Open AccessCongruent melting kinetics of albite: Theory and experiment
Author(s) -
Greenwood James P.,
Hess Paul C.
Publication year - 1998
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/98jb02300
Subject(s) - premelting , superheating , thermodynamics , albite , melting point , kinetics , materials science , wetting , viscosity , melting point depression , physics , metallurgy , composite material , classical mechanics , quartz
Congruent melting of albite, NaAlSi 3 O 8 , is found to be a surface‐initiated process, with melt nucleating at external surfaces and internal cracks and cleavage planes. Melting rates are found to be within a factor of 5 of rates calculated by a normal growth model. The melting point of albite is shown to be in the 1100° to 1120°C range. Melting rates are found to be proportional to the amount of superheat and inversely proportional to the viscosity of the melt phase. The strong dependence of melting rates on viscosity is related to the configurational entropy by the Adam and Gibbs [1965] theory. The normal growth model is shown to be appropriate for describing the congruent melting kinetics of silicates and oxides at moderate amounts of superheat. Homogeneous melting models are probably predicting the temperature of mechanical instability of the solid, rather than the true melting point. Surface premelting is discussed and shown to not be related to the premelting effects described by Richet et al . [1994]. Surface premelting is predicted for albite.