Olivines (Ol) belong to the most REE-depleted minerals. By means of neutron-activation analysis with preliminary radiochemical concentration, a pattern of REE partitioning is studied in Ol from ophiolite peridotites - harzburgites, dunites, lherzolites, and wehrlites of the Shaman, Naran, and other massifs (dunite-harzburgite formation), as well as from some rocks of the Dovyren Massif (dunite-troctolite-gabbro formation). The relict blocks of the central part of the Shaman Massif contain Ol with protogranular microstructure, characterized by chondrite partitioning of REE. In olivines subjected to more intense plastic strains within the Earth's crust (porphyroclastic and porphyrolath structures), the REE content is considerably decreased, and their partitioning in this case does not correspond to the chondrite pattern. A positive correlation is revealed between contents of the majority of REE in Ol and the amount of Ca admixture. In addition to REE entering the Ol structure in the form of impurity defects, some REE, especially light ones, are concentrated in fluid and solid inclusions as well as microfractures. REE ratios in olivines and coexisting ortho- and clinopyroxenes are estimated. The conclusion is made that data of REE partitioning obtained by NAA with the use of radiochemistry should be more widely used in study of typomorphism of olivines and other minerals of mafic and ultramafic associations.
