Volatiles and Intraplate Magmatism: a Variable Role for Carbonated and Altered Oceanic Lithosphere in Ocean Island Basalt Formation

Abstract Recycling of material at subduction zones has fundamental implications for melt composition and mantle rheology. Ocean island basalts (OIBs) sample parts the from variable depths that have been diversely affected by zone processes materials, including subducted slab, metasomatising melts fluids. Resultant geochemical differences are preserved a variety scales inclusions to whole rocks, individual islands chains islands. Here we examine global dataset ocean basalt compositions with view understanding connection between silica-saturation, olivine compositions, halogens in glass olivine-hosted reveal information regarding sources intraplate magmatism. We find minor elements incorporated into olivine, although informative, cannot unambiguously discriminate different source contributions, but indicate none OIB analysed here derived solely dry peridotite melting. Nor can lithospheric thickness explain trace element variability present new halogen (F, Cl, Br/Cl, I/Cl) data along incompatible array encourage measurement fluorine heavier obtain better insight cycling. suggest Ti-rich silica-undersaturated require contribution carbonated lithosphere, either or eclogite an important component sampled basalts, together altered oceanic crust. These results provide insights our mantle-scale cycles, also lead potential transition as underestimated observed volatile trace-element enrichment basalts.