Open AccessHigh‐pressure polymorphism of FeO? An alternative interpretation and its implications for the Earth's core
Author(s) -
Liu Lingun,
Shen Pouyan,
Bassett William A.
Publication year - 1982
Publication title -
geophysical journal of the royal astronomical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0016-8009
DOI - 10.1111/j.1365-246x.1982.tb06391.x
Subject(s) - stoichiometry , outer core , homogeneous , inner core , core (optical fiber) , oxygen , materials science , thermodynamics , earth (classical element) , mineralogy , analytical chemistry (journal) , chemistry , physics , composite material , mathematical physics , chromatography , organic chemistry
Summary. It has been reported that no stoichiometric FeO can be formed at temperatures above about 600°C regardless of pressure. The stoichiometry of Fe X O quenched from static high pressure and temperature experiments appears to decrease with increasing pressure in the range 100–300kbar. On the basis of these observations, we have re‐interpreted the recent shock results on Fe 0.94 O, and have found that the Hugoniot data can be reasonable interpreted by the same shift in stoichiometry as observed in the static high‐pressure experiments instead of a first‐order transformation as proposed. If oxygen is assumed to be the light component of the outer core, the outer core can be chemically homogeneous only if the stoichiometry of Fe X O decreases with increasing pressure. A constant stoichiometry would demand that the oxygen content decreases by a factor of 2 from the top to the bottom of the outer core. A chemically homogeneous outer core is consistent with a convecting outer core.