DATING CHALK PRECIPITATES WITH RADIOACTIVE CARBON

It is shown that secondary chalk precipitates contain radioactive carbon and can be dated with the C/sup 14/ method. The initial C/sup 14/ content of chalk sinter is higher than expected, owing to exchange effects. The necessary corrections are made in part by measuring the C/sup 13//C/sup 12/ isotope ratio. The first measurement results are given. (tr-auth)