ES 4971-4973 Petrology
Lab 5 Thin Section Investigations 2
Mineral Associations
Name: _______________________________
For this lab session we will look more closely at the contacts between minerals.
A Michel-Levy chart was provided earlier. For slides with Quartz, give the thickness.
MAKE TWO SKETCHES FOR EACH SLIDE AND INDENTIFY COMMON MINERALS
Procedure: Using your microscope, examine the thin sections provided. In each thin
section or region of the same slide, identify associations of the common rock forming
minerals (list below) we have studied, and draw their appearance in quick pencil
sketches.
Example
a.
b.
1. Thin section name: Morton Gneiss
Locality: Minnesota, Minnesota River valley from an area midway between New Ulm
and Franklin
Mineral contacts seen: a. Sericitic Plagioclase and Quartz; b. Plagioclase phenocrysts and
Biotite and Quartz
Comments: Age is Archean, 3.6By. Samples are predominantly Plagioclase phenocrysts;
in a. with abundant undulose (deformed) Quartz; in b. Plag separated by bands of
Biotite. Locally migmatitic. Composition is Tonalitic: high Plag. low K-spars.
2. Thin Section name: _______________________________________________
Locality: __________________________________________________________
Mineral contacts seen: ________________________________________________
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Comments:_______________________________________________________
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3. Thin Section name: _____
3. Thin Section name: _______________________________________________
Locality: __________________________________________________________
Mineral contacts seen: ________________________________________________
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Comments:_______________________________________________________
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4. Thin Section name: _______________________________________________
Locality: __________________________________________________________
Mineral contacts seen: ________________________________________________
___________________________________________________________________
Comments:_______________________________________________________
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