The NE Fennoscandian Shield comprises the Northern Belt in Finland and the Southern Belt in Karelia. They host mafic-ultramafic layered Cu-Ni-Cr and Pt-Pd-bearing intrusions. Precise U-Pb and Sm-Nd analyses indicate the 130-Ma evolution of these intrusions, with major events at 2.53, 2.50, 2.45, and 2.40 Ga. Barren phases were dated at 2.53 Ga for orthopyroxenites and olivine gabbro in the Fedorovo-Pansky massif. PGE-bearing phases of gabbronorites (Pechenga, Fedorovo-Pansky, Monchetundra massifs) and norites (Monchepluton) are 2.50 Ga old. Anorthosites of Mt. Generalskaya (Pechenga), the Fedorovo-Pansky, and Monchetundra massifs occurred at 2.45 Ga. This event produced layered PGE-bearing intrusions in Finland (Penikat, Kemi, Koitelainen) and mafic intrusions in Karelia. The Imandra lopolith dikes occurred at the final phase (2.40 Ga). Slightly negative εNd and ISr values (0.703–0.704) suggest that intrusions originated from an enriched mantle reservoir. Low 3He/4He ratios in accessory minerals (ilmenite and magnetite) indicate an upper mantle source. Large-scale correlations link the Fennoscandian Shield with the Superior and Wyoming cratons.
Several deposits of low-sulfide Pt–Pd ores have been discovered in recent decades in the Paleoproterozoic Fedorova–Pana Layered Complex located in the Kola Region (Murmansk Oblast) of Russia. The deposits are divided into two types: reef-style, associated with the layered central portions of intrusions, and contact-style, localized in the lower parts of intrusions near the contact with the Archean basement. The Kievey and the North Kamennik deposits represent the first ore type and are confined to the North PGE Reef located 600–800 m above the base of the West Pana Intrusion. The reef is associated with a horizon of cyclically interlayered orthopyroxenite, gabbronorite and anorthosite. The average contents of Au, Pt and Pd in the Kievey ore are 0.15, 0.53 and 3.32 ppm, respectively. The North Kamennik deposit has similar contents of noble metals. The Fedorova Tundra deposit belongs to the second ore type and has been explored in two sites in the lower part of the Fedorova intrusion. Mineralization is mainly associated mainly with taxitic or varied-textured gabbronorites, forming a matrix of intrusive breccia with fragments of barren orthopyroxenite. The ores contain an average of 0.08 ppm Au, 0.29 ppm Pt and 1.20 ppm Pd. In terms of PGE resources, the Fedorova Tundra is the largest deposit in Europe, hosting more than 300 tons of noble metals.
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