Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: Journal of Geophysical Research: Solid Earth
Supercritical fluids—hydrous silicate liquids where water and melt become fully miscible—are believed to play a key role in chemical transport and element redistribution in subduction zones. However, the atomic-scale processes underlying their high mobility are poorly understood.
Chen et al. [2025] use first-principle molecular dynamics simulations to examine the diopside–H2O system over a wide range of water contents, pressures (up to 12 gigapascals), and temperature (3000 kelvin). Their results show that water promotes the breakdown of the silicate network by converting bridging oxygens (BOs) into non-bridging oxygens (NBOs), leading to the formation of smaller, less polymerized silicate clusters with greater diffusivity and structural stability. This depolymerization enhances atomic mobility and reduces viscosity, with strong linear correlations observed between polymerization degree and transport properties. The findings identify water-induced depolymerization as the primary mechanism behind the high mobility of supercritical fluids.
These insights have broad implications for understanding magma transport dynamics and the geochemical signatures—such as uranium-thorium disequilibria—in arc lavas. The study highlights the critical role of water in regulating the structure and dynamics of silicate fluids in subduction-related magmatic and mineralizing processes.
Citation: Chen, B., Song, J., Zhang, Y., Wang, W., Zhao, Y., Wu, Z., & Wu, X. (2025). Water dissolution driving high mobility of diopside-H2O supercritical fluid. Journal of Geophysical Research: Solid Earth, 130, e2024JB030956. https://doi.org/10.1029/2024JB030956
—Jun Tsuchiya, Editor, JGR: Solid Earth
