dataset modifications
dataset modifications
What bothers me often and where I have absolutely no knowledge about is, how much can I alter the datasets without producing nonsense? That is, my main concern is, lets say in the Holland & Powell dataset, what if I e.g. don't trust the solution for Mn in biotite: am I allowed to exclude the Mn in biotite from the solution or would the result get inconsistent / wrong if I do so? My best guess is that if I alter anything concerning the solution model for a phase, it will result in utter nonsense (?) but sometimes I would like to exclude some of the solutions for (more exotic) things as e.g. Fe3+ or Mn in biotite etc.
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DougTinkham
- Posts: 13
- Joined: 30 Oct 2015, 16:31
Re: dataset modifications
What bothers me often and where I have absolutely no knowledge about is, how much can I alter the datasets without producing nonsense? That is, my main concern is, lets say in the Holland & Powell dataset, what if I e.g. don't trust the solution for Mn in biotite: am I allowed to exclude the Mn in biotite from the solution or would the result get inconsistent / wrong if I do so? My best guess is that if I alter anything concerning the solution model for a phase, it will result in utter nonsense (?) but sometimes I would like to exclude some of the solutions for (more exotic) things as e.g. Fe3+ or Mn in biotite etc.
Hi Sina,
Whether or not you can simply exclude phase components from a model is dependent on how the a-x model is formulated and the chemical system you are working in. Where you can run in to problems are with the reciprocal style solution models because the models are formulated with a linearly independent set of phase components.
Take KFMASH biotite for example. The incorporation of octahedral Al is done using the eastonite phase component, and there is therefore no siderophyllite component in the model (it would be a linearly dependent member as it can be constructed from eastonite, annite, and phlogopite). If you wanted to do a calculation using biotite in the KFASH system, you would need to rewrite the entire model in terms of the components phl-ann-sdph because if you simply eliminate eastonite from the existing model, the model would not allow any octahedral Al because you would not have a phase component that incorporates octahedral Al.
Extend that rationale to Mn-bearing systems, and you can easily determine if eliminating a Mn member is possible or not. For most phases, you can simply remove the Mn member and you will be fine, but always make sure first by looking at the substitution vectors and the phase components present.
Doug
Re: dataset modifications
Dear Doug,
thank you for your answer, it is very helpful.
Best,
Sina
thank you for your answer, it is very helpful.
Best,
Sina
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jakub_haifler
- Posts: 5
- Joined: 11 Jan 2021, 17:17
Re: dataset modifications
EDIT: I have fixed it. This is discussed in the next post.
Hi everybody.
I attempted to implement a thermodynamic model of a Ca-Mg-Fe carbonate (Franzolin et al., 2011) into Theriak-Domino to model solvi in the ternary composition space at variable P, T. I coded (I think I did) the solution model in a similar manner like the models added by D. Tinkham, such as e.g. augitic clinopyroxene after Green et al. (2016).
Unfortunately, the calculations by means of THERTER (Ca-Mg-Fe space) or THERBIN (Ca-Mg subspace) gave disastrous results. The calculations run to completition, although warnings such as Gibbs-Duhem test failed or fatal error: the system is not binary appeared. However, the plotted tie-lines make absolutely no sense.
THERBIN gave relatively meaningful result for a CaCO3-FeCO3 subsystem, although the position of the solvus was not exactly the same as in the publication of Franzolin et al. This imply that the trouble may be caused particularly by definition of the linearly dependent end-members.
My calculation failed with mineral data taken from both, Holland and Powell (1998+) and Holland and Powell (2011) datasets.
Furthermore, I tested the solution model of Ca-Mg carbonate after Holland and Powell (2003), which is coded in the dataset tcdb55… - it nicely reproduced the shape of the solvus in the X-T diagram from the paper.
I would like to ask well experienced users of whether they could have a look at the coding to find the cause of the error.
Or does somebody know whether it is possible to load the A-X model from the dataset and to output the Margules parameters, van Laar coefficients or site occupancies on screen to check whether they are correctly input?
Thank you very much. Jakub Haifler
EDIT: THE CODE IS FIXED, endmember data are from tc5. See next post for tc6-based code.
THERIN input for calculating CaCO3-MgCO3 binary plot.
The disastrous output:
Hi everybody.
I attempted to implement a thermodynamic model of a Ca-Mg-Fe carbonate (Franzolin et al., 2011) into Theriak-Domino to model solvi in the ternary composition space at variable P, T. I coded (I think I did) the solution model in a similar manner like the models added by D. Tinkham, such as e.g. augitic clinopyroxene after Green et al. (2016).
Unfortunately, the calculations by means of THERTER (Ca-Mg-Fe space) or THERBIN (Ca-Mg subspace) gave disastrous results. The calculations run to completition, although warnings such as Gibbs-Duhem test failed or fatal error: the system is not binary appeared. However, the plotted tie-lines make absolutely no sense.
THERBIN gave relatively meaningful result for a CaCO3-FeCO3 subsystem, although the position of the solvus was not exactly the same as in the publication of Franzolin et al. This imply that the trouble may be caused particularly by definition of the linearly dependent end-members.
My calculation failed with mineral data taken from both, Holland and Powell (1998+) and Holland and Powell (2011) datasets.
Furthermore, I tested the solution model of Ca-Mg carbonate after Holland and Powell (2003), which is coded in the dataset tcdb55… - it nicely reproduced the shape of the solvus in the X-T diagram from the paper.
I would like to ask well experienced users of whether they could have a look at the coding to find the cause of the error.
Or does somebody know whether it is possible to load the A-X model from the dataset and to output the Margules parameters, van Laar coefficients or site occupancies on screen to check whether they are correctly input?
Thank you very much. Jakub Haifler
EDIT: THE CODE IS FIXED, endmember data are from tc5. See next post for tc6-based code.
Code: Select all
25
O AL BA C CA CL CO
CU F FE H K MN MG
NA NI P S SI SR TI
ZN ZR B E
15.99940 26.98154 137.32700 12.01100 40.07800 35.45270 58.93320
63.54600 18.99840 55.84700 1.00794 39.09830 54.93085 24.30500
22.98977 58.69000 30.97362 32.06600 28.08550 87.62000 47.88000
65.39000 91.22400 10.81000 1.00000
0.0 1.5 1.0 2.0 1.0 0.0 1.0
1.0 0.0 1.0 0.5 0.5 1.0 1.0
0.5 1.0 1.0 0.0 2.0 1.0 2.0
1.0 2.0 0.0 0.0
**** MINERAL DATA ***** Holland and Powell (1998+)
calcite CA(1)O(3)C(1) cc 1nh
ST 0.0 -1207470.000 92.5000 3.6890
C3 140.90000 0.0050290 -950700.0 -858.400 0.00
VHP 0.000044000 760.0 1240.0000 10.00 0.04000
VH2 10.0000 4.0000 -0.000114000
magnesite MG(1)O(3)C(1) mag 1nh
ST 0.0 -1111360.000 65.1000 2.8030
C3 186.40000 -0.0037720 0.0 -1886.200 0.00
VHP 0.000064800 1460.0 0.0000 0.00 0.00000
VH2 10.0000 4.0000 -0.000219000
siderite FE(1)O(3)C(1) sid 1nh
ST 0.0 -761440.000 95.0000 2.9380
C3 168.40000 0.0000000 0.0 -1483.600 0.00
VHP 0.000110000 1200.0 0.0000 0.00 0.00000
VH2 10.0000 4.0000 -0.000180000
!==================================
! Calcite - magnesite - siderite - dolomite - ankerite (Franzolin et al., 2011), added by Jakub Haifler
!==================================
odol MG(0.5)CA(0.5)O(3)C(1) dol2 1nh
ST 0.0 -1000.000 0.0000 0.0000
COM calcite[0.5]magnesite[0.5]
oank MG(0.25)FE(0.25)CA(0.5)O(3)C(1) oank 1nh
ST 0.0 -750.000 0.0000 0.0000
COM calcite[0.5]magnesite[0.25]siderite[0.25]
***** SOLUTION DATA *****
CARB_EF (SITE,MARGULES)1/4 M1(2):Ca,Mg,Fe - M2a(1):Ca,Mg,Fe - M2b(1):Ca,Mg,Fe
calcite Ca,Ca - Ca - Ca 0.25 0.000929 0
magnesite Mg,Mg - Mg - Mg 1 0 0
siderite Fe,Fe - Fe - Fe 0.01 0.000666 0
odol Ca,Ca - Mg - Mg 0.95 0 0
oank Ca,Ca - Fe - Mg 0.929 0 0
!
***** MARGULES PARAMETERS *****
calcite - magnesite
12 28000 0.00 0.00
calcite - odol
12 11200 0.00 0.00
magnesite - odol
12 14000 0.00 0.00
calcite - siderite
12 20503 0.00 0.00
oank - siderite
12 73650 50.0 0.00
calcite - oank
12 12730 10.0 0.00
magnesite - siderite
12 10000 0.00 0.00
siderite - odol
12 51190 30.0 0.00
odol - oank
12 -5000 0.00 0.00
magnesite - oank
12 30000 0.00 0.00
Code: Select all
0 CA(10)C(10)O(30)MG(10)C(10)O(30) *- carb_error.jpg (253.54 KiB) Viewed 37705 times
Last edited by jakub_haifler on 14 Jan 2021, 09:29, edited 1 time in total.
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jakub_haifler
- Posts: 5
- Joined: 11 Jan 2021, 17:17
Re: dataset modifications
Hi everyone.
In my previous post, I asked for some help with coding of a solid solution model of Ca-Mg-Fe carbonate callibrated by Franzolin et al. (2011). Fortunately, I fixed the problem, so I share the code below.
The difficulties I had occurred due to incorrect sign in van Laar parameters, namely αS. I think, it may be quite interesting to discuss this a little bit, as a temperature-related fraction of van Laar coefficient is quite uncommon in the dataset.
Franzolin et al. (2011) in their Table 2 reported positive WS parameters for mixing of siderite and dolomite and two more pairs, which means that Margules parameter Wsid-odol decreases with increasing temperature, because W=WH-WS*T+WV*P. The equation for alpha’s is similar to the equation for W’s. Given that αH of Cc a Sid are much lower numbers compared to the other endmembers, I assume that the term –αS*T should be positive and grows with increasing temperature, which means negative αS. This agrees with the minus signs of the coefficients in the Table 2 of Franzolin et al. (2011). However, in Theriak-Domino, the equation is as follows:
α= α0 + αT *T + αP *P (page 71 in the guide), so that the coefficients must be positive.
Franzolin et al. (2011) reported (page 223) that they used Holland’s and Powell’s dataset updated in 2002, which should correspond to tc5... in TD. I used THERBIN and THERTER together with tc5 to calculate binary and ternary diagrams (Figs. 6, 7, 8) in the paper by Franzolin et al. (2011). Fig. 6 shows perfect agreement, Fig. 7 relatively good agreement (miscibility gaps are somewhat larger close to the CaMg(CO3)2 – Ca(Mg0.5Fe0.5)(CO3)2 join (=linearly dependent endmembers) in my version. However, Fig. 8a is poorly reproduced using tc5 dataset.
By contrast, the dataset tc6... gave quite nice agreement between the original and the reproduced diagrams. The diagrams are shown here, you may compare them with the original paper:
Here I attach the code for the solid solution model. Thermodynamic data of endmembers are taken from the tc6 database:
A fixed code using data from tc5 dataset is attached in my previous post. The disastrous diagram in the previous post was created before the correction, now both the codes I input nicely reproduce Fig. 6 in Franzolin et al. (2011).
Jakub
In my previous post, I asked for some help with coding of a solid solution model of Ca-Mg-Fe carbonate callibrated by Franzolin et al. (2011). Fortunately, I fixed the problem, so I share the code below.
The difficulties I had occurred due to incorrect sign in van Laar parameters, namely αS. I think, it may be quite interesting to discuss this a little bit, as a temperature-related fraction of van Laar coefficient is quite uncommon in the dataset.
Franzolin et al. (2011) in their Table 2 reported positive WS parameters for mixing of siderite and dolomite and two more pairs, which means that Margules parameter Wsid-odol decreases with increasing temperature, because W=WH-WS*T+WV*P. The equation for alpha’s is similar to the equation for W’s. Given that αH of Cc a Sid are much lower numbers compared to the other endmembers, I assume that the term –αS*T should be positive and grows with increasing temperature, which means negative αS. This agrees with the minus signs of the coefficients in the Table 2 of Franzolin et al. (2011). However, in Theriak-Domino, the equation is as follows:
α= α0 + αT *T + αP *P (page 71 in the guide), so that the coefficients must be positive.
Franzolin et al. (2011) reported (page 223) that they used Holland’s and Powell’s dataset updated in 2002, which should correspond to tc5... in TD. I used THERBIN and THERTER together with tc5 to calculate binary and ternary diagrams (Figs. 6, 7, 8) in the paper by Franzolin et al. (2011). Fig. 6 shows perfect agreement, Fig. 7 relatively good agreement (miscibility gaps are somewhat larger close to the CaMg(CO3)2 – Ca(Mg0.5Fe0.5)(CO3)2 join (=linearly dependent endmembers) in my version. However, Fig. 8a is poorly reproduced using tc5 dataset.
By contrast, the dataset tc6... gave quite nice agreement between the original and the reproduced diagrams. The diagrams are shown here, you may compare them with the original paper:
- franzolin.jpg (242.89 KiB) Viewed 37670 times
Code: Select all
26
O AL BA C CA CL CO
CU F FE H K MN MG
NA NI P S SI SR TI
ZN ZR B CR E
15.99940 26.98154 137.32700 12.01100 40.07800 35.45270 58.93320
63.54600 18.99840 55.84700 1.00794 39.09830 54.93085 24.30500
22.98977 58.69000 30.97362 32.06600 28.08550 87.62000 47.88000
65.39000 91.22400 10.81000 51.99610 1.00000
0.0 1.5 1.0 2.0 1.0 0.0 1.0
1.0 0.0 1.0 0.5 0.5 1.0 1.0
0.5 1.0 1.0 0.0 2.0 1.0 2.0
1.0 2.0 0.0 0.0
!
**** MINERAL DATA ***** Holland and Powell (2011)
calcite CA(1)O(3)C(1) cc 1nh
ST 0.0 -1207760.000 92.5000 3.6890
C3 140.90000 0.0050290 -950700.0 -858.400 0.00
V11 0.000025200 733.00 4.0600 -0.005500 1.00
LA1 1240.00 10.0000 0.04000
magnesite MG(1)O(3)C(1) mag 1nh
ST 0.0 -1110920.000 65.5000 2.8030
C3 186.40000 -0.0037720 0.0 -1886.200 0.00
V11 0.000033800 1028.00 5.4100 -0.005300 0.00
siderite FE(1)O(3)C(1) sid 1nh
ST 0.0 -762220.000 93.3000 2.9430
C3 168.40000 0.0000000 0.0 -1483.600 0.00
V11 0.000043900 1200.00 4.0700 -0.003400 0.00
!==================================
! Calcite - magnesite - siderite - dolomite - ankerite (Franzolin et al., 2011), added by Jakub Haifler
!==================================
**** MINERAL DATA *****
odol MG(0.5)CA(0.5)O(3)C(1) odol 1nh
ST 0.0 -1000.000 0.0000 0.0000
COM calcite[0.5]magnesite[0.5]
oank MG(0.25)FE(0.25)CA(0.5)O(3)C(1) oank 1nh
ST 0.0 -750.000 0.0000 0.0000
COM calcite[0.5]magnesite[0.25]siderite[0.25]
***** SOLUTION DATA *****
CARB_EF (SITE,MARGULES)1/4 M1(2):Ca,Mg,Fe - M2a(1):Ca,Mg,Fe - M2b(1):Ca,Mg,Fe
calcite Ca,Ca - Ca - Ca 0.25 0.000929 0
magnesite Mg,Mg - Mg - Mg 1 0 0
siderite Fe,Fe - Fe - Fe 0.01 0.000666 0
odol Ca,Ca - Mg - Mg 0.95 0 0
oank Ca,Ca - Fe - Mg 0.929 0 0
!
***** MARGULES PARAMETERS *****
calcite - magnesite
12 28000 0.00 0.00
calcite - odol
12 11200 0.00 0.00
magnesite - odol
12 14000 0.00 0.00
calcite - siderite
12 20503 0.00 0.00
oank - siderite
12 73650 50.0 0.00
calcite - oank
12 12730 10.0 0.00
magnesite - siderite
12 10000 0.00 0.00
siderite - odol
12 51190 30.0 0.00
odol - oank
12 -5000 0.00 0.00
magnesite - oank
12 30000 0.00 0.00
Jakub
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