Distribution of quaternary rhyolite dome of the Coso Range, California: Implications for extent of the geothermal anomaly

Journal Article · Sat May 10 00:00:00 EDT 1980 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JB085iB05p02425· OSTI ID:5195934

Bacon, C R; Duffield, W A; Nakamura, K

Thirty-eight separate domes and flows of phenocryst-poor, high-silica rhyolite of similar major element chemical composition were erupted over the past 1 m.y. from vents arranged in a crudely S-shaped array atop a granitic horst in the Coso Range, California. Most of the extrusions are probably less than about 0.3 m.y. old. The area is one of Quaternary basaltic volcanism and crustal extension. The central part of the rhyolite field is characterized by high heat flow, low apparent resistivity, and substantial fumarolic activity indicative of an active geothermal system. The immediate source of heat for the surficial geothermal phenomena is probably a silicic magma reservoir that may still contain molten or partially molten material at a depth of at least 8 km beneath the central part of the rhyolite field. Outlying rhyolite extrusions probably reflect the presence of feeder dikes emanating from the reservoir beneath the central region. Azimuths of dikes appear to be parallel to the regional tectonic axis of maximum horizontal compression, analogous to some dike-fed flank eruptions on basaltic shields and andesitic strato-volcanoes. The areal extent of a magma reservoir and the present total heat content of the silicic magma system at Coso may be less than was previously estimated. However, the area is still considered to be one of significant geothermal potential.

• Research Organization: U.S. Geological Survey, Menlo Park, California 94025
• OSTI ID: 5195934
• Journal Information: J. Geophys. Res.; (United States), Vol. 85:B5
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
COSO HOT SPRINGS
GEOLOGIC HISTORY
VOLCANISM
BASALT
FUMAROLIC FLUIDS
GEOTHERMAL FIELDS
HEAT FLOW
QUATERNARY PERIOD
RHYOLITES
CALIFORNIA
CENOZOIC ERA
FLUIDS
GEOLOGIC AGES
GEOTHERMAL FLUIDS
IGNEOUS ROCKS
NORTH AMERICA
ROCKS
USA
VOLCANIC ROCKS
WESTERN REGION
150201* - Geology & Hydrology of Geothermal Systems- USA- (-1989)