Na2O-CaO-Al2O3-SiO2     &    Na2O-CaO-MgO-Al2O3-SiO2

Pargasite enthalpy is now fitted to the experimental data of Lykins & Jenkins (1993) for the reaction 2parg + 5en = 2di + 8fo + 2an + 2abh + 2H2O. The composition of the amphiboles were shown by Lykins & Jenkins (1993) to be close to pargasite, in contrast to the experiments of Sharma (1995) which involved tremolitic amphiboles with a small pargasite component. Therefore it would be unwise to extract thermodynamic data for pargasite from the experiments of Sharma (1995), especially as there probably exists a large miscibility gap between the tremolitic and pargasitic ends of the solid solution series.

*  4law + ab = 2zo + pa + 2q + 6H2O   (Heinrich & Althaus, 1980)
 
  ln_K  x(CO2)  P(kbar)      T(C)     H(low) H(high)  miss   calc   2sd        summary
     0     0      7.0     360  400   400.86  411.85    -18    342     4    ** NOT USED **
     0     0      9.5     405  445   401.08  413.48    -22    383     4   cH = 395.25 (sd  0.95)
     0     0     12.0     435  465   398.94  408.05    -12    423     6   
 
*  4law + jd = 2zo + pa + q + 6H2O   (Heinrich & Althaus, 1980)
 
  ln_K  x(CO2)  P(kbar)      T(C)     H(low) H(high)  miss   calc   2sd        summary
     0     0     12.0     435  465   404.34  414.59    -15    420     6    ** NOT USED **
     0     0     15.0     460  480   395.37  401.98           472     6   cH = 399.36 (sd  0.97)
 
214)  2parg + 5en = 2di + 8fo + 2an + 2abh + 2H2O   (Lykins & Jenkins, 1992)
 
  ln_K  x(CO2)  P(kbar)      T(C)     H(low) H(high)  miss   calc   2sd        summary
 -2.09     0      0.5     760  790   303.89  310.98           787    14   3 (308.21 <-> 312.43)
 -2.09     0      1.0     828  860   307.02  313.91           843    16   cH = 310.32 (sd  1.66) 
 -2.09     0      1.5     880  900   309.61  313.66           884    16   within bracket
                                                                          uH = 1.66, d/s = 0.4, h = 1.00