Pyroxene thermometry in simple and complex systems

Abstract

Simple mixing models have been applied to ortho- and clinopyroxene solid solutions and a semi-empirical equation of state extracted from the available experimental data for the diopside-enstatite miscibility gap. This equation successfully reproduces the miscibility gap over a temperature range of 800 °C to 1700 °C and is apparently also applicable to aluminous pyroxenes in the system CaSiO3-MgSiO3-Al2O3. The effect of iron solubility in the pyroxenes has been calibrated empirically using most of the available experimental data for multicomponent pyroxenes. This semi-empirical model reproduces most of the experimental data within 70 °C. Temperatures calculated for naturally equilibrated Mg-rich two-pyroxene assemblages deviate markedly from those estimated using the thermometer of Wood and Banno (1973). These discrepancies can be attributed to large inaccuracies in the thermometer of Wood and Banno (1973) for Mg-rich compositions.

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Wells, P.R.A. Pyroxene thermometry in simple and complex systems. Contr. Mineral. and Petrol. 62, 129–139 (1977). https://doi.org/10.1007/BF00372872

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Keywords

  • Iron
  • Experimental Data
  • Solid Solution
  • Complex System
  • Mineral Resource