Igneous Rocks_JFreeman

 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.