Practical Aspects of Mineral Thermobarometry

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Chlorite activity coding

FMASH

Listed below is the chlorite code from the example file thdkfm.txt. The variable Q is half the order parameter defined as X(Al,M4)-X(Al,M1). It would be better to use N for this variable, since Q usually stands for the order parameter itself.

%__________________________________________________________________
      
chl 4 

      x(chl) 0.35
      y(chl) 0.51
      Q(chl) 0.485

  p(afchl) 1  1    1  2 -1  y -1  Q
  
  p(clin)  2  1    0  1  2  Q
              2    0  1 -2/5  x    3  1 -1  y
     
  p(daph)  1  2    0  1  2/5  x    3  1 -1  y
  
  p(ames)  1  1    0  2  1  y -1  Q
  
  sf
  
  W(afch,clin)  18   0  0 
  W(afchl,daph) 14.5 0  0
  W(afchl,ames) 20   0  0
  W(clin,daph)   2.5 0  0
  W(clin,ames)  18   0  0 
  W(daph,ames)  13.5 0  0 
   
 10 
  
  x(Fe,M23)  1  1    0  1  1  x 
  x(Mg,M23)  1  1    1  1 -1  x  
  
  x(Al,M1)   1  1    0  2  1  y -1  Q   
  x(Fe,M1)   1  2    0  1  1  x     1  2 -1  y  1  Q 
  x(Mg,M1)   1  2    1  1 -1  x     1  2 -1  y  1  Q 
    
  x(Al,M4)   1  1    0  2  1  y  1  Q   
  x(Fe,M4)   1  2    0  1  1  x     1  2 -1  y -1  Q   
  x(Mg,M4)   1  2    1  1 -1  x     1  2 -1  y -1  Q 
    
  x(Al,T2)   1  1    0  1  1  y   
  x(Si,T2)   1  1    1  1 -1  y  

 afchl  1  4    x(Mg,M23) 4   x(Mg,M1) 1   x(Mg,M4) 1   x(Si,T2) 2   
   check 0 0 0   
         
 clin   4  5    x(Mg,M23) 4   x(Mg,M1) 1   x(Al,M4) 1   x(Al,T2) 1  x(Si,T2) 1
   check 0 1/2 1/2   
 
 daph   4  5    x(Fe,M23) 4   x(Fe,M1) 1   x(Al,M4) 1   x(Al,T2) 1  x(Si,T2) 1
   check 1 1/2 1/2   

 ames   1  4    x(Mg,M23) 4   x(Al,M1) 1   x(Al,M4) 1   x(Al,T2) 2
   check 0 1 0   
 
% __________________________________________________________________

MnFMASH

This is the same model extended to treat Mn-bearing chlorites. Mn, Fe and Mg are presumed to be evenly partitioned across the sites they occupy.

% Mn-bearing chlorite with Al ordering - recoded DJW 27 Aug 03

chl 5

  x(chl) 0.35      % Fe/(Fe+Mg+Mn)
  y(chl) 0.51      % X(Al,T2) (clin = 0.5)
  N(chl) 0.48      % order parameter Q/2 = [x(Al,M4)-x(Al,M1)]/2
  m(chl) 0.001     % Mn/(Fe+Mg+Mn)

  p(afchl) 1  1    1  2 -1  y -1  N
  p(clin)  2  1    0  1  2  N
              2    0  2 -2/5 x -2/5 m    3  1 -1  y
  p(daph)  1  2    0  1  2/5 x    3  1 -1  y
  p(ames)  1  1    0  2  1  y -1  N
  p(mnchl) 1  2    0  1  2/5 m    3  1 -1  y
  
  sf
  W(afch,clin)  18   0  0 
  W(afchl,daph) 14.5 0  0
  W(afchl,ames) 20   0  0
  W(afchl,mnchl) 0   0  0
  W(clin,daph)   2.5 0  0
  W(clin,ames)  18   0  0 
  W(clin,mnchl)  0   0  0
  W(daph,ames)  13.5 0  0 
  W(daph,mnchl)  0   0  0
  W(ames,mnchl)  0   0  0
   
  13 
  
  x(Fe,M23)  1  1    0  1  1  x
  x(Mg,M23)  1  1    1  2 -1  x -1  m
  x(Mn,M23)  1  1    0  1  1  m
  
  x(Al,M1)   1  1    0  2  1  y -1  N   
  x(Fe,M1)   1  2    0  1  1  x          1  2 -1  y  1  N 
  x(Mg,M1)   1  2    1  2 -1  x -1  m    1  2 -1  y  1  N 
  x(Mn,M1)   1  2    0  1  1  m          1  2 -1  y  1  N 
    
  x(Al,M4)   1  1    0  2  1  y  1  N   
  x(Fe,M4)   1  2    0  1  1  x          1  2 -1  y -1  N   
  x(Mg,M4)   1  2    1  2 -1  x -1  m    1  2 -1  y -1  N 
  x(Mn,M4)   1  2    0  1  1  m          1  2 -1  y -1  N   
    
  x(Al,T2)   1  1    0  1  1  y   
  x(Si,T2)   1  1    1  1 -1  y  

 afchl  1  4    x(Mg,M23) 4   x(Mg,M1) 1   x(Mg,M4) 1   x(Si,T2) 2   
        check 0 0 0 0
 clin   4  5    x(Mg,M23) 4   x(Mg,M1) 1   x(Al,M4) 1   x(Al,T2) 1  x(Si,T2) 1
        check 0 1/2 1/2 0
 daph   4  5    x(Fe,M23) 4   x(Fe,M1) 1   x(Al,M4) 1   x(Al,T2) 1  x(Si,T2) 1
        check 1 1/2 1/2 0
 ames   1  4    x(Mg,M23) 4   x(Al,M1) 1   x(Al,M4) 1   x(Al,T2) 2
        check 0 1 0 0
 mnchl  4  5    x(Mn,M23) 4   x(Mn,M1) 1   x(Al,M4) 1   x(Al,T2) 1  x(Si,T2) 1
        check 0 1/2 1/2 1

Content last modified 28 Aug 03