Alumina (Al2O3)-bearing minerals are hosted in carbonate-rich sediments, potentially interacting with CaCO3 during subduction. Here, the authors study the influence of Al2O3 particle size on carbonate stability at 0.5–2.8 GPa and 350–1050 °C, showing that CaCO3 remains thermodynamically stable when coexisting with micron-sized Al2O3 and Al(OH)3, whereas Al2O3 nanoparticles trigger decarbonation, forming CaAl4O7, CO2, and trace graphite.
- Jun Hu
- Jin Liu
- Yongjun Tian