography for Compound-Specific Radiocarbon Dating

      Hodgins, Gregory L.; Butters, T. D.; Bronk Ramsey, Christopher; Hedges, Robert E. M. (Department of Geosciences, The University of Arizona, 2001-01-01)
      Preliminary experiments were carried out on archaeological wood to investigate methods of cellulose hydrolysis and carbohydrate monomer purification for the purpose of compound-specific radiocarbon dating. The Chelford log, a known 14C dead source of wood cellulose, was selected for study in order to investigate the levels of contamination introduced during sample purification. Two methods of hydrolysis were examined, mineral acid hydrolysis and enzyme hydrolysis using cellulase from Penicillium funiculosum. Under the conditions described, enzymolysis was far superior to acid hydrolysis in terms of the glucose monomer yield. Glucose monomer purification was accomplished using high pH anion exchange chromatography with pulsed amperometric detection. This high performance liquid chromatography (HPLC) method does not require sample derivatization and the chromatography products can be collected in water. These characteristics make it potentially well suited to carbon dating applications. 14C dating of chromatographically purified glucose fractions revealed significant levels of contamination had accumulated during both protocols. Glucose contamination from the cellulase enzyme preparation was a major source of contamination within the enzymatically hydrolyzed samples. Ultrafiltration of the enzyme removed some but not all of this contamination. The contamination must be reduced 10-fold before the methodology could be viable for dating. This hydrolysis/HPLC method is also being investigated for 14C dating of other carbohydrate polymers such as chitin.
    • Transition Dating' – A Heuristic Mathematical Approach to the Collation of Radiocarbon Dates from Stratified Sequences

      Sharon, Ilan (Department of Geosciences, The University of Arizona, 2001-01-01)
      A heuristic approach, nicknamed "transition dating," was used to date sequences of early Iron Age contexts using a series of 14C determinations. The basic principles of transition dating are simple and intuitive: 1) attempt to date transitions between periods, phases, etc. Rather than the phases themselves, and 2) the most plausible date for that transition is one that is later than the dates from contexts preceding it, and is still earlier than the dates succeeding it. Hypotheses regarding the actual date of each transition may be evaluated using an appropriate loss function. These loss functions can also be adjusted or weighted by the user to account differentially for the various factors causing the distortion or "fuzz" in the dates.