Abstract <p>Based on large-scale geological mapping, petrographic, and mineralogical-geochemical data, the facies composition and stages of formation of hydrothermal–metasomatic units associated with lithium-fluorine granites of the Severny massif on Chaun–Chukotka were studied. The identification of zwitters of the Severny massif — quartz– topaz–zinnwaldite greisens accompanying Li–F granites and bearing rare-metal (Nb, REE, Y, Li, Bi, Sn, W) mineralization is justified. The bulk of the zwitter mineralization is distributed over the massif area in the moderately altered biotite leucogranites. The facies diversity of tourmalinite metasomatites has been established. Muscovite–quartz–tourmaline, albite–tourmaline–quartz, chlorite–muscovite–tourmaline, and adularia–tourmaline metasomatic facies with tourmaline of three types were identified. A scheme of facies subdivision of ore-bearing metasomatites and a sequence of stages of their formation have been developed: 1) albitites, 2) zwitters, 3) tourmalinite, 4) chloritites, 5) argillisites. The zwitter–tourmalinite metasomatic complex of the massif is characterized by the tight spatial association with Li–F granites, systematic sequence of formation and geochemical evolution, and similarity of accessory and ore mineralization of metasomatites. The ore prospects of the Severny massif are related to the tin-bearing tourmalinite, uranium-bearing argillisites, and rare-metal zwitters.</p>