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German teaching materials – Geology– Web-Apps


Minetosh online Geology

A simple garnet-plagioclase barometer

Minetosh

This simple program serves for estimating metamorphic pressure with the help of geochemical analyzes (microprobe) of rocks. The pressure is estimated according to GHENT & STOUT (1981) and HODGES & SPEAR (1984) using the minerals garnet, biotite, muscovite and plagioclase. The temperature can be chosen freely.

Crossed hammers

The barometer

Enter your data in the fields below.

You can enter the values individually in the fields or use the input fields. Here you enter the values as rows separated by single spaces (see placeholders). 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.

If you want, you can first delete the example data in the tables:

Input Garnet – Oxides (lightblue) and Cations (lightyellow):

Input Biotite – Oxides (lightblue) and Cations (lightyellow):

Input Muscovite – Oxides (lightblue) and Cations (lightyellow):

Input Plagioclase – Oxides (lightblue) and Cations (lightyellow):

To the calculation

Garnet

Name

SiO₂

TiO₂

Al₂O₃

Cr₂O₃

Fe₂O₃

MgO

CaO

MnO

FeO

Total

Cations O=24

Si

Ti

Al

Cr

Fe³⁺

Mg

Ca

Mn

Fe²⁺

Total

Biotite

Name

SiO₂

TiO₂

Al₂O₃

Cr₂O₃

MgO

CaO

MnO

FeO

BaO

Na₂O

K₂O

H₂O

Total

Cations O=22

Si

Ti

Al

Cr

Mg

Ca

Mn

Fe

Ba

Na

K

Total

Muscovite

Name

SiO₂

TiO₂

Al₂O₃

Cr₂O₃

MgO

CaO

MnO

FeO

BaO

Na₂O

K₂O

H₂O

Total

Cations O=22

Si

Ti

Al

Cr

Mg

Ca

Mn

Fe

Ba

Na

K

Total

Plagioclase

Name

SiO₂

Al₂O₃

MgO

CaO

MnO

FeO

BaO

Na₂O

K₂O

Total

Cations O=8

Si

Al

Mg

Ca

Mn

Fe

Ba

Na

K

Total

Temperature setting (°C)

Result

GHENT & STOUT (1981)

Ga+Plg+AS+Mu+Bt+Qz

P1: kbar

P2: kbar

HODGES & SPEAR (1984)

Ga+Plg+AS+Mu+Bt+Qz

P: kbar

Click to see your data in a simplified PT-diagram

P1 GHENT & STOUT: Yellow with red rim
P2 GHENT & STOUT: Red
HODGES & SPEAR: Blue

Captions

D: Diagenesis — Z: Zeolite — H: Hornfels — S: Sanidinite — P/P: Prehnite-pumpellyite — GS: Greenschist — A: Amphibolite — G: Granulite — B: Blueschist — E: Eclogite

Download data

Current date

Enter a title

Sample number, etc.

Download data file (*.csv)