Deep carbon cycling

The stable host phases for carbon in Earth’s mantle, which have controlled storage and fluxes of carbon through the planet over geologic time, impacting the surface climate as well as carrying records of geologic processes (e.g., the form of diamonds and their inclusions). Subduction of carbonates is the main mechanism that transports carbon from Earth’s surface to its interior. However, the carbon input to the convecting mantle and the hosts of carbon at lower mantle conditions remain uncertain, due to limited understanding of fate of subducted carbonates in the lower mantle (Figure after Hoernle et al. 2002).

I am conducting various experiments and modeling to investigate the fate of subducted carbonates, including: (1) carbonate polymorphism; (2) physical properties of carbonate and carbonated peridotite or eclogite; (3) carbonate-silicate exchange reactions and phase equilibrium; (4) reduction of carbonate solid or melt through reaction with iron or other reduced phases; (5) decarbonization with free silica phase to form silicates, CO2, or C.