ISOLATION OF URANIUM AND THORIUM FOR AGE-DETERMINATION OF FOSSIL BONES BY URANIUM SERIES METHOD

An ion exchange procedure for age determination of fossil bones by the uranium series method was developed. Its applicability was proved using both "artificial bones" (calcium phosphate matrix) and real bone samples with and without addition of chemical standards of uranium and thorium. For both elements the recoveries were determined as a function of the calcium phosphate amount present in the sample. The yields obtained were quantitative for sample amounts up to 2.5 g of bone matrix. The conditions were optimized in respect to the required statistical accuracy for the alpha-spectrometric determination of the uranium and thorium activities. The procedure was used for the determination of the uranium - thorium ages of two "young" fossil bone samples from the cave of Vindjia, Yugoslavia. For one sample age comparison with the radiocarbon method was performed.