The results of studies of wallrock hydrothermal-metasomatic processes at a large polymetallic deposit located in the central part of the Novaya Zemlya Archipelago are considered. The geological position and control factors of mineralization, pre-ore and wallrock metasomatites are shown. The material composition of metasomatites has been studied in detail, and rare minerals, such as zinc-bearing dolomite, kimrites, and barium-bearing mica, among others, have been discovered and described, and specific morphology and composition have been revealed for those. According to the structure and material composition of metasomatites and some minerals, the formation conditions are defined as low-temperature near-surface.