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Fe‐Mg partitioning between (Mg, Fe)SiO 3 post‐perovskite, perovskite, and magnesiowüstite in the Earth's lower mantle
Author(s) -
Kobayashi Yusuke,
Kondo Tadashi,
Ohtani Eiji,
Hirao Naohisa,
Miyajima Nobuyoshi,
Yagi Takehiko,
Nagase Toshiro,
Kikegawa Takumi
Publication year - 2005
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 - 10.1029/2005gl023257
Subject(s) - wüstite , materials science , perovskite (structure) , mantle (geology) , analytical chemistry (journal) , synchrotron , post perovskite , metal , phase boundary , mineralogy , phase (matter) , geology , metallurgy , crystallography , magnetite , chemistry , geochemistry , physics , organic chemistry , chromatography , nuclear physics
We report here new data on pressure dependence of Fe‐Mg partitioning between (Mg, Fe)SiO 3 perovskite (Pv) and magnesiowüstite (Mw), K Pv/Mw , and (Mg, Fe)SiO 3 post‐perovskite (PPv) and Mw, K PPv/Mw , up to 123.6 GPa at 1600 K measured by synchrotron X‐ray diffraction method and analytical transmission electron microscopy (ATEM). We observed a high FeO content in PPv coexisting with Mw [ K PPv/Mw = (FeO/MgO) PPv /(FeO/MgO) Mw = 0.30] compared to that in Pv [ K Pv/Mw = (FeO/MgO) Pv /(FeO/MgO) Mw = 0.12] observed from 23.0 to 95.4 GPa. K Pv/Mw keeps a constant value of 0.12 up to the PPv phase boundary. Our results also support the possibility that a metallic phase may form in the lower mantle. The assemblage of PPv and Mw is 1.5–1.7% denser than the Pv bearing assemblage, which results in a gravitational stabilization of the lowermost mantle.