Mono Lake Vol Field
Long Valley Caldera and Mono-Inyo Craters
Volcanic Field, California
Location: 37.6N, 118.8W
Long Valley caldera, located at the boundary between the Sierra Nevada and the Basin and Range Province, is one of the largest Quaternary rhyolitic volcanic centers in North America. The caldera is elliptical in shape and 10 by 20 miles (15 by 30 km) in size. The elevation of the floor of the caldera is 6,500 feet (2,000 m) in the east and 8,500 feet (2600 m) in the west. The elevation of the walls of the caldera reach elevations of 9,800-11,500 feet (3000-3500 m) except in the east where the wall rises only 500 feet (150 m) to an elevation of 7,550 feet (2,300 m).
The Bishop tuff was erupted during the catastrophic eruption that created Long Valley caldera. This photo shows the Bishop tuff exposed in the Owens River Gorge in the eastern Sierra Nevada about 240 miles (380 km) north of Los Angeles. The White Mountains are in the background. View is to the southeast. Photo by R. Forrest Hopson.
Rhyolitic volcanism began on the Mono Craters chain northwest of the caldera about 35,000 years ago. Mono Craters consists of a chain of at least 30 coalesced domes, flows, and craters. The youngest feature is only 600 years old.
Sources of Information:
Bailey, R.C., 1989, Geologic map of Long Valley caldera, Mono-Inyo Craters volcanic chain, and vicinity, eastern California: U.S. Geological Survey, Miscellaneous Investigations Series Map I-1933, scale 1:62,500.
Bailey, R.C., 1987, Long Valley caldera, eastern California, in Hill, M.L., ed., Centennial Field Guide Volume 1 Cordilleran Section of the Geological Society of America, p. 163-168.
Bailey, R.C., 1983, Mammoth Lakes earthquakes and ground uplift: Precursors to possible volcanic activity?: Earthquake Information Bulletin, May-June 1983, v. 15, no. 3, p. 88-102.
Bailey, R.C., and Koeppen, R.P., 1977, Preliminary geologic map of Long Valley caldera, Mono County, California, U.S. Geological Survey Open-File Report 77-468, 2 sheets, scale 1:62,500.
Bailey, R.C., Miller, C.D., and Seih, K., 1989, Excursion 13B: Long Valley caldera and Mono-Inyo Craters volcanic chain, eastern California, in Chapin, C.E. and Zidek, J., eds., Field excursions to volcanic terranes in the western United States, Volume II: Cascades and intermountain west; Memoir 47, New Mexico Bureau of Mines & Mineral Resources, p. 227-254.
Farrar, C.D., and others, 1995, Forest-killing diffuse CO2 emission at Mammoth Mountain as a sign of magmatic unrest: Nature, v. 376, p. 675-678.
Izett, G.A., Obradovich, J.D., and Mehnert, H.H., 1982, The Bishop ash bed and some older closely related ash beds in California, Nevada, and Utah: U.S. Geological Survey Open-File Report 82-584, 60 p.
Miller, C.D., Mullineaux, D.R., Crandell, D.R., and Bailey, R.C., 1982, Potential hazards of future volcanic eruptions in the Long Valley-Mono Lake area, east-central California and southwest Nevada: U.S. Geological Survey Circular 877, 10 p.
Miller, C.D., 1985, Holocene eruption at the Inyo volcanic chain, California: implications for future eruptions in Long Valley: Geology, v. 13, p. 14-17.