Subduction-zone magmas are characterized by high fluid contents and Fe3+/ΣFe ratios, which are closely associated with slab-derived fluids during subduction. However, instead of a heavier iron isotope composition preferred under an oxidized state, arc magmas have lighter iron isotope compositions than seafloor basalts, including mid-ocean ridge basalts (MORB) and oceanic island basalts (OIB).
Click here for original story, Study reveals heterogeneous mantle source compositions for boninite from Bonin and Troodos
Source: Phys.org