Toward a Thermodynamic Understanding of Feldspars: Order Parameters of Na-Feldspar and the Iī–Pī Phase Transition in Anorthite

  • E. Salje
Part of the Advances in Physical Geochemistry book series (PHYSICAL GEOCHE, volume 7)


Considerable progress has been made in recent years on the experimental investigation and theoretical understanding of the thermodynamic behavior of feldspars. Although a comprehensive model for all structural phase transitions in the feldspar system is still lacking, much is known about the enthalpies of ordering of plagioclases (e.g., Carpenter et al. 1985; Newton et al. 1980) and the excess specific heat of displacive phase transitions in alkali feldspar (Salje et al. 1985a). It has also been shown that most results of earlier investigations of lattice parameters (e.g., Grundy and Brown, 1969; see Smith, 1974, for review) and domain patterns in feldspars (Brown and Parsons, 1983; Fitzgerald and McLaren, 1982) can now be understood within the framework of Landau theory (Salje, 1985; Salje et al. 1985b).


Structural Phase Transition Landau Theory Excess Free Energy Symmetry Reduction Spontaneous Strain 
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© Springer-Verlag New York Inc. 1988

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  • E. Salje

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