The boundary phase and the melting of CaSiO3 and MgSiO3 perovskites

• We have investigated the melting temperatures of MgSiO3 and CaSiO3 perovskites at high pressure conditions, using an empirical melting equation, combined with the assumption of a boundary phase existing at the melting point. This study indicates that both CaSiO3 and MgSiO3 perovskites have a cubic structure near the melting boundary, and that the obtained melting temperatures are in good agreement with experimental measurements (Zerr et al., Geophys. Res. Lett. 24 (1998) 909; J.S. Sweeney, D.L. Heinz, High Pressure-Temperature Research: Properties of Earth and Planetary Materials, in: M.H. Manghnani, T. Yagi (Eds.), AGU, (1998) p. 185]. Additionally, our results reveal that CaSiO3 and MgSiO3 perovskites cannot cause a partial melting at the core-mantle boundary. Our calculation and assumption suggest that the Lindemann law is valid to estimate the melting temperatures of silicates as the silicate phases near the melting boundary are definitely determined and chosen.

Subject headings

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Geokemi (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Geochemistry (hsv//eng)

Publication and Content Type

ref (subject category)

art (subject category)