Multiple metasomatism of the lithospheric mantle beneath the northeastern North China Craton

Abstract Mantle xenoliths carried by the Cenozoic basalts in Huinan are composed of harzburgite, dunite, lherzolite, wehrlite, and pyroxenite. These rocks provide an opportunity to trace the composition and evolution of the lithospheric mantle beneath the northeastern North China Craton (NCC). Major and trace element analyses reveal that the primary compositions of these xenoliths are widely modified by partial melting and multistage metasomatism. Three types of metasomatic agents are identified based on the geochemical features of clinopyroxene. The high 87Sr/86Sr (>0.7065), high Ti/Eu but low Ca/Al ratios of clinopyroxene core in one refractory harzburgite indicate an early metasomatic event caused by subducted Paleo-Asian Oceanic slab-derived high-87Sr/86Sr silicate melts. The variation trend of clinopyroxenes in harzburgite, dunite, and wehrlite xenoliths in the plot of Ti/Eu-(La/Yb)N indicate the overprinting of subsequent carbonatite metasomatism. The low 87Sr/86Sr ratio (