Quantitative chemical analyses of rocks with X-ray fluorescence analyzer: (3) Rare earth elements

Analytical procedures for rare earth elements in rocks, namely La, Ce, Nd, Sm and Yb, are summarized. The analyses were performed by means of an X-ray fluorescence analyzer RIGAKU RIX3000 with a dual target, Rh/W, X-ray tube at the National Institute of Polar Research. Glass beads were prepared for the analyses from powder samples that were diluted two times by Spectroflux No. 100B (80% LiBO_2+20% Li_2B_4O_7). The peak-over-back method and the matrix correction method are compared with respect to accuracy, and the results show that the peak-over-back method is preferable to the matrix correction method. A procedure for major and minor element analyses in rocks using the same diluted glass beads is also reported. Furthermore, a new calibration curve method for major element analyses in ultrabasic rocks, using glass beads diluted with five times by flux (Li_2B_4O_7), is presented.