Stockholm Natural Radiocarbon Measurements III

Abstract

This paper is a direct continuation of the second date list released from this laboratory (Östlund, 1959), and the technique of preparation and the characteristics of our two 3-atmospheres carbon dioxide counters are substantially unchanged (Östlund 1957a, b). As in previous lists, our standard is oak wood, grown, A. D. 1845–1855 in Stockholm. corrected for radioactive decay to 1960. As usual, the counting rates have been corrected according to the massspectrometrically measured C¹³/C¹²ratio in each sample of purified carbon dioxide. In this scale the U. S. National Bureau of Standards Natural Radiocarbon Standard (NBS standard) gives a counting rate which is 104.5 ± 0.4% of our age-corrected oak standard. Taking into account that our oak has a C¹³/C¹²ratio of 25 per mil lower than the Chicago PDB-C¹³standard, our age figures can, by subtracting 55 years, be converted to the new, international radiocarbon age scale proposed by Broecker and Olson (1959).