• IntCal09 and Marine09 Radiocarbon Age Calibration Curves, 0-50,000 Years cal BP

      Reimer, P. J.; Baillie, M. G. L.; Bard, E.; Bayliss, A.; Beck, J. W.; Blackwell, P. G.; Bronk Ramsey, C.; Buck, C. E.; Burr, G. S.; Edwards, R. L.; et al. (Department of Geosciences, The University of Arizona, 2009-01-01)
      The IntCal04 and Marine04 radiocarbon calibration curves have been updated from 12 cal kBP (cal kBP is here defined as thousands of calibrated years before AD 1950), and extended to 50 cal kBP, utilizing newly available data sets that meet the IntCal Working Group criteria for pristine corals and other carbonates and for quantification of uncertainty in both the 14C and calendar timescales as established in 2002. No change was made to the curves from 0-12 cal kBP. The curves were constructed using a Markov chain Monte Carlo (MCMC) implementation of the random walk model used for IntCal04 and Marine04. The new curves were ratified at the 20th International Radiocarbon Conference in June 2009 and are available in the Supplemental Material at www.radiocarbon.org.
    • Investigating the Interhemispheric 14C Offset in the 1st Millennium AD and Assessment of Laboratory Bias and Calibration Errors

      Hogg, Alan; Palmer, Jonathan; Boswijk, Gretel; Reimer, Paula; Brown, David (Department of Geosciences, The University of Arizona, 2009-01-01)
      Past measurements of the radiocarbon interhemispheric offset have been restricted to relatively young samples because of a lack of older dendrochronologically secure Southern Hemisphere tree-ring chronologies. The Southern Hemisphere calibration data set SHCal04 earlier than AD 950 utilizes a variable interhemispheric offset derived from measured 2nd millennium AD Southern Hemisphere/Northern Hemisphere sample pairs with the assumption of stable Holocene ocean/atmosphere interactions. This study extends the range of measured interhemispheric offset values with 20 decadal New Zealand kauri and Irish oak sample pairs from 3 selected time intervals in the 1st millennium AD and is part of a larger program to obtain high-precision Southern Hemisphere 14C data continuously back to 200 BC. We found an average interhemispheric offset of 35 +/- 6 yr, which although consistent with previously published 2nd millennium AD measurements, is lower than the offset of 55-58 yr utilized in SHCal04. We concur with McCormac et al. (2008) that the IntCal04 measurement for AD 775 may indeed be slightly too old but also suggest the McCormac results appear excessively young for the interval AD 755-785. In addition, we raise the issue of laboratory bias and calibration errors, and encourage all laboratories to check their consistency with appropriate calibration curves and invest more effort into improving the accuracy of those curves.
    • Letter from the Guest Editor

      Reimer, Paula J. (Department of Geosciences, The University of Arizona, 2009-01-01)
    • Radiocarbon Laboratories

      Department of Geosciences, The University of Arizona, 2009-01-01
    • Table of Contents

      Department of Geosciences, The University of Arizona, 2009-01-01