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Melting relations in the iron-sulfur system at ultra-high pressures - Implications for the thermal state of the earthThe melting temperatures of FeS-troilite and of a 10-wt-pct sulfur iron alloy have been measured to pressures of 120 and 90 GPa, respectively. The results document that FeS melts at a temperature of 4100 (+ or - 300) K at the pressure of the core-mantle boundary. Eutecticlike behavior persists in the iron-sulfur system to the highest pressures of measurements, in marked contrast to the solid-solutionlike behavior observed at high pressures in the iron-iron oxide system. Iron with 10-wt-pct sulfur melts at a similar temperature as FeS at core-mantle boundary conditions. If the sole alloying elements of iron within the core are sulfur and oxygen and the outer core is entirely liquid, the minimum temperature at the top of the outer core is 4900 (+ or - 400) K. Calculations of mantle geotherms dictate that there must be a temperature increase of between 1000 and 2000 K across thermal boundary layers within the mantle. If D-double-prime is compositionally stratified, it could accommodate the bulk of this temperature jump.
Document ID
19910031969
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Williams, Quentin
(California Univ. Berkeley, CA, United States)
Jeanloz, Raymond
(California, University Berkeley, United States)
Date Acquired
August 15, 2013
Publication Date
November 10, 1990
Publication Information
Publication: Journal of Geophysical Research
Volume: 95
ISSN: 0148-0227
Subject Category
Geophysics
Accession Number
91A16592
Distribution Limits
Public
Copyright
Other

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