Southwestern Virginia Case Study

A4 Mylonite 1

Elizabeth Johnson

Outcrop and Hand Sample Photos and Videos

Click on the image to enlarge.

This is one continuous outcrop containing mylonite 1 (this page) and mylonite 2 (next page).  Can you see the mylonite fabric (looks like a foliation) in the rock?  The protolith of Mylonite 1 was probably one of the Cranberry Gneiss units.

This cut hand sample shows the mylonite texture in more detail.

Thin Section Photos and Videos

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

Hopefully you can see porphyroclasts (augens) and mylonite texture in the thin section images below.  Porphyroclasts are mostly qtz, rusty brown layers are clays produced by shearing.

 

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

Media Attributions

  • OLYMPUS DIGITAL CAMERA
  • OLYMPUS DIGITAL CAMERA
  • A4 Mylonite 1 ppl 4x
  • S5 Cranberry xpl 4x
  • A4 mylonite1 ppl
  • A4 mylonite1 xpl

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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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