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THERMOCALC (TC)
1. Where can I download the program package and What you need in the package?
2. How to set up the program (step by step)? (Click to download PDF version)
3. Suggestions before constructing pseudosection using THERMOCALC
4. Instruction onconstructing pseudosections using THERMOCALC
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P-T pseudosection construction procedure
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Step by step instruction
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Tips and key notes during peudosection construction
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Pseudosection with mineral isopleths
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Calculating equilibria bulk composition at a fixed P ans T
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P-X pseudosection constructing procedure
1. Where I can download the program package and What you need in the package?
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Homepage for downloading THERMOCALC package (in case of TC 3.47):link: https://hpxeosandthermocalc.org/
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The package should include four major exe. files or scripts (see image for all files).
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1) Major TC program and associated files (TC exe., tc-prefs.txt, tc-<project>.txt)
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2) Internally consistent dataset file: tc-ds<version>.txt
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3) mineral activity-composition relation file: tc-<system>.txt
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4) Output print exe. file and associated files.
2. How to set up the program (step by step)? (Click to download PDF version)
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Setting up TC is not like installing TD or Perple_X. Setting up TC is to put all necessary files in a working folder. The insdie of the files should like these:
Setting up file/tc-<project>.txt
tc-prefs.txt
dr-prefs.txt
dr-<project>.txt
3. Suggestions before constructing pseudosection using THERMOCALC
1) Personally we don't suggest beginners use TC if you don't have a strong background on phase relations of metamorphic minerals at the pressure-temperature of your interest; This is mainly due to no enough time budget due to time-consuming learning and calculating manually; Also, TC can't calculate mineral volume% and mineral physical properties.
2) Selecting mineral assemblage is the most challenging part. The best way for mineral selection is to check the mineral phases from similar literature and check the relations between minerals.
3) The starting phase should be the one having "0" variality (as below).
4) The original "starting guess" in the TC-<project>.tex is the best one but still nedd to change when some minerals don't work out the calculation.
4. Instruction onconstructing pseudosections using THERMOCALC
1) Open files: tc347-win and enter code "1" for phase diagram construction
2) This step is to enter the phases (better to choose the lowest variety based on the phase rule: P). In this case, we use TM-15 as an example and start from the gl, o, dio, g, bi, chl, law, ru, ta, and H2O, and to find "ta" and "dio" boundaries (if you have added the H2O and ru in the to the "setexcess" in the tc-<project>.txt, you don't have to add them here).
In addition, you need to enter the phase boundary you want to calculate first, for example, "ta" in this case; then entering you want to calculate P at T or T at P; Then entering P or T range and calculation interval.
3) The calculated results (ta boundary) have been put in the "tc-tm15-dr.txt" file. Copy the output in the file to the "dr-tm15.txt" file. And run the app "drawpd118" or "drawpd117". The "ta" boundray can be found n the dr-tm15.eps. You can open this file with file opner
4) This step is to calculate "dio" (dioposide). Same procedure with step 3).
5) Copy the "dio" boundary data in the "tc-tm15-dr" file to the end of the script of the last phase boundary, and open the "drawpd118" app to draw the phase line (remember to provide line number).
6) In the second screenshot of step 2) and 4), we can see the phase calculation is stoped by the "chl" (chlorite) phase-out (0). This means the "ta" and "dio" phase boundaries have been cut by "chl" phase-out. Therefore, we can calculate the interactions of "chl-ta" and "dio-chl" (two points).
7) Copy the interactions of "chl-ta" and "dio-chl" (two points generated in the "tc-tm15-dr" file) to the end of the script in last time, and open the "drawpd118" app to draw the points (remember to provide point number).
8) At this step, we are going to calculate three lines. "chl" boundary in "ta-in & dio-out", "ta-in & dio-int", and "ta-out & dio-in". Then, we are going to connect the lines and points.
9) Copy the three lines ("chl" boundaries:"ta-in & dio-out", "ta-in & dio-int", and "ta-out & dio-in") in the "tc-tm15-dr" file to the "dr-tm15" file. Also to connect the lines and points in the "dr-tm15" file.
10) At this step, we will calculate two lines: "dio" and "ta" boundaries in the "chl-out" field (remember to connect points and lines).
11) Copy the generated "ta" and "dio" lines in the "chl-out" field to "dr-tm15" file and connect the two lines with point 1 and 2. Then, open the "drawpd118" app to draw the two lines.
12) The knowledge of metamorphic rock or mineral phase relations indicates that it's highly possible to have "mu" (muscovite) appearing in the higher temperature direction of "chl". Therefore, in this step, we will try to calculate the "mu" phase boundary by adding "mu" into the calculation phase assemblage in the "chl-out" direction.
13) Copy the generated "mu" lines in the "dio-in & ta-in", dio-in & ta-out, and dio-out & ta-in" to "dr-tm15" file and then open the "drawpd118" app to draw the three lines.
14) This step is to calculate two intersections of "ta-mu" and "dio-mu" and connect the calculated lines and points, and then plot them out.
15) This step is to calculate two lines, which are "ta" and "dio" in the "mu-in" field, and connect them with points 3 and 4, and lines 6 and 7.
16) In this way, the two lines 11 and 12 (phase boundaries of "ta" and "dio" in the "mu-in" field) can be drawn. These two lines are stoped by the "bi-out", and hence next step, the "bi" phase boundary can be found.
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The complete phase diagram is as below. Then you can use Illustrate program to edit the diagram, for example, adding the pressure, temperature, and phase assemblage labels.
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