Carbonatite Metasomatism in a Subvolcanic Setting: Breccia at the Badou Carbonatite in the North China Craton and Implications for Magmatic Evolution and Eruptive Style.

This article focuses on the petrogenesis and crustal evolution of the subvolcanic Badou carbonatite in the North China Craton, emphasizing its mantle origin and subsequent modification through interaction with crustal materials. Mineralogical, isotopic, and geochemical analyses reveal that the carbonatite melt originated from direct mantle melting, evidenced by Cr- and Ni-rich clinopyroxene and mica phenocrysts, and was extensively contaminated by silica-rich crustal rocks forming antiskarn assemblages. This crustal assimilation altered the melt’s composition by sequestering Mg and Fe into silicate minerals and generating CO₂ vapor, which increased magma viscosity and conduit overpressure, thereby enhancing the potential for explosive volcanic activity. The study suggests that such complex melt-crust interactions contribute to the compositional diversity of carbonatites and influence their eruptive behaviors.