资源环境科技发展态势分析平台

Wadsleyite can store significant amounts of H₂O in its crystal structure as hydroxyl. However, H₂O solubility in Fe‐bearing wadsleyite remains poorly constrained at mantle transition zone temperatures. Previous studies (e.g. Demouchy et al., 2005; Litasov et al., 2011) focused primarily on Fe‐free systems, which do not represent the Earth’s interior because Fe may affect the H₂O solubility. Here we investigated the temperature dependence of H₂O solubility in Fe‐bearing and Fe‐free wadsleyite at 1500‐2100 K. The results indicate that H₂O solubility in Fe‐bearing wadsleyite is higher than in Fe‐free samples at 1800‐1900 K, corresponding to transition zone geotherm, but there is no clear Fe content dependence in the Fe‐bearing samples. Wadsleyite can contain approximately 1.0 wt.% H₂O at transition zone temperatures. The H₂O solubility in wadsleyite is lower than ringwoodite along a plume geotherm, which may result in dehydration melting at the 520‐km discontinuity by upwelling flow in plumes.