IntCal and the future of radiocarbon calibration

PAGES News, Vol.14 • No 3 • December 2006 S ci en ce H ig h lig ht s: 14 C C h ro n ol og y can defi ne (through calculation) what the ‘true’ C age will be (the consensus value) and then we can estimate for each laboratory, whether there is a constant off set (or a bias) from this consensus. The current program of inter-laboratory comparisons has aff orded an opportunity for laboratories to assess their accuracy. In each intercomparison, the consensus values for the unknown age samples was calculated and reported. Figure 2, , shows the off set (and 95% confi dence interval) for individual laboratories based on the dendrochronologically dated samples included in FIRI. The sample dendro-ages were 3200-3239 BC, 3299 3257 BC and 313-294 BC. Conclusions Analyses of results from FIRI and phase 1 of VIRI support the fact that radiocarbon laboratories are generally accurate and precise. The results from FIRI are signifi cant in that they show broad agreement between measurements made in diff erent laboratories on a wide range of materials, and they also demonstrate no statistically signifi cant diff erence between measurements made by radiometric or AMS techniques. As a result of the inter-comparison program, an extensive suite of natural reference materials (such as wood, carbonate, etc) spanning the applied C timescale has been created by the C dating community. These can now be used by C labs to improve their dating accuracy and are thus of great benefi t to the users of C dates.