Experimental Crystallization of Chevkinite/Perrierite from REE-enriched Silicate Liquids at High Pressure and Temperature

T. H. Green and N. J. Pearson
School of Earth Sciences, Macquarie University, North Ryde, NSW 2113, Australia

Abstract: Chevkinite/perrierite crystallized from a series of REE-enriched compositions, ranging from basalt through andesite to rhyolite at pressures from 7.5 to 20 kbar and temperatures from 900–1050°C The Al2O3 content increased with increasing pressure, but no other consistent composition change was observed with pressure and temperature variation in this range. The REE partition pattern consistently favoured light over heavy REE, with a regular decrease in partition coefficients (D) from La through to Lu. D values increase with decreasing temperature and decreasing REE content (i.e. Henry's Law does not apply, as REE are essential structural constituents of chevkinite/perrierite), but appear unaffected by pressure and fo2. Chevkinite/perrierite may be a significant fractionating phase in evolving silicic magmas, or a residual phase from low degrees of partial melting of granulites. In both these circumstances it will exert a major control on the REE content of derivative liquids.

Keywords: chevkinite • perrierite • rare earth elements • silicate liquids

Mineralogical Magazine; March 1988 v. 52; no. 364; p. 113-120; DOI: 10.1180/minmag.1988.052.364.10
© 1988, The Mineralogical Society
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