Butte Fault, Grand Canyon, Coconino County | The Butte fault is responsible for much of the present day depth of the Grand Canyon. In this aerial photo, the fault can be seen just left of center at the upturned edge of gray and red strata. During the Laramide Orogeny (70 to 40 Ma), the fault experienced about 300 m (1,000 feet) of west-side up motion (left). This placed Proterozoic Chuar Group sediments (lower left) next to Mississippian Redwall Limestone and Pennsylvanian Supai Group rocks (right). In the Late Proterozoic, the fault had an opposite sense of motion, with the west side (left) of the section downthrown 3,200 m (10,500 feet) to create the Chuar Syncline, visible in the pyramid shaped butte known as Nankoweap Butte in the middle distance. Note the Marble Platform in the upper right at an elevation of about 5,000 feet. These same rocks appear across the Butte Fault and off to the left of the photo are at 8,000 feet, giving the North Rim of Grand Canyon its high elevation. The muddy Colorado River is visible in the far right hand portion of the photograph in Marble Canyon. Contributed by Wayne Ranney.