Low‐Degree Melt Metasomatic Origin of Global Upper Mantle Fe Isotope Fractionation

Abstract The upper mantle is heterogeneous in Fe isotope compositions, but the origin of heterogeneity needs understanding. Recent studies on oceanic basalts demonstrate that results from low‐degree melt metasomatism. However, whether this hypothesis global significance testing continental settings. Here we present an isotopic study intraplate alkali China, which are shown to have derived containing more metasomatized lithologies. show first‐order positive correlations δ 56 with indices metasomatism (e.g., [La/Sm] N ), which, together so‐far published mid‐ocean ridge data, define trends, substantiating causing variation. We, thus, suggest a globally effective process preferentially concentrate heavy isotopes metasomatic lithologies at conditions both today and Earth's history.