Differentiation between carbonate and silicate metasomatism based on lithium isotopic compositions of alkali basalts

Abstract Carbonate and silicate metasomatism occurring in subduction zones is an important mechanism underlying mantle heterogeneity compositional diversity of mantle-derived rocks. However, distinguishing between the two kinds often difficult. Lithium (Li) its isotopes have great potential this regard because different Li isotopic compositions recycled marine carbonate components. We report data from Cenozoic Mesozoic alkali basalts West Qinling orogen central China. Relative to those for normal basalts, very high δ7Li values (up +11.2‰) were observed but significantly systematically lower (as low as −3.3‰) estimated basalts. Their abnormal compositions, combined with major- trace-element contents Sr-Mg isotope ratios, indicate that originated carbonated silicated sources, respectively, reflecting by slab-derived melts during Paleotethyan oceanic subduction. Interactions such peridotite channels can account elemental differences studied The present study demonstrates effective way distinguish studying highlights prospect tracing deep carbon cycle.