Melting of (Mg,Fe) 2 SiO 4 at the Core-Mantle Boundary of the Earth

Abstract
The lower mantle of the Earth is believed to be largely composed of (Mg,Fe)O (magnesiowüstite) and (Mg,Fe)SiO3 (perovskite). Radiative temperatures of single-crystal olivine [(Mg0.9,Fe0.1)2SiO4] decreased abruptly from 7040 ± 315 to 4300 ± 270 kelvin upon shock compression above 80 gigapascals. The data indicate that an upper bound to the solidus of the magnesiowüstite and perovskite assemblage at 4300 ± 270 kelvin is 130 ± 3 gigapascals. These conditions correspond to those for partial melting at the base of the mantle, as has been suggested occurs within the ultralow-velocity zone beneath the central Pacific.