Properties and effects of supercritical fluids

Enhanced mutual solubility between silicate and water at elevated temperature and pressure in Earth’s interior (subduction zones in particular) allows the formation of supercritical geofluids with composition intermediate between silicate melts and aqueous fluids. The forming conditions of supercritical fluids are controlled by the critical curves, the wet solidi curves and the second critical endpoints of rock-H₂O systems. With unusual physicochemical properties, supercritical fluids have the potential to play a crucial role in mediating material recycling at subduction zones, mobilizing and enriching ore-forming elements, inducing intermediate to deep focus earthquakes, and modulating Earth’s habitability. Challenges in the study of supercritical fluids using experimental and computational simulations as well as natural rocks and mineral deposits demand breakthroughs in future development of transformative technologies.