Rift-related alkaline magmatism of the south-eastern part of the Russian Far East

Areas of alkaline magmatism active in the Paleoproterozoic and Phanerozoic have been delineated and characterized in the south-eastern part of the Russia Far East. A total of six alkaline igneous complexes associated with rift-related magmatism are recognized: Paleoproterozoic (Karelian), Neoproterozoic, Late Paleozoic, Late Jurassic-Early Cretaceous, Late Cretaceous-Early Paleogene, and Neogene- Early Quaternary. Their compositions in different-age igneous complexes vary from ultrabasic to acidic. They mainly occur in Precambrian blocks of the Aldan-Stanovoy shield and Central Asian orogenic belt and in the rear parts of the Eastern Sikhote-Alin Mesozoic volcanic chain of the Sikhote-Alin orogenic belt. Alkaline magmatism proceeded in five geodynamic settings: 1) Proterozoic rift-related sub-alkaline-alkaline magmatism, 2) plume-related ultrabasic-acidic magmatism, 3) rift-related magmatism of Late Paleozoic and Late Mesozoic active continental margins, 4) tension-related magmatism resulting from collisions between the Amurian and Eurasia plates, and 5) Cenozoic alkaline magmatism in zones distant from the active continental margin. Key minerals of rift-related magmatism are rare and rare-earth elements, uranium, gold, molybdenum; less important (for Precambrian rifts) are beryllium, phosphorus and iron.