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High-pressure compressibility and thermal expansion of aragonite

Sarah E. M. Palaich, Robert A. Heffern, Michael Hanfland, Andrea Lausi, Abby Kavner, Craig E. Manning and Marco Merlini
High-pressure compressibility and thermal expansion of aragonite
American Mineralogist (July 2016) 101 (7): 1651-1658

Abstract

The structure and isothermal equation of state of aragonite were determined to 40 GPa using synchrotron single-crystal X-ray techniques. In addition, powder diffraction techniques were used to determine thermal expansion between 298-673 K. At room temperature, aragonite has orthorhombic Pnma structure to 40 GPa, with an isothermal bulk modulus of 66.5(7) GPa and K' = 5.0(1). Between 25-30 GPa the aragonite unit cell begins to distort due to a stiffening of the c-axis compressibility, which is controlled by the orientation and distortion of the carbonate groups. The ambient pressure thermal expansion measurements yielded thermal expansion coefficients a (sub 0) = 4.9(2) X 10 (super -5) and a (sub 1) = 3.7(5) X 10 (super -8) . The combined results allow the derivation of a thermal equation of state. The new data provide constraints on the behavior of carbonates and carbon cycling in the Earth's crust and mantle.


ISSN: 0003-004X
EISSN: 1945-3027
Coden: AMMIAY
Serial Title: American Mineralogist
Serial Volume: 101
Serial Issue: 7
Title: High-pressure compressibility and thermal expansion of aragonite
Affiliation: University of California at Los Angeles, Department of Earth, Planetary and Space Sciences, Los Angeles, CA, United States
Pages: 1651-1658
Published: 201607
Text Language: English
Publisher: Mineralogical Society of America, Washington, DC, United States
References: 30
Accession Number: 2016-079225
Categories: Geophysics of minerals and rocks
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 2 tables
Secondary Affiliation: European Synchrotron, FRA, FranceElettra Sincrotrone Trieste, ITA, ItalyUniversita degli Studi di Milano, ITA, Italy
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Abstract, copyright, Mineralogical Society of America. Reference includes data from GeoScienceWorld, Alexandria, VA, United States
Update Code: 201638
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