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5.7: A1 B2 Schist

  • Page ID
    11140
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    Outcrop and Hand Sample Photos and Videos

    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.

    A1-B2-Schist-3-scaled-1.jpg
    A1-B2-Schist-2-scaled-1.jpg

    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

    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.

    A1-B2-4x-ppl-no2-300x225.jpg
    A1-B2-4x-xpl-no2-300x225.jpg

    Area 2

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

    A1-B2-4x-ppl-no4-300x225.jpg
    A1-B2-4x-xpl-no4-300x225.jpg

    Area 3

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

    A1-B2-4x-ppl-no3-300x225.jpg
    A1-B2-4x-xpl-no3-300x225.jpg

    Area 4

    A1-B2-4x-ppl-no1-300x225.jpg
    A1-B2-4x-xpl-no1-300x225.jpg

    Entire thin section scan. 1st = ppl; 2nd = xpl. 

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

    A1-B2-ppl-scaled-1.jpg
    A1-B2-xpl-scaled-1.jpg

    This page titled 5.7: A1 B2 Schist 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.

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