Clear Lake Volcanic Field

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Clear Lake Volcanic Field
Elevation 4,724 ft (1,440 m)[1]
Location Lake County, California,
United States
Range North Coast Ranges
Coordinates 38°58′N 122°46′W / 38.97°N 122.77°W / 38.97; -122.77Coordinates: 38°58′N 122°46′W / 38.97°N 122.77°W / 38.97; -122.77[2]
Topo map USGS Kelseyville
Type lava domes, cinder cones, maars within volcanic field[2]
Age of rock less than 2.1 million years[3]
Last eruption Holocene[2]

The Clear Lake Volcanic Field is a volcanic field beside Clear Lake in California's northern Coast Ranges. The site of late-Pliocene to early Holocene activity, the volcanic field consists of lava domes, cinder cones, and maars with eruptive products varying from basalt to rhyolite.[2] Cobb Mountain and Mount Konocti are the two highest peaks in the volcanic field, at 4,724 feet (1,440 m)[1] and 4,285 feet (1,306 m)[4] respectively.

The field's magma chamber also powers a geothermal field called The Geysers, which hosts the largest complex of geothermal power plants in the world.[5] These can generate approximately 2000 megawatts, enough to power two cities the size of San Francisco.[3]

The Clear Lake volcanics are thought to have been the heat source for the hot springs and hydrothermal activity that formed the mercury ores at the Sulphur Bank Mine, and the gold ore at the McLaughlin Mine.[6]


  1. ^ a b U.S. Geological Survey Geographic Names Information System: Cobb Mountain. Retrieved 2008-08-19.
  2. ^ a b c d "Clear Lake". Global Volcanism Program. Smithsonian Institution. Retrieved 2008-08-19. 
  3. ^ a b Wood, Charles A.; Jűrgen Kienle (1993). Volcanoes of North America. Cambridge University Press. pp. 226–229. ISBN 0-521-43811-X. 
  4. ^ U.S. Geological Survey Geographic Names Information System: Mount Konocti. Retrieved 2008-08-19.
  5. ^ W. Jacquelyne Kious; Robert I. Tilling (February 1996). "This Dynamic Earth: The Story of Plate Tectonics: USGS General Interest Publication" (PDF). 1.13. United States Geological Survey. p. 98. Retrieved 2009-01-06. 
  6. ^

External links[edit]