Post‐perovskite phase transition and mineral chemistry in the pyrolitic lowermost mantle
- 4 February 2005
- journal article
- Published by American Geophysical Union (AGU) in Geophysical Research Letters
- Vol. 32 (3)
- https://doi.org/10.1029/2004gl021956
Abstract
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). MgSiO3‐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 CaSiO3‐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.Keywords
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