Some problems in connection with the evaluation of C14 dates

Abstract

The contamination problem is discussed and diagrams given, allowing an estimation of the error for a certain contamination and different age differences between the contaminant and the sample. Contamination of organic deposits, carbonate samples and bone samples are discussed, as well as the methods of removing the contaminants in order to arrive at a reliable fraction for dating. The apparent age of different reservoirs is discussed. The hard-water effect is especially stressed. A mean-value of 420 years for the apparent age of the surface water to the west of Scandinavia is given. The choice of calibration curve to eliminate the influence on the dates of the secular variations is discussed and it is concluded that in all probability different calibration curves must be used for different samples. The effect of C¹³/C¹² normalization is summarized.