An on-line application for ΔR calculation

A regional offset (ΔR) from the marine radiocarbon calibration curve is widely used in calibration software (eg CALIB, OxCal) but often is not calculated correctly. While relatively straightforward for known age samples, such as mollusks from museum collections or banded corals, it is more difficult to calculate ΔR and the uncertainty in ΔR for 14C dates on paired marine and terrestrial samples. Previous researchers have often utilized classical intercept methods (Reimer et al. 2002; Dewar et al. 2012, Russell et al. 2011) but this does not account for the full calibrated probability density function (PDF). We have developed an on-line application for performing these calculations for known age, paired marine and terrestrial 14C dates, or U-Th dated corals which is available at http://calib.qub.ac.uk/deltar