Broken Top
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| Broken Top | |
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| Elevation | 9,175 feet (2,797 m)[1] |
| Location | Deschutes County, Oregon, USA |
| Range | Cascade Range |
| Prominence | 2,175 feet (663 m)[2] |
| Coordinates | [3] |
| Topo map | USGS Broken Top |
| Type | Stratovolcano |
| Volcanic arc/belt | Cascade Volcanic Arc |
| Age of rock | Pleistocene |
| Last eruption | about 100,000 years ago[4] |
Broken Top is a stratovolcano highly eroded by glaciation.[5] It is located south of the Three Sisters group of volcanoes in the Cascade Range of central Oregon and within the Three Sisters Wilderness.[6] Broken Top is about 20 miles (32 km) west of Bend, Oregon in Deschutes County.
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[edit] Geology
Pleistocene eruptions originally created a broad shield of basaltic andesite. Intermittently, more silicic magma was erupted, ranging from andesite to dacite to rhyodacite. Intrusive dikes and pyroclastic flow deposits can also be found in the layers of Broken Top's flanks. Ice Age glaciers have carved into the volcano on three sides, exposing its internal structure.[7]
[edit] See also
[edit] References
- ^ Northwest GeoData Clearinghouse. Department of Geology: Portland State University. Retrieved on 2008-03-31.
- ^ Broken Top. Peakbagger.com. Retrieved on 2008-03-31.
- ^ USGS GNIS: Broken Top. Retrieved on 2008-03-31.
- ^ Deschutes & Ochoco National Forests - Broken Top Volcano. USDA Forest Service (2003-11-26). Retrieved on 2008-03-18.
- ^ Wood, Charles A.; Jűrgen Kienle (1993). Volcanoes of North America. Cambridge University Press, p. 183. ISBN 0-512-43811-X.
- ^ Three Sisters Wilderness. Willamette National Forest. United States Forest Service (2004-07-29). Retrieved on 2008-05-18.
- ^ Broken Top Volcano, Oregon. USGS Cascades Volcano Observatory. Retrieved on 2008-03-18.
[edit] External links
- Broken Top. Summitpost.org. Retrieved on 2008-03-18.
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