INTCAL98 radiocarbon age calibration, 24,000-0 cal BP

The focus of this paper is the conversion of radiocarbon ages to calibrated (cal) ages for the interval 24,000-0 cal BP (Before Present, 0 cal BP = AD 1950), based upon a sample set of dendrochronologically dated tree rings, uranium-thorium dated corals, and varve-counted marine sediment. The (14)C age-cal age information, produced by many laboratories, is converted to Delta(14)C profiles and calibration curves, for the atmosphere as well as the oceans. We discuss offsets in measured (14)C ages and the errors therein, regional (14)C age differences, tree-coral (14)C age comparisons and the time dependence of marine reservoir ages, and evaluate decadal vs. single-year (14)C results. Changes in oceanic deepwater circulation, especially for the 16,000-11,000 cal sp interval, are reflected in the Delta(14)C values of INTCAL98

Late glacial 14C ages from a floating, 1382-ring pine chronology

We built a floating, 1382-ring pine chronology covering the radiocarbon age interval of 12,000 to 10,650 BP. Based on the strong rise of \u39414C at the onset of the Younger Dryas (YD) and wiggle-matching of the decadal-scale \u39414C fluctuations, we can anchor the floating chronology to the Cariaco varve chronology. We observe a marine reservoir correction higher than hitherto assumed for the Cariaco site, of up to 650 yr instead of 400 yr, for the full length of the comparison interval. The tree-ring \u39414C shows several strong fluctuations of short duration (a few decades) at 13,800; 13,600; and 13,350 cal BP. The amplitude of the strong \u39414C rise at the onset of the YD is about 40%, whereas in the marine data set the signal appears stronger due to a re-adjustment of the marine mixed-layer \u39414C towards the atmospheric level. \ua9 2004 by the Arizona Board of Regents on behalf of the University of Arizona