• On the 14C and 39Ar Distribution in the Central Arctic Ocean: Implications for Deep Water Formation

      Schlosser, Peter; Kromer, Bernd; Östlund, Gote; Ekwurzel, Brenda; Bönisch, Gerhard; Loosli, H. H.; Purtschert, Roland (Department of Geosciences, The University of Arizona, 1994-01-01)
      We present Delta-14C and 39Ar data collected in the Nansen, Amundsen and Makarov basins during two expeditions to the central Arctic Ocean (RV Polarstern cruises ARK IV/3, 1987 and ARK VIII/3,1991). The data are used, together with published Delta-14C values, to describe the distribution of Delta-14C in all major basins of the Arctic Ocean (Nansen, Amundsen, Makarov and Canada Basins), as well as the 39Ar distribution in the Nansen Basin and the deep waters of the Amundsen and Makarov Basins. From the combined Delta-14C and 39Ar distributions, we derive information on the mean "isolation ages" of the deep and bottom waters of the Arctic Ocean. The data point toward mean ages of the bottom waters in the Eurasian Basin (Nansen and Amundsen Basins) of ca. 250-300 yr. The deep waters of the Amundsen Basin show slightly higher 3H concentrations than those in the Nansen Basin, indicating the addition of a higher fraction of water that has been at the sea surface during the past few decades. Correction for the bomb 14C added to the deep waters along with bomb 3H yields isolation ages for the bulk of the deep and bottom waters of the Amundsen Basin similar to those estimated for the Nansen Basin. This finding agrees well with the 39Ar data. Deep and bottom waters in the Canadian Basin (Makarov and Canada Basins) are very homogeneous, with an isolation age of ca. 450 yr. Delta-14C and 39Ar data and a simple inverse model treating the Canadian Basin Deep Water (CBDW) as one well-mixed reservoir renewed by a mixture of Atlantic Water (29%), Eurasian Basin Deep Water (69%) and brine-enriched shelf water (2%) yield a mean residence time of CBDW of ca. 300 yr.
    • Radiocarbon, Volume 36, Number 3 (1994)

      Department of Geosciences, The University of Arizona, 1994-01-01
    • Radiocarbon Dating of the Stone and Bronze Age Sites in Primorye (Russian Far East)

      Kuzmin, Yaroslav V.; Orlova, Lyobov A.; Sulerzhitsky, Leopold D.; Jull, A. J. T. (Department of Geosciences, The University of Arizona, 1994-01-01)
    • 1995 Price List

      Department of Geosciences, The University of Arizona, 1994-01-01
    • Comparison of Manual and Automated Pretreatment Methods for AMS Radiocarbon Dating of Plant Fossils

      Bradley, Lee-Ann; Stafford, Thomas W. (Department of Geosciences, The University of Arizona, 1994-01-01)
      A new automated pretreatment system for the preparation of materials submitted for accelerator mass spectrometry (AMS) analysis is less time-consuming and results in a higher sample yield. The new procedure was tested using two groups of plant fossils: one group was pretreated using the traditional method, and the second, using the automated pretreatment apparatus. We compared the time it took to complete the procedure and the amount of sample material remaining. The automated pretreatment apparatus proved to be more than three times faster and, in most cases, produced a higher yield. We also observed a darker discoloration of the KOH solutions, indicating that the automated system is more thorough in removing humates from the specimen compared to the manual method.
    • Radiocarbon Updates

      Department of Geosciences, The University of Arizona, 1994-01-01
    • Dating the Prehistoric Site Nahal Issaron in the Southern Negev, Israel

      Carmi, Israel; Segal, Dror; Goring-Morris, A. N.; Gopher, Avi (Department of Geosciences, The University of Arizona, 1994-01-01)
      The prehistoric site Nahal Issaron is located on the alluvial fan of Nahal Issaron, a short wadi draining into Biqat Uvda some 50 km north of Eilat. Excavated in the early 1980s, it constitutes a major Pre-Pottery Neolithic B (PPNB) layer, with continued but sporadic occupation throughout the Late Neolithic to the Chalcolithic period. In the PPNB layer, a dense agglomeration of rounded, polygonal and rectangular structures was found, with courtyards and a variety of features such as hearths and ovens. The upper layer is badly preserved, apart from the hearths and ovens. Thirty samples from the site were 14C-dated in the Rehovot laboratory and five in the Pretoria laboratory. The results enabled a fine temporal resolution between layers and a refinement of the 7th through 5th millennium BC chronology. The dates also placed the sequence of changes in architecture and lithics within a more robust temporal framework, thus making the site a key chronological anchor in the Neolithic of Southern Israel, Sinai and Jordan.
    • From Radiocarbon: Calibration 1993

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

      Department of Geosciences, The University of Arizona, 1994-01-01
    • From Radiocarbon: Late Quaternary Chronology and Paleoclimates of the Eastern Mediterranean

      Department of Geosciences, The University of Arizona, 1994-01-01
    • 7th International Conference on Accelerator Mass Spectrometry

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

      Department of Geosciences, The University of Arizona, 1994-01-01
    • Human Settlements and the Last Deglaciation in the French Alps

      Evin, Jacques; Bintz, Pierre; Monjuvent, Guy (Department of Geosciences, The University of Arizona, 1994-01-01)
      According to most geological and geomorphological studies, the maximal advance of the Wurmian glaciers in the French Alps occurred at least before 40 ka BP and cannot be dated by 14C. Scientists believed that this dating method could be used for dating the last glacial advance and late deglaciation in the region. The scarce and scattered 14C dating results available from geological samples do not confirm an early (ca. 18 or 20 ka BP) age for the total cooling of the ice nor do they prove that residual ice sheets remained at low elevations. Attempting to solve this chronological problem, we compiled current archaeological knowledge of the oldest Late Paleolithic sites. A review of their 14C results shows that no site older than 15 ka BP (with Gravettian, Solutrean or early Magdalenian industries) can be found east of the Saone-Rhone Valley, even at low elevations. Only rare sites, dated to ca. 14.5 ka BP, may be found close to the mountain regions that were suddenly occupied around the beginning of the Bulling period (ca. 13.5 ka BP). Thus, it seems that the eastern Alps offer no evidence for direct association between glacial retreat and human settlement or simultaneous occurrence in early or late deglaciated areas.
    • From Radiocarbon: LSC 92

      Department of Geosciences, The University of Arizona, 1994-01-01
    • Associate Editors

      Department of Geosciences, The University of Arizona, 1994-01-01
    • Author Index – Volume 36, 1994

      Department of Geosciences, The University of Arizona, 1994-01-01
    • Radiocarbon Dating Sites of Northwest Russia and Latvia

      Zaitseva, G. I.; Popov, S. G. (Department of Geosciences, The University of Arizona, 1994-01-01)
      We describe applications of radiocarbon dating used for establishing a chronology of archaeological sites of the Novgorod region at the end of the first millennium AD. We have 14C-dated known-age tree rings from sites in Latvia and ancient Novgorod, northwest Russia, as well as charcoal and wood from Novgorod. Calendar ages of 14C-dated tree rings span the interval, AD 765-999. We used the Groningen calibration program, CAL15 (van der Plicht 1993) to calibrate 14C ages to calendar years. Comparisons between 14C results and archaeological data show good agreement, and enable us to narrow the calendar interval of calibrated 14C determinations.
    • Subject Index – Volume 36, 1994

      Department of Geosciences, The University of Arizona, 1994-01-01
    • From the Editors

      Long, Austin; Jull, A. J. T.; Kra, Renee S. (Department of Geosciences, The University of Arizona, 1994-01-01)