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Science 25 August 1995:
Vol. 269. no. 5227, pp. 1095 - 1098
DOI: 10.1126/science.269.5227.1095
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Articles

Catalysis of the Olivine to Spinel Transformation by High Clinoenstatite

T. G. Sharp 1 and D. C. Rubie 1

1 Bayerisches Geoinstitut, Universität Bayreuth, D-95440 Bayreuth, Germany

Although enstatite is a major constituent of the Earth's upper mantle and subducting lithosphere, most kinetic studies of olivine phase transformations have typically involved single-phase polycrystalline aggregates. Transmission electron microscopy investigations of olivine to spinel and modified spinel (beta phase) reactions in the (Mg, Fe)2SiO4-(Mg,Fe)SiO3 system show that transformation of olivine in the stability field of spinel plus phase begins with coherent nucleation of spinel on high-clinoenstatite grains. These observations demonstrate that high clinoenstatite can catalyze the transformation by enhancing nucleation kinetics and therefore imply that secondary phases can influence reaction kinetics during high-pressure mineral transformations.

Submitted on February 8, 1995
Accepted on May 19, 1995


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Kinetics of high-pressure mineral phase transformations using in situ time-resolved X-ray diffraction in the Paris-Edinburgh cell: a practical guide for data acquisition and treatment.
J. P. Perrillat (2008)
Mineralogical Magazine 72, 683-695
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Science. ISSN 0036-8075 (print), 1095-9203 (online)