Oxygen fugacity (fO₂) is a key variable that describes the redox state of a system. In the mantle, the storage form of carbon is closely related to oxygen fugacity: under high oxygen fugacity conditions, carbon mainly exists in the form of carbonate minerals, which can significantly reduce the solidus temperature of the mantle and promote the formation of carbonate carbonate silicate melts in the mantle. On the contrary, in low oxygen fugacity environments, carbon mainly exists in the form of diamond or graphite, and has a relatively small impact on the mantle melting process. Therefore, accurately constraining mantle oxygen fugacity is of crucial significance for a deeper understanding of deep carbon cycling processes