Phase Equilibria in the System LamprophylliteNepheline

V. A. Zaitsev, L. N. Kogarko, and V. G. Senin

Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences,
ul. Kosygina 19, Moscow, 119991 Russia

e-mail: alkaline@geokhi.ru

Received October 26, 2012; in final form, April 10, 2013

Abstract—Experimental studies of the melting diagram for the lamprophyllite–nepheline system and data on
the phases crystallizing in this system indicate that lamprophyllite incongruently melts with the origin of melt
and titanium oxide. The maximum temperature at which nepheline and lamprophyllite can occur in equilibrium
is estimated at 833 6C.
Our pioneering data on lamprophyllite crystallization from melt prove that this mineral can be of magmatic gen-
esis. The distribution coefficients between lamprophyllite and melt are evaluated for K (0.1–0.25), Mn (0.82–
1.06), Fe (0.13–0.40), and Mg (0.82–1.5); and the Sr/Ba lamprophyllite/melt exchange coefficient is estimated
at 1.8–3.7.

Keywords: titanosilicates, melting curves diagram, lamprophyllite, nepheline, titanosilicate melts, phase equi-
libria, distribution coefficients, tausonite, freudenbergite, rutile

DOI: 10.1134/S0016702913110104

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