Mount Jefferson (Oregon)

Mount Jefferson is an inactive stratovolcano in the Cascade Range. He is with 3199 m the second highest mountain in the U.S. state of Oregon. His rock is essentially composed of andesite, dacite and Basaltandesit.

Mt Jefferson is very rugged and has several glaciers. Its western side is occupied by the Nature Reserve Mount Jefferson Wilderness and the Willamette National Forest. The east side belongs since 1855 to the Warm Springs Indian Reservation, although the area was originally settled by the Molala who now live further north-west in the Grand Ronde Indian Reservation.

The mountain was named in 1806 by the participants of the Lewis and Clark expedition to President Thomas Jefferson, who had given the expedition in order. After further research into the early 19th century that in 1888 two residents of Salem the first ascent. The ascent to the summit is technically very demanding and designed due to the steep, ice-encrusted rocks difficult.

The last major eruption phase of the Mount Jefferson itself lies about 15,000 years ago. The volcanic activity has taken place since to have shifted further south. To 4500 BC and 950 AD lava flows from the monogenetic vents Forked Butte and South Cinder Peak can be reported.