Virtual Vista: Photomicrographs of Metamorphic Rocks

The Virtual Vistas on this page are photomicrographs of thin-sections of metamorphic rocks linked to the website Dr. Allen Glazner at the University of North Carolina in Chapel Hill, North Carolina, USA.

Each photomicrograph shows a representative texture and mineral composition of a common metamorphic rock type that you learned about in Chapter 7 of your text.

<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=jpg::Slate::http://www.geolab.unc.edu/Petunia/IgMetAtlas/meta-micro/slate.UX.jpg','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif">Slate (937.8K)</a>Slate

The image of slate above illustrates the very fine-grained nature of this low grade metamorphic rock.

<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=jpg::Phyllite::http://www.geolab.unc.edu/Petunia/IgMetAtlas/meta-micro/phyllite.X.jpg','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif">Phyllite (969.2K)</a>Phyllite

Note in this image of phyllite above that the size of individual crystals is somewhat larger than in the preceding image of slate.

<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=jpg::Schist::http://www.geolab.unc.edu/Petunia/IgMetAtlas/meta-micro/crenulation.X.jpg','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif">Schist (105.5K)</a>Schist

Foliation is evident in this photomicrograph of a muscovite-biotite garnet schist.

<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=jpg::Gneiss::http://www.geolab.unc.edu/Petunia/IgMetAtlas/meta-micro/gneiss.X.jpg','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif">Gneiss (563.4K)</a>Gneiss

The photomicrograph above shows the coarse grain size and texture of a gneiss. Note that the interlocking crystals composing this rock are reminiscent of the interlocking texture of crystals in an igneous rock. Why might this be so?

Points to Ponder:

1. Print a copy of this page with the photomircrographs and sketch lines showing foliation on each image.

2. What causes the foliation to be more easily identified in the phyllite and shist?

3. Is folation evident in the image of gneiss? Why or why not?