I decided to visit Devil’s Tower, in Wyoming. A geographical
oddity, Devil’s Tower is an igneous rock made of phonolite porphyry. As magma
cooled, it condensed into columns that make up Devil’s Tower. There is some
debate as to how exactly Devil’s Tower came to be, the simplest theory is a
stock. A small intrusive body formed by magma cooled underground and was later
exposed by erosion. Another theory suggest the Devil’s Tower is a volcanic plug
or the neck of an extinct volcano. However, the lack of volcanic activity
(volcanic ash or debris) doesn’t support this conclusion. The phonolite that
makes up the tower has a grey or greenish grey hue to it. The rock has a
phaneritic texture, easily determined by the crystals of white feldspar visible
to the naked eye.
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