ABSTRACT
In recent years the development of modern microprobe methods of REE determining, and the lowering of the limits of REE detection, have expanded the study on the regularities of distribution of these impurities not only on rock-forming, but also on minor and accessory minerals of the ultramafic and mafic rocks, which include garnets, chrome-spinels, ilmenites, zircons, apatites, titanites, perovskites and micas. As it was shown in previous chapters, these minerals are significantly different from each other in the general chemical composition, crystal-chemical properties and formation conditions, have different abilities to accumulate REE and other impurities. There are reasons to believe that an appropriate use of data on the REE distribution in these minerals can help to gain additional geochemical criteria and typomorphic signs for their diagnosis, discrimination, systematization and genetic interpretation.
