The Geology of Bryce Canyon: How the World's Largest Collection of Hoodoos Formed

The park

Bryce Canyon National Park sits at the edge of the high plateau country of south-central Utah, in Kane and Garfield Counties. Its roughly 14,502 hectares (35,835 acres) hold brightly colored pinnacles, walls, fins, canyons, alcoves, windows, bridges and spires standing in horseshoe-shaped amphitheaters — the largest collection of hoodoos in the world, drawing millions of visitors a year.

• June 8, 1923: proclaimed a national monument.
• June 7, 1924: redesignated Utah National Park.
• February 25, 1928: renamed Bryce Canyon National Park.

Hoodoos and spires at Bryce Canyon, dusted with snow. Image from the NPS's page.

How the hoodoos formed

Bryce's scenery comes from differential erosion of the freshwater limestones of the Tertiary-age Claron Formation, exposed along and below the rim of the Paunsaugunt Plateau.

• The hoodoos, fluted cliffs, columns, spires, windows and arches form along a network of joints — fractures in the rock.
• Tiny cracks are widened by freeze and thaw, water erosion and chemical weathering.
• In the park's north are klippes, where older Cretaceous rock was thrust over younger Tertiary rock along faults.

Fossils

The park's fossils include marine and land animals — ammonites, turtles, dinosaurs and early mammals — that lived in or along an inland sea that divided North America during the Cretaceous Period (100–65 million years ago). Fossils in the Claron Formation are scarce. Park fossils are protected by the Paleontological Resources Preservation Act of 2009.

Regional setting

Bryce Canyon belongs to the Colorado Plateaus province, sharing its geologic history with a region that reaches far beyond the park.

Bryce Canyon National Park geology, from the Geologic Resources Inventory. NPS figure.

Maps and reports

The Park Service's Geologic Resources Inventory produces digital geologic maps, reports, posters and scoping summaries for more than 270 natural resource parks — the report covering each park's setting, notable features and processes, management issues and geologic history. Bryce Canyon's products are on the NPS DataStore. The Park Service's Geodiversity Atlas, which this entry belongs to, supports education, geoconservation and managing the living and non-living parts of park ecosystems together.

Sources

Based on "NPS Geodiversity Atlas—Bryce Canyon National Park, Utah," National Park Service, drawing on Bowers (1991, USGS map and report I-2108) and Anderson (2017); a work of the United States government in the public domain.