| Crooked River caldera | |
|---|---|
  Crooked River caldera
| |
| Highest point | |
| Coordinates | 44°18′N 120°54′W / 44.3°N 120.9°W / 44.3; -120.9 |
| Geography | |
| Location | Deschutes, Crook, and Jefferson counties, Oregon, U.S. |
| Geology | |
| Rock age | 29.5 Ma |
| Mountain type(s) | Caldera, supervolcano |
| Volcanic arc | Cascade Volcanic Arc, Ochoco Mountains |
| Last eruption | 29.5 million years ago |
The Crooked River caldera is a large and ancient volcano that straddles three central Oregon counties. The diameter of the caldera is about 41 by 27 kilometres (25 mi × 17 mi) and is notable for the welded tuff present at Gray Butte, Smith Rock, Powell Buttes, Grizzly Mountain and Barnes Butte. The volcano is considered extinct and last erupted about 29.5 Ma.
References
- The Crooked River Caldera is also a supervolcano. "Field trip guide to the Oligocene Crooked River caldera: Central Oregon's Supervolcano, Crook, Deschutes, and Jefferson Counties, Oregon" (PDF). Oregon Geology. Oregon Department of Geology and Mineral Studies. 2009. Retrieved 2014-12-29.