Stockholm Natural Radiocarbon Measurements IV

Abstract

This paper is a direct continuation of the third dating list (Stockholm III), and the entire technique is virtually unchanged, using one 0.5–1 and one 1.0.1 3 atm CO2proportional counter. Ages are calculated according to the recommendation given in the introduction of this book, and δC13has been measured for unknown samples and for the different CO2preparations of the NBS oxalic-acid standard. Since the numerical relationship between the C14activity of our old oak standard and that of NBS was valid for a δC13value of almost exactly −19 for the NBS preparation in question, it still holds true that all dates given in Stockholm I, II and III can be converted to the new scale by subtracting 55 yr. The NBS preparation St-532 measured by Craig (1961) having a δC13value of −17.2 is only one of several preparations with values between −17 and −20. Age figures are given in C14yr before A.D. 1950; the half life for C14is taken as 5568 ± 30 yr.