• A Regional Geochronological Study of Late Pleistocene Permafrost

      Kostyukevich, V. V. (Department of Geosciences, The University of Arizona, 1993-01-01)
      The use of radiocarbon dating in geocryological investigations makes it possible to establish a chronology for permafrost-geological development during the Late Pleistocene. Both global and regional time scales for the formation of Late Pleistocene permafrost have been worked out over the past 15-20 years at the Permafrost Institute of the Siberian Branch of the Russian Academy of Sciences. I present here results from study areas of northwestern Siberia and of North, Central and West Yakutia.
    • An Improved Method for Radiocarbon Dating Fossil Bones

      Arslanov, Kh A.; Svezhentsev, Yu S. (Department of Geosciences, The University of Arizona, 1993-01-01)
      We demonstrate here that the use of either the acid-alkali or Longin method alone does not fully extract contaminants from bone-collagen fractions. We present our methods and results of extracting bone collagen that involve successive use of both of these methods.
    • Dynamics of Radiocarbon in Soils

      Cherkinsky, A. E.; Brovkin, V. A. (Department of Geosciences, The University of Arizona, 1993-01-01)
      We present here a model of humus accumulation in recent soils. We have estimated the coefficients of mineralization of humus and humic acid for a typical Chemozem soil. We suggest a technique for calculating the renewal time of soil with specific activity higher than the modem standard and discuss the results for different soils.
    • Late Paleolithic Chronology of the East European Plain

      Svezhentsev, Yu S.; Popov, S. G. (Department of Geosciences, The University of Arizona, 1993-01-01)
      We report 172 dates on osseous material from Paleolithic sites of the East European Plain.
    • Problems and Methods of Dating Low-Activity Samples by Liquid Scintillation Counting

      Arslanov, Kh A.; Tertychnaya, T. V.; Chernov, S. B. (Department of Geosciences, The University of Arizona, 1993-01-01)
      The important problem of contamination of old samples by younger 14C necessitates treatment of organic and carbonate samples to ensure more complete removal of contaminating carbon. Here we present studies of chemical procedures for the liquid scintillation method of 14C dating undertaken since 1960 in the former USSR. We discuss new procedures such as lithium carbide synthesis from charred organic samples and benzene synthesis on a V2O5.Al2O3.SiO2 catalyst, as well as memory effect in the carbide synthesis procedure and characteristics of two homemade counters.
    • Problems in Radiocarbon Dating of Soils

      Chichagova, O. A.; Cherkinsky, A. E. (Department of Geosciences, The University of Arizona, 1993-01-01)
      We discuss our progress in three principal applications of 14C dating of recent and fossil soils: 1) new methods; 2) problems of interpreting 14C soil data (e.g.,14C age of soils, age of soils, duration of humus formation, rate of carbon cycling); and 3) 14C analysis of soil organic matter (OM) in pedology and paleogeography (e.g., soil genesis and evolution, humus formation and OM metamorphosis, geochronology and stratigraphy of Late Pleistocene and Holocene sediments). We suggest exploring the above issues in the analysis of each 14C profile in conjunction with paleogeographical data, and by simulation of the carbon cycle in each type of profile.
    • Radiocarbon Dating Organic Detritus: Implications for Studying Ice Sheet Dynamics

      Punning, Jaan-Mati; Rajamäe, Raivo (Department of Geosciences, The University of Arizona, 1993-01-01)
      We present here a description of the 14C dating method used at the Institute of Geology, Estonian Academy of Science. We discuss results of geochronological studies of several stratigraphic sections, from which we estimate the age of the Late Weichselian (Late Valdaian) glacial maximum. 14C and paleobotanical data indicate that biodetrital materials comprise organic debris from various sources and suggest only a maximum age of investigated strata (16,000 BP).
    • The Reliability of Radiocarbon Dating Buried Soils

      Orlova, L. A.; Panychev, V. A. (Department of Geosciences, The University of Arizona, 1993-01-01)
      Variable 14C ages of paleosol organic matter (OM) cause difficulties in interpreting 14C data. We attempt to determine the reliability of OM 14C dates by examining different carbon-containing materials from soil horizons and paleosol fractions.