Three Fingered Jack
Three Fingered Jack is part of a group of more than 30 large shield volcanoes and stratovolcanoes that form a segment of Pleistocene-to-Holocene-epoch volcanic vents that produced mafic lava (rich in magnesium and iron). Three Fingered Jack includes several overlapping cinder cones and composite cones over underlying lava flows from shield volcano activity. These volcanic edifices and their lava flow deposits cover an area of .
Details
- Age
- older than 200,000 years
- Topo
- USGS Three Fingered Jack
- Type
- Summit, Shield volcano
- Range
- Cascades
- Location
- Jefferson and Linn counties, Oregon, U.S.
- Image Alt
- A jagged mountain with spires rises above its lightly forested slope, with a more heavily forested area in the foreground of the picture.
- Elevation Ft
- 7844
- First Ascent
- 1923 by E. McNeal and party
- Volcanic Arc
- Cascade Volcanic Arc
- Last Eruption
- Pleistocene