Transportation of water into the deep Earth by Al-phase D

Researchers have recently measured the propagation speed of ultrasonic waves in an aluminum-rich hydrous mineral called Al-phase D at pressure conditions relevant to the Earth’s deep mantle. Their results suggest that seismic shear anomalies observed locally beneath subduction zones may reveal the presence of hydrous minerals in the uppermost lower mantle, which would have important implications for the Earth’s interior because hydrogen affects considerably the physical and chemical properties of mantle minerals.