• Small Sample Dating in China

      Zhou, Weijian; Head, M. J.; Kaihola, Lauri (Department of Geosciences, The University of Arizona, 1994-01-01)
      The Xi'an Laboratory of Loess and Quaternary Geology has developed a small sample 14C dating facility consisting of a Wallac 1220 Quantulus(TM) liquid scintillation spectrometer, and a miniature benzene synthesis line based on the synthesis procedures used at the Australian National University (ANT). This line can produce ca. 0.3-ml benzene samples, which are then measured for 14C activity using 0.3-ml Teflon vials developed by Wallac Oy. The counting performance of the Quantulus(TM) spectrometer using 0.3-ml vials has been evaluated, and a potential age limit of ca. 45,000 BP has been obtained for samples containing up to 250 mg carbon. This dating facility fills the gap between large sample (2.4-6 g carbon) and microsample (<1 mg carbon) handling to form a 14C dating method sequence.
    • From the Editor

      Long, Austin (Department of Geosciences, The University of Arizona, 1994-01-01)
    • Hans E. Suess, 1909-1993

      Arnold, James R. (Department of Geosciences, The University of Arizona, 1994-01-01)
    • Stratigraphic Division of Holocene Loess in China

      Zhou, Weijian; An, Zhisheng; Head, M. J. (Department of Geosciences, The University of Arizona, 1994-01-01)
      Loess deposition within the Loess Plateau of China records the history of environmental change over the last 2.5 Myr. Loess-paleosol sequences of the last 10 ka, which have preserved information of global climate change, relate closely to human occupation of the area. Hence, studies of the deposition and development of Holocene loess are significant for studying environmental change and problems associated with engineering geology. We present here stratigraphic relations among four profiles from the south, west and center of the Loess Plateau. On the basis of 14C radiometric and AMS dates of organic material extracted from the paleosols, together with magnetic susceptibility measurements down each profile, we discuss Holocene stratigraphic divisions within the Loess Plateau, and suggest that the Holocene optimum, characterized by paleosol complexes, occurred between 10 and 5 ka BP. From 5 ka BP to the present, neoglacial activity is characterized by recently deposited loess.
    • Jean-Charles Fontes (3 November 1936 – 2 February 1994)

      Fritz, Peter; Gonfiantini, Roberto; Zuppi, GianMaria (Department of Geosciences, The University of Arizona, 1994-01-01)
    • Radiocarbon Dates

      Department of Geosciences, The University of Arizona, 1994-01-01
    • Radiocarbon After Four Decades: An Interdisciplinary Perspective [Announcement]

      Department of Geosciences, The University of Arizona, 1994-01-01
    • Radiocarbon 1994 Price List

      Department of Geosciences, The University of Arizona, 1994-01-01