Do We Really Need Mantle Components to Define Mantle Composition?

We discuss the concept of components in the Earth’s mantle starting from a petrological and geochemical approach, but adopting a new method of projection of geochemical and isotopic data.This allows the compositional variability of magmatic associations to be evalu-ated in multi-dimensional space, thus simultaneously accounting for a large number of compositional variables.We demonstrate that ocean island basalts (OIB) and mid-ocean ridge basalts (MORB) are derived from a marble-cake mantle, in which different degrees of partial melting of recycled lithosphere, which are heterogeneous in age and composition, contribute to the magma genesis. This view is supported by the variability in the geochemical and isotopic signa-tures of OIB that are observed on the scale of a single ocean island as well as on that of an ocean, mostly varying between two extreme com-positions, that are not strictly related to the commonly accepted mantle components (DMM, EMI, EMII, HIMU). Rather they