Rainbow Bridge National Monument sits in a southern canyon arm of Lake Powell, next to Glen Canyon National Recreation Area, in San Juan County, Utah. Established on May 30, 1910, its 105 hectares (160 acres) protect one of the world's largest natural bridges, rising 88 m (290 ft) above the canyon floor, about 13 km (8 miles) up Bridge Creek from its confluence with the Colorado River, in remote canyon country.
The bridge is sacred to several tribes, including the Hopi Tribe, Kaibab Paiute Tribe, Navajo Nation, San Juan Southern Paiute Tribe, Pueblo of Zuni and the Ute Mountain Ute Tribe (White Mesa Band).
A tour boat entering Rainbow Bridge canyon. NPS
The rocks
The monument's geology is entirely Early Jurassic:
| Formation | Where |
|---|---|
| Navajo Sandstone | the bridge itself and the surrounding cliffs |
| Kayenta Formation | exposed beneath the bridge and in the channel of Bridge Creek |
How the bridge formed
Rainbow Bridge was carved by stream erosion working steadily over a long time, helped by:
- regional uplift of the Colorado Plateau, which gave rivers new cutting power to carve channels down through the Navajo Sandstone;
- fractures and joints in the rock;
- wind and water;
- the rock's own character.
A stream's tight meanders, preserved in the rock, slowly weather through into holes — "windows" — that widen into features like Rainbow Bridge.
The monument belongs to the Colorado Plateaus physiographic province and shares its geologic history with a much larger region.
The Geologic Resources Inventory map of the monument. NPS
Geodiversity and data
Geodiversity is the full range of a park's geologic and soil resources and processes. The Park Service's Geodiversity Atlas, from the Geologic Resources Inventory, supports education, geoconservation and managing living and non-living resources together. The inventory makes digital maps and reports for more than 270 parks; Rainbow Bridge's are in the NPS DataStore (saved search 3153), along with its completed Soil Resources Inventory (saved search 3104).
More: Rainbow Bridge geologic formations · geoheritage · photo gallery · park home · NPS arid landforms · Utah Geological Survey.
Sources
Based on "NPS Geodiversity Atlas—Rainbow Bridge National Monument, Utah," National Park Service; a work of the United States government in the public domain. It cites Sproul (2001) and Graham (2009).
Licence: CC0 1.0 (public domain) · Adapted from www.nps.gov
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