Lassen geothermal system
The Lassen geothermal system consists of a central vapor-dominated reservoir underlain by hot water that discharges peripherally at lower elevations. The major thermal upflow at Bumpass Hell (elevation 2500 m) displays numerour superheated fumaroles, one of which in 1976 was 159/sup 0/C. Gas geothermometers from the fumarole areas and water geothermometers from boiling Cl-bearing waters at Morgan Hot Springs (elevation 1530 m; 8 km south of Bumpass Hell) and from 176/sup 0/C waters in a well 12 km southeast of Bumpass Hell both indicate 230 to 240/sup 0/C for the deep thermal water. With increasing distance from Bumpass Hell, gases are progressively depleted in H/sub 2/S relative to CO/sub 2/ and N/sub 2/, owing to oxidation of H/sub 2/S to pyrite, sulfur, and sulfates and to dilution with atmospheric N/sub 2/. H/sub 2/O/gas ratios and degree of superheat of fumaroles can be explained by mixing of steam of maximum enthalpy (2804 J g/sup -1/) with near-surface water and with the condensate layer overlying the vapor-dominated reservoir.
- Research Organization:
- Geological Survey, Menlo Park, CA (USA)
- OSTI ID:
- 5456485
- Report Number(s):
- USGS-OFR-82-926; ON: DE84900439
- Resource Relation:
- Other Information: Portions are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
Similar Records
Hot Spring Monitoring at Lassen Volcanic National Park, California 1983-1985
Preliminary chemical studies of thermal waters in Lassen Volcanic National Park and vicinity
Related Subjects
CALIFORNIA
GEOCHEMICAL SURVEYS
GEOTHERMAL SYSTEMS
CASCADE MOUNTAINS
FUMAROLES
GEOTHERMOMETRY
VAPOR-DOMINATED SYSTEMS
ENERGY SYSTEMS
FEDERAL REGION IX
HYDROTHERMAL SYSTEMS
MOUNTAINS
NORTH AMERICA
SURVEYS
USA
Geothermal Legacy
150302* - Geothermal Exploration & Exploration Technology- Geochemical Techniques & Surveys
150201 - Geology & Hydrology of Geothermal Systems- USA- (-1989)