Dense iron oxyhydroxides as possible reservoirs of water under deep mantle conditions

Nature Geoscience, Published online: 08 September 2026; doi:10.1038/s41561-026-02067-1 Dense iron oxyhydroxide phases may form from an early basal magma ocean, trapping water and potentially contributing to the formation of thermochemical anomalies in the deep mantle, according to high-pressure and high-temperature experiments.