Browsing Radiocarbon, Volume 40, Number 3 (1998) by Subjects
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High-Precision Radiocarbon Age Calibration for Terrestrial and Marine SamplesSingle-year and decadal radiocarbon tree-ring ages are tabulated and discussed in terms of 14C age calibration. The single-year data form the basis of a detailed 14C age calibration curve for the cal AD 1510-1954 interval ("cal" denotes calibrated). The Seattle decadal data set (back to 11,617 cal BP, with 0 BP = AD 1950) is a component of the integrated decadal INTCAL98 14C age curve (Stuiver et al. 1998). Atmospheric 14C ages can be transformed into 14C ages of the global ocean using a carbon reservoir model. INTCAL98 14C ages, used for these calculations, yield global ocean 14C ages differing slightly from previously published ones (Stuiver and Braziunas 1993b). We include discussions of offsets, error multipliers, regional 14C age differences and marine 14C age response to oceanic and atmospheric forcing.
Variations of Radiocarbon in Tree Rings: Southern Hemisphere Offset Preliminary ResultsThe Queen's University of Belfast, Northern Ireland and University of Waikato, Hamilton, New Zealand radiocarbon laboratories have undertaken a series of high-precision measurements on decadal samples of dendrochronologically dated oak (Quercus patrea) and cedar (Libocedrus bidwillii) from Great Britain and New Zealand, respectively. The results show a real atmospheric offset of 3.4 +/0.6% (27.2 +/4.7 14C yr) between the two locations for the interval AD 1725 to AD 1885, with the Southern Hemisphere being depleted in 4C. This result is less than the value currently used to correct Southern Hemisphere calibrations, possibly indicating a gradient in Delta-14C within the Southern Hemisphere.