Devils Tower is an ancient and mysterious formation that has captivated the minds of many. Located in northeastern Wyoming, this impressive igneous intrusion stands at 5112 feet (1558 m) above sea level and is the centerpiece of the Devils Tower National Monument. It was the first national monument in the United States, established on September 24, 1906 by President Theodore Roosevelt. The columns of Devils Tower, which rise hundreds of feet in the air and extend up to 10 feet wide, are truly spectacular.
It is believed that these columns were formed when volcanic rocks slowly cooled, isolated by sediments. This formation was created when magma (volcanic rock molten inside the earth) was placed in place underground. At the time the Devil's Tower was formed, the surface of the surrounding land was almost 915 m (3,000 feet) higher than it is today. After the magma hardened and cooled, the area eroded. There are two theories about how Devils Tower was formed.
One theory holds that Devils Tower is a laccolite. A laccolite is a large mass of igneous (volcanic) rock that penetrated through sedimentary rock beds, but did not actually reach the surface, producing a rounded bulge in the upper sedimentary layers. The other theory is that Devils Tower is a volcanic plug, or the neck of an extinct volcano. The composition of the volcanic material that forms Devils Tower suggests that the magma body was quite thick when it formed, which allowed it to maintain the shape it currently has. But because it was relatively thick, the magma became a massive lump, forming its visible shape.
The magma then solidified, preserving Devils Tower. Some mysteries still surround the formation of Devils Tower. Some pyroclastic materials the same age as Devils Tower have been identified elsewhere in Wyoming. Presumably, if the Devil's Tower were a volcanic plug, any volcanic created by it volcanic ash, lava flows and volcanic debris would have eroded long ago. Ironically, the erosion exposed by the Tower also erased the evidence needed to determine which theory of the formation of the Devil's Tower is correct. Wooden Leg, a Cheyenne from the north, recounted another legend told to him by an old man as they traveled together through the Devil's Tower between 1866 and 1868. Some of these wooden stakes are still intact and are visible in the tower when walking the 1.3 mile (2.1 km) Tower Trail at the Devils Tower National Monument. As rain and snow continue to erode the sedimentary rocks surrounding the base of the Tower, more Devils Tower will be exposed.
The columns of Devils Tower are almost the same height, suggesting that the whole had been a single pool of magma, but fractured into separate columns as it cooled. Devils Tower is an incredible formation that has captivated people for centuries with its mysterious origins and unique shape. Whether it is a laccolite or a volcanic plug remains unknown but its beauty will continue to draw visitors for years to come.