• 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.
    • 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.
    • Geochronology of Late Quaternary Events in Northeastern Russia

      Lozhkin, A. V. (Department of Geosciences, The University of Arizona, 1993-01-01)
      Radiocarbon-dated paleobotanical and palynological samples record complex changes of vegetation and climate in northeastern Russia during the Late Pleistocene and Holocene. Since the Kargin Interval (middle Wisconsin equivalent), which started 50 ka ago, we can distinguish two periods that were colder than the present. The Kirgilyakh was the earliest Karginsk cool period, dating to 45–39 ka BP. The second significant cool period dates to 33–30 ka BP. The boundary between the Kargin Interval and the last Late Pleistocene glaciation (Sartan, late Wisconsin equivalent) dates from 27 ka BP. The sharp change from herbaceous mossy tundra (Sartan) to light-coniferous larch forests (Holocene) in northeastern Russia dates to 12.5 ka ago. The Holocene thermal maximum, linked to the expansion of woody plants into the modern barren-ground tundra, dates from 9.5–8 ka BP.
    • Geochronology of the Nival-Glacial Deposits of the Ukrainian Carpathian Mountains

      Kovalyukh, N. N.; Petrenko, L. V.; Kovalenko, V. V. (Department of Geosciences, The University of Arizona, 1993-01-01)
    • Late Pleistocene Geochronology of European Russia

      Arslanov, Kh A. (Department of Geosciences, The University of Arizona, 1993-01-01)
      I constructed a Late Pleistocene geochronological scale for European Russia employing 14C dating and paleobotanical studies of several reference sections.
    • Radiocarbon Chronology of Paleogeographic Events of the Late Pleistocene and Holocene in Russia

      Kaplin, P. A.; Svitoch, A. A.; Parunin, O. B. (Department of Geosciences, The University of Arizona, 1993-01-01)
      14C chronology of Late Pleistocene paleogeographical events in the Black Sea-Caspian Sea region shows that the following transgressions partly correlate with each other: Karangat and Khazarian; Neo-Euxinian and Khvalyn; Holocene and Neo-Caspian. The main climatic events were synchronous in intercontinental Siberia. In the far eastern region, the Middle-Wisconsinan transgression is reflected by Chukotka and western Kamchatka terraces and by submerged ancient shorelines in Primorye.
    • 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).