Monument Valley
The Navajo Nation's iconic red buttes and mesas on the Arizona–Utah line — De Chelly Sandstone cliffs on Organ Rock, capped by resistant Moenkopi and Shinarump.
Also known as: Tsé Biiʼ Ndzisgaii
Monument Valley is the iconic cluster of red sandstone buttes and mesas on the Navajo Nation astride the Arizona–Utah line — the towers that stand in for the American West in a century of films. The buttes are erosional remnants of a once-continuous plateau: a base of soft Organ Rock Shale, sheer cliffs of the Permian De Chelly Sandstone (an old dune field), and a hard caprock of Moenkopi and Shinarump that has slowed their retreat. The vivid red comes from iron oxide; the darker streaks are manganese.
Geology
Formation: Erosional buttes and mesas left as a plateau eroded away: a base of soft Organ Rock siltstone, sheer cliffs of the Permian De Chelly Sandstone (an ancient erg), and a resistant Moenkopi–Shinarump caprock that armors the tops and slows their retreat.
A classic demonstration of caprock-controlled butte-and-mesa erosion, where a resistant cap over softer beds preserves isolated monoliths hundreds of feet above the valley floor.
Primary formation: Organ Rock Formation
Age: Permian (275 Mya)
The largest buttes rise ~1,000 ft above the floor; red from iron oxide, blue-gray streaks from manganese oxide.
History
Navajo Tsé Biiʼ Ndzisgaii, 'valley of the rocks'; 'Monument Valley' for its monolithic buttes.
A sacred landscape within the Navajo Nation, world-famous through Western films since the 1930s.