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Post‐perovskite phase transition and mineral chemistry in the pyrolitic lowermost mantle
Author(s) -
Murakami Motohiko,
Hirose Kei,
Sata Nagayoshi,
Ohishi Yasuo
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 - 10.1029/2004gl021956
Subject(s) - post perovskite , mantle (geology) , core–mantle boundary , wüstite , perovskite (structure) , geology , transition zone , diamond anvil cell , mineralogy , phase transition , chemical composition , transmission electron microscopy , inner core , analytical chemistry (journal) , materials science , diffraction , geochemistry , geophysics , crystallography , hematite , thermodynamics , chemistry , nanotechnology , optics , chromatography , physics
Phase relations of a natural mantle composition were determined up to 126 GPa and 2450 K by in‐situ x‐ray diffraction measurements in a laser‐heated diamond‐anvil cell (LHDAC). MgSiO 3 ‐rich perovskite (MgPv) transforms to a post‐perovskite phase (MgPP) at about 113 GPa and 2500 K (400‐km above the core‐mantle boundary) and the lowermost mantle consists of MgPP, (Mg, Fe)O magnesiowüstite (Mw), and CaSiO 3 ‐rich perovskite (CaPv). Chemical analyses on recovered samples using transmission electron microscope (TEM) show that the distribution of iron significantly changes at the post‐perovskite phase transition. A strong enrichment of iron in Mw leads to the unique geophysical and geochemical properties of the lowermost mantle.