Geochemistry of Super-Large Deposits of Eastern Fennoscandia (Kola Peninsula)

Geochemical data on three superlarge rare-metal deposits of Eastern Fennoscandian are generalized for the first time. Using loparite, eudialyte, and apatite deposits of the Kola Peninsula as an example, it is shown that the early saturation of an alkaline magma in an ore phase is a necessary condition for the formation of a magmatic deposit. An important factor is an active convection in the magma chamber, which causes the mineral phases to be sorted by size, thus leading to the formation of magmatic deposits. The absence of Eu anomaly in the REE distribution patterns for apatite, loparite and eudialyte ores indicates that primary magma did not experience fractionation of plagioclase. The primary magma of these deposits was olivine-melanephelinite in composition.