Wednesday, October 28, 2020

Week 2 Igneous Rocks

This past week my fiance and I visited Devils Tower in Crook County, Wyoming. While there I explained to my fiance how the tower received its name. Devil's Tower received its name by a misinterpretation from an expedition. Most early maps have Devil's Tower marked as Bear Lodge but an expedition misinterpreted the Native American saying and said it was called "Bad God Tower" which eventually turned into Devil's Tower. She was blown away by the history behind the tower and wanted to know more so I told her that it was an igneous rock that is made of phonolite porphyry. We weren't sure of how the tower was formed so we asked a park ranger who said that it was formed by magma that was cooled underground and exposed by erosion. Some people believe that the tower is the remains of a laccolith, the splitting of strata due to igneous intrusion. The rock surrounding the tower is sedimentary and composed of dark red sandstone and siltstone. The different red tones in the rocks are caused by high amounts of iron that have oxidized over time.  There was so much more to be learned while at the tower, especially when it came to the geology surrounding the monument. I guess this means that we have to go back again to learn a little more!


No comments:

Post a Comment