Unique paragenesis of cerium and yttrium allanites in tourmalinite of the Severny massif (Chukotka).

A description of hydrothermal allanite-(Y) and its unique association with allanite-(Ce) from tourmaline metasomatic rock of the Severny granite massif in Chukotka is presented in the article. Examination of the composition of metasomatic rims in allanite-(Y) allowed us to estimate the limit of isomorphic replacement in allanite of Y and heavy lanthanides by LREE, reaching 25%. [ABSTRACT FROM AUTHOR]