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Porphyritic Rhyolites (Missouri)
Missouri Rhyolite
Brown, but its also a dark reddish color and has a purple hue. Rhyolite makes up the majority of igneous rock in the area and the early geologists recognized two kinds of rhyolites- porphyries proper and porphyrites.
This a scan of part of the map for SE Missouri that has the Granite and Rhyolite locations. The Rhyolite areas are colored brown. The Granite areas are reddish. There are some spots that are outside of the scan I could make, but this is the center of activity.
Brown, but its also a dark reddish color and has a purple hue. Rhyolite makes up the majority of igneous rock in the area and the early geologists recognized two kinds of rhyolites- porphyries proper and porphyrites.
This a scan of part of the map for SE Missouri that has the Granite and Rhyolite locations. The Rhyolite areas are colored brown. The Granite areas are reddish. There are some spots that are outside of the scan I could make, but this is the center of activity.