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High-pressure phase of brucite stable at Earth's mantle transition zone and lower mantle conditions.

Title: High-pressure phase of brucite stable at Earth's mantle transition zone and lower mantle conditions.
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Name(s): Hermann, Andreas, author
Mookherjee, Mainak, author
Type of Resource: text
Genre: Journal Article
Text
Date Issued: 2016-12-06
Physical Form: computer
online resource
Extent: 1 online resource
Language(s): English
Abstract/Description: We investigate the high-pressure phase diagram of the hydrous mineral brucite, Mg(OH), using structure search algorithms and ab initio simulations. We predict a high-pressure phase stable at pressure and temperature conditions found in cold subducting slabs in Earth's mantle transition zone and lower mantle. This prediction implies that brucite can play a much more important role in water transport and storage in Earth's interior than hitherto thought. The predicted high-pressure phase, stable in calculations between 20 and 35 GPa and up to 800 K, features MgO octahedral units arranged in the anatase-TiO structure. Our findings suggest that brucite will transform from a layered to a compact 3D network structure before eventual decomposition into periclase and ice. We show that the high-pressure phase has unique spectroscopic fingerprints that should allow for straightforward detection in experiments. The phase also has distinct elastic properties that might make its direct detection in the deep Earth possible with geophysical methods.
Identifier: FSU_pmch_27872307 (IID), 10.1073/pnas.1611571113 (DOI), PMC5150419 (PMCID), 27872307 (RID), 27872307 (EID), 1611571113 (PII)
Keywords: Brucite, Electronic structure calculations, Phase transition, Pressure
Publication Note: This NIH-funded author manuscript originally appeared in PubMed Central at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5150419.
Persistent Link to This Record: http://purl.flvc.org/fsu/fd/FSU_pmch_27872307
Owner Institution: FSU
Is Part Of: Proceedings of the National Academy of Sciences of the United States of America.
1091-6490
Issue: iss. 49, vol. 113

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Hermann, A., & Mookherjee, M. (2016). High-pressure phase of brucite stable at Earth's mantle transition zone and lower mantle conditions. Proceedings Of The National Academy Of Sciences Of The United States Of America. Retrieved from http://purl.flvc.org/fsu/fd/FSU_pmch_27872307