Carbon is a crucial element for planetary habitability, but the vast majority of carbon in terrestrial planets such as the Earth may reside at depth. Key questions about deep carbon budget and fluxes on geological timescales are complicated by carbon’s volatility and redox-dependent chemistry. What was the total carbon budget at Earth's formation, and how much has been lost? How has carbon been repartitioned among the crust, mantle and core? What are the major phases in planetary interiors that host carbon and in what quantities? These questions must be addressed with a multidisciplinary approach that includes natural observation, experiments, and modelling. In recent decades discoveries have illuminated the variety of hosts for carbon including carbonates, silicate melts, crystalline metallic alloys, metallic liquids and elemental forms. In this session, we solicit contributions from wide-ranging disciplines that address forms of deep carbon and carbon cycles within Earth and other planetary bodies.

• MSA: Mineralogical Society of America -