UCLA Radiocarbon Dates VI

Abstract

The measurements reported have been carried out during 1966 in the Isotope Laboratory of the Institute of Geophysics and Planetary Physics as a continuation of the UCLA date lists I through V. Samples were analyzed as CO2-gas at one atm in a 7.5 L proportional counter with three energy channels. The all-solid-state unit is supplied with high voltage from a remarkably stable and interference-free battery source. Radiocarbon ages have been calculated on the basis of a 5568-yr half-life as was recommended by the Sixth International C14 and H3 Dating Conference, June 1965, in Pullman, Washington. The standard for the contemporary biosphere remains as 95% of the count rate of NBS oxalic acid for radiocarbon laboratories. Background determinations have been based on CO2 obtained from marble. The error listed is always at least a one-sigma statistical counting error. In critical cases C13/C12 isotope ratio measurements were made to correct the dates. All samples were subjected to accepted pretreatments differing in the individual cases to exclude contamination.