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Melting boundary of Fe‐17%Si up to 5.5 GPa and the timing of core formation
Author(s) -
Yang Haitao,
Secco Richard A.
Publication year - 1999
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 - 10.1029/1998gl900292
Subject(s) - materials science , metal , thermodynamics , melting point , phase (matter) , earth (classical element) , discontinuity (linguistics) , analytical chemistry (journal) , phase boundary , partial melting , melting temperature , mineralogy , mantle (geology) , geology , metallurgy , composite material , chemistry , geophysics , physics , organic chemistry , chromatography , mathematical analysis , mathematics , mathematical physics
Melting of Fe‐17wt%Si has been investigated at temperatures up to 1600°C and pressures up to 5.5 GPa in a cubic anvil press. The melting temperature, T M , was identified with the discontinuity in temperature and pressure dependence of electrical resistance. Two types of electrode materials, Pt and Fe, were used and gave consistent melting results. T M increases with pressure from 1200°C at 1 atm to 1430°C at 5.5 GPa. dT M /dP decreases with pressure and reaches a value of zero at P∼5 GPa. Combined with the thermal profiles of the proto‐Earth, the pressure independence of the melting boundary of Fe‐17%Si at the highest pressures of this study suggests core formation began early in Earth accretion with a substantial liquid metal phase fraction between 30 Ma and 42 Ma.