Reverse faults shorten horizontal layers and are therefore contractional faults. This is an example of a reverse fault in fine-grained sandstones and siltstones of the Entrada Sandstone (lower reddish part) and Curtis Formation (upper part) – part of the Jurassic stratigraphy of the Colorado Plateau.
Reverse faults (and any other type of fault for that matter) may look nice and clean on drawn-up cross-sections or seismic images, but in detail they tend to be more complicated. In this case it is being composed of several strands and numerous small-scale deformation structures. Hence at this scale the structure is better termed a fault zone than a single fault.
This is an outstanding outcrop where the fault zone can be studied in three perpendicular vertical sections, in addition to the top section. The deformation is likely related to the Cretaceous Sevier orogeny, which is better expressed in western Utah and Nevada.
The locality is found along the western margin of Cedar Mountain in the northern part of the San Rafael swell east of Castle Dale, Utah. The place is known as the Ketobe Knob among structural geologists. Look out for rattlesnakes at this locality…