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In situ-X-ray study of perovskite (MgSiO (sub 3) ); phase transition and dissociation at mantle conditions

Surendra X. Saxena, Leonid S. Dubrovinsky, Peter Lazor and Jingzhu Hu
In situ-X-ray study of perovskite (MgSiO (sub 3) ); phase transition and dissociation at mantle conditions
European Journal of Mineralogy (December 1998) 10 (6): 1275-1281

Abstract

The dissociation reaction: MgSiO (sub 3) (perovskite) = MgO (periclase) + SiO (sub 2) (high pressure silica phase) was studied at 82 (3) GPa by in situ heating to temperatures between 300 and 1780 (50) K and X-ray diffraction. The orthorhombic perovskite changed to a pseudo-cubic phase between 1280 to 1485 K followed by a break down to the oxide mixture which was observed to grow at temperatures between 1600 to 1700 K; orthorhombic perovskite was recovered upon cooling at 1140 K. In yet another experiment, MgO and the silica phase grew from a sample of enstatite composition at 82 GPa and 1250 K. Compositionally, the instability of perovskite makes the oxide mixture as the most probable mantle material which can provide a variety of possible mantle compositions. Dynamically, the lighter SiO (sub 2) component would facilitate differentiation of the lower mantle.


ISSN: 0935-1221
Serial Title: European Journal of Mineralogy
Serial Volume: 10
Serial Issue: 6
Title: In situ-X-ray study of perovskite (MgSiO (sub 3) ); phase transition and dissociation at mantle conditions
Affiliation: Uppsala University, Institute of Earth Sciences, Uppsala, Sweden
Pages: 1275-1281
Published: 199812
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Federal Republic of Germany
References: 12
Accession Number: 1999-018599
Categories: Geophysics of minerals and rocks
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 table
Secondary Affiliation: Carnegie Institution of Washington, USA, United States
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 199907
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