Southwestern Virginia Case Study

A1 B2 Schist

Elizabeth Johnson

Outcrop and Hand Sample Photos and Videos

Click on the image to enlarge.

This outcrop is on a busy road.  The schist is coated in a dark later of pollution from car exhaust, making it look black on the outcrop.  A fresh surface reveals a shiny silver schist.

The staurolite is the large orange porphyroblasts in the hand sample.  Dark minerals are biotite.  Much of the rock is muscovite, some quartz, a little plagioclase.  Kyanite is rumored to be present.  Tiny garnets are hardly visible in hand sample.

 

 

Thin Section Photos and Videos

Click on the image to make it larger. 1st = plane polarized light; 2nd = cross-polarized light.

Area 1

Biotite (brown in ppl) and staurolite (yellow in ppl, top left) porphyroblasts.  High-relief euhedral mineral is garnet.  Qtz and muscovite are also present.

Area 2

Staurolite (yellow), qtz, garnet (isotropic, high relief), a little muscovite.

Area 3

Close up of garnets (+ stl, qtz, musc).  Note the pattern of inclusions in the garnet in ppl.

Area 4

Entire thin section scan. 1st = ppl; 2nd = xpl. Click on the image to make it larger.

This thin section is super interesting for thinking about deformation and metamorphic events.

Media Attributions

  • A1-B2-Schist-3
  • A1-B2-Schist-2
  • A1 B2 4x ppl no2
  • A1 B2 4x xpl no2
  • A1 B2 4x ppl no4
  • A1 B2 4x xpl no4
  • A1 B2 4x ppl no3
  • A1 B2 4x xpl no3
  • A1 B2 4x ppl no1
  • A1 B2 4x xpl no1
  • A1 B2 ppl
  • A1 B2 xpl

License

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Introduction to Petrology by Elizabeth Johnson is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License, except where otherwise noted.

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