|Vertical aerial view of Newberry caldera. Paulina Lake (left) and East Lake (right) are within the caldera. Central pumice cone is between the lakes. Big Obsidian flow is the light colored area directly south (below) of Paulina Lake and central pumice cone. The south margin of the caldera rim is just south (below) Big Obsidian flow. Many of the 400 cinder cones on the flank of the volcano can be seen. Photograph courtesy of National High Altitude Photo graphy Program.|
Newberry volcano is about 20 miles (30 km) southeast of Bend and is one of the largest volcanoes in the Cascades. The base of this shield volcano is 25 miles (40 km) in diameter. The summit caldera is 3 by 4 m iles (5 by 7 km). The highest point of the volcano, Paulina Peak, is 7,984 feet (2,434 m). Paulina and East lakes are inside the caldera. The present caldera is thought to be several overlapping calderas that formed at different times.
The volcano is made of basalt and basaltic andesite lava flows, andesite and rhyolite pyroclastic deposits, and dacite and rhyolite domes. The oldest dated rocks are about 500,000 years old. There have been numerous eruptions in the last 1 0,000 years, most in the caldera and most rhyolite in composition. The most recent eruption was 1,400 years ago.
Paulina Peak with Paulina Lake in the foreground. Paulina Peak, a rhyolite dome, is probably about 400,000 years old. Photo courtesy of the Oregon State Highway Travel Division.
View from Paulina Peak looking northeast to East Lake. Central pumice cone is in the left-center of the photo. It is about 6,600-6,700 years old. Big Obsidian flow is in the bottom part of the photo. Big Obsidian flow is about 1,400 years old. Photog raph by Dick Van Effen, August, 1989.
Looking south to interlake obsidian flow (foreground), central pumice cone (middle ground), Big Obsidian flow (upper right margin), and the inner and outer walls of Newberry caldera. East Lake is on the left and Paulina Lake is on the right. Photo courtesy of the Oregon Department of Geology and Mineral Industries. Special thanks to Rosemary Kenney.
View from Paulina Peak looking northwest to Paulina Lake. The northwest margin of the lake is bounded by the northwest rim of the caldera. Photograph by Dick Van Effen, August, 1989.
Lava Butte is a basaltic andesite cinder cone and an associated lava flow. The cone and flow are about 6,100 years old. Photo courtesy of the Oregon Department of Geology and Mineral Industries.
View of Big Obsidian flow looking south. The south rim of the caldera is marked by the steep cliff just south (above) the flow. Photograph from U.S. Geological Survey Circular 838 and courtesy of Oregon Department of Transportation. Photograph by David Sherrod of the U.S. Geological Survey.
View to the south along the front of the Big Obsidian flow. The southwest rim of the caldera is in the background. Photograph by Dick Van Effen, August, 1989.
Photograph of Newberry shield by Kyle Jones, August 1989.
Additional information about Newberry volcano is presented on the Cascade Volcano Observatory homepage of the U.S. Geological Survey.
Sources of Information:
Fitterman, D.V., Overview of the structure and geothermal potential of Newberry Volcano, Oregon: Journal of Geophysical Research, v. 93, p. 10,059-10,066.
MacLeod, N.S., Sherrod, D.R., Chitwood, L., and McKee, E., 1981, Newberry Volcano, Oregon in Johnston, D.A., and Donnelly-Nolan, J., eds. Guides to some volcanic terranes in Washington, Idaho, Oregon, and northern California, U.S. Geological Survey 838, p . 85-104.
MacLeod, N.S., and D.R. Sherrod, 1988, Geologic evidence for a magma chamber beneath Newberry Volcano, Oregon: Journal of Geophysical Research, v. 93, p.
Williams, H., 1935, Newberry volcano of central Oregon: Geological Society of America Bulletin, v. 46, p. 253-304.
Wood, C.A., and Kienle, J., 1993, Volcanoes of North America: Cambridge University Press, New York, 354 p.