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The Amphibole-Plagioclase Thermometer of Holland & Blundy (1994)
Thermometer B
This program is used for the recalculation of trivalent iron and the calculation of the occupations/activities in amphiboles. Pressure is calculated according to Johnson & Rutherford (1989). A temperature calculation is then carried out using the hornblende plagioclase thermometer according to Holland & Blundy (1994).
This is the \"Thermometer B\" version. In silica-undersaturated rocks or magmas thermometer B alone can be applied. For silica-saturated rocks both thermometers (A and B) may be applied.
Link to "Thermometer A": >Thermometer A
References
Holland, T., Blundy, J. (1994): Non-ideal interactions in calcic amphiboles and their bearing on amphibole-plagioclase thermometry. – Contr. Mineral. and Petrol. 116, 433–447 (1994).
https://doi.org/10.1007/BF00310910
Johnson, M.C. & Rutherford, M.J., 1989: Experimental calibration of the aluminum-in-hornblende geobarometer with application to Long Valley caldera (California) volcanic rocks. – Geology (1989) 17 (9): 837–841.
See this publication on GeoScienceWorld (GSW), a nonprofit collaborative and comprehensive resource for research and communications in the Earth Sciences.
The amphibole-plagioclase thermometer B
Recalculation of trivalent iron and calculation of occupancy/activities in amphiboles, as well as temperature calculation with the hornblende-plagioclase thermometer according to Holland & Blundy (1994).
Thermometer B, prevailing conditions: Temp.: 500–900°C; Plg: 0.1<Xan<0.9; Amph.: XNa/M4>0.03; AlVI<1.8 pfu; Si: 6.0–7.7 pfu.
NB: As stated above, thermometer B alone can be applied in silica-undersaturated rocks or magmas!
You can enter the values individually in the table or use the input fields. Here you enter the values as rows separated by single spaces (see placeholders; 200 characters max.). Note the order of the elements in the table! Additionally, the sample designation must come first and the sum last. You can use the period or the comma as a decimal separator.
Data input
| Oxides | Cations | |
|---|---|---|
| SiO2 | ||
| TiO2 | ||
| Al2O3 | ||
| MgO | ||
| CaO | ||
| MnO | ||
| FeO | ||
| Na2O | ||
| K2O | ||
| Total |
Plagioclase
Please enter the appropriate values!
| XAb: | XAn: |
Calculation of YAb-An (Plagioclase) [kJ]
| XAb > 0.5 | |
| XAb < 0.5 |
YAb-An value for temperature calculation:
You can either fill in the value manually or have it filled in automatically. Activate the control field if you want to use the automatic function.
Execute all calculations
Cation calculation
| Normalized | Fe²⁺/Fe³⁺ | |
|---|---|---|
| Si | ||
| Ti | ||
| Al | ||
| Mg | ||
| Ca | ||
| Mn | ||
| Fetot | ||
| Fe2+ | ||
| Fe3+ | ||
| Na | ||
| K | ||
| Total |
Pressure calculation after Johnson & Rutherford
Defining the factors fi (Caution: Observe the boundary conditions!)
A
| f1 | ||
| f2 | ||
| f3 | ||
| f4 | ||
| f5 |
If a value in the left column of group A is > 1, then this value is automatically set to 1 (light blue, right column). I.e. all of the iron is calculated as Fe²⁺.
B
| f6 | |
| f7 | |
| f8 | |
| f9 | |
| f10 |
If a value from group B is > 1, the amphibole cannot be calculated stoichiometrically!
Selection of fA and fB
| fA | fB |
Fixing the mean value fav
An average between fA and fB (with fA > fB) is sought. If fB > fA, the analysis fails one of the above conditions for stoichiometry.
| fav from fA and fB | fav total | |
|---|---|---|
Site allocations
| cm * | |
| * cm = Cummingtonite substitution | |
| X Si/T1 | |
| X Al/T1 | |
| X Al/M2 | |
| X Na/A | |
| X Na/M4 | |
| X Ca/M4 | |
Temperature calculation
| Counter | |
| Numerator Bracket | |
| Denominator Bracket | |
| Bracket | |
| ln Bracket | |
| Denominator |
Result
| T [K] | |
| T [°C] |
Table of results
| Oxides | Cations | ||
|---|---|---|---|
| SiO2 | Si | ||
| TiO2 | Ti | ||
| Al2O3 | Al | ||
| MgO | Mg | ||
| CaO | Ca | ||
| MnO | Mn | ||
| FeO | Fe | ||
| Fe2+ | |||
| Fe3+ | |||
| Na2O | Na | ||
| K2O | K | ||
| Total | Total | ||
Plagioclase
| XAb | XAn |
|---|---|
Temperature
| T [K] | T [°C] |
|---|---|
Pressure
Download data
Current date
Enter a title
Sample number, etc.
Download data file (*.csv)