Refinement of radiocarbon dates for higher precision and accuracy

Abstract

Correction and calibration of radiocarbon dates are indispensable procedures for accurate and precise age estimation. The most significant factors for correction and calibration are reservoir effect isotopic fractionation, and secular variation in atmospheric 14C-concentration. The correction of the reservoir effect is enabled by carbon-cycle modeling or by dating preatomic age marine sample of known age. The effect of isotpic fractionation ranges from zero to -50 permill δ13C or up to 400 14C yrs. This effect is easily corrected through δ13C measurement using a mass spectorometer. Accumulated 14C dates of dendrochronologically dated tree ring samples made is possible to calibrate the deviation caused by 14C concentration variation. Now versatile correction and calibration programs for personal computers are available. -from English summary