Enriched Hf Nd isotopic signature of veined pyroxenite-infiltrated peridotite as a possible source for E-MORB

Pyroxenite-peridotite sequences from the External Liguride (EL) Jurassic ophiolites (Northern Apennines, Italy) consist of portions fertile MORB mantle that were modified by deep melt infiltration and melt-peridotite reaction. They represent an excellent natural example a MORB-like veined including unmodified peridotite, pyroxenite layers metasomatized peridotite. We carried out spatially controlled Hf isotope study on these to investigate how Nd isotopic systems are affected emplacement interactions. Present-day LuHf compositions lithologies show large range 176Lu/177Hf 176Hf/177Hf ratios correlated with their compositions. Pyroxenite-free peridotites delineate HfNd array corresponds Proterozoic age (> 1.5 Ga) which is likely related accretion subcontinental lithosphere this sector. Heterogeneous in pyroxenites mostly correlate significant variations reflect variable garnet abundance primary modal assemblage. Over time, acquired ?Hf values, encompass global isotopes ocean ridge basalts. Infiltration pyroxenite-derived melts led host peridotite acquire low Lu/Hf consequent development lower than generating equivalent enriched component. This interaction occurred during 430 Ma ago, as confirmed two local pyroxenite-peridotite isochrons. The chemical changes produced, over spread signatures EL mantle, covering almost entire published Pyroxenite metasomatism thus created domains, making first reported formed through combined effect interaction. structure characteristics used model produced decompression melting three-component heterogeneous sources, providing additional scenario generation EMORB erupted at mid-ocean settings. Our results emphasize potential role modifying creating domains.