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Metamorphic Rocks |
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Metamorphic Rocks |
A pelitic schist from the Llano Uplift, Central Texas (color, 630Kb) Quartz is red, plagioclase is dark blue, sillimanite is light blue, and there bright green is epoxy. Black areas are biotite and/or garnet. Another image from the same rock. The sillimanite comes up a slightly different color, but that's peril of filter-assembled color images.
Another pelitic schist from the Llano Uplift (color, 473Kb) Quartz is red, plagioclase is blue.
In CL imaging, nothing is ever straightforward. The red zoned inclusions in the blue feldspar are probably sillimanite. I had trouble with that (zoned sillimanite in feldspar?), but EDS indicated Al, Si, and O were the only elements in the inclusions, and the optics and metamorphic grade say it has to be sillimanite. So apparently sillimanite can be either bright blue-green or red. Sample from the Willimantic Dome, Connecticut.
Luminescence haloes can also be seen in the quartz (red) around the garnets (black) in this strange garnetiferous rock from the Park Range of Colorado (color, 252Kb). Bright blue grains are microcline feldspar, dark blue grains in the lower right corner are calcite or dolomite. Sample courtesy of J. Rougvie.
A microfracture in a strange garnet-quartz-carbonate-microcline rock from the Park Range of Colorado (color, 264 Kb). Bright blue grains are microcline feldspar, red grains are quartz, black grains are mostly garnet. SEI image of this same area shows fracture in microcline is filled, fracture in quartz is partially-filled. Sample courtesy of J. Rougvie.
Element mapping with the electron microprobe followed by scanned CL, not a good mix. Look at this poor metamorphic quartz.
A quartzose calc-schist with magnetite from the Precambrian of west Texas (color, 378Kb). Quartz is red, calcite is blue, magnetites are black with spots, talc is black. Sample courtesy of S. Grimes
more of the same sample (color, 536Kb)
and still more (color, 410Kb)
