David R.M. Pattison Pattison Home page

PROGRAMS RCLC AND RCLC-P

GARNET-ORTHOPYROXENE THERMOBAROMETRY

CORRECTED FOR LATE FE-MG EXCHANGE

Electronic Appendix A of:

RCLC and RCLC-P are ‘command-line’ programs that calculate pressure-temperature (P-T) conditions of Grt-Opx-Pl-Qtz±Crd±Bt assemblages based on Al-solubility in Opx in equilibrium with Grt, corrected for late Fe-Mg exchange. ‘RCLC’ is short for ‘recalculation’. RCLC solves for P and T, whereas RCLC-P solves for T at a user-specified pressure.  

The rationale and calculation method for the programs is described in Chacko et al. (1996) and in Pattison et al. (2003). Figure. 3 of Pattison et al. (2003) (shown above) shows graphically how RCLC works.

Both programs are written in BASIC and were compiled on a PC.

RCLC was originally written by Tom Chacko and James Farquhar in 1996 and subsequently modified by Chris McFarlane, David Pattison and Tom Chacko between 1997 and 2002, the latter period during which time RCLC-P was spun out of RCLC.

Files needed to run and test the programs (RCLC.ZIP)

Click on the title above to get a zip file of the necessary files. After unzipping, you should have the following 8 files:  

RCLC&RCLC-P.DOC
RCLC.EXE
RCLC-P.EXE 
PCFM-1
PCFM-1.RC
PCFM-1.RCP
165-241
165-241.RC 

RCLC&RCLC-P.DOC is this document. RCLC-EXE and RCLC-P.EXE are the executable programs that do the calculations. PCFM-1 is a sample input file for the mineral composition data in Table 4 of Pattison et al. (2003). PCFM-1.RC is the output file for sample PCFM-1 after having run it through RCLC.EXE, whereas PCFM-1.RCP is the output file for sample PCFM-1 after having run it through RCLC-P.EXE. 165-241 is a sample input file in which Opx contains significant Fe³⁺, whereas 165-241.RC is the corresponding output file after having run it through RCLC.EXE. The two input and three output files are shown and described below.  

** The files should be EXACTLY as shown, ie, with no extra extensions on any of the files. If there are any extra extensions that have been added in transit, edit them out so that the file names are exactly as shown above.**

** We suggest that you rename the three output (.RC and .RCP) files, because when you run RCLC or RCLC-P with the corresponding input files, these will be overwritten!**

 Input and output filenames for RCLC and RCLC-P

The same input file is used for both RCLC and RCLC-P. The input file names can take no more than 8 characters and have no file extension. For example, TC13-83 is acceptable; TC13-83.IN or TC13-83.TXT are not. The output file names are the same as the input file names but with the extensions ‘.RC’ or ‘.RCP’ added during running of the program, depending on whether RCLC or RCLC-P was run. For the above input filename, the output file names would be TC13-83.RC or TC13-83.RCP.

* The input and output files can be edited by any text editor, such as 'Wordpad'. For the input file, any file extension on the input file (eg, .txt, .doc , etc.) must be removed before running the program. *

Input file format for RCLC and RCLC-P

Two example inputs are shown below. PCFM-1 is the sample in Table 4 and Fig. 3 of Pattison et al. (2003). (Note that there is a slight difference in the example shown below compared to Fig. 3 of Pattison et al. (2003), because the modes of Crd and Bt have been set to 10.0 and 10.0, respectively, rather than 0.0 and 0.0 as in Fig. 3). 165-241 is a sample from Chacko et al. (1987; 1996).

 PCFM-1, Fe   , Mn   , Mg   , Ca   , MODEGAR
     GT, 1.550, 0.200, 1.140, 0.110, 10.0
     OP, Si   , Ti   , Al   , Cr   , Fe3+ , Fe2+ , Mn   , Mg   , Ca   , MODEOPX
     OP, 1.900, 0.010, 0.200, 0.000, 0.000, 0.660, 0.010, 1.230, 0.000, 10.0
    CRD, Fe   , Mn   , Mg   , MODECRD
    CRD, 0.340, 0.010, 1.660, 10.0
     BT, Si   , Ti   , Al   , Fe   , Mn   , Mg   , Na   , K    , MODEBT
     BT, 2.760, 0.240, 1.300, 0.780, 0.010, 1.780, 0.010, 0.970, 10.0
   PLAG, Ca   , Na   , K
   PLAG, 0.310, 0.670, 0.020

165-241,  Fe  ,  Mn  ,  Mg  ,  Ca  , MODEGAR
     GT, 1.842, 0.175, 0.849, 0.191, 10.0
     OP, Si   , Ti   , Al   ,  Cr  , Fe3+ , Fe2+ ,  Mn  ,  Mg  , Ca  , MODEOPX
     OP, 1.864, 0.003, 0.227, 0.000, 0.037, 0.851, 0.029, 0.969, 0.015, 40.0
    CRD,  Fe  ,  Mn  ,  Mg  , MODECRD
    CRD, 0.000, 0.000, 0.000,  0.0
     BT,  Si  ,  Ti  ,  Al  ,  Fe  ,  Mn  ,  Mg  ,  Na  ,  K   , MODEBT
     BT, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000, 0.000,  0.0
   PLAG,  Ca  ,  Na  , K
   PLAG, 0.354, 0.581, 0.045

If there is no Crd or Bt in the rock, as in 165-241,zeroes are inserted and the program still works.

For RCLC-P, the program ignores whatever values are inserted for Pl.

 Fe³⁺ and minor elements in Opx

As shown above, RCLC and RCLC-P allow Fe³⁺ and Fe²⁺ in Opx to be entered separately. The Fe²⁺/Fe³⁺ calculation is done beforehand by the user (it is not performed in RCLC). If all Fe is assumed to be Fe²⁺ (such as in PCFM-1), zero is inserted for Fe³⁺.

Running of RCLC

Once the program is launched, the following appears on the screen:

RCLC: GRT-OPX-PL-QTZ P-T ESTIMATES CORRECTED FOR LATE FE-MG EXCHANGE

TYPE IN FILE TO READ (E.G., C10B):

Type in the file name (eg, for the above example, PCFM-1)and hit return. The following appears:

TYPE IN A TITLE OR SHORT DESCRIPTION OF THE SAMPLE:

You have 60 characters in which to do so. Hit return. The following appears:

YOU HAVE A CHOICE FOR CALCULATING XALM IN OPX.

THE FOLLOWING FORMULAE ASSUME A 6-OXYGEN OPX FORMULA.

1: XALM = Al - (2 - Si)
2: XALM = Al/2
3: XALM = (Al/2) / (Fe2+ + Mg + Mn + Ca + (Al/2) )
4: XALM = (Al - Fe3+ - Cr - (2*Ti) ) / 2

PLEASE ENTER 1,2,3,4:

Enter your choice for calculating XALM (= octahedral Al in Opx, ie, X_Al^M1 = X_Al^Opx) and hit return. Pros and cons of the different models are discussed in Pattison et al. (2003). We used Model 2 because it allowed comparison between a large number of samples from the literature, some of which reported minor elements and Fe³⁺ and others which did not. Model 4 is the only model that allows a correction for Fe³⁺ in Opx, although there can be dangers in taking this approach because of imprecision in schemes for estimating Fe³⁺ in Opx from stoichiometry (see discussion in Pattison et al., 2003).

The program does the calculations and and allows you to choose a different Al-in-Opx model:

ANOTHER AL-IN-OPX MODEL (Y/y)

If you choose no, the program takes you to the next question. If you choose yes, it returns you to the above choices. The results for each new Al-in-Opx model are appended to the bottom of the output file (ie, the earlier results are not over-written).

ANOTHER SAMPLE (Y/y)

If you choose no, the program closes. If you choose yes, you are returned to the line at which you enter the input file name, and a new output file is created for that new input file when you start to answer the questions.

Example #1 of output from RCLC - PCFM-1.RC

Sample outputs from RCLC for PCFM-1 and 165-241 are shown below (the output files are named PCFM-1.RC and 165-241.RC). PCFM-1.RC will be used to describe the parameters listed in the output. For PCFM-1.RC, Model 2 for X_Al^Opx was chosen.

RCLC: GRT-OPX-PL-QTZ P-T ESTIMATES CORRECTED FOR LATE FE-MG EXCHANGE
            THERMODYNAMIC DATA AND EXPRESSIONS FROM TWQ202B

PCFM-1: Grt-Opx-Crd-Bt-Pl-Qtz sample from Table 4 of Pattison et al. (2003)

MODEL 2  XAlOpx (1-site Opx) = (Al/2) / 2
XFeOpx = Fe2+/2    XMgOpx = Mg/2

ModeGrt = 10.00  ModeOpx = 10.00  ModeBt  = 10.00  ModeCrd = 10.00
XFeGrt  = 0.517  XMgGrt  = 0.380  XMnGrt  = 0.067  XCaGrt  = 0.037
XFeOpx  = 0.330  XMgOpx  = 0.615  XAlOpx  = 0.050  TotOpx  = 1.005
XFeBt   = 0.272  XMgBt   = 0.620  XAlBt   = 0.021  XTiBt   = 0.084
XFeCrd  = 0.169  XMgCrd  = 0.826  XMnCrd  = 0.005
XAnPl   = 0.310  XAbPl   = 0.670  XOrPl   = 0.020

 INITIAL AND CONVERGED P-T ESTIMATES AND MINERAL COMPOSITIONS

              CONVERGED (FINAL)     INITIAL          DIFFERENCE
Fe Al  GOPQ   857 C  7.76 KB    807 C  7.63 KB    50 C  0.13 KB
GrtOpx GOPQ   857 C  7.76 KB    703 C  6.28 KB   154 C  1.48 KB
GrtBt  GOPQ   857 C  7.76 KB    666 C  5.81 KB   191 C  1.95 KB
GrtCrd GOPQ   857 C  7.76 KB    694 C  6.16 KB   163 C  1.59 KB
M/FM rock         0.613             0.613             0.000    
M/FM Grt          0.472             0.424             0.048    
M/FM Opx          0.647             0.651            -0.004    
M/FM Bt           0.661             0.695            -0.035    
M/FM Crd          0.781             0.830            -0.049     

Explanation of RCLC output 

Following the heading, sample number and sample description, the chosen X_Al^Opx model is specified and the Opx compositional parameters further down are defined. The modes and some key mineral compositional parameters are then listed. Definitions of some of the compositional parameters are as follows:

XiGrt = i/(Fe+Mg+Ca+Mn)
TotOpx = XAlOpx + FeOpx + XMgOpx + Ti/2 + Fe³⁺/2 + Cr/2 + Mn/2 + Ca/2*
XiBt = i/(Fe+Mg+Mn+Ti+Al^vi) where Al^vi = Al^tot – (4 – Si)
XiCrd = i/(Fe+Mg+Mn)
XiPl = i/(Ca+Na+K)

* Note that regardless of choice of X_Al^Opx model, TotOpx (total octahedral cations for a one-site Opx) includes all minor elements.*

The initial and converged P-T estimates and Mg/(Mg+Fe) ratios are then listed, along with the differences. The quantities are defined as follows:

Fe Al  GOPQ = intersection of equilibria 8 (Fe-end member Grt-Opx Al-solubility equilibrium) and 9 (Fe-end member Grt-Opx-Pl-Qtz equilibrium). The ‘initial’ values are for the Fe-Mg ratios of the measured minerals and correspond to point B in Fig. 3a of Pattison et al. (2003), whereas the ‘converged’ values correspond to point C in Fig. 3b.

GrtOpx GOPQ = intersection of equilibria 7 (Grt-Opx Fe-Mg exchange equilibrium) and 9 (Fe-end member Grt-Opx-Pl-Qtz equilibrium). The ‘initial’ values are for the Fe-Mg ratios of the measured minerals and correspond to point A in Fig. 3a of Pattison et al. (2003), whereas the ‘converged’ values correspond to point C in Fig. 3b.

GrtBt  GOPQ = intersection of Grt-Bt Fe-Mg exchange equilibrium with equilibrium 9 (Fe-end member Grt-Opx-Pl-Qtz equilibrium). The ‘initial’ values are for the Fe-Mg ratios of the measured minerals, whereas the ‘converged’ values are for point C in Fig. 3b.

GrtCrd GOPQ = intersection of Grt-Crd Fe-Mg exchange equilibrium with equilibrium 9 (Fe-end member Grt-Opx-Pl-Qtz equilibrium). The ‘initial’ values are for the Fe-Mg ratios of the measured minerals, whereas the ‘converged’ values are for point C in Fig. 3b.

M/FM rock = Mg/(Mg+Fe) of whole rock based on modes of Grt, Opx, Crd and Bt and their Mg/(Mg+Fe) ratios. After varying the Mg/(Mg+Fe) ratios of the phases to obtain convergence at point C in Fig. 3b, the whole rock Mg/(Mg+Fe) is recalculated to ensure that it is the same as the initial value.

M/FM Grt  = Mg/(Mg+Fe) of Grt
M/FM Opx  = Mg/(Mg+Fe) of Opx.
M/FM Bt   = Mg/(Mg+Fe) of Bt.
M/FM Crd  = Mg/(Mg+Fe) of Crd.

** Remember that the calculated values above are slightly different than those shown in Fig. 3 of Pattison et al. (2003) because the mineral modes are different.**

Example #2 of output from RCLC - 165-241.RC

The output for 165-241.RC is listed below and shows the effect of using the four different X_Al^Opx models. The Fe³⁺-corrected X_Al^Opx model (Model 4) gives lower temperatures by about 50 °C than the simple Al/2 model (Model 2).

RCLC: GRT-OPX-PL-QTZ P-T ESTIMATES CORRECTED FOR LATE FE-MG EXCHANGE
             THERMODYNAMIC DATA AND EXPRESSIONS FROM TWQ202B

165-241: sample from the Kerala Khondalite Belt (Chacko et al,1987;1996) 

MODEL 1  XAlOpx (1-site Opx) = (Al - (2-Si) )/2
XFeOpx = Fe2+/2    XMgOpx = Mg/2

ModeGrt = 10.00  ModeOpx = 40.00  ModeBt  =  0.00  ModeCrd =  0.00
FeGrt  = 0.603  XMgGrt  = 0.278  XMnGrt  = 0.057  XCaGrt  = 0.062
XFeOpx  = 0.426  XMgOpx  = 0.484  XAlOpx  = 0.045  TotOpx  = 0.998
XAnPl   = 0.361  XAbPl   = 0.593  XOrPl   = 0.046

INITIAL AND CONVERGED P-T ESTIMATES AND MINERAL COMPOSITIONS

              CONVERGED (FINAL)     INITIAL          DIFFERENCE
Fe Al  GOPQ   944 C  8.88 KB    905 C  8.74 KB    39 C  0.14 KB
GrtOpx GOPQ   944 C  8.88 KB    793 C  7.14 KB   151 C  1.74 KB
M/FM rock         0.495             0.495             0.000    
M/FM Grt          0.352             0.315             0.037    
M/FM Opx          0.525             0.532            -0.008    


MODEL 2  XAlOpx (1-site Opx) = (Al/2) / 2
XFeOpx = Fe2+/2    XMgOpx = Mg/2

ModeGrt = 10.00  ModeOpx = 40.00  ModeBt  =  0.00  ModeCrd =  0.00
XFeGrt  = 0.603  XMgGrt  = 0.278  XMnGrt  = 0.057  XCaGrt  = 0.062
XFeOpx  = 0.426  XMgOpx  = 0.484  XAlOpx  = 0.057  TotOpx  = 1.009
XAnPl   = 0.361  XAbPl   = 0.593  XOrPl   = 0.046

INITIAL AND CONVERGED P-T ESTIMATES AND MINERAL COMPOSITIONS

             CONVERGED (FINAL)     INITIAL          DIFFERENCE
Fe Al  GOPQ  1025 C  9.89 KB    963 C  9.65 KB    63 C  0.24 KB
GrtOpx GOPQ  1025 C  9.89 KB    788 C  7.13 KB   237 C  2.76 KB
M/FM rock         0.495             0.495             0.000    
M/FM Grt          0.370             0.315             0.054    
M/FM Opx          0.521             0.532            -0.011    


MODEL 3  XAlOpx (1-site Opx) = (Al/2) / sum
where sum = Fe2+ + Mg + Mn + Ca + (Al/2). XFeOpx = Fe2+/sum

ModeGrt = 10.00  ModeOpx = 40.00  ModeBt  =  0.00  ModeCrd =  0.00
XFeGrt  = 0.603  XMgGrt  = 0.278  XMnGrt  = 0.057  XCaGrt  = 0.062
XFeOpx  = 0.430  XMgOpx  = 0.490  XAlOpx  = 0.057  TotOpx  = 1.020
XAnPl   = 0.361  XAbPl   = 0.593  XOrPl   = 0.046

INITIAL AND CONVERGED P-T ESTIMATES AND MINERAL COMPOSITIONS

             CONVERGED (FINAL)     INITIAL          DIFFERENCE
Fe Al  GOPQ  1030 C  9.95 KB    964 C  9.56 KB    65 C  0.38 KB
GrtOpx GOPQ  1030 C  9.95 KB    787 C  7.02 KB   243 C  2.93 KB
M/FM rock         0.495             0.495             0.000    
M/FM Grt          0.371             0.315             0.055    
M/FM Opx          0.521             0.532            -0.011    


MODEL 4  XAlOpx (1-site Opx) =  ((Al - Fe3+ - Cr - (2*Ti))/2) / 2
XFeOpx = Fe2+/2    XMgOpx = MgOpx/2

ModeGrt = 10.00  ModeOpx = 40.00  ModeBt  =  0.00  ModeCrd =  0.00
XFeGrt  = 0.603  XMgGrt  = 0.278  XMnGrt  = 0.057  XCaGrt  = 0.062
XFeOpx  = 0.426  XMgOpx  = 0.484  XAlOpx  = 0.046  TotOpx  = 0.998
XAnPl   = 0.361  XAbPl   = 0.593  XOrPl   = 0.046

INITIAL AND CONVERGED P-T ESTIMATES AND MINERAL COMPOSITIONS

             CONVERGED (FINAL)     INITIAL          DIFFERENCE
Fe Al  GOPQ   948 C  8.92 KB    908 C  8.78 KB    40 C  0.15 KB
GrtOpx GOPQ   948 C  8.92 KB    793 C  7.14 KB   155 C  1.78 KB
M/FM rock         0.495             0.495             0.000    
M/FM Grt          0.353             0.315             0.037    
M/FM Opx          0.525             0.532            -0.008    

Running of RCLC-P

The program runs the same as RCLC with a couple of exceptions. To indicate that you are running RCLC-P and not RCLC, the opening title that appears on the screen when the program is launched is:

RCLC-P - GRT-OPX T ESTIMATES AT A GIVEN P, CORRECTED FOR LATE FE-MG EXCHANGE

After the Al-in-Opx model is chosen, you must input the assumed pressure:

TYPE IN THE PRESSURE IN KBAR

Enter your choice and hit return. The program does the calculations and and allows you to choose a different pressure:

ANOTHER PRESSURE (Y/y)

If you choose no, the program proceeds from here as in RCLC. If you choose yes, you are returned to the prompt above. As was the case for a different Al-in-Opx model, the results for each new pressure model are appended to the bottom of the output file (ie, the earlier results are not over-written).

Output of RCLC-P

The output for PCFM-1, in which Model 2 for Al-in-Opx was chosen and pressures of 10 and 6 kbar were input, is in the file PCFM-1.RCP. It is as follows:

RCLC-P: GRT-OPX T ESTIMATES AT FIXED P, CORRECTED FOR LATE EXCHANGE
            THERMODYNAMIC DATA AND EXPRESSIONS FROM TWQ202B

PCFM-1: Grt-Opx-Crd-Bt-Pl-Qtz sample from Table 4 of Pattison et al. (2003)

MODEL 2  XAlOpx (1-site Opx) = (Al/2) / 2
XFeOpx = Fe2+/2    XMgOpx = Mg/2

ModeGrt = 10.00  ModeOpx = 10.00  ModeBt  = 10.00  ModeCrd = 10.00
XFeGrt  = 0.517  XMgGrt  = 0.380  XMnGrt  = 0.067  XCaGrt  = 0.037
XFeOpx  = 0.330  XMgOpx  = 0.615  XAlOpx  = 0.050  TotOpx  = 1.005
XFeBt   = 0.272  XMgBt   = 0.620  XAlBt   = 0.021  XTiBt   = 0.084
XFeCrd  = 0.169  XMgCrd  = 0.826  XMnCrd  = 0.005
XAnPl   = 0.310  XAbPl   = 0.670  XOrPl   = 0.020

PRESSURE (KBAR) = 10.00

INITIAL AND CONVERGED T ESTIMATES AND MINERAL COMPOSITIONS

       CONVERGED  INITIAL   DIFFERENCE
Fe Al      908 C     850 C    58 C
GrtOpx     908 C     729 C   179 C
GrtBt      908 C     690 C   218 C
GrtCrd     908 C     697 C   211 C
M/FM rock  0.613    0.613    0.000
M/FM Grt   0.482    0.424    0.058
M/FM Opx   0.647    0.651   -0.004
M/FM Bt    0.655    0.695   -0.040
M/FM Crd   0.765    0.830   -0.065

PRESSURE (KBAR) =  6.00

INITIAL AND CONVERGED T ESTIMATES AND MINERAL COMPOSITIONS