Hydrothermal alteration at the Roosevelt Hot Springs Thermal Area, Utah. Final report

Technical Report · Wed Nov 01 04:00:00 EST 1978

DOI:https://doi.org/10.2172/6564287· OSTI ID:6564287

Parry, W T; Bryant, N L; Dedolph, R E; Ballantyne, J M; Ballantyne, G H; Rohrs, D T; Mason, J L

Hot spring deposits in the Roosevelt thermal area consist of opaline sinter, and siliceous-sinter-cemented alluvium. Alluvium, granite to granodiorite plutonic rocks, and amphibolite facies gneiss have been altered by acid-sulfate water to alunite and opal at the surface, and to kaolinite, alunite, montmorillonite, and muscovite to a depth of 60 m. Marcasite and pyrite occur below the water table at about 30m. Deeper alteration sampled to a depth of 2.26 km consists of muscovite, chlorite, calcite, K-feldspar, albite, and epidote with pyrite and sparse chalcopyrite. Thermal water is dilute (ionic strength 0.1 to 0.2) sodium chloride brine. Surface water contains 10 times as much calcium and 100 times as much magnesium as the deep water. Sulfate varies from 48 to 200 mg/l. Present-day spring temperature is 25/sup 0/C but in 1950 the spring temperature was 85/sup 0/C. Computed Na-K-Ca temperature is 241/sup 0/C for the present-day spring, 274/sup 0/C for a well and 283/sup 0/C for the 1957 spring. Quartz saturation temperatures are 170/sup 0/C for the present-day spring, 283/sup 0/C for the well, and 213/sup 0/C for the 1957 spring. A plausible model for development of the near-surface alteration consists of hydrothermal fluid which convectively rises along major fractures. Water cools by conduction and steam separation, and hydrogen ion is produced by oxidation of hydrogen sulfide. The low pH water percolates from the surface downward and reacts with rocks to produce alunite, kaolinite, montmorillonite, and muscovite as hydrogen is consumed.

• Research Organization: Utah Univ., Salt Lake City (USA). Dept. of Geology and Geophysics
• DOE Contract Number: AC07-78ET28392
• OSTI ID: 6564287
• Report Number(s): DOE/ET/28392-17
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
150201* -- Geology & Hydrology of Geothermal Systems-- USA-- (-1989)
ALBITE
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM SILICATES
CALCIUM COMPOUNDS
CALCIUM SILICATES
CHLORITE MINERALS
CLAYS
EPIDOTES
FELDSPARS
FLUIDS
GEOLOGY
GEOTHERMAL FLUIDS
GEOTHERMOMETRY
GRANITES
GRANODIORITES
Geothermal Legacy
HYDROTHERMAL ALTERATION
IGNEOUS ROCKS
INORGANIC ION EXCHANGERS
ION EXCHANGE MATERIALS
IRON COMPOUNDS
IRON SILICATES
KAOLINITE
KGRA
MATERIALS
MICA
MINERALOGY
MINERALS
MONTMORILLONITE
MUSCOVITE
NORTH AMERICA
OXYGEN COMPOUNDS
PLUTONIC ROCKS
ROCKS
ROCKY MOUNTAIN REGION
ROOSEVELT HOT SPRINGS
SILICATES
SILICON COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
USA
UTAH