As a result of active intrusive activity, the Monchegorsk and Monchetundra stratified arrays were formed over a not significant period. They form the Monchegorsk magmatic node. Significant deposits are associated with them elements of the platinum group. At the same time, questions remain related to the determination of magma sources, the duration of their active activity, the composition of magmas that formed intrusions and the conditions of crystallization. Calculations using rocks of the intrusive boundary group (model 791-1123, 791-1135) at a pressure of 6.5–5.5 kbar showed that the melt, equilibrium with Ol. It contained SiO2 ≤ 55 wt %, TiO2 ≤ 0.50 wt %, MgO ≤ 14 wt %. The temperature of the initial magma could be equal to 1390°C. At a lower pressure (below 6.5 kbar), an increase in the silica content is observed in the resulting melt. In the Monchegorsk intrusive, the composition of intratelluric olivine in this model could vary within 88–92 mol % Fo. The amount of intratelluric olivine in the melt, depending on the pressure, could vary from 11 to 24 vol %.