Atomic ratios of rare-earth elements in rocks of various composition
Calculations showed that atomic ratios of some Y-group rare earth elements such as Lu, Yb, Tm, Er, Ho, Dy, Tb, are statistically constant and do not depend on the type of rock, the place of their sampling, the REE cumulative concentration. The most variable are ratios of the Ce-group elements: La, Ce, Nd, Pr. It is suggested that variations in the index values of these elements can provide additional information concerning the geological or geochemical setting, the depth of the rock or its age.