More Photos for Paradox Basin


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The Cache Valley in Arches National Park is a good example of a collapsed salt anticline. At some time in the past, Pennsylvanian salt beneath the anticline rose up towards the surface of the Earth beneath the Cache Valley. Eventually the salt penetrated so close to the surface that groundwater was able to reach the salt and the salt consequently dissolved. Once the salt was removed the anticline above it collapsed. The hill in the middle of the photo is composed of the Jurassic Morrison Formation.


 

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How did groundwater reach the salt? Joints in the Slickrock Member of the Entrada Sandstone in the Fiery Furnace area of Arches National Park are conduits for fluid movement. These joints form where rocks are exposed to tensile stresses, along the crest of an anticline for example.


 

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More joints in the Entrada. If these joints formed due to tension across the crest of an anticline in which direction was the long axis of the anticline oriented? This photo is taken just to the northwest of Arches National Park.