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

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