GarnetCalc automatically calculates garnet compositions from microprobe analyses.
Results are plotted in the P-GA-AS diagram.
Calculation of garnet composition normalized to 8 cations with the tetrahedron position filled up with Al³⁺. Fe³⁺ estimation and end-member calculation (Uwarowite, Ti-Andradite, Andradite, Pyrope, Spessartine, Grossular, Almandine) for garnets with (Mg+Mn) < Al and (Cr+Ti+Fe³⁺) < Ca. Drawing of the P-GA-AS diagram.
You can enter the values individually in the table below or use the input fields. Here you enter for up to 5 garnets the values (oxides) as rows separated by single spaces (see placeholders; 200 characters max.). Note the order of the elements in the table: Mg, Al, Si, Ca, Ti, Cr, Mn, Fe (total Fe as FeO)! Additionally, the sample designation must come first. You can use the period or the comma as a decimal separator.
Further
down below
you also have the possibility to enter data for the P-GA-AS diagram manually.
You can also enter your data (oxides) here (into the light-blue fields).
Name | |||||
Oxides | Oxides | Oxides | Oxides | Oxides | |
MgO | |||||
Al2O3 | |||||
SiO2 | |||||
CaO | |||||
TiO2 | |||||
Cr2O3 | |||||
MnO | |||||
FeO | |||||
Total | |||||
Settings | |||||
Ratio of Fe³⁺ to total Fe [Fe³⁺/(Fe³⁺+Fe²⁺)] | |||||
Oxides [wt.-%] | Mol wt. (AW) | – | Atom Prop. | Oxygen | Cations | |
---|---|---|---|---|---|---|
SiO2 | ||||||
TiO2 | ||||||
Al2O3 | ||||||
Cr2O3 | ||||||
Fe2O3 | ||||||
MgO | ||||||
CaO | ||||||
MnO | ||||||
FeO | ||||||
Total | ||||||
Fetot. | ||||||
Garnet 2 | ||||||
SiO2 | ||||||
TiO2 | ||||||
Al2O3 | ||||||
Cr2O3 | ||||||
Fe2O3 | ||||||
MgO | ||||||
CaO | ||||||
MnO | ||||||
FeO | ||||||
Total | ||||||
Fetot. | ||||||
Garnet 3 | ||||||
SiO2 | ||||||
TiO2 | ||||||
Al2O3 | ||||||
Cr2O3 | ||||||
Fe2O3 | ||||||
MgO | ||||||
CaO | ||||||
MnO | ||||||
FeO | ||||||
Total | ||||||
Fetot. | ||||||
Garnet 4 | ||||||
SiO2 | ||||||
TiO2 | ||||||
Al2O3 | ||||||
Cr2O3 | ||||||
Fe2O3 | ||||||
MgO | ||||||
CaO | ||||||
MnO | ||||||
FeO | ||||||
Total | ||||||
Fetot. | ||||||
Garnet 5 | ||||||
SiO2 | ||||||
TiO2 | ||||||
Al2O3 | ||||||
Cr2O3 | ||||||
Fe2O3 | ||||||
MgO | ||||||
CaO | ||||||
MnO | ||||||
FeO | ||||||
Total | ||||||
Fetot. |
Garnet 1 | Garnet 2 | Garnet 3 | Garnet 4 | Garnet 5 | |
---|---|---|---|---|---|
Fe2O3 [wt.-%] | |||||
FeO [wt.-%] | |||||
Total oxides [wt.-%] | |||||
Corr. Si cations ≤ 3 | |||||
Corr. Si cations > 3 | |||||
Si [wt.-%] | |||||
Ti [wt.-%] | |||||
Al [wt.-%] | |||||
Cr [wt.-%] | |||||
Fe³⁺ [wt.-%] | |||||
Mg [wt.-%] | |||||
Ca [wt.-%] | |||||
Mn [wt.-%] | |||||
Fe²⁺ [wt.-%] | |||||
Total | |||||
Fe³⁺/Fetot. | |||||
Mg/Mg+Fe | |||||
Fe/Fe+Mg | |||||
Z | |||||
Al³⁺ (Z) | |||||
Al³⁺ (Y) | |||||
Y | |||||
X | |||||
Difference | |||||
Total | |||||
Ca-Cr | |||||
Ca Rest | |||||
Ca-Ti | |||||
Ca Rest | |||||
Ca-Fe | |||||
Ca Rest | |||||
Mg-Al | |||||
Al Rest | |||||
Mn-Al | |||||
Al Rest | |||||
Ca-Al | |||||
Ca Rest | |||||
Al Rest | |||||
Fe-Al | |||||
Al Rest | |||||
Fe²⁺ Rest | |||||
Total | |||||
Ca-Cr (×100) | |||||
Ca-Ti (×100) | |||||
Ca-Fe (×100) | |||||
Mg-Al (×100) | |||||
Mn-Al (×100) | |||||
Ca-Al (×100) | |||||
Fe-Al (×100) | |||||
Total |
Garnet 1 | Garnet 2 | Garnet 3 | Garnet 4 | Garnet 5 | |
---|---|---|---|---|---|
SiO2 | |||||
TiO2 | |||||
Al2O3 | |||||
Cr2O3 | |||||
Fe2O3 | |||||
MgO | |||||
CaO | |||||
MnO | |||||
FeO | |||||
Total | |||||
Cations | |||||
Si | |||||
Ti | |||||
Al | |||||
Cr | |||||
Fe³⁺ | |||||
Mg | |||||
Ca | |||||
Mn | |||||
Fe²⁺ | |||||
Total | |||||
Grid occupation | |||||
Z
The Z (R) site is usually occupied by quadrivalent cations in an tetrahedral framework (surrounded by four O²⁻), mostly Si⁴⁺, but also Al³⁺, Fe³⁺, Ti⁴⁺, P⁵⁺, As⁵⁺, V⁵⁺.
|
|||||
Al³⁺ (Z) | |||||
Y
The Y (B) site is usually occupied by trivalent cations in an octahedral/tetrahedral framework, mostly Al³⁺, Fe³⁺, Cr³⁺ und V³⁺. But also Ti⁴⁺, Zr⁴⁺, Sn⁴⁺, Sb⁵⁺ or Mg²⁺, Mn²⁺. The [SiO₄]⁴⁻ is occupying the tetrahedra. On the octahedral Y site Al³⁺ can be replaced by Fe³⁺.
|
|||||
Al³⁺ (Y)
Al³⁺ (Y): Pyralspite garnets – aluminium in Y site: Almandine (Fe₃Al₂(SiO₄)₃), Pyrope (Mg₃Al₂(SiO₄)₃), Spessartine: (Mn₃Al₂(SiO₄)₃).
|
|||||
X
The X (A) site is usually occupied by divalent cations, mostly Mg²⁺, Fe²⁺, Mn²⁺ und Ca²⁺, but also Y³⁺ or Na⁺.
|
|||||
Total | |||||
Cation ratios | |||||
Fe³⁺/Fetot. | |||||
Mg/Mg+Fe | |||||
Fe/Fe+Mg | |||||
End-members | |||||
Uvarovite
Uvarovite: Ca₃Cr₂Si₃O₁₂
|
|||||
Ti-Andradite
Ti-Andradite: Ti-content is up to 5% in Melanites, black varieties of Andradite (Ca₃(Fe³⁺, Ti)₂Si₃O₁₂). It may even reach up to 20%.
|
|||||
Andradite
Andradite: Ca₃(Fe³⁺, Ti)₂Si₃O₁₂
|
|||||
Pyrope
Pyrope: Mg₃Al₂Si₃O₁₂
|
|||||
Spessartine
Spessartine: Mn₃Al₂Si₃O₁₂
|
|||||
Grossular
Grossular: Ca₃Al₂Si₃O₁₂
|
|||||
Almandine
Almandine: Fe²⁺₃Al₂Si₃O₁₂
|
|||||
Total | |||||
P-GA-AS Diagram | |||||
P
P = Pyrope
|
|||||
GA
GA = Grossular + Andradite
|
|||||
AS
AS = Almandine + Spessartine
|
|||||
Total | |||||
The ratio (FeO+MgO)/(CaO+MnO)
For Ca-poor garnets there appears to be a continuous variation of (FeO+MgO) against (CaO+MnO) with metamorphic grade. The increase in (FeO+MgO)/(CaO+MnO) is a useful indicator of increase in grade (Deer et al., 19992).
|
|||||
FeO+MgO | |||||
CaO+MnO | |||||
(FeO+MgO)/(CaO+MnO) | |||||
P-GA-AS Diagram (normalized to 100%) | |||||
P | |||||
GA | |||||
AS | |||||
Total |
Here you may enter known values for P-GA-AS to plot them in the ternary diagram.
Name | |||||
P | |||||
GA | |||||
AS |
Current date
Enter a title
Sample number, etc.