Geochemical studies of rocks, water, and gases at Mt. Hood, Oregon
Mr. Hood, a composite andesitic volcano, located near Portland, Oregon, is one of several large eruptive centers which dominate the Cascade Mountains of the western United States. As part of a program of geologic, geophysical and geochemical studies to examine Mt. Hood's geothermal resource potential, samples of warm-and cold-spring water, water from a geothermal test well in Old Maid Flat, fumarolic gases, and rocks were collected and analyzed for major chemical constituents and trace elements. The only warm-spring area on Mt. Hood is Swim Springs, located on the south flank. Orifices at Swim were sampled repeatedly with little overall change noted in water chemistry between summer and winter. Oxygen and hydrogen isotope data and mixing calculations based on analyses of Swim Springs and numerous cold springs, indicate that a large component of the warm water at Swim is from near-surface runoff. Chemical geothermometry suggests that temperatures at depth in the Swim Springs system are within the range 104 to 170/sup 0/C; the temperature of unmixed hot water may exceed 200/sup 0/C. Higher-than-background chloride contents and specific conductances of cold springs on the south flank of the mountain suggest that there is a small component of thermal water in these sources. A geothermal model of Mt. Hood is proposed wherein snow- and glacier-melt water near the summit comes in close promimity to the hot central neck of the mountain, manifested by the summit-crater fumaroles.Iridium was detected in warm and cold spring waters and in a sample of altered andesite.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 6322623
- Report Number(s):
- LBL-7092
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
FUMAROLIC FLUIDS
CHEMICAL COMPOSITION
OREGON
GEOCHEMICAL SURVEYS
GEOTHERMAL RESOURCES
THERMAL SPRINGS
THERMAL WATERS
CHLORIDES
GEOTHERMAL WELLS
GEOTHERMOMETRY
HYDROGEN ISOTOPES
OXYGEN ISOTOPES
RESOURCE POTENTIAL
ROCKS
VOLCANOES
CHLORINE COMPOUNDS
FLUIDS
GEOTHERMAL FLUIDS
HALIDES
HALOGEN COMPOUNDS
NORTH AMERICA
PACIFIC NORTHWEST REGION
RESOURCES
USA
WELLS
Geothermal Legacy
150302* - Geothermal Exploration & Exploration Technology- Geochemical Techniques & Surveys