Genesis of carbonatite and associated U–Nb–REE mineralization at Huayangchuan, central China: Insights from mineral paragenesis, chemical and Sr-Nd-C-O isotopic compositons of calcite

•Four-type calcites were identified in the Huayangchuan carbonatite-related U-Nb-REE deposit.•Chemical and Sr-Nd isotopic compositions of calcite can effectively trace the evolution of carbonatite magma and associated mineralization process.•Crystallization of LREE-bearing minerals resulted in significant differentiation between LREE and HREE prior to extensive carbonatite-exsolved U-Nb-REE-rich fluids.•U–Nb–REE mineralization occurred in the late magmatic–hydrothermal stage owing to extensive exsolution of ore-forming fluids during highly evolved carbonatite magma.