Determination of the isotope composition of lead in sandstones containing uranium and lead by means of an MI-1309 type mass spectrometer

Chemical and mass spectrometric procedures were developed for the determination of the isotope composition of lead in sandstones containing U and Pb minerals. For the measurements, an MI-1309 type mass spectrometer and single-filament silicate-phosphate and silicate-phosphate + stabilizer emitters were used. The instrument was calibrated using NBS lead isotope standards. If the concentration of the 208Pb is about 50 percent, and that of the 207Pb and 206Pb isotopes is over 20 percent, the relative error of the measurements does not exceed +-0,2 percent in the case of the 208Pb isotope, +-0,3 percent in case of the 207 Pb and 206Pb isotopes and +-0,2 percent for the 204Pb isotope, respectively. The results show that the method developed for lead isotope ratio determination had satisfactory precision for the purposes of uranium ore prospecting. (author)