TY - JOUR
T1 - Immiscible two-liquid regions in the Fe-O-S system at high pressure
T2 - Implications for planetary cores
AU - Tsuno, Kyusei
AU - Ohtani, Eiji
AU - Terasaki, Hidenori
N1 - Funding Information:
We are grateful to T. Kondo and A. Suzuki of Tohoku University for their useful discussion. We thank Y. Ito for the electron microprobe analysis of the run products. This work was supported by a Grant-in-Aid for Scientific Research (S) of the Ministry of Education, Culture, Science, Sport, and Technology of Japanese Government (No. 14102009) to Eiji Ohtani, and conducted as a part of the 21st Century Center-of-Excellence program, ‘Advanced Science and Technology Center for the Dynamic Earth’.
Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2007/1/16
Y1 - 2007/1/16
N2 - We have determined phase relations in the Fe-O and Fe-O-S systems in the range of 15-21 GPa and 1825-2300 °C. Below the liquidus temperatures, solid FeO and metallic liquids are observed in both the Fe-O and the Fe-O-S systems. An immiscible two-liquid region exists in the Fe-O binary system in the pressure range investigated, and the immiscibility gap between Fe-rich metallic liquid and FeO-rich ionic liquid does not greatly change with either pressure or temperature. On the other hand, an immiscible two-liquid region in the Fe-O-S ternary system narrows significantly with increasing pressure at constant temperature and vice versa, and it almost disappears at 21 GPa, and 2300 °C. Immiscible two-liquid regions are thus not expected to exist in the Fe-O-S system in the Earth's core, suggesting that both oxygen and sulfur can be incorporated into the core. Our results are consistent with a geochemical model for the core containing 5.8 wt.% oxygen and 1.9 wt.% sulfur as proposed by McDonough and Sun [McDonough, W.F., Sun, S.-S., 1995. The composition of the Earth. Chem. Geol. 120, 223-253].
AB - We have determined phase relations in the Fe-O and Fe-O-S systems in the range of 15-21 GPa and 1825-2300 °C. Below the liquidus temperatures, solid FeO and metallic liquids are observed in both the Fe-O and the Fe-O-S systems. An immiscible two-liquid region exists in the Fe-O binary system in the pressure range investigated, and the immiscibility gap between Fe-rich metallic liquid and FeO-rich ionic liquid does not greatly change with either pressure or temperature. On the other hand, an immiscible two-liquid region in the Fe-O-S ternary system narrows significantly with increasing pressure at constant temperature and vice versa, and it almost disappears at 21 GPa, and 2300 °C. Immiscible two-liquid regions are thus not expected to exist in the Fe-O-S system in the Earth's core, suggesting that both oxygen and sulfur can be incorporated into the core. Our results are consistent with a geochemical model for the core containing 5.8 wt.% oxygen and 1.9 wt.% sulfur as proposed by McDonough and Sun [McDonough, W.F., Sun, S.-S., 1995. The composition of the Earth. Chem. Geol. 120, 223-253].
KW - Core
KW - Fe-alloys
KW - High pressure
KW - Liquid immiscibility
KW - Miscibility
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U2 - 10.1016/j.pepi.2006.09.004
DO - 10.1016/j.pepi.2006.09.004
M3 - Article
AN - SCOPUS:33845652264
SN - 0031-9201
VL - 160
SP - 75
EP - 85
JO - Physics of the Earth and Planetary Interiors
JF - Physics of the Earth and Planetary Interiors
IS - 1
ER -