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Geosciences LibreTexts

5.12: Cranberry Gneiss (Orthogneiss)

  • Page ID
    11145
  • Outcrop and Hand Sample Photos and Videos

    No outcrop images available. This was collected near Independence, not too far away from the other Cranberry Gneiss sample (next page).

    The classic interpretation of the Cranberry Gneiss is that it is a paragneiss (sedimentary protolith). This is true in many places, including sample S5 (next page). However, the Cranberry Gneiss on this page is pretty clearly an orthogneiss (igneous protolith). Field mappers in the area are now starting to distinguish between these two types of gneisses.

    Thumbnail for the embedded element "Cranberry gneiss hand sample"

    A YouTube element has been excluded from this version of the text. You can view it online here: pb.libretexts.org/petrology/?p=342

    Thin Section Photos and Videos

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

    Spot 1

    Biotite (brown), orthoclase, recrystallized quartz.

    Spot 2

    Biotite,quarts, magnetite, plagioclase, dusty orthoclase, a zircon (inside the magnetite at bottom right).

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

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