ICP-MS ANALYSIS OF GEOLOGICAL STANDARD ROCKS FOR YTTRIUM, LANTHANOIDS, THORIUM AND URANIUM

Inductively coupled plasma mass spectrometry (ICP-MS)is applied to geo logical standard rocks for the determination of Y, lanthanoids (Ln's), Th and U. Internal standardization is employed for the precise measur ement: Rh for Y, In and Tl for Ln's, Bi for Th and U. For Ln's, linear interpolation correction is used. Our ICP-MS data agree with the reco mmended values within 10% for most samples. Their chondrite-normalized Ln abundance patterns are smooth, suggesting that our ICP-MS data are highly accurate and can be used for discussing detailed abundances of Ln's. The Y, Th and U data are as precise as the Ln data. The simulta neous and precise determination of Ln's, Th and U enable us to extend the geochemical discussion in better detail than before.