by Michael J. Oard

Devils Tower, Wyoming, is likely the conduit of an eroded volcano, but there are three other hypotheses for its origin. Regardless, more than 300 m of High Plains sedimentary rock was eroded with the Tower hardly touched. The uniformitarian story, as formerly stated on a road sign north of the Tower, is that erosion of the High Plains sedimentary rocks took more than 40 Ma. That sign has been replaced, and it now says it took only 1 to 2 Ma. However, the erosion of such a vertical tower should be rapid and complete well within 100,000 years. Although the Tower is actively eroding today, it has not decreased much in size, implying a very recent exposure. Such a deduction is consistent with the sheet flow erosion during the runoff of the floodwater: a contention contrary to the uniformitarian paradigm.

Devils Tower in the Powder River basin of northeast Wyoming, United States, is one of the most impressive erosional remnants on Earth (figure 1). It stands 390 m high above the Belle Fouche River, reaching an altitude of 1,560 m above sea level. It is about 275 m above the general altitude of the plains. Because of its scenic beauty and scientific interest, President Theodore Roosevelt established Devils Tower and a small area surrounding it as the first national monument in 1906.

The vertical, round tower is 300 m in diameter at its base and is composed of phonolite porphyry, a hard igneous intrusive rock. The same rock also intrudes elsewhere through sedimentary rocks in the region.1 For instance, just west of Devils Tower are the Missouri Buttes with the same kind of rock.

When the igneous rock of Devils Tower cooled and contracted, vertical columns with regular cracks were formed similar to those in the large basalt flows cooled in the extensive Columbia River Basalt flows in Washington, northern Oregon, and adjacent Idaho (figure 2). A Kiowa Native American legend suggests the vertical columns were caused by a great bear raking the sides in trying to get to some children at the top of the Tower. The phonolite porphyry is believed to be 33 to 55 Ma (million years) old and therefore erupted in the early to middle Cenozoic of the uniformitarian timescale.1

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