• W. F. Libby and the Archaeologists, 1946-1948

      Marlowe, Greg (American Journal of Science, 1980-01-01)
      Archaeologists began to participate in cross-disciplinary endeavors in the 1930's, albeit on a very limited basis. The passage of time found members of that discipline unprepared for collaboration with physical scientists when W F Libby announced the development of the radiocarbon dating method. Libby proposed to apply to archeologic and geologic samples techniques based on ideas that were completely foreign to archeology.... The initial reactions of archeologists were sometimes amusing but more often significant, for they led to the foundation and emergence of the radiocarbon chronology that has so profoundly affected our understanding of prehistory (Johnson, 1967, p 165). To date, our historical knowledge about the nature, function, and impact of the early (1946-1948) relations between Libby and American archaeologists has come to us in the form of published anecdotes, many of which contain inaccurate information. The author's access to W F Libby's private 14C correspondence, combined with data obtained from interviews with some of the principal participants throughout this period, offers many new or different insights into the nascent years of radiocarbon dating. When, and under what unexpected cricumstances, did Libby first encounter representatives of the achaeologic community? What strategies were employed to facilitate diffusion of knowledge about 14C dating across disciplinary boundaries? How did archaeologists respond to the introduction or "intrusion" into their field of Libby's radioactive age-measurement tool?
    • Wadi Shaw 82/52: 14C Dates from a Peridynastic Site in Northwest Sudan, Supporting the Egyptian Historical Chronology

      Lange, Mathias (Department of Geosciences, The University of Arizona, 1998-01-01)
      In the framework of the interdisciplinary project "Settlement History of the Eastern Sahara" at the Universitat zu Koln, a large number of sites were excavated during the 1980s in northern Sudan, where the Laqiya-region with the Wadi Shaw and Wadi Sahal was one of the main research areas. About 150 sites have been surveyed and partly excavated. One of these sites, Wadi Shaw 82/52, yielded sherds of a Maidum bowl, which is dateable to the Egyptian IVth and Vth Dynasty. This site was dated by four radiocarbon dates. The dates are compared with the historical chronology of Egypt for the IVth and Vth Dynasty, and are shown to be in good agreement.
    • Washington State University Natural Radiocarbon II

      Sheppard, J. C.; Chatters, R. M. (American Journal of Science, 1976-01-01)
    • Washington State University Natural Radiocarbon Measurements I

      Chatters, Roy M. (American Journal of Science, 1968-01-01)
    • Water Column Profiles of Dissolved Inorganic Radiocarbon for the Kuroshio Region, Offshore of the Southern Japanese Coast

      Tsuboi, Tatsuya; Iwata, Hiroshi; Wada, Hideki; Matsuzaki, Hiroyuki; Sohrin, Rumi; Hiroe, Yutaka; Ichikawa, Tadafumi; Hidaka, Kiyotaka; Watanabe, Tomoo (Department of Geosciences, The University of Arizona, 2011-12-16)
      We present the water column profiles (surface to 2000 m depth) for dissolved inorganic radiocarbon ([delta]14CDIC) from 2 stations in the Kuroshio region including the Kuroshio large meander (LM) of 2004–2005. Surprisingly, the [delta]14CDIC value varied up to 125‰ in the intermediate layer, especially near 600 m depth. In addition, the [delta]14CDIC value was approximately -150‰ at 200 m depth at the northern station of Kuroshio in August 2005. This value is ~100‰ less than other [delta]14CDIC values for the same depth. In comparison, the [delta]14CDIC water column profiles for the southern station of Kuroshio and GEOSECS station 224 decrease down to 600 m depth and were similar below 600 m depth. Our results suggest that strong upwelling associated with the Kuroshio LM has a powerful influence on the [delta]14CDIC water column profiles in the study region.
    • Welcoming Address on Behalf of the Local Organising Committee

      Harkness, Doug (Department of Geosciences, The University of Arizona, 1995-01-01)
    • What Future for Radiocarbon?

      Scott, E. M.; Harkness, D. D. (Department of Geosciences, The University of Arizona, 2000-01-01)
      n this short article, we summarize some milestones in the 50-yr-long development of natural 14C measurement. In the light of this appraisal we presume to hazard some personal opinions and forecasts as to where best opportunities might lie for future gains from the continued investment in applied 14C science. The technique and the journal are one and the same in this regard.
    • Who's That Lying in My Coffin? An Imposter Exposed by 14C Dating

      Sowada, Karin; Jacobsen, Geraldine E.; Bertuch, Fiona; Palmer, Tim; Jenkinson, Andrew (Department of Geosciences, The University of Arizona, 2011-01-01)
      In the 19th and early 20th centuries, many museums acquired Egyptian coffins containing mummies from private donors who bought them from dealers in Egypt. Owing to the unknown context of such acquisitions, it cannot be assumed that the mummified individual inside the coffin is the same person named on it. Radiocarbon dating is a key diagnostic test, within the framework of a multidisciplinary study, to help resolve this question. The dating of an adult mummy in the Nicholson Museum at the University of Sydney was therefore checked using 14C dating. For over 150 yr, mummy NM R28.2 was identified as Padiashaikhet as per his coffin, dated to the 25th Dynasty, about 725-700 BC. 14C results from samples of linen wrappings revealed that the mummy was an unknown individual from the Roman period, cal AD 68-129. The mummification technique can now be understood within its correct historical context.
    • 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.
    • 'Wiggle Matching’ Radiocarbon Dates

      Bronk Ramsey, Christopher; van der Plicht, Johannes; Weninger, B. (Department of Geosciences, The University of Arizona, 2001-01-01)
      This paper covers three different methods of matching radiocarbon dates to the "wiggles" of the calibration curve in those situations where the age difference between the 14C dates is known. These methods are most often applied to tree-ring sequences. The simplest approach is to use a classical Chi-squared fit of the 14C data to the 14C curve. This gives the calendar date where the data fit best and allows tests of how good the fit is. The only drawback of this method is that it is difficult to ascertain the uncertainty in the date found in this way. An extension of this technique uses a Monte-Carlo simulation to sample possible 14C concentrations consistent with the measurement made and for each of these possibilities performs a Chi-squared fit. This method yields a distribution of values in the calendrical time-scale, from which the overall dating uncertainty can be derived. A third, rather different approach, based on Bayesian statistics, calculates the relative likelihood of each possible calendar year fit. This can then be used to calculate a range of most likely dates in a similar way to the probability method of 14C calibration. The theories underlying all three methods are discussed in this paper and a comparison made for the fitting of specific model sequences. All three methods are found to give consistent results and the application of any one of them depends on the nature of the scientific question being addressed.
    • Wiggle-Match Dating of Tree-Ring Sequences

      Galimberti, Mariagrazia; Bronk Ramsey, Christopher; Manning, Sturt W. (Department of Geosciences, The University of Arizona, 2004-01-01)
      Given the non-monotonic form of the radiocarbon calibration curve, the precision of single 14C dates on the calendar timescale will always be limited. One way around this limitation is through comparison of time-series, which should exhibit the same irregular patterning as the calibration curve. This approach can be employed most directly in the case of wood samples with many years growth present (but not able to be dated by dendrochronology), where the tree-ring series of unknown date can be compared against the similarly constructed 14C calibration curve built from known-age wood. This process of curve-fitting has come to be called "wiggle-matching." in this paper, we look at the requirements for getting good precision by this method: sequence length, sampling frequency, and measurement precision. We also look at 3 case studies: one a piece of wood which has been independently dendrochronologically dated, and two others of unknown age relating to archaeological activity at Silchester, UK (Roman) and Miletos, Anatolia (relating to the volcanic eruption at Thera).
    • Wiggle-Match Dating of Wooden Samples from Iron Age Sites in Northern Italy

      Quarta, G.; Pezzo, M. I.; Marconi, S.; Tecchiati, U.; D'Elia, M.; Calcagnile, L. (Department of Geosciences, The University of Arizona, 2010-01-01)
      Archaeological excavations carried out at the sites of Laion/Lajen (Bolzano/Bozen) and Stufles-Oberegger (Bressanone/Brixen) in northern Italy uncovered well-preserved wooden samples in cultural layers archaeologically dated to the Iron Age. From the 2 sites, different wooden samples were recovered that were well preserved enough to allow clear identification of the tree species and of the ring structure. Among the different wooden samples, 2 were selected for radiocarbon analyses: from Laion/Lajen, a beam with an unbroken sequence of 158 rings; from Stufles-Oberegger, a combusted trunk with a sequence of 217 rings. Both samples were identified as Larix decidua species. From each sequence, single rings were selected and submitted for accelerator mass spectrometry (AMS) 14C dating analysis at CEDAD. Conventional 14C ages were then calibrated to calendar ages using the IntCal04 atmospheric data set, while the statistical constraints resulting from the defined ring sequence were used to develop a wiggle-matching approach by making use of the Bayesian analysis functions available in OxCal. The obtained results are an important contribution in refining the chronology of the studied sites.
    • Wiggle-Matching Using Known-Age Pine from Jermyn Street, London

      Tyers, Cathy; Sidell, Jane; van der Plicht, Johannes; Marshall, Peter; Cook, Gordon; Bronk Ramsey, Christopher; Bayliss, Alex (Department of Geosciences, The University of Arizona, 2009-01-01)
      A slice of pine from the period covered by single-year calibration data (Stuiver 1993) was selected to serve as part of the quality assurance procedures of the English Heritage radiocarbon dating program, following successful wiggle-matching of 14C measurements from structural 15th century English oak timbers (Hamilton et al. 2007). The timber selected was a roofing element from a house on Jermyn Street, central London, demonstrated by dendrochronology to have been felled in AD 1670. Eighteen single-ring samples were dated by the 14C laboratories at Groningen, Oxford, and SUERC: each laboratory was sent a random selection of 6 samples. This approach was intended to mimic the mix of samples and relative ages incorporated into Bayesian chronological models during routine project research. This paper presents the results of this study.
    • WOCE AMS Radiocarbon I: Pacific Ocean Results (P6, P16 and P17)

      Key, Robert M.; Quay, Paul D.; Jones, Glenn A.; McNichol, A. P.; Von Reden, K. F.; Schneider, Robert J. (Department of Geosciences, The University of Arizona, 1996-01-01)
      AMS radiocarbon results from the World Ocean Circulation Experiment in the Pacific Ocean show dramatic changes in the inventory and distribution of bomb-produced 14C since the time of the GEOSECS survey (8/73-6/74). Nearsurface 14C values for the eastern portion of both the northern and southern subtropical gyres decreased by 25-50 per mil, with the change being greater in the north. Equatorial near-surface values have increased by ca. 25 per mil. Changes in the 250-750-m depth range are dramatically different between the northern and southern basins. The intermediate and mode waters of the southern basin have increased by as much as 75 per mil since GEOSECS. Waters of similar density in the northern hemisphere are not exposed to the Southern Ocean circulation regime and are significantly less ventilated, showing maximum changes of ca. 50 per mil.
    • WOCE Pacific Ocean Radiocarbon Program

      Key, Robert M. (Department of Geosciences, The University of Arizona, 1996-01-01)
      Fieldwork for the World Ocean Circulation Experiment (WOCE) radiocarbon program was recently completed. Ca. 9000 samples were collected for analysis using both conventional beta-counting techniques and the newer AMS technique. The mean uncertainty for the beta analyses is 3 per mil; for AMS analyses, ca. 4.5 per mil degrees.
    • 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.
    • Woods Hole Oceanographic Institution Radiocarbon Laboratory: Sample Treatment and Gas Preparation

      Griffin, Sheila; Druffel, Ellen R. M. (American Journal of Science, 1985-01-01)
    • Workshop on 14C Reporting

      Stuiver, Minze (American Journal of Science, 1980-01-01)
    • Yale Natural Radiocarbon Measurements IV

      Deevey, Edward S.; Gralenski, L. J.; Hoffrén, Väinö (American Journal of Science, 1959-01-01)
    • Yale Natural Radiocarbon Measurements IX

      Stuiver, Minze (American Journal of Science, 1969-01-01)