Distinct chalcophile-element inheritance from subducted continental crust in metasomatized mantle

Abstract

Subduction recycles surface materials into the mantle and shapes its chemical evolution. Whether continental subduction leaves chalcophile-element imprints in the mantle that differ from those of oceanic subduction remains poorly understood. Here, we show that primitive basaltic magmas from the North China Craton exhibit pronounced copper depletion, silver enrichment, and low copper/silver (200 to 1200), together with continental crust–like trace element patterns and radiogenic-isotope compositions. These features contrast sharply with those of the convective mantle, mid-ocean ridge basalts, and oceanic arc basalts, and reflect chemical signatures inherited from subducted continental crust and retained over geological timescales in metasomatized domains of a relatively cold lithospheric mantle. Coupled lead enrichment and unradiogenic lead-isotope signatures further identify metasomatized mantle as an important reservoir of Earth’s unradiogenic lead. Our results reveal distinct modes of chalcophile-element recycling and mantle inheritance during continental and oceanic subduction, with broad implications for mantle chemical evolution and the critical-metal fertility of continental lithosphere.