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Melting of CaSiO 3 perovskite to 430 kbar and first in‐situ measurements of lower mantle eutectic temperatures
Author(s) -
Zerr A.,
Serghiou G.,
Boehler R.
Publication year - 1997
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/97gl00829
Subject(s) - eutectic system , diamond anvil cell , materials science , mantle (geology) , halide , mineralogy , melting temperature , analytical chemistry (journal) , thermodynamics , geology , metallurgy , inorganic chemistry , microstructure , geochemistry , chemistry , composite material , high pressure , physics , chromatography
Melting temperatures of CaSiO 3 perovskite were measured between 160 and 430 kbar in a diamond anvil cell under hydrostatic, inert conditions using CO 2 ‐laser heating. The melting temperatures are higher than those obtained in previous YAG‐laser heating experiments [ Shen and Lazor , 1995], where chemical reactions of the sample with rhenium might have caused a lowering in the melting temperatures. The melting temperatures of CaSiO 3 perovskite are slightly higher than those of (Mg,Fe)SiO 3 perovskite [ Zerr and Boehler , 1993], thus making the two major minerals of the lower mantle Mg‐Si‐perovskite and magnesiowüsite the low‐melting components. First in‐situ measurements of the eutectic melting temperatures of these two minerals are presented. The data suggest that eutectic melting depression in the lower mantle may be insignificant. An alternate solution for the extrapolation of the measured melting temperatures to higher pressures, based on recent observations on the highly compressible alkali halides, yields melting temperatures at the bottom of the lower mantle below 6000 K.