Water-storage capacity of davemaoite

Determine the water-storage capacity of davemaoite under lower-mantle conditions in order to constrain the amount of hydrogen that may influence its electrical conductivity.

Background

Hydrogen may substantially enhance electrical transport in nominally anhydrous minerals, and even low water contents have been shown to increase the conductivity of bridgmanite. Davemaoite may therefore contribute differently to the conductivity of subducted oceanic crust depending on its actual hydrogen or water content.

Published estimates of davemaoite’s water-storage capacity span a wide range, from approximately 100–1000 ppm H2O to more than 4000 ppm H2O, while a more recent study reports approximately 0.04–0.08 wt% H2O under lower-mantle conditions. Resolving this uncertainty is important for evaluating hydrous davemaoite and subduction-related conductivity anomalies.

References

The water-storage capacity of davemaoite remains uncertain, with reported estimates ranging from approximately 100–1000 ppm H2O (Hirschmann, 2006; Keppler and Bolfan-Casanova, 2006; Németh et al., 2017) to >4000 ppm H2O (Chen et al., 2020; Murakami et al., 2002).

— Low electrical conductivity of dry CaSiO3 perovskite under lower mantle conditions  (2609.04499 - Okuda et al., 3 Sep 2026) in Section 4.3, page 18