Minerals, melts, and fluids play critical roles in geological processes across a wide range of spatial and temporal scales. Together, they govern the storage and transport of heat and mass and affect planetary evolution, especially on Earth. The stability of these materials is controlled, in part, by pressure and temperature. At the same time, these intensive parameters influence the physical and chemical behaviour of these materials, such as density, rheology, reactivity, and transport properties.

Seemingly, these physicochemical properties influence how minerals, melts, and fluids interact with one another and thus their roles in various geological processes. For instance, such interactions drive metamorphism, magmatism, hydrothermal circulation, and the formation of valuable mineral deposits in the crust. They also influence the mechanical behaviour of rocks, affecting deformation, faulting, and earthquake generation. At deep Earth, mineral-melt-fluid interactions regulate element mobility, mantle metasomatism, volatile recycling, and chemical differentiation. The migration of such fluids and melts can link deep planetary interiors to shallower regions. Nevertheless, their stagnation or pooling can concentrate heat and influence the chemical reactions. Understanding the behaviour and interactions of minerals, melts, and fluids under high-pressure-temperature conditions is therefore paramount for constraining geologic processes from the atomic to planetary scale.

This session invites contributions which examine the behaviour and interactions of minerals, melts, and fluids across a wide range of conditions relevant to planetary interiors and the implications for geological processes. We welcome a broad range of studies, including those from experiments, computational simulations and modelling, and analyses of natural samples.