• 25 Years of Trospheric 14C Observations

      Ingeborg Levin; Kromer, Bernd; Schoch-Fischer, Hildegard; Michael Bruns; Münnich, Marianne; Berdau, Dietrich; Vogel, John C.; Münnich, Karl Otto (American Journal of Science, 1985-01-01)
      A long-term mountain station series of tropospheric 14C data for the period 1959 to 1984 is presented. This series is considered representative of the higher altitude 14C level over central Europe. Even tree-ring 14C levels from a rural ground level site in southern Germany are consistently lower (by Delta-14C depression = -15 per mil if compared with the mountain station summer average in atmospheric CO2). The rural tree-ring series is considered to represent the additional continental Suess effect at ground level without local contamination. This Suess effect decreases gradually with the distance from the ground (ie, source) level. We therefore estimate the additional continental Suess effect in the vegetation period to be Delta-14C depression = -5 per mil for the mountain station and -20 per mil for a rural ground level site, respectively. Based on this assumption, yearly mean tropospheric 14C levels corrected for fossil fuel contamination and representative of the Northern Hemisphere are provided for use in global carbon cycle models.
    • Amplitude of Sunspot-Dependent Radiocarbon Variations: Data from Corals and Wine

      Magaritz, Mordeckai; Carmi, Israel; Sirkes, Ziv (American Journal of Science, 1985-01-01)
    • Contamination Studies on Mollusk Shell Samples

      Goslar, Tomasz; Pazdur, Mieczysław F. (American Journal of Science, 1985-01-01)
      A series of shell samples has been studied to determine the magnitude and mechanisms of carbon exchange between shells and their environment. Laboratory contamination experiments included the storing of shell samples in acid and calcareous environments of different 14C concentrations as well as studies of carbon exchange in the course of thermal recrystallization in solid state in an atomosphere of carbon dioxide. The applicability of differential thermal analysis to studies of the structure and texture of shells is discussed.
    • Gliwice Radiocarbon Dates X

      Pazdur, Mieczysław F.; Awsiuk, Romuald; Bluszcz, Andrzej; Goslar, Tomasz; Pazdur, Anna; Walanus, Adam; Zastawny, Andrezej (American Journal of Science, 1985-01-01)
    • Harwell Radiocarbon Measurements IV

      Walker, A. J.; Otlet, R. L. (American Journal of Science, 1985-01-01)
    • La Jolla Measurements of Radiocarbon in South German Oak Tree-Ring Chronologies

      Linick, T. W.; Suess, H. E.; Brecker, Bernd (American Journal of Science, 1985-01-01)
      Radiocarbon measurements made by the La Jolla laboratory on tree-ring samples from South German oak chronologies are presented. Several previously separate treering series have been reduced to one absolutely dendro-dated chronology spanning the period from 4066 BC to the present and one still-floating chronology which spans the approximate period 7225 to 4125 BC. Previous estimates of the dendro-years made by the authors are compared with the dendro-years now assigned.
    • Notice to Readers and Contributors

      American Journal of Science, 1985-01-01
    • Physical Research Laboratory Radiocarbon Date List V

      Agrawal, D. P.; Krishnamurthy, R. V.; Kusumgar, Sheela (American Journal of Science, 1985-01-01)
    • Radiocarbon, Volume 27, Number 1 (1985)

      American Journal of Science, 1985-01-01
    • Woods Hole Oceanographic Institution Radiocarbon Laboratory: Sample Treatment and Gas Preparation

      Griffin, Sheila; Druffel, Ellen R. M. (American Journal of Science, 1985-01-01)