ABOUT THIS COLLECTION

Radiocarbon is the main international journal of record for research articles and date lists relevant to 14C and other radioisotopes and techniques used in archaeological, geophysical, oceanographic, and related dating.

This archive provides access to Radiocarbon Volumes 1-54 (1959-2012).

As of 2016, Radiocarbon is published by Cambridge University Press. The journal is published quarterly. Radiocarbon also publishes conference proceedings and monographs on topics related to fields of interest. Visit Cambridge Online for new Radiocarbon content and to submit manuscripts.

ISSN: 0033-8222

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  • Sponsors

    Department of Geosciences, The University of Arizona, 2004-01-01
  • International Advisory Board, New Zealand Organizing Committee, and Editorial Board

    Department of Geosciences, The University of Arizona, 2004-01-01
  • From the Guest Editors

    Sparks, Roger J.; Athfield, Nancy Beavan (Department of Geosciences, The University of Arizona, 2004-01-01)
  • From the Guest Editor

    Reimer, Paula J. (Department of Geosciences, The University of Arizona, 2004-01-01)
  • Editorial Board

    Department of Geosciences, The University of Arizona, 2004-01-01
  • Conference Participants

    Department of Geosciences, The University of Arizona, 2004-01-01
  • Chronology of Prehistoric Cultural Complexes of Sakhalin Island (Russian Far East)

    Kuzmin, Yaroslav V.; Vasilevski, Alexander A.; Gorbunov, Sergei V.; Burr, G. S.; Jull, A. J. Timothy; Orlova, Lyobov A.; Shubina, Olga A. (Department of Geosciences, The University of Arizona, 2004-01-01)
    A chronological framework for the prehistoric cultural complexes of Sakhalin Island is presented based on 160 radiocarbon dates from 74 sites. The earliest 14C-dated site, Ogonki 5, corresponds to the Upper Paleolithic, about 19,500-17,800 BP. According to the 14C data, since about 8800 BP, there is a continuous sequence of Neolithic, Early Iron Age, and Medieval complexes. The Neolithic existed during approximately 8800-2800 BP. Transitional Neolithic-Early Iron Age complexes are dated to about 2800-2300 BP. The Early Iron Age may be dated to about 2500-1300 BP. The Middle Ages period is dated to approximately 1300-300 BP (VII-XVII centuries AD).
  • 2004 Price List

    Department of Geosciences, The University of Arizona, 2004-01-01
  • 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).
  • Variation of the Radiocarbon Content in Tree Rings During the Spoerer Minimum

    Miyahara, Hiroko; Masuda, Kimiaki; Furuzawa, Hideki; Menjo, Hiroaki; Muraki, Yasushi; Kitagawa, Hiroyuki; Nakamura Toshio (Department of Geosciences, The University of Arizona, 2004-01-01)
    This paper presents the variation of radiocarbon content in annual tree rings for the period AD 1413-1553, which includes the Spoerer Minimum period (AD 1415-1534). Since the variation of the production rate of 14C is strongly related to solar activity, the variation of 14C content in annual tree rings gives us information on the characteristics of variation of solar activity. We have studied solar activity during the grand solar minima, focusing especially on the stability of the 11-yr cycle. The minima are determined to have been almost free of sunspots. Our results, however, have revealed quite remarkably the existence of the 11-yr cycle for most of the time during the Spoerer Minimum. The 11-yr variation weakened around AD 1460-1510, suggesting that solar activity might have been strongly suppressed during these 50 yr.
  • Variability of Monthly Radiocarbon During the 1760s in Corals from the Galapagos Islands

    Druffel, Ellen R. M.; Griffin, Sheila; Hwang, Jeomshik; Komada, Tomoko; Beaupre, Steven R.; Druffel-Rodriguez, Kevin C.; Santos, Guaciara M.; Southon, John (Department of Geosciences, The University of Arizona, 2004-01-01)
    Radiocarbon (∆14C) measurements of monthly samples from a Galapagos surface coral are among the first data sets from the new Keck Carbon Cycle Accelerator Mass Spectrometry laboratory at the University of California, Irvine. An average ∆14C value of -62 is obtained for 144 measurements of samples from monthly coral bands that lived from about AD 1760-1771 (+/6 yr). High ∆14C values were found during January through March, when upwelling was weak or absent at the Galapagos Islands. Low ∆14C values were obtained mid-year during strong upwelling. The average seasonal variability of ∆14C was 15-25 ppm, which is greater than that at other tropical and subtropical locations in the Pacific Ocean because of intense seasonal upwelling at this site. Periods of sustained high ∆14C values were found during 1762-1763 and 1766. A spectral analysis revealed that the spectral density for the ∆14C data displays most of its variance at the 5-yr cycle, which is reflective of El Niño periodicity during the 20th century.
  • Using a Gas Ion Source for Radiocarbon AMS and GC-AMS

    Bronk Ramsey, Christopher; Ditchfield, Peter; Humm, Martin (Department of Geosciences, The University of Arizona, 2004-01-01)
    This paper reports on the performance of a new method of sample injection using the High Voltage Engineering Europa (HVEE) SO-110 ion source jointly developed between HVEE and Oxford. In order to use this source, we have developed a new gas handling system which works on the direct injection of carbon dioxide mixed into a continuous flow of helium. Preliminary work has also been carried out on online gas chromatography-accelerator mass spectrometry (GC-AMS). In this application, a GC is directly coupled to the AMS system using a GC-IRMS combustion interface and Nafion(TM) drier. We show here results for the measurement of natural abundance in separated compounds with good peak separation and precisions of about 10%. This type of system should be ideal for source apportionment studies, biomedical, and other similar work where high precision is not required but where sample sizes are very low.
  • Tree-Ring Records of Near-Younger Dryas Time in Central North America—Preliminary Results from the Lincoln Quarry Site, Central Illinois, USA

    Panyushkina, Irina P.; Leavitt, Steven W.; Wiedenhoeft, Alex; Noggle, Sarah; Curry, Brandon; Grimm, Eric (Department of Geosciences, The University of Arizona, 2004-01-01)
    The abrupt millennial-scale changes associated with the Younger Dryas (YD) event ("chronozone") near the dawn of the Holocene are at least hemispheric, if not global, in extent. Evidence for the YD cold excursion is abundant in Europe but fairly meager in central North America. We are engaged in an investigation of high-resolution environmental changes in mid-North America over several millennia (about 10,000 to 14,000 BP) during the Late Glacial-Early Holocene transition, including the YD interval. Several sites containing logs or stumps have been identified and we are in the process of initial sampling or re-sampling them for this project. Here, we report on a site in central Illinois containing a deposit of logs initially thought to be of YD age preserved in alluvial sands. The assemblage of wood represents hardwood (angiosperm) trees, and the ring-width characteristics are favorable to developing formal tree-ring chronologies. However, 4 new radiocarbon dates indicate deposition of wood may have taken place over at least 8000 14C yr (6000-14,000 BP). This complicates the effort to develop a single floating chronology of several hundred years at this site, but it may provide wood from a restricted region over a long period of time from which to develop a sequence of floating chronologies, the timing of deposition and preservation of which could be related to paleoclimatic events and conditions.
  • Time-Dependent Factors Inherent in the Age Equation for Determining Residence Times of Groundwater Using 14C: A procedure to Compensate for the Past Variability of 14C in Atmospheric Carbon Dioxide, with Application to the Wairau Deep Aquifer, Marlborough, New Zealand

    Taylor, Claude B. (Department of Geosciences, The University of Arizona, 2004-01-01)
    The radiocarbon concentration of dissolved inorganic carbon in groundwater is most logically and completely represented as the product of 5 time-variable factors; these are mutually independent, and all must be considered and evaluated to determine a groundwater residence time. In the case of one factor, the 14C/(12C+13C) ratio of atmospheric CO2, its time variability can be side-stepped by assuming it to be constant at the pre-bomb 1950 value, and assigning an apparent half-life in the radioactive decay term. Apparent half-lives are calculated here for 5 separate periods extending back to 24,000 BP, working from the INTCAL98 atmospheric calibration. This approach can be extended further back in time when the necessary atmospheric calibrations are updated with greater certainty. The procedure is applied to the recently-explored Wairau Deep Aquifer, underlying central areas of the coastal Wairau Plain, Marlborough. The evolution of dissolved inorganic carbon concentration for this river-recharged groundwater is apparent from distinct trends in 13C, and is confirmed by hydrochemical modelling. Extension to 14C concentrations yields minimum/maximum limits for groundwater residence times to 3 wells. In all 3 cases, the maximum is uncertain due to present uncertainty of the apparent half-life applicable before 24,000 BP. Residence times for the 2 wells closest to the recharge area are at least 17,400 yr, while that for a well further down the aquifer is at least 38,500 yr. Recharge, therefore, occurred during the Otiran glaciation, while the present-day near-surface fluvioglacial deposits of the Wairau Plain were accumulating. Drawdown-recovery records over 3 yr indicate a permeable connection to compensating recharge, enabling limited exploitation for vineyard irrigation.
  • Towards Achieving Low Background Levels in Routine Dating by Liquid Scintillation Spectrometry

    Hogg, Alan G. (Department of Geosciences, The University of Arizona, 2004-01-01)
    International radiocarbon intercalibration studies have revealed that radiometric laboratories using liquid scintillation (LS) spectrometry of benzene reported, on average, younger ages for near-background standards than either gas proportional counter (GPC) or accelerator mass spectrometry (AMS) laboratories. These studies suggested that the younger LS ages are probably related to the use of spectrophotometric benzene as a background standard. An analysis of successive 110-ka subfossil wood (Airedale Reef Ancient Wood: ARAW) standards shows that vacuum line memory effects occur in LS spectrometry and, consequently, must be corrected to obtain accurate 14C dates. ARAW standards, measured at monthly intervals in the Waikato laboratory, are used to provide blank corrections for both research and routine dating applications. The strong correlation between the ARAW Delta-14C data and the sample activities that preceded the standards may provide an opportunity to obtain sample-specific blank correlations. Lithium carbide synthesis is likely to prove a source of contamination. This work suggests that reproducible background levels for routine dating of less than 0.1 pMC (55 ka 14C yr) are achievable.
  • Towards High-Precision AMS: Progress and Limitations

    Bronk Ramsey, Christopher; Higham, Thomas; Leach, Philip (Department of Geosciences, The University of Arizona, 2004-01-01)
    Precision and accuracy in accelerator mass spectrometry (AMS) dating relies on the systematic reduction of errors at all stages of the dating process, from sampling to AMS measurement. With new AMS systems providing much better precision and accuracy for the final stage of the process, we need to review the process as a whole to test the accuracy of reported results. A new High Voltage Engineering Europa (HVEE) AMS system was accepted at Oxford in September 2002. Since then, the system has been in routine use for AMS dating and here we report on our experiences during the first year. The AMS system itself is known to be capable of making measurements on single targets to a precision of better than 0.2% for the 14C/13C ratio and better than 0.1% for the 13C/12C ratio. In routine operation, we measure known-age wood to a precision of just above 0.3%, including uncertainties in background and pretreatment. At these levels, the scatter in results is no higher than reported errors, suggesting that uncertainties of +/25 to +/30 14C yr can be reliably reported on single target measurements. This provides a test of all parts of the process for a particular material in a particular state of preservation. More generally, sample pretreatment should remove as much contamination as feasible from the sample while adding as little laboratory contamination as possible. For more complex materials, such as bone, there is clearly more work needed to prove good reproducibility and insignificant offsets in all circumstances. Strategies for testing accuracy and precision on unknown material are discussed here, as well as the possibilities of one day reaching precisions equivalent to errors of < +/20 14C yr.
  • The Tropospheric 14CO2 Level in Mid-Latitudes of the Northern Hemisphere (1959-2003)

    Levin, Ingeborg; Kromer, Bernd (Department of Geosciences, The University of Arizona, 2004-01-01)
    A comprehensive tropospheric 14CO2 data set of quasi-continuous observations covering the time span from 1959 to 2003 is presented. Samples were collected at 3 European mountain sites at height levels of 1205 m (Schauinsland), 1800 m (Vermunt), and 3450 m asl (Jungfraujoch), and analyzed in the Heidelberg Radiocarbon Laboratory. The data set from Jungfraujoch (1986-2003) is considered to represent the free tropospheric background level at mid-latitudes of the Northern Hemisphere, as it compares well with recent (yet unpublished) measurements made at the marine baseline station Mace Head (west coast of Ireland). The Vermunt and Schauinsland records are significantly influenced by regional European fossil fuel CO2 emissions. The respective Delta-14CO2 depletions, on an annual mean basis, are, however, only 5 ppm less than at Jungfraujoch. Vermunt and Schauinsland both represent the mean continental European troposphere.

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