Skip to main content
Library homepage
 
Geosciences LibreTexts

5.11: A4 Mylonite 2

  • Page ID
    11144
  • \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\)

    Outcrop and Hand Sample Photos and Videos

    Click on the image to enlarge.

    This mylonite is located in the same outcrop as mylonite 1 (mylonite 2 is farther south than mylonite 1). It is hard to know what the protolith was, but based upon the porphyroclasts it was likely an ultramafic or mafic rock.

    Can you see the mylonite fabric in this photo?

    A4-Mylonite-2-A-scaled-1.jpg

    The students are pointing to one metamorphic feature with their pencils. There is another structure above and to the left of the blue pencil. Can you identify it also?

    A4-Mylonite-2-C-scaled-1.jpg

    It’s huge! What am I standing next to?

    A4-Mylonite-2-B-scaled-1.jpg

    Thin Section Photos and Videos

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

    The brown minerals (in ppl) are likely some type of amphibole. Green in ppl is chlorite. Qtz is also present. Are the amphiboles prophyroclasts or porphyroblasts?

    A4-mylonite-2-4x-ppl-300x225.jpg
    A4-mylonite-2-4x-xpl-300x225.jpg

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

    S-C fabric is visible in the thin section.

    A4-mylonite2-ppl-scaled-1.jpg
    A4-mylonite2-xpl-scaled-1.jpg

    This page titled 5.11: A4 Mylonite 2 is shared under a CC BY-NC-SA 4.0 license and was authored, remixed, and/or curated by Elizabeth Johnson and Juhong Christie Liu (Virtual Library of Virginia) via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.