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Biotite
Biotite automatically calculates biotite compositions from microprobe analyses.
The results are presented in tables and in various diagrams (A'KF diagram, AFM- (Ms and Kf) diagram, etc.). For further details see below.
Biotite: Composition and classification of biotites
Using microprobe analyses, this program can be used to automatically calculate biotite compositions based on 22 oxygen atoms. The oxides, the cations, the lattice site occupancies, data for triangular diagrams and the end members (after Holdaway et al. 1988) are calculated.
The micas are classified using the A'KF diagram, the AFM(Ms) diagram and the AFM(Kf) diagram.
You can enter the values individually in the table below or use the input fields. Here you enter for up to 5 biotites the values (oxides) as rows separated by single spaces (see placeholders; 200 characters max.). Note the order of the elements: SiO₂ TiO₂ Al₂O₃ FeO (total Fe as FeO) MnO MgO CaO Na₂O K₂O BaO H₂O Cr₂O₃ CuO ZnO Total! Additionally, the sample designation must come first. You can use the period or the comma as a decimal separator.
Your biotites
You can also enter your data (oxides) here (into the light-blue fields).
| Name | |||||
| Oxides | Oxides | Oxides | Oxides | Oxides | |
| SiO2 | |||||
| TiO2 | |||||
| Al2O3 | |||||
| FeO | |||||
| MnO | |||||
| MgO | |||||
| CaO | |||||
| Na2O | |||||
| K2O | |||||
| BaO | |||||
| H2O | |||||
| Cr2O3 | |||||
| CuO | |||||
| ZnO | |||||
| Total |
Constants and intermediate results
| Oxides [wt.-%] | Mol mass | Mol-Prop. | Element | Wt.-% | Atom-Prop. | Oxygen | Cations (O=22) | |
|---|---|---|---|---|---|---|---|---|
| Biotite 1 | ||||||||
| SiO2 | Si | |||||||
| TiO2 | Ti | |||||||
| Al2O3 | Al | |||||||
| Cr2O3 | Cr | |||||||
| MgO | Mg | |||||||
| CaO | Ca | |||||||
| MnO | Mn | |||||||
| FeO | Fe | |||||||
| CuO | Cu | |||||||
| ZnO | Zn | |||||||
| BaO | Ba | |||||||
| Na2O | Na | |||||||
| K2O | K | |||||||
| Totals | *without Water | |||||||
| Factor O=22 | ||||||||
| Biotite 2 | ||||||||
| SiO2 | Si | |||||||
| TiO2 | Ti | |||||||
| Al2O3 | Al | |||||||
| Cr2O3 | Cr | |||||||
| MgO | Mg | |||||||
| CaO | Ca | |||||||
| MnO | Mn | |||||||
| FeO | Fe | |||||||
| CuO | Cu | |||||||
| ZnO | Zn | |||||||
| BaO | Ba | |||||||
| Na2O | Na | |||||||
| K2O | K | |||||||
| Totals | *without Water | |||||||
| Factor O=22 | ||||||||
| Biotite 3 | ||||||||
| SiO2 | Si | |||||||
| TiO2 | Ti | |||||||
| Al2O3 | Al | |||||||
| Cr2O3 | Cr | |||||||
| MgO | Mg | |||||||
| CaO | Ca | |||||||
| MnO | Mn | |||||||
| FeO | Fe | |||||||
| CuO | Cu | |||||||
| ZnO | Zn | |||||||
| BaO | Ba | |||||||
| Na2O | Na | |||||||
| K2O | K | |||||||
| Totals | *without Water | |||||||
| Factor O=22 | ||||||||
| Biotite 4 | ||||||||
| SiO2 | Si | |||||||
| TiO2 | Ti | |||||||
| Al2O3 | Al | |||||||
| Cr2O3 | Cr | |||||||
| MgO | Mg | |||||||
| CaO | Ca | |||||||
| MnO | Mn | |||||||
| FeO | Fe | |||||||
| CuO | Cu | |||||||
| ZnO | Zn | |||||||
| BaO | Ba | |||||||
| Na2O | Na | |||||||
| K2O | K | |||||||
| Totals | *without Water | |||||||
| Factor O=22 | ||||||||
| Biotite 5 | ||||||||
| SiO2 | Si | |||||||
| TiO2 | Ti | |||||||
| Al2O3 | Al | |||||||
| Cr2O3 | Cr | |||||||
| MgO | Mg | |||||||
| CaO | Ca | |||||||
| MnO | Mn | |||||||
| FeO | Fe | |||||||
| CuO | Cu | |||||||
| ZnO | Zn | |||||||
| BaO | Ba | |||||||
| Na2O | Na | |||||||
| K2O | K | |||||||
| Totals | *without Water | |||||||
| Factor O=22 | ||||||||
| Biotite 1 | Biotite 2 | Biotite 3 | Biotite 4 | Biotite 5 | |
|---|---|---|---|---|---|
| Si | |||||
| Al tetr. | |||||
| Tetrahedron | |||||
| Al | |||||
| Cr | |||||
| Ti | |||||
| Fe | |||||
| Mn | |||||
| Mg | |||||
| Cu | |||||
| Zn | |||||
| Octahedron | |||||
| Ba | |||||
| Ca | |||||
| Na | |||||
| K | |||||
| Interlayer | |||||
| Total |
| Biotite 1 | Biotite 2 | Biotite 3 | Biotite 4 | Biotite 5 | |
|---|---|---|---|---|---|
| Grid occupation | |||||
| Tetrahedron | |||||
| Tetrahedral Al | |||||
| Octahedral Al | |||||
| Octahedron | |||||
| Interlayer | |||||
| Total | |||||
Check total
Compares the sum of the cations (O=22) with the sum of the lattice occupation. These should be equal, so the difference should be 0. Minor deviations can be attributed to rounding errors. Otherwise there may be an analysis error.
|
|||||
| A´KF | |||||
| A´ | |||||
| K | |||||
| F | |||||
| Total | |||||
| A´KF (100) | |||||
| A´ | |||||
| K | |||||
| F | |||||
| Total | |||||
| AFM (Ms) | |||||
| A (Ms) | |||||
| F | |||||
| M | |||||
| AFM (Kf) | |||||
| A (Kf) | |||||
| F | |||||
| M | |||||
| End-member calculation (after Holdaway et al., 1988) | |||
|---|---|---|---|
| Biotite 1 | |||
| Ba-Biotite | |||
| Ti-Biotite | |||
| Talc-Minnesodaite | |||
| Muscovite | |||
| Eastonite-Siderophyllite | |||
| Wonesite | |||
| Phlogopite-Annite | |||
| Total | |||
| Biotite 2 | |||
| Ba-Biotite | |||
| Ti-Biotite | |||
| Talc-Minnesodaite | |||
| Muscovite | |||
| Eastonite-Siderophyllite | |||
| Wonesite | |||
| Phlogopite-Annite | |||
| Total | |||
| Biotite 3 | |||
| Ba-Biotite | |||
| Ti-Biotite | |||
| Talc-Minnesodaite | |||
| Muscovite | |||
| Eastonite-Siderophyllite | |||
| Wonesite | |||
| Phlogopite-Annite | |||
| Total | |||
| Biotite 4 | |||
| Ba-Biotite | |||
| Ti-Biotite | |||
| Talc-Minnesodaite | |||
| Muscovite | |||
| Eastonite-Siderophyllite | |||
| Wonesite | |||
| Phlogopite-Annite | |||
| Total | |||
| Biotite 5 | |||
| Ba-Biotite | |||
| Ti-Biotite | |||
| Talc-Minnesodaite | |||
| Muscovite | |||
| Eastonite-Siderophyllite | |||
| Wonesite | |||
| Phlogopite-Annite | |||
| Total | |||
Errors / Warnungen
| Mica 1 | Mica 2 | Mica 3 | Mica 4 | Mica 5 |
|---|---|---|---|---|
Results
Biotite (22 oxygens)
| Biotite 1 | Biotite 2 | Biotite 3 | Biotite 4 | Biotite 5 | |
|---|---|---|---|---|---|
| SiO2 | |||||
| TiO2 | |||||
| Al2O3 | |||||
| Cr2O3 | |||||
| MgO | |||||
| CaO | |||||
| MnO | |||||
| FeO | |||||
| CuO | |||||
| ZnO | |||||
| BaO | |||||
| Na2O | |||||
| K2O | |||||
| H2O | |||||
| Total | |||||
| Cations | |||||
| Si | |||||
| Ti | |||||
| Al | |||||
| Cr | |||||
| Mg | |||||
| Ca | |||||
| Mn | |||||
| Fe²⁺ (Fe total) | |||||
| Cu | |||||
| Zn | |||||
| Ba | |||||
| Na | |||||
| K | |||||
| Total | |||||
| The ratio FeO/(FeO+MgO): X(Fe) | |||||
| X(Fe) | |||||
| The ratio Mg/(Mg+Fe): X(Mg) (M) | |||||
| X(Mg) | |||||
| Grid occupation | |||||
| Si | |||||
| AlIV | |||||
| Tetrahedron | |||||
| AlVI | |||||
| Cr | |||||
| Ti | |||||
| Fe²⁺ (Fe total) | |||||
| Mn | |||||
| Mg | |||||
| Cu | |||||
| Zn | |||||
| Octahedron | |||||
| Ba | |||||
| Ca | |||||
| Na | |||||
| K | |||||
| Interlayer | |||||
| Total | |||||
| End-members (after Holdaway et al.,1988) | |||||
| Ba-Biotite | |||||
| Ti-Biotite | |||||
| Talc-Minnesodaite | |||||
| Muscovite | |||||
| Eastonite-Siderophyllite | |||||
| Wonesite | |||||
| Phlogopite-Annite | |||||
| Total | |||||
| The A'KF diagram | |||||
| A' | |||||
| K | |||||
| F | |||||
| Total | |||||
| The AFM(Ms) diagram | |||||
| A (Ms) | |||||
| F | |||||
| M | |||||
| The AFM(Kf) diagram | |||||
| A (Kf) | |||||
| F | |||||
| M | |||||
| Total | |||||
| Errors / Warnungen | |||||
|
|
|
|
|
|
|
| Comments | |||||
The A'KF diagram
The biotites shown in the A'KF diagram. For infos see captions below. After Ehlers & Blatt (1982).
Captions
|
• |
Biotite 1 |
|
• |
Biotite 2 |
|
• |
Biotite 3 |
|
• |
Biotite 4 |
|
• |
Biotite 5 |
|
Bottom corner |
F = Fe0+MgO+MnO |
|
Red dot bottom corner |
Antophyllite, Opx |
|
Dark green field |
Chlorite |
|
White dot in dark green field |
Almandine |
|
Top right corner |
K = K₂O |
|
Purple dot top right corner |
K-feldspar |
|
Red dot at end of phengite line |
Muscovite |
|
Top left corner |
A' = (Al₂O₃+Fe₂0₃)-(Na₂O+K₂O+CaO) |
|
Green dot top left corner |
Kyanite, Andalusite, Sillimanite |
The AFM(Ms) diagram
The biotites shown in the AFM(Ms) diagram. For infos see below. After Nelson, S.A. (2011).
Captions
|
• |
Biotite 1 |
|
• |
Biotite 2 |
|
• |
Biotite 3 |
|
• |
Biotite 4 |
|
• |
Biotite 5 |
|
Red field |
Biotite |
|
Green field |
Chlorite |
|
Grey field |
Staurolite |
|
A |
Al₂O₃ |
|
F |
FeO |
|
M |
MgO |
|
Ch |
Chloritoid |
|
Co |
Cordierite |
|
G |
Garnet |
|
St |
Stilpnomelane |
The AFM(Kf) diagram
.svg)
The biotites shown in the AFM(Kf) diagram. For infos see below. After Nelson, S.A. (2011).
Captions
|
• |
Mica 1 |
|
• |
Mica 2 |
|
• |
Mica 3 |
|
• |
Mica 4 |
|
• |
Mica 5 |
|
Red field |
Biotite |
|
Top corner |
A |
|
Left corner |
F |
|
Right corner |
M |
The biotites in the Al₂O₃–MgO diagram
The biotites shown in the Al₂O₃–MgO discrimination diagram (after Abdel-Rahman, A.M., 1994). For infos see below.
Captions
|
• |
Biotite 1 |
|
• |
Biotite 2 |
|
• |
Biotite 3 |
|
• |
Biotite 4 |
|
• |
Biotite 5 |
|
Y-axis |
% Al₂O₃ |
|
X-axis |
% MgO |
|
P |
Peraluminous (including S-type) |
|
C |
Calc-alkaline, Orogenic suites |
|
A |
Anorogenic, Alkaline suites |
The Ti-in-biotite geothermometer
Isotherms according to the Ti-in-biotite geothermometer in metapelites (after Henry et al., 2005) and the data-points of the biotites. For infos see below.
Captions
|
• |
Biotite 1 |
|
• |
Biotite 2 |
|
• |
Biotite 3 |
|
• |
Biotite 4 |
|
• |
Biotite 5 |
|
Y-axis |
Ti [pfu] |
|
X-axis |
Mg/(Mg+Fe) |
Download data
Current date
Enter a title
Sample number, etc.
Download data file (*.csv)
Literature
- Abdel-Rahman A.M., 1994: Nature of biotites from alkaline, calc-alkaline, and peraluminous magmas, Journal of Petrology 35 (2) (1994) 525–541.
- Deer, W.A., Howie, R.A. & Zussman, J. (1992): An introduction to the rock-forming minerals. – Longman Scientific & Technical, Harlow, 2nd edition 1992: 696 p.
- Ehlers, E.G. and Blatt, H. (1982): Petrology: Igneous, Sedimentary and Metamorphic. W. H. Freeman, New York, 732 p.
- Henry D.J., Guidotti V.C. & Thomson A.J., 2005: The Ti-saturation surface for low to medium pressure metapelitic biotites: Implications for geothermometry and Ti-substitution mechanisms. Amer. Mineralogist 90, 316—328.
- Matthes S. (1987): Mineralogie – Eine Einführung in die spezielle Mineralogie, Petrologie und Lagerstättenkunde. – Springer-Verlag, Berlin, Heidelberg, 1987: 444 p.
- Nelson, S.A. (2011): Triangular Plots in Metamorphic Petrology – EENS 2120; Tulane University. – https://www2.tulane.edu/~sanelson/eens212/triangular_plots_metamo.pdf
- Schäfer, J. (1996): Mikrosondenuntersuchungen an Geröllen und detritischen Mineralen im Flysch des Saxothuringikums: Ein Beitrag zur Exhumierungsgeschichte des Liefergebietes. – Inaugural dissertation to obtain a doctorate in natural sciences from the Justus Liebig University in Giessen (Department of Geosciences and Geography), Giessen, March 1996; 176 p.; German with English and French summaries.