Chemical characteristics of the major thermal springs of Montana
Twenty-one thermal springs in western Montana were sampled for chemical, isotope, and gas compositions. Most of the springs issue dilute to slightly saline sodium-bicarbonate waters of neutral to slightly alkaline pH. A few of the springs issue sodium-mixed anion waters of near neutral pH. Fluoride concentrations are high in most of the thermal waters, up to 18 miligrams per litre, while F/Cl ratios range from 3/1 in the dilute waters to 1/10 in the slightly saline waters. Most of the springs are theoretically in thermodynamic equilibrium with respect to calcite and fluorite. Nitrogen is the major gas escaping from most of the hot springs; however, Hunters Hot Springs issue principally methane. The deuterium content of the hot spring waters is typical of meteoric water in western Montana. Geothermal calculations based on silica concentrations and Na-K-Ca ratios indicate that most of the springs are associated with low temperature aquifers (less than 100/sup 0/C). Chalcedony may be controlling the silica concentrations in these low temperature aquifers even in ''granitic'' terranes.
- Research Organization:
- Geological Survey, Menlo Park, Calif. (USA)
- OSTI ID:
- 7331302
- Report Number(s):
- USGS-OFR-76-480
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
MONTANA
GEOTHERMAL SYSTEMS
THERMAL SPRINGS
GEOCHEMISTRY
THERMAL WATERS
CHEMICAL COMPOSITION
CALCIUM
CHEMICAL ANALYSIS
DEUTERIUM
FLUORINE
GASES
GEOTHERMOMETRY
ISOTOPE RATIO
METHANE
MINERALS
NITROGEN
PH VALUE
POTASSIUM
SAMPLING
SODIUM
TRACE AMOUNTS
ALKALI METALS
ALKALINE EARTH METALS
ALKANES
CHEMISTRY
CRYOGENIC FLUIDS
ELEMENTS
FLUIDS
HALOGENS
HYDROCARBONS
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
METALS
NONMETALS
NORTH AMERICA
NUCLEI
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ROCKY MOUNTAIN REGION
STABLE ISOTOPES
USA
Geothermal Legacy
150302* - Geothermal Exploration & Exploration Technology- Geochemical Techniques & Surveys