EQUILIBRIUM K-BEARING CLINOPYROXENE-MELT AS A MODEL FOR BAROMETRY OF MANTLE-DERIVED MINERAL ASSEMBLAGES
O.G. Safonov1,2, L.L. Perchuk1,2, and Yu.A. Litvin1
1Institute of Experimental Mineralogy, Russian Academy of Sciences,
4 ul. Institutskaya, Chernogolovka, Moscow Region, 142432, Russia
2Chair of Petrology, Geological Department, Lomonosov Moscow State University,
Vorob'evy Gory, Moscow, 119234, Russia
Keywords: K-bearing clinopyroxene, K-rich melts, mantle, inclusions in diamonds
Pages: 1300-1316
Abstract
Experimental data on synthesis of potassium-bearing clinopyroxene in systems of different compositions are reviewed. The partitioning of K between clinopyroxene and melt is governed mainly by such factors as pressure, concentrations of K, Si, and Al in coexisting aluminosilicate melt, and jadeite and Ca-Tschermak contents in clinopyroxene. Temperature has a minor effect on partition coefficient, especially for natural clinopyroxenes of complex composition. Based on these observations, a thermodynamic equation for the KAlSi2O6 (Cpx) = KAlSi2O6 (melt) equilibrium at 1-11 GPa and 1100-1900
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