Role of pyroxenite mantle in magma genesis of the oligocene basalts from the northern part of east sikhote alin

Identification of magma sources as well as its role in creating the diversity of magma compositions still remains one of the fundamental petrological problems. In our work, on the basis of new comprehensive isotope-geochemical and mineralogical data, we made an attempt to reconstruct the contribution of pyroxenite mantle source in the Oligocene basaltic magma genesis of the northern part of East Sikhote Alin volcanic belt. The most important indicators of this source are significant variations the first order transit elements ratios (Zn/Fe = 11–17, Zn/Mn = 6–10, Cr/Ni (1.8–6) and concentration of Ni (2000–3600 г/т) in olivine. LIL elements behavior suggests the presence of amphibole in pyroxenite substrate. The data obtained can be useful for the correct reconstruction of the magma generation and the geodynamic environment of this territory at the Late Cenozoic.