The albite fusion curve re-examined: New experiments and the high-pressure density and compressibility of high albite and NaAlSi3O8 liquid

Travis J. Tenner, Rebecca A. Lange, Robert T. Downs

Research output: Contribution to journalArticle

34 Scopus citations

Abstract

Experimental brackets on the melting temperature of high albite (NaAlSi3O8) were determined at 2.33 ± 0.03 GPa (1360-1370 °C) and 2.79 ± 0.03 GPa (1370-1389 °C) in a piston-cylinder apparatus. All run products that quenched to a glass were analyzed by Fourier-transform infrared spectroscopy and found to contain ≤500 ppm H2O. In addition, new X-ray diffraction experiments on fully disordered albite are reported to 7.6 GPa; the fitted results lead to a zero-pressure bulk modulus (K0) of 56.4 ± 0.7 and a pressure derivative (K'0) of 3.9 ± 0.3 in a third-order Birch-Murnaghan equation of state. Revised values for the enthalpy and entropy of fusion of high albite at one bar and 1100 °C [ΔHTf = 64.5 ± 2.1 kJ/mol and ΔSTf = 47.0 J/(mol·K)] are recommended on the basis of improved heat capacity equations for NaAlSi3O8 glass and liquid. On the basis of these new results on the fusion curve and thermodynamic data for high albite, the pressure dependence of the NaAlSi3O8 liquid compressibility (K'0) is constrained to be 10.8 ± 1.5 in a third-order Birch-Murnaghan equation of state. The uncertainty in K'0 of ± 1.5 contributes an error to melt density at 3 GPa (2.543 ± 0.010 g/cm3 at 1500 °C) of ±0.4%.

Original languageEnglish (US)
Pages (from-to)1573-1585
Number of pages13
JournalAmerican Mineralogist
Volume92
Issue number10
DOIs
StatePublished - Oct 1 2007

Keywords

  • Albite
  • Compressibility measurements
  • High-pressure studies
  • High-temperature studies
  • Phase equilibria
  • Thermodynamics

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology

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