• Why Early-Historical Radiocarbon Dates Downwind from the Mediterranean are Too Early

      Keenan, Douglas J. (Department of Geosciences, The University of Arizona, 2002-01-01)
      Several authors have claimed that radiocarbon dates in the Ancient Near East are too early. Herein, a hypothesis that might explain this is presented. Marine degassing of "old" carbon (i.e. 14C-deficient C), induced by upwelling of old subsurface water, has been observed, n modern times, to cause century-scale 14C ages in the surface atmosphere. A review of the Mediterranean Sea post-ice-age circulation concludes that the subsurface waters became very old, primarily due to millennia-long stagnation. It is hypothesized that as the stagnation ended, subsurface waters were brought towards the surface, where they degassed old carbon. Additionally, Anatolian dendrochronology is shown to not contradict the hypothesis.
    • WOCE Radiocarbon IV: Pacific Ocean Results; P10, P13N, P14C, P18, P19 & S4P

      Key, Robert M.; Quay, Paul D.; Schlosser, Peter; McNichol, A. P.; von Reden, K. F.; Schneider, Robert J.; Elder, Kathy L.; Stuiver, Minze; Östlund, H. Göte (Department of Geosciences, The University of Arizona, 2002-01-01)
      The World Ocean Circulation Experiment, carried out between 1990 and 1997, provided the most comprehensive oceanic study of radiocarbon to date. Approximately 10,000 samples were collected in the Pacific Ocean by U.S. Investigators for both conventional large volume B counting and small volume accelerator mass spectrometry analysis techniques. Results from six cruises are presented. The data quality is as good or better than previous large-scale surveys. The 14C distribution for the entire WOCE Pacific data set is graphically described using mean vertical profiles and sections, and property-property plots.