Premium
Melting Experiments on Liquidus Phase Relations in the Fe‐S‐O Ternary System Under Core Pressures
Author(s) -
Yokoo Shunpei,
Hirose Kei,
Sinmyo Ryosuke,
Tagawa Shoh
Publication year - 2019
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 - 10.1029/2019gl082277
Subject(s) - liquidus , eutectic system , ternary operation , supercooling , outer core , electron microprobe , materials science , inner core , melting point , oxygen , phase (matter) , analytical chemistry (journal) , diamond anvil cell , sulfur , core (optical fiber) , thermodynamics , chemistry , metallurgy , high pressure , microstructure , alloy , chromatography , physics , organic chemistry , computer science , composite material , programming language
Melting experiments on the Fe‐S‐O ternary system were performed to 208 GPa in a laser‐heated diamond‐anvil cell. Compositions of liquids and coexisting solids in recovered samples were examined using a field‐emission‐type electron microprobe. The results demonstrate that the ternary eutectic point shifts toward the oxygen‐rich, sulfur‐poor side with increasing pressure, in accordance with changes in eutectic liquid compositions in the Fe‐O and Fe‐S binary systems. We also found that solid Fe crystallizing from liquid Fe‐S‐O does not include oxygen, while the partitioning of sulfur into solid Fe is enhanced with increasing pressure. These indicate that oxygen‐rich, sulfur‐poor liquid crystallizes Fe at the inner core boundary; however, it makes a large density difference between the liquid and solid core, which is inconsistent with observations. Alternatively, we found that a range of C‐bearing, S‐poor/O‐rich liquids account for the density and velocity in the outer core and the density in the inner core.