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Natural radioactivity in geothermal waters, Alhambra Hot Springs and nearby areas, Jefferson County, Montana

Journal of Research of the U.S. Geological Survey

By:
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Abstract

Radioactive hot springs issue from a fault zone in crystalline rock of the Boulder batholith at Alhambra, Jefferson County, in southwestern Montana. The discharge contains high concentrations of radon, and the gross alpha activity and the concentration of adium-226 exceed maximum levels recommended by the Environmental Protection Agency for drinking water. Part of the discharge is diverted for space heating, bathing, and domestic use. The radioactive thermal waters at measured temperatures of about 60°C are of the sodium bicarbonate type and saturated with respect to calcium carbonate. Radium-226 in the rock and on fractured surfaces or coprecipitated with calcium carbonate probably is the principal source of radon that is dissolved in the thermal water and discharged with other gases from some wells and springs. Local surface water and shallow ground water are of the calcium bicarbonate type and exhibit low background activity. The temperature, percent sodium, and radioactivity of mixed waters adjacent to the fault zone increase with depth. Samples from most of the major hot springs in southwestern Montana have been analyzed for gross alpha and beta activity. The high level of radioactivity at Alhambra appears to be related to leaching of radioactive material from siliceous veins by ascending thermal waters and is not a normal characteristic of hot springs issuing from fractured crystalline rock in Montana.

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Natural radioactivity in geothermal waters, Alhambra Hot Springs and nearby areas, Jefferson County, Montana
Series title:
Journal of Research of the U.S. Geological Survey
Volume
6
Issue:
4
Year Published:
1978
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Reston, VA
Contributing office(s):
Energy Resources Program
Description:
12 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Research of the U.S. Geological Survey
First page:
529
Last page:
540
Country:
United States
State:
Montana
County:
Jefferson County
Other Geospatial:
Alhambra Hot Springs