Volcano Type: Stratovolcano
Volcano Status: Tephrochronology
Last Known Eruption: 5800 BC ± 1000 years
Summit Elevation: 2763 m 9,065 feet
Latitude: 43.979°N 43°58’46″N
Longitude: 121.688°W 121°41’15″W
Mount Bachelor is approximately 12,000 years old. Volcanic eruptions ceased before the eruption of Mount Mazama. Scientists know this because tephra from that eruption has been found on Mount Bachelor. They believe that its last episode occurred about 8,000 and 10,000 years ago.
The 25-km-long Mount Bachelor volcanic chain consists of a symmetrical late-Pleistocene to Holocene stratovolcano SE of South Sister volcano and a roughly N-S-trending chain of scoria cones and small shield volcanoes. The youthful basaltic-andesite and basaltic Mount Bachelor volcanic chain was formed in four eruptive episodes dating back to about 18,000-15,000 years before present (BP). Construction of the NNW-SSE scoria cone chain south of Mount Bachelor was completed by about 12,000 years BP. The 2763-m-high Mount Bachelor (formerly known as Bachelor Butte) on the north topographically dominates the chain and is one of its youngest features. The latest activity from the chain produced early Holocene lava flows from Egan scoria cone on the north flank of Mount Bachelor that slightly preceded the eruption of the Mazama ash from Crater Lake about 6850 years ago.
Mt Bachelor Volcano is located in central Oregon. The volcano extends for 25 km and consists of scoria cones, small shield volcanoes, and lava flows. The most recent eruption occurred at Egan scoria cone on the north flank, which produced a lava flow, and Crater Lake, which produced ash.
Originally posted 2010-08-26 04:51:37.
