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Compressibility of clinochlore to 8 GPa at 298 K and a comparison with micas

Mark D. Welch and Wilson A. Crichton
Compressibility of clinochlore to 8 GPa at 298 K and a comparison with micas
European Journal of Mineralogy (June 2002) 14 (3): 561-565


The equation of state of deuterated synthetic end-member C2/m clinochlore, Mg (sub 5) Al(Si (sub 3) Al)O (sub 10) (OD) (sub 8) , has been determined by synchrotron X-ray powder diffraction in the pressure range 0-7.7 GPa. The room-temperature bulk modulus K (sub 0) obtained from a fit of sixteen measurements to a second-order Birch-Murnaghan equation of state (K' (sub 0) = 4) is K (sub 0) = 81.0+ or -0.5 GPa. Fitting to a third-order Birch-Murnaghan equation of state gives K (sub 0) = 83.1+ or -1.7 GPa and K' (sub 0) = 3.3+ or -0.6 and, within error, the two fits are indistinguishable over this pressure range. Axial moduli (K' (sub 0) = 4) for clinochlore are: K (sub 0a) = 91(1) GPa, K (sub 0b) = 89(1) GPa, K (sub 0c) = 67(2) GPa. Comparison with published compressibilities for phlogopite, muscovite and phengite reveals that the micas are slightly less compressible along [100] and [010] than clinochlore, but micas are three times more compressible than clinochlore normal to the (001) structural layering. The very different compressibilities of micas and clinochlore normal to their polyhedral sheets indicates that the type of interlayer bonding has a major effect upon compressibility.

ISSN: 0935-1221
EISSN: 1617-4011
Serial Title: European Journal of Mineralogy
Serial Volume: 14
Serial Issue: 3
Title: Compressibility of clinochlore to 8 GPa at 298 K and a comparison with micas
Affiliation: Natural History Museum, Department of Mineralogy, London, United Kingdom
Pages: 561-565
Published: 200206
Text Language: English
Publisher: Schweizerbart'sche Verlagsbuchhandlung (Naegele u. Obermiller), Stuttgart, Federal Republic of Germany
References: 20
Accession Number: 2002-047657
Categories: General geophysics
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 2 tables
Secondary Affiliation: European Synchrotron Radiation Facility, FRA, France
Country of Publication: Germany
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 200216
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