(Mg,Fe)SiO 3 -Perovskite Stability Under Lower Mantle Conditions

Abstract

In three different experiments up to 100 gigapascals and 3000 kelvin, (Mg,Fe)SiO 3 -perovskite, the major component of the lower mantle, remained stable and did not decompose to its component oxides (Mg,Fe)O and SiO 2 . Perovskite was formed from these oxides when heated in a diamond anvil cell at pressures up to 100 gigapascals. Both MgSiO 3 crystals and glasses heated to 3000 kelvin at 75 gigapascals also formed perovskite as a single phase, as evident from Raman spectra. Moreover, fluorescence measurements on chromium-doped samples synthesized at these conditions gave no indication of the presence of MgO.