On the precision of the radiometric age methods (I): 14 C and related ones

The present Radiometric Age Methods (RAMs) are classified into two groups according to the experimental procedure in which the age of a sample is determined. First group contains 14 C, 210 Pb and T methods in which the sample age is calculated as a function of both initial and remaining concentration of radioactive nuclei. For this kind of RAMs the initial concentration of 14 C, 210 Pb or T radionuclides is considered to be equal to the actual one. The second group consists of K-Ar, Rb-Sr, U-Pb and Th-Pb RAM and for this method the age is determined by taking into account the concentration of decayed as well as of the remaining radioactive nuclei. For the first category of RAMs an optimization criterion based upon the minimization of relative errors of the sample age is presented. According to this criterion, for 14 C, 210 Pb, T, the intervals of sample ages for which these methods provide best theoretical precision are calculated. (authors)