Reevaluation of Rare Earth Element Abundances in Japanese Standard Rock Samples, JG-1 and JB-1

We have determined rare earth elements(REE) in JG-1 and JB-1, standard rock samples issued by the Geological Survey of Japan, by radiochemical and instrumental neutron activation analyses. Our new data are mostly consistent with the recommended values for all the REE of JB-1 and the light and middle REE in JG-1, except for Tb. Our Tb values of JB-1 and JG-1 are about 2 times larger than the previously compiled values. For the heavy REE of JG-1, the neutron activation analysis data involving the literature values are systematicaily larger than the mass spectrometric isotope dilution data, with the former being as large as a factor of two for Yb and Lu compared to the latter. Incomplete decomposition of rock samples with HF and HCIOi is suggested as a possible cause for such large discrepancies.