MAGMATIC SOURCES OF QUATERNARY LAVAS IN THE KURIL ISLAND ARC: NEW DATA ON SR AND ND ISOTOPY

Abstract

Subduction zones of oceanic plates are among the most complicated tectonomagmatic systems in our planet. The relative contribution of the three major geochemical reservoirs into magma genesis (suprasubduction mantle wedge, crust, and oceanic lithosphere) is substantially governed by the geodynamic parameters of the subduction process, including the vector of the convergence of interacting plates, the inclination of the subducting plate, and the activity of back-arc processes and transform faults. Therefore, resolution of issues related to the origin and evolution of primary melts in island arcs requires a complex approach, which includes the study of lateral isotope-geochemical variations in the composition of igneous rocks.