Mount Bachelor
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| Mount Bachelor | |
|---|---|
 Mount Bachelor from Sparks Lake |
|
| Elevation | 9,068 feet (2,764 m)[1] |
| Location | Deschutes County, Oregon, USA |
| Range | Cascade Range |
| Prominence | 2,665 feet (812 m) [2] |
| Coordinates | [3] |
| Topo map | USGS Mount Bachelor |
| Type | Stratovolcano (on top of a shield volcano) |
| Volcanic arc/belt | Cascade Volcanic Arc |
| Age of rock | less than 15,000 years |
| Last eruption | 8,000 to 10,000 years ago |
| Easiest route | ski lift |
Mount Bachelor, formerly named Bachelor Butte, is a stratovolcano atop a shield volcano in the Cascade Volcanic Arc and the Cascade Range of central Oregon.[4] The Mt. Bachelor ski resort has operated on the mountain since the 1980s.
The volcano lies at the northern end of the 15 miles (24 km) long Mount Bachelor Volcanic Chain.[5]
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[edit] Geology
Mount Bachelor was born between 11,000 and 15,000 years ago as a shield volcano but was later capped with a stratovolcano as the eruptions apparently became more explosive over time. It is the youngest prominent volcano in the Three Sisters area of Oregon. Bachelor is composed mainly of basalt and basaltic andesite.
It last erupted between 8,000 and 10,000 years ago and is entirely covered with Mazama ash from the catastrophic eruption of Mount Mazama about 6,845 years ago. There is no geothermal activity at present.[5]
[edit] Mount Bachelor Volcanic Chain
Portions of this section include public domain text from the USFS Deschutes & Ochoco National Forests - Crooked River National Grassland.
The 15 mile long Mount Bachelor volcanic chain, south east of South Sister, consists of Mount Bachelor itself and a series of cinder cones, lava flows and three shield volcanoes.[6] The northernmost shield is capped by a steep-sided summit cone of Mount Bachelor. Minor explosive activity built the many cinder cones which fed the many lava flows that account for the bulk of the erupted material.[7]
Eruptive activity of the chain can be divided into four episodes:
- The oldest episode occurred approximately 18,000 - 15,000 years ago during glacial retreat. Most activity during this episode was located in the central part of the chain and built a shield volcano called Sheridan Mountain. In an area near Sparks Lake a group of vents formed beneath glacial ice and interacted with the ice to form hyaloclastite deposits and thick lava flows impounded by glacial ice. The resulting steep sided plateau is capped by Talapus and Katsuk Buttes.[7]
- During the second episode, eruptive activity was along the chain of scoria cones and lava flows that extends from the south side of Sheridan Mountain to the explosion crater at the south end of the chain.[7]
- During the third episode of eruptive activity built the shield volcano of which is capped by Kwohl Butte and the shield that underlies Mount Bachelor. The final phase of this episode built the summit cone of Mount Bachelor. The oldest glacial moraines recognized on Mount Bachelor are approximately 12,000 years old so the cone had nearly attained its present size by then. These moraines are overlain by the youngest lava flows of the third episode.[7]
- The last eruptive episode occurred approximately 8,000 to 10,000 years ago and produced a scoria cone and lava flows on the lower north flank of Mount Bachelor. All activity ended before 6,845 C-14 years BP, since tephra from the climactic eruption of Mount Mazama is found on all deposits of the Bachelor chain.[7]
[edit] Skiing
Mt. Bachelor ski area operates chairlifts to the summit during the summer as well as during the ski season (weather permitting). The resort is one of the largest in the Pacific Northwest with a skiable area of 3,683 acres (14.9 km²) and a vertical drop of 3,365 feet (1,026 m).[8]
[edit] Name
Mount Bachelor is so called because it "stands apart" from the Three Sisters, a group of three volcanic mountains that are northwest of Mount Bachelor. In early days Bachelor Butte (as it was originally named) was frequently called "Brother Jonathan".[9] The resort developers were concerned that skiing on a butte might be perceived by consumers as "small-time" and so named their resort Mt. Bachelor.[9] Over time the popularity of the ski area led to the name Mount Bachelor coming into popular usage and in a divided decision, the Oregon Geographic Names Board voted to change the name from Bachelor Butte to Mount Bachelor.[9][3]
[edit] See also
[edit] References
- ^ NGS Data Sheet for Bachelor Butte. Retrieved on 2008-03-31.
- ^ Mount Bachelor. Peakbagger.com. Retrieved on 2008-03-31.
- ^ a b USGS GNIS: Mount Bachelor
- ^ Deschutes & Ochoco National Forests - Mt. Bachelor Volcanic Chain. USDA Forest Service (2003-12-10). Retrieved on 2008-03-26.
- ^ a b USGS Cascade Volcano Observatory Description: Mount Bachelor Volcanic Chain
- ^ Smithsonian Institution Global Volcanism Program: Mount Bachelor
- ^ a b c d e Oregon Volcanoes - Mt. Bachelor Volcanic Chain. Deschutes & Ochoco National Forests - Crooked River National Grassland. United States Forest Service (2003-12-10). Retrieved on 2008-05-13.
- ^ Mt. Bachelor Mountain Statistics
- ^ a b c McArthur, Lewis A.; Lewis L. McArthur [1928] (2003). Oregon Geographic Names, Seventh Edition, Portland, Oregon: Oregon Historical Society Press, 664. ISBN 0-87595-277-1.
[edit] External links
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