Geochemical data on earlier unstudied Late Pleistocene complexes of the Tolbachik volcanic massif (Kamchatka) are presented.

The variations in geochemistry are attributed to the change of the geodynamical conditions.

Crystallization at different water activity is responsible for two (middle-K and high-K) rock series.

Variable depletion of NMORB- mantle due to formation of rift-like structure below Tolbachik massif was suggested.

Crustal assimilation of the pedestal, stratovolcano and dike complexes was shown.