Thermal fluid geochemistry of the Makushin and Akutan geothermal prospects
- ed.
The Makushin and Akutan geothermal prospects occur in the eastern Aleutian island arc, on northern Unalaska Island and on Akutan Island, respectively. Surface manifestations of the geothermal resources in both localities consists of solfatara fields and thermal springs. Distinct differences in chemistries of thermal springs and fumaroles associated with the two geothermal prospects reflect differences in the type of subsurface reservoirs underlying the two regions. Thermal springs at Makushin are typically near-neutral in pH, have very low chloride levels (< 10 ppM), and are comparatively rich in Mg, Ca, SO/sub 4/, HCO/sub 3/, and SiO/sub 2/. Similarities in cation and isotopic compositions of Makushin thermal springs compared to local surface streams indicate the thermal waters are locally derived meteoric waters infiltrating to relatively shallow depths where they are heated by steam and gases rising from at least a shallow vapor-dominated zone. Predominate fumarolic gases are CO/sub 2/, N/sub 2/, and sulfur gases. Thermal springs located in Akutan Hot Springs Bay Valley have very low Mg (< 2 ppM), are SiO/sub 2/-rich, and are moderately concentrated in Na-Cl, a chemistry typically associated with hot-water hydrothermal systems. B/Cl ratios indicate the several sets of springs are derived from a common parent hot-water reservoir. Application of silica, cation, and sulfate-water oxygen-isotope geothermometry gives a range of 160 to 190/sup 0/C for the parent reservoir.
- Research Organization:
- Geological and Geophysical Surveys, College, AK
- OSTI ID:
- 7369497
- Report Number(s):
- DOE/ID/12079-71-Vol.1; ESL-98-Vol.1; CONF-820491-Vol.1-1; ON: DE82019912
- Resource Relation:
- Conference: Geothermal energy exploration and resource assessment technical conference, Salt Lake City, UT, USA, 5 Apr 1982; Related Information: In: Geothermal direct heat program roundup technical conference proceedings, by
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ALASKA
HOT SPRINGS
FUMAROLIC FLUIDS
CHEMICAL COMPOSITION
GEOCHEMISTRY
THERMAL WATERS
FUMAROLES
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GEOLOGY
GEOTHERMOMETRY
ISOTOPE RATIO
VOLCANOES
CHEMISTRY
FEDERAL REGION X
FLUIDS
GEOTHERMAL FLUIDS
NORTH AMERICA
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THERMAL SPRINGS
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WATER SPRINGS
Geothermal Legacy
150302* - Geothermal Exploration & Exploration Technology- Geochemical Techniques & Surveys