The Cracks | Holbrook Basin, Navajo County, Arizona
Pictured here is a large bedrock fracture in 260-million-year-old Coconino Sandstone in Holbrook Basin's 'The Cracks' area. This fracture is ~ 4 to 8 feet wide, 100+ of feet in length, with an apparent depth of 50 to 75 feet. The real depth remains undetermined but is likely to be hundreds of feet. This fracture has been a favorite of local kids for several generations. Though not evident in this image, the rock on the left is downdropped about 2-3 feet in contrast to the rock on the right.
These bedrock fractures may be the result of dissolution of the Supai Formation followed by subsidence.