How big was the volcanic eruption? Imagine a cube of lava, one that's 1.5 miles (2.4 km) long by 1.5 miles (2.4 km) wide by 1.5 miles (2.4 km) high.[1]
Ashflows include
Desert Spring Tuff,
Bend Pumice
Tumalo Tuff, and
Shevlin Park Tuff.
The area has many rhyoliticdomes, such as Melvin Butte, plus andesiticcinder cones, including those of the Triangle Hill and Triangle Peak area, whose composition is similar to the Tumalo Tuff (and Bend Pumice), and Shevlin Park Tuff.[2]
^*Harris, S. L. (2005). "Chapter 13: The Three Sisters". Fire Mountains of the West: The Cascade and Mono Lake Volcanoes (Third ed.). Missoula, Montana: Mountain Press Publishing Company. p. 33. ISBN978-0-87842-511-2.
^Plummer, Charles C.; McGeary, David (1988). Physical Geology (4th ed.). Dubuque, Iowa: Wm. C. Brown Publishers. p. 54. ISBN978-0-697-05092-2.
^Faculty of the School of Geography, Geology and Environmental Science (2006). "Rhyolite". The University of Auckland. Retrieved November 29, 2017.