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Melting of iron‐magnesium‐silicate perovskite
Author(s) -
Sweeney Jeffrey S.,
Heinz Dion L.
Publication year - 1993
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 - 10.1029/93gl00556
Subject(s) - liquidus , solidus , melting curve analysis , diamond anvil cell , silicate , magnesium , materials science , perovskite (structure) , mineralogy , cooling curve , signal (programming language) , analytical chemistry (journal) , melting temperature , thermodynamics , geology , metallurgy , chemistry , crystallography , high pressure , physics , composite material , gene , polymerase chain reaction , biochemistry , organic chemistry , alloy , chromatography , computer science , programming language
Iron‐magnesium‐silicate perovskite was melted in a laser‐heated diamond anvil cell and monitored by thermal analysis. Two signals were identified at each pressure: a lower temperature signal and a higher temperature signal. The lower signal may correspond to the temperature where iron diffuses rapidly. The higher signal would then correspond to melting of magnesium‐enriched silicate perovskite. Alternatively, the lower signal may be the solidus where (Fe .14 Mg .86 )SiO 3 undergoes incongruent melting to an iron‐magnesium‐enriched solid plus a silica‐enriched liquid. Then, the higher signal would be the liquidus. The slope for the melting curve (the higher signal) between 30GPa and 94GPa is slightly negative. Fitting to a straight line gives a value for the slope of −2.5 ± 0.6K/GPa. At 30GPa, the lower signal is ≈300K below the melting curve. They converge slightly at higher pressures and differ by ≈140K at 94GPa. Our melting curve is several hundred degrees (K) below previous estimates.