Colorful hydrothermally altered volcanic rocks (yellow, orange, red, and white) in Marysvale Canyon along US-89, named after the folk song once locals posted a joke roadside sign. Colors come from iron oxides plus alunite and kaolinite left by 21-million-year-old alteration of Bullion Canyon Volcanics.
Field facts
| Region | Piute County, UT |
|---|---|
| Coordinates | 38.5074, -112.2738 |
| Access | Viewed from US-89 a few miles north of Marysvale; roadside pullouts; resort property is private |
| Geology | Altered Bullion Canyon Volcanics (jarosite, hematite, alunite, kaolinite) |
| Agency | Utah Geological Survey GeoSights interpretation; highway corridor public views |
| Culture | Named after the “Big Rock Candy Mountain” folk song |
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Public recreation data — BLM & Recreation.gov (RIDB). Verify current access, fees, and seasonal closures before traveling.
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