Geothermal investigations in Idaho. Part 6. Geochemistry and geologic setting of the thermal and mineral waters of the Blackfoot Reservoir area, Caribou County, Idaho

Technical Report · Sun Aug 01 04:00:00 EDT 1976

OSTI ID:7215614

Mitchell, J C

Geologic evidence of geothermal activity is abundant in the Blackfoot Reservoir area. The Intermountain Seismic Belt passing through the area coincides with a zone of high heat flow manifested by numerous thermal springs. A geothermal gradient of 1/sup 0/C per 25 meters has been reported for the area. Basalt flows less than 700,000 years old exist west and south of the Blackfoot Reservoir. Gravity and magnetic data reveal a geologically very young volcanic collapse structure (caldera) or a mass of low density intrusive rocks near the center of the area. Rhyolite cones reportedly 100,000 years old, thermal springs, spring deposits, and geyser activity indicate the presence of geothermal activity. An audio-magnetotelluric survey, conducted during 1973 indicated that shallow, low conductive zones do not exist in the survey area at a depth of less than 2 kilometers. If any geothermal reservoirs or aquifers exist in the area, they are probably very deep (greater than 2 kilometers). The silica geochemical thermometers indicates that the thermal waters of the Blackfoot Reservoir area are not from high temperature reservoirs or aquifers. Higher temperatures were predicted by the sodium-potassium-calcium (Na-K-Ca) geochemical thermometers; however, in many cases active travertine deposition influenced the reliability of the calculated Na-K-Ca aquifer temperatures. Published estimates of geothermal gradient suggest these waters could be ascending from depths as shallow as 1 kilometer along normal faults closely associated with the springs.

• Research Organization: Idaho Dept. of Water Resources, Boise (USA)
• OSTI ID: 7215614
• Report Number(s): NP-22003/6
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
150201* -- Geology & Hydrology of Geothermal Systems-- USA-- (-1989)
150302 -- Geothermal Exploration & Exploration Technology-- Geochemical Techniques & Surveys
AQUIFERS
CHEMICAL ANALYSIS
CHEMISTRY
ELEMENTS
EXPLORATION
GEOCHEMISTRY
GEOLOGICAL SURVEYS
GEOLOGY
GEOPHYSICAL SURVEYS
GEOTHERMAL EXPLORATION
GEOTHERMAL FIELDS
GEOTHERMAL GRADIENTS
GEOTHERMAL WELLS
GEOTHERMOMETRY
GEYSERS
HEAT FLOW
IDAHO
ISOTHERM
MAPS
METALS
MINERAL SPRINGS
NORTH AMERICA
PACIFIC NORTHWEST REGION
TEMPERATURE GRADIENTS
THERMAL SPRINGS
THERMAL WATERS
TRACE AMOUNTS
USA
VOLCANIC REGIONS
WELLS