Mount Bachelor | |
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Mount Bachelor from Little Lava Lake
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Highest point | |
Elevation | 9,068 ft (2,764 m) NAVD 88 |
Prominence | 2,665 ft (812 m) |
Coordinates | 43°58′46″N 121°41′19″W / 43.979415733°N 121.688507775°WCoordinates: 43°58′46″N 121°41′19″W / 43.979415733°N 121.688507775°W |
Geography | |
Location | Deschutes County, Oregon, U.S. |
Parent range | Cascade Range |
Topo map | USGS Mount Bachelor |
Geology | |
Age of rock | less than 15,000 years |
Mountain type | Stratovolcano (on top of a shield volcano) |
Volcanic arc | Cascade Volcanic Arc |
Last eruption | 5800 BC ± 1000 years |
Climbing | |
Easiest route | Ski lifts |
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. The Mount Bachelor ski area has operated on the mountain since 1958.
The volcano lies at the northern end of the 15-mile (24 km) long Mount Bachelor Volcanic Chain.
Mount Bachelor was formed between 15,000 and 11,000 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 10,000 and 8,000 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, though some areas popularly thought to be fumaroles are caused by air movement through the porous structure. Several are near the top of the Pine Marten chairlift and occasionally present a hazard to skiers and snowboarders where the snow is undermined.
The Mount Bachelor volcanic chain, southeast of South Sister, consists of Mount Bachelor itself and a series of cinder cones, lava flows and three shield volcanoes. 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.
Eruptive activity of the chain can be considered in four major episodes:
Mount Bachelor ski area operates a chairlift 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).