This directory contains source code for the olivine-spinel geothermometer 
(GEOTHERMOMETER.FOR) and source code for activity-composition relations for 
spinel minerals (ACTIVITIES.FOR) as described in:

Sack RO, Ghiorso MS (1991) Chromian spinels as petrogenetic indicators:
     Thermodynamics and petrological applications. American Mineralogist
     76: 827-847

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To get the activity/composition subroutines working:

(1) Copy the source file ACTIVITIES.FOR to your machine.

(2) Compile the code.

(3) Write a main program to call the routine ACT_SPN. Input and output 
    parameters are described within the first 50 lines of the file
    ACTIVITIES.FOR. 

(4) Link your program with the compiled subroutines.

The spinel activity/composition code has been tested on a VAX 3100 using the 
DIGITAL FORTRAN compiler.

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To get the geothermometer program working:

(1a) Copy the source file GEOTHERMOMETER.FOR to your machine.
(1b) Copy the BinHex file geothermometer-sit.hqx to your Macintosh.
     Use Stuffit (vers 1.6 or latter) to de-BinHex the file and
                 unstuff the various files. You will get all the
                 source files, a THINK C project library and two versions
                 of the executable (one for co-processor machines and
                 one for non-co-processor machines)
     Proceed to test the code with the executables provided, or...

(2) Compile and link the code.

(3) Run the test case indicated below.

Example (Vax 3100 running VMS 5.4):

$ fort geothermometer
$ link geothermometer
$ run geothermometer

Input the composition of the spinel phase:
     Wt % of TiO2  [default is 0.00]: 2.2
     Wt % of Al2O3 [default is 0.00]: 5.92
     Wt % of Cr2O3 [default is 0.00]: 57.02
     Wt % of V2O3  [default is 0.00]: .69
     Wt % of Fe2O3 [default is 0.00]:
     Wt % of FeO   [default is 0.00]: 31.04
     Wt % of MgO   [default is 0.00]: 2.6
     Wt % of MnO   [default is 0.00]: .96
     Wt % of ZnO   [default is 0.00]:
     Wt % of CoO   [default is 0.00]:
     Wt % of NiO   [default is 0.00]:
     Mole fractions of FeAl2O4 (X1): -0.017483
     Mole fractions of MgAl2O4 (X2):  0.140735
     Mole fractions of FeCr2O4 (X3):  0.806146
     Mole fractions of Fe2TiO4 (X4):  0.058450
     Mole fractions of Fe3O4   (X5):  0.012152

Input the composition of the olivine phase:
     Wt % of FeO   [default is 0.00]: 13
     Wt % of MgO   [default is 0.00]: 46
     Mole fractions of Mg2SiO4 (XFO):  0.863136
     Mole fractions of Fe2SiO4 (XFO):  0.136864
%GTH_I_NEWTON, Newton iteration: T , delta G:   604.476222     -0.323667
%GTH_I_NEWTON, Newton iteration: T , delta G:   603.225998      0.007603
%GTH_I_NEWTON, Newton iteration: T , delta G:   603.240187     -0.000087
%GTH_I_NEWTON, Newton iteration: T , delta G:   603.240191      0.000000

*****************************************************************************
Final equilibration temperature:   603.24
******************************************************************************

Spinel ordering parameters and site mole fractions:
s1,s2,s3,s4:   0.131237  0.121381  0.806146 -0.003038
X Mg2+ tet:    0.135986
X Fe2+ tet:    0.846954
X Al3+ tet:    0.001870
X Fe3+ tet:    0.015190
X Cr3+ tet:    0.000000
X Mg2+ oct:    0.002374
X Fe2+ oct:    0.035381
X Al3+ oct:    0.122316
X Fe3+ oct:    0.004557
X Cr3+ oct:    0.806146
X Ti4+ oct:    0.029225
FORTRAN STOP
$

The code has been tested on a VAX 3100 using the DIGITAL FORTRAN compiler.
The C version has been tested on a Macintosh SE (no co-processor) and on 
a Macintosh SE/30 and Mac IIx (with co-processor).

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If you have any questions, or if you have a problem, contact:

Mark S. Ghiorso
Department of Geological Sciences, AJ-20
University of Washington
Seattle, WA 98l95

Telephone: (206)-685-2482
Fax:       (206)-543-3836
e-mail:    ghiorso@fondue.geology.washington.edu  (internet)


*END-OF-FILE README*