Three Fingered Jack

For the Jamaican outlaw known as Three Fingered Jack, see Three Fingered Jack (Jamaica). For the outlaw known as Three Fingered Jack, see Jack Dunlop.

Three Fingered Jack
A jagged mountain with spires rises above its lightly forested slope, with a more heavily forested area in the foreground of the picture.
Southwest side of Three Fingered Jack seen from Pacific Crest Trail
Highest point
Elevation7,844 ft (2,391 m) NAVD 88[1]
Coordinates44°28′44″N 121°50′35″W / 44.478965122°N 121.843058797°W / 44.478965122; -121.843058797[1]
Geography
Three Fingered Jack is located in the United States
Three Fingered Jack
Three Fingered Jack
Jefferson and Linn counties, Oregon, U.S.[2]
Three Fingered Jack is located in Oregon
Three Fingered Jack
Three Fingered Jack
Three Fingered Jack (Oregon)
Parent rangeCascades
Topo mapUSGS Three Fingered Jack
Geology
Rock ageolder than 200,000 years
Mountain type(s)Summit, Shield volcano
Volcanic arcCascade Volcanic Arc
Last eruptionPleistocene
Climbing
First ascent1923 by E. McNeal and party[3]

Three Fingered Jack is a summit of a shield volcano of the Cascade Range in the U.S. state of Oregon. Formed during the Pleistocene epoch, the mountain consists mainly of basaltic andesite lava and was heavily glaciated in the past. While other Oregon volcanoes that were heavily glaciated—such as Mount Washington and Mount Thielsen—display eroded volcanic necks, Three Fingered Jack's present summit is a comparatively narrow ridge of loose tephra supported by a dike only 10 feet (3.0 m) thick on a generally north–south axis. Glaciation exposed radiating dikes and plugs that support this summit. The volcano has long been inactive and is highly eroded.

Three Fingered Jack has diverse flora, fauna, and fungi. The Molala people, one of the indigenous groups in the northwestern United States, historically inhabited the area around the volcano. Not much is known about Molala culture, other than that the group fished for salmon and collected berries, fruits, obsidian, and dried herbs. David Douglas was the first person of non-indigenous descent to reach the area in 1825, followed by Peter Skene Ogden the following year. The first group to ascend the volcano reached its summit in September 1923. Three Fingered Jack can still be climbed, but climbers can require rescue after becoming disoriented in low visibility conditions.

  1. ^ a b "Three Fingered Jack=Hayrick". NGS Data Sheet. National Geodetic Survey, National Oceanic and Atmospheric Administration, United States Department of Commerce. Retrieved May 29, 2018.
  2. ^ "Three Fingered Jack". Geographic Names Information System. United States Geological Survey, United States Department of the Interior. Retrieved June 1, 2018.
  3. ^ Sellars 1923, pp. 69–75.