Aluminous hydrous mineral δ-AlOOH as a carrier of hydrogen into the core-mantle boundary

In-situ X-ray diffraction experiments were conducted to determine the stability field of the aluminous hydrous mineral delta-AlOOH over the entire conditions of the lower mantle. We observed delta-AlOOH at pressures from 33 to 134 GPa at 1350-2300 K, indicating that this hydrous mineral in the sediment layer of a subducting slab could transport hydrogen into the core-mantle boundary (CMB).