Crust–Mantle Architecture Remodelled by Mantle Plumes: Evidence From Late Permian (ca. 260 Ma) Gabbro–Monzonite Association in the Inner Zone of the Emeishan Large Igneous Province

ABSTRACT Crust–mantle architecture in large igneous provinces (LIPs) controls magma generation and crustal growth. The coeval gabbro and monzonite in the inner zone of the Emeishan Large Igneous Province (ELIP) provide a key opportunity. They display different whole‐rock and mineral compositions, indicating different sources and melting conditions. The gabbro displays moderate TiO 2 and MgO contents, with Ti/Y ratios of 408–413. Its elevated Nb/Ta and Zr/Hf ratios, evolved zircon Hf isotope, and apatite chemistry suggest a volatile‐poor primitive melt, which was derived from the melting of sub‐continental lithospheric mantle. The monzonite displays high Zr and Nb contents, TFeO/MgO and 10,000 × Ga/Al ratios, indicating high‐temperature melting of mafic lower crust, the high Sr contents suggest plagioclase incorporation into the melts. Its relatively depleted isotopic compositions ( ε Nd ( t ) = +3.2 to +3.7; ε Hf ( t ) = +0.87 to +0.88) reveal a juvenile crust source region. Apatite in the monzonite indicates a volatile‐rich melt, supporting a high‐temperature crustal melting origin. This geochemical dichotomy illuminates a two‐stage crustal evolution model: (1) melting of plume‐modified lithospheric mantle to generate the gabbro, followed by (2) thermal remelting of the juvenile mafic crust to form the monzonite. Such plume‐induced crust–mantle interaction offers a window into understanding crust–mantle architecture in global LIPs.