Shoshonite
A rock classification type
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Name:
the name, given by Iddings in 1895, is derived from the Shoshone River, WY.
A potassic basaltic-trachyandesite where (Na2O-2) < K2O .
A trachyandesite composed of olivine and augite phenocrysts in a groundmass of labradorite with alkali feldspar rims, olivine, augite, a small amount of leucite, and some dark-colored glass. Shoshonite grades into absarokite with an increase in olivine and into banakite with more sanidine.
Ref: AGI
A trachyandesite composed of olivine and augite phenocrysts in a groundmass of labradorite with alkali feldspar rims, olivine, augite, a small amount of leucite, and some dark-colored glass. Shoshonite grades into absarokite with an increase in olivine and into banakite with more sanidine.
Ref: AGI
Unique Identifiers
Mindat ID:
48463
Long-form identifier:
mindat:1:1:48463:3
Classification of Shoshonite

Shoshonite is found in field S2 in the TAS diagram.
Sub-divisions of Shoshonite
- Shoshonite
Mineralogy of Shoshonite
Essential minerals - these are minerals that are required within the classification of this rock:
| Feldspar > Alkali Feldspar > Orthoclase | K(AlSi3O8) |
| Olivine | M2SiO4 |
| Pyroxene > Clinopyroxene > Augite | (CaxMgyFez)(Mgy1Fez1)Si2O6 |
Internet Links for Shoshonite
mindat.org URL:
https://www.mindat.org/min-48463.html
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References for Shoshonite
Reference List: