Probable Occurrence of the Bishop Tuff in the Salton Sea Scientific Drilling Project Borehole, Salton Sea Geothermal System, California
- Key words
- Exploration; USA; California; Imperial; Salton Sea; Alteration; Ash Flow Tuff; Geochronology; Geology; Igneous; Petrographic Studies; Petrography; Pyroelastic; Volcanics; Subsidence; Caldera; Geochemistry; Trace Elements
- Location
- Salton Sea, California; Imperial Valley; Salton Trough
- Conference
- Geothermal Resources Council Transactions
- Year
- 1988
- Session
- Exploration; Geological surveys; Petrology/petrography; Tuff
- Language
- English
Abstract
In spite of extensive drilling, the age of the geothermal systems in the Salton Trough and the rocks in which they occurred is poorly known. The chemical composition of a silicic tuff recovered into eh State 2-14 research borehole of the Salton Sea Scientific Drilling Project suggests that it is correlative with the Durmid Hill tuff cropping out 25 km NE. In turn, both of these volcanic rocks appear to be deposits of the Bishop Tuff, erupted 0.7 Ma ago from the Long Valley caldera of central California. If the age of the State 2-14 tuff is 0.7 Ma, its occurrence at a depth of 1704 m indicates a combines sedimentation and subsidence rate of 2.4 mm/yr for this part of the Salton Sea Geothermal System during this time interval, and that the Plio-Pleistocene boundary should occur at a depth of about 3.8 km in this region of the Salton Trough.
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