skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Melt zones beneath five volcanic complexes in California: an assessment of shallow magma occurrences

Abstract

Recent geological and geophysical data for five magma-hydrothermal systems were studied for the purpose of developing estimates for the depth, volume and location of magma beneath each area. The areas studied were: (1) Salton Trough, (2) The Geysers-Clear Lake, (3) Long Valley caldera, (4) Coso volcanic field, and (5) Medicine Lake volcano, all located in California and all selected on the basis of recent volcanic activity and published indications of crustal melt zones. 23 figs.

Authors:
;
Publication Date:
Research Org.:
Lawrence Berkeley Lab., CA (USA)
OSTI Identifier:
5791709
Report Number(s):
LBL-18232
ON: DE85010644
DOE Contract Number:
AC03-76SF00098
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
15 GEOTHERMAL ENERGY; CALIFORNIA; MAGMA SYSTEMS; COSO HOT SPRINGS; GEOLOGY; GEOPHYSICAL SURVEYS; GEYSERS GEOTHERMAL FIELD; LONG VALLEY; SALTON SEA GEOTHERMAL FIELD; HYDROTHERMAL SYSTEMS; MAGMA; VOLCANOES; ENERGY SYSTEMS; FEDERAL REGION IX; GEOTHERMAL FIELDS; GEOTHERMAL SYSTEMS; NORTH AMERICA; SURVEYS; USA; Geothermal Legacy

Citation Formats

Goldstein, N.E., and Flexser, S. Melt zones beneath five volcanic complexes in California: an assessment of shallow magma occurrences. United States: N. p., 1984. Web. doi:10.2172/5791709.
Copy to clipboard
Goldstein, N.E., & Flexser, S. Melt zones beneath five volcanic complexes in California: an assessment of shallow magma occurrences. United States. doi:10.2172/5791709.
Copy to clipboard
Goldstein, N.E., and Flexser, S. Sat . "Melt zones beneath five volcanic complexes in California: an assessment of shallow magma occurrences". United States. doi:10.2172/5791709. https://www.osti.gov/servlets/purl/5791709.
Copy to clipboard
@article{osti_5791709,
title = {Melt zones beneath five volcanic complexes in California: an assessment of shallow magma occurrences},
author = {Goldstein, N.E. and Flexser, S.},
abstractNote = {Recent geological and geophysical data for five magma-hydrothermal systems were studied for the purpose of developing estimates for the depth, volume and location of magma beneath each area. The areas studied were: (1) Salton Trough, (2) The Geysers-Clear Lake, (3) Long Valley caldera, (4) Coso volcanic field, and (5) Medicine Lake volcano, all located in California and all selected on the basis of recent volcanic activity and published indications of crustal melt zones. 23 figs.},
doi = {10.2172/5791709},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sat Dec 01 00:00:00 EST 1984},
month = {Sat Dec 01 00:00:00 EST 1984}
}
Copy to clipboard
Technical Report:
View Technical Report (6.09 MB)
DOI:  10.2172/5791709
Save / Share:
Export Metadata
Save to My Library
You must Sign In or Create an Account in order to save documents to your library.

  • This report summarizes our investigations of seismic data from the Long Valley caldera region based mainly on data obtained from the USGS-Doe seismic network. During the period several thousands of earthquakes were recorded and located, including the extensive aftershock sequence of the July 1986 Chalfant Valley. This contract has provided partial operating support for this network, including the establishment of the first permanently-recording wideband digital station in the Mammoth Lakes region. Results presented here unclude five manuscripts involving various aspects of the research. These manuscripts cover: (1) a general description of unusual seismic phase near Mammoth Lakes and their possiblemore » use in the delineation of shallow-crustal anomalous bodies, (2) a paper which pinpoints the location of a shallow-crustal anomaly about 6 km deep and 2 to 3 km in lateral near the south end of Hilton Creek fault, (3) the documentation of a strong lateral structural change in the vicinity of Inyo Craters, and (4) papers contributing to knowledge of the tectonics of the Mammoth Lakes area.« less

  • Systematic chemical and mineralogical variability occurs in samples from drill holes through Obsidian Dome, the conduit to the dome, and a nearby associated feeder dike. The drill hole samples that occur at the margins of the conduit and most of the lower portion of the dome are high-Ba, low-silica rhyolites, with two populations of phenocrysts, and represent commingled magmas. Whereas samples from the dike and upper portions of the dome are low-Ba, higher silica rhyolites, and do not reflect commingled magmas, samples from the center of the conduit are low-Ba, higher silica rhyolites that are only slightly mixed. A majormore » part of the variability within the drill core samples of the dome and conduit reflects the juxtaposition, and commingling of two distinct magmas during their passage throughout the conduit.« less

  • ;
    The geology and salient aspects of geophysics and hydrogeochemistry of five high-grade geothermal systems in the USA are reviewed. On the basis of this information, a target location is suggested for a deep (5- to 8-km) borehole that will maximize the amount of scientific information to be learned at each of the five geothermal areas.

  • ;
    A comparative assessment of five potential hydrothermal-magma sites for this facet of the Thermal Regimes part of the CSDP has been prepared for the DOE Office of Basic Energy Sciences. The five sites are: The Geysers-Clear Lake, CA, Long Valley, CA, Rio Grande Rift, NM, Roosevelt Hot Springs, UT, and Salton Trough, CA. This site assessment study has drawn together background information (geology, geochemistry, geophysics, and energy transport) on the five sites as a preliminary stage to site selection. Criteria for site selection are that potential sites have identifiable, or likely, hydrothermal systems and associated magma sources, and the importantmore » scientific questions can be identified and answered by deep scientific holes. Recommendations were made.« less

  • A brief discussion is given of the geochemical objectives and questions that must be addressed in such an evaluation. A summary of the currently published literature that is pertinent in answering these questions is presented for each of the five areas: The Geysers-Clear Lake region, Long Valley, Rio Grand Rift, Roosevelt Hot Springs, and the Salton Trough. The major geochemical processes associated with proposed hydrothermal sites are categorized into three groups for presentation: geochemistry of magma and associated volcanic rocks, geochemistry of hydrothermal solutions, and geochemistry of hydrothermal alteration. (MHR)