Wasatch Fault, Little Cottonwood Canyon, Utah
Steven Dutch, Professor Emeritus, Natural and Applied Sciences, Universityof Wisconsin - Green Bay
These photos were taken on a Geological Society of America field trip, October 15, 2005, run by Ron Bruhn, Christopher DuRoss, Ronald Harris and William Lund, supplemented by others taken a few days later.
Little Cottonwood Canyon is a marvelous glacial trough that exits through the Wasatch front. Adjacent to the front, the Wasatch Fault (green, above) offsets glacial moraines. A graben along the fault is shown in red. A geological overlook (yellow) offers views.
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Left and below: distant views of Little Cottonwood Canyon. The smaller glacial tough to the right (south) is Bells Canyon. |
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Bells Canyon is a spectacular glacial trough but much smaller than Little Cottonwood Canyon. |
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Left and below: looking up Little Cottonwood Canyon. |
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The moraine between Little Cottonwood and Bells Canyon. There's no corresponding moraine north (left) of Little Cottonwood Canyon, probably because this is a medial moraine and there is no corresponding valley on the other side of Little Cottonwood Canyon. |
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The moraine, showing a fault offset (far right). |
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There are actually several fault offsets in the moraine. |
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The best part (the Wasatch is a low-angle normal fault) is that
fault offset has actually created a graben in the moraine. How many places can you actually see a cross-section of a graben? How many places can you see one above you? |
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Approaching the fault scarps on Utah 209. |
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The fault offset at highway level. |
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Looking north along the graben. Note the houses in the graben. |
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The Wasatch front north of Little Cottonwood Canyon. |
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Left and below: looking north along the Wasatch Front. |
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Looking south along the Wasatch Front, showing some of its famous faceted spurs. |
Reference
Bruhn, R. L., DuRoss, C. B., Harris, R. A., and Lund, W. R., 2005; Neotectonics and Paleoseismology of the Wasatch Fault, Utah, in Pedersen, J. and Dehler, C. M., eds., Interior Western United States: Geological Society of America Field Guide number 6, p. 231-250, doi: 10.1130/2005.fld006(11).
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Created 18 November 2005, Last Update 06 June 2020