A significant part of the area of the Pechenga district is composed of sedimentary‑volcanogenic strata, representing an alternation of low‑thickness packs of sedimentary‑metamorphic rocks and thicker volcanogenic units. Middle Proterozoic metagabbro‑diabase intrusions and late Proterozoic intrusions of basic and ultrabasic rocks occur within the rocks of the Pechenga series. To the north and south of the Pechenga Series occur gneisses and strongly metamorphosed rocks of the Archean.