Diverse late Neoarchean magmatism in northeastern North China Craton: Consequences of crustal growth, recycling, and magma mixing

The North China Craton (NCC) preserves a wide range of Neoarchean magmatic rocks, which provide valuable insights into the origins of magmatic diversity and associated tectonic processes that occurred on the early Earth. Here, we examine three lithologies from the southern Jilin terrane, a major component of the NCC: potassic granites, sanukitoids (granodiorite and diorite), and mafic enclaves (amphibolite and hornblendite). Zircon UPb geochronology confirms that these units crystallized around 2510 Ma. The potassic granites exhibit typical geochemical characteristics of crust-derived rocks, indicating that their magma source was related to partial melting of early-formed TTG rocks within a thickened lower crust. Whole-rock geochemistry, Nd isotopes, and zircon Hf isotope data reveal that the amphibolite enclaves formed from mafic magmas derived from partial melting of an enriched lithospheric mantle. In contrast, the hornblendite enclaves are interpreted as altered cumulates that formed through low-pressure (0.6–1.0 GPa) fractionation of 25–45 vol% clinopyroxene and olivine from the amphibolite parental magmas. The sanukitoids contain abundant mafic microgranular enclaves and exhibit disequilibrium textures. These characteristics, together with hybrid geochemical signatures, suggest a magma mixing origin. Geochemical modelling further indicates that the granodiorite and diorite resulted from mixing 70–50 vol% syenogranite with 30–50 vol% amphibolite. These findings, together with previous studies, provide evidence for a Neoarchean subduction-collision-dominated geodynamic mechanism leading to the evolution of continental crust in the northeastern NCC, with localized contributions from mantle plumes.