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• 21. [Image] Thermal springs list for the United States; National Oceanic and Atmospheric Administration Key to Geophysical Records Documentation No. 12

  	The compilation has 1702 thermal spring locations in 23 of the 50 States, arranged alphabetically by State (Postal Service abbreviation) and degrees of latitude and longitude within the State. It shows ...
  	Citation × Citation Citation Abstract Copy Title: Thermal springs list for the United States; National Oceanic and Atmospheric Administration Key to Geophysical Records Documentation No. 12 Author: Berry, G.W. Year: 1980 The compilation has 1702 thermal spring locations in 23 of the 50 States, arranged alphabetically by State (Postal Service abbreviation) and degrees of latitude and longitude within the State. It shows spring name, surface temperature in degrees Fahrenheit and degrees Celsius; USGS Professional Paper 492 number, USGS Circular 790 number, NOAA number, north to south on each degree of latitude and longitude of the listed. USGS 1:250,000-scale (AMS) map; and the USGS topographic map coverage, 1:63360- or 1:62500-scale (15-minute) or 1:24000-scale (7.5-minute) quadrangle also included is an alphabetized list showing only the spring name and the State in which it is located. Unnamed springs are omitted. The list includes natural surface hydrothermal features: springs, pools, mud pots, mud volcanoes, geysers, fumaroles, and steam vents at temperature of 20{sup 0}C (68[sup 0}F) or greater. It does not include wells or mines, except at sites where they supplement or replace natural vents presently or recently active, or, in some places, where orifices are not distinguishable as natural or artificial. The listed springs are located on the USGS 1:250,000 (AMS) topographic maps. (MHR) Title: Thermal springs list for the United States; National Oceanic and Atmospheric Administration Key to Geophysical Records Documentation No. 12 Author: Berry, G.W. Year: 1980 The compilation has 1702 thermal spring locations in 23 of the 50 States, arranged alphabetically by State (Postal Service abbreviation) and degrees of latitude and longitude within the State. It shows spring name, surface temperature in degrees Fahrenheit and degrees Celsius; USGS Professional Paper 492 number, USGS Circular 790 number, NOAA number, north to south on each degree of latitude and longitude of the listed. USGS 1:250,000-scale (AMS) map; and the USGS topographic map coverage, 1:63360- or 1:62500-scale (15-minute) or 1:24000-scale (7.5-minute) quadrangle also included is an alphabetized list showing only the spring name and the State in which it is located. Unnamed springs are omitted. The list includes natural surface hydrothermal features: springs, pools, mud pots, mud volcanoes, geysers, fumaroles, and steam vents at temperature of 20{sup 0}C (68[sup 0}F) or greater. It does not include wells or mines, except at sites where they supplement or replace natural vents presently or recently active, or, in some places, where orifices are not distinguishable as natural or artificial. The listed springs are located on the USGS 1:250,000 (AMS) topographic maps. (MHR) Close

• 22. [Image] Dipole-Dipole Resistivity Surveys, Roosevelt Hot Springs KGRA. Final Report, Volume 2

  	Dipole-dipole Resistivity surveys were conducted at Roosevelt Hot Springs KGRA. Three different dipole spacings were used; 99km of traverse line were surveyed with 100m dipoles, 50km with 300m dipoles, ...
  	Citation × Citation Citation Abstract Copy Title: Dipole-Dipole Resistivity Surveys, Roosevelt Hot Springs KGRA. Final Report, Volume 2 Author: Ward, S.H. Year: 1976 Dipole-dipole Resistivity surveys were conducted at Roosevelt Hot Springs KGRA. Three different dipole spacings were used; 99km of traverse line were surveyed with 100m dipoles, 50km with 300m dipoles, and 44km with 1km dipoles. The objectives of the Resistivity surveying were to detect and delineate regions of low Resistivity associated with fracturing, brines, high temperatures, and clay alteration. The Resistivity of rocks that are typical of hydrothermal environments is due to two main conduction mechanisms: (1) electrolytic conduction through pores and fractures; and (2) surface conduction due to a thin zone of cations attracted to those mineral surfaces with net negative charges (especially clay minerals). For saturated rocks, the Resistivity due to electrolytic conduction is a function of the effective porosity of the fractured rock, of the temperature, and of the salinity of the fluid filling the pores and fractures. The Resistivity decreases as the effective porosity, water saturation, salinity, and temperature increase. The presence of clay minerals and pyrite will also decrease the Resistivity Title: Dipole-Dipole Resistivity Surveys, Roosevelt Hot Springs KGRA. Final Report, Volume 2 Author: Ward, S.H. Year: 1976 Dipole-dipole Resistivity surveys were conducted at Roosevelt Hot Springs KGRA. Three different dipole spacings were used; 99km of traverse line were surveyed with 100m dipoles, 50km with 300m dipoles, and 44km with 1km dipoles. The objectives of the Resistivity surveying were to detect and delineate regions of low Resistivity associated with fracturing, brines, high temperatures, and clay alteration. The Resistivity of rocks that are typical of hydrothermal environments is due to two main conduction mechanisms: (1) electrolytic conduction through pores and fractures; and (2) surface conduction due to a thin zone of cations attracted to those mineral surfaces with net negative charges (especially clay minerals). For saturated rocks, the Resistivity due to electrolytic conduction is a function of the effective porosity of the fractured rock, of the temperature, and of the salinity of the fluid filling the pores and fractures. The Resistivity decreases as the effective porosity, water saturation, salinity, and temperature increase. The presence of clay minerals and pyrite will also decrease the Resistivity Close

• 23. [Image] Geologic Interpretation of the Geothermal Potential of the North Bonneville Area

  	Possible geothermal development for the township of North Bonneville, Washington is being investigated because of the proximity of the town to hot springs in a geologic province of good geothermal potential. ...
  	Citation × Citation Citation Abstract Copy Title: Geologic Interpretation of the Geothermal Potential of the North Bonneville Area Author: Nielson, D.L. Year: 1980 Possible geothermal development for the township of North Bonneville, Washington is being investigated because of the proximity of the town to hot springs in a geologic province of good geothermal potential. Surface expression of geothermal resources is provided by conduits through an impermeable reservoir cap and is therefore generally structurally controlled. Near North Bonneville the geologic formations that underlie potential drilling sites are the Eagle Creek formation and the Ohanpecosh Formation. The Lower Miocene Eagle Creek Formation is composed of poorly consolidated volcanic conglomerates, sandstOnes, tuffs, and includes a few minor interbedded lava flows. The Eocene-Oligiocene Ohanapecosh (Weigle) Formation in its nearest exposures to North Bonneville is composed of Volcaniclastics and lava flows. The Ohanapecosh has been altered to zeolites and clays and is therefore Well consolidated and impermeable. The lack of permeability provides the necessary reservoir cap for any geothermal system that may be present at depth. This formation, to the northeast, in the Wind River drainage is greater than 19,000 ft. thick. Circulation of geothermal heated water from this thick sequence of impermeable strata must be associated with penetrating fracture zones Title: Geologic Interpretation of the Geothermal Potential of the North Bonneville Area Author: Nielson, D.L. Year: 1980 Possible geothermal development for the township of North Bonneville, Washington is being investigated because of the proximity of the town to hot springs in a geologic province of good geothermal potential. Surface expression of geothermal resources is provided by conduits through an impermeable reservoir cap and is therefore generally structurally controlled. Near North Bonneville the geologic formations that underlie potential drilling sites are the Eagle Creek formation and the Ohanpecosh Formation. The Lower Miocene Eagle Creek Formation is composed of poorly consolidated volcanic conglomerates, sandstOnes, tuffs, and includes a few minor interbedded lava flows. The Eocene-Oligiocene Ohanapecosh (Weigle) Formation in its nearest exposures to North Bonneville is composed of Volcaniclastics and lava flows. The Ohanapecosh has been altered to zeolites and clays and is therefore Well consolidated and impermeable. The lack of permeability provides the necessary reservoir cap for any geothermal system that may be present at depth. This formation, to the northeast, in the Wind River drainage is greater than 19,000 ft. thick. Circulation of geothermal heated water from this thick sequence of impermeable strata must be associated with penetrating fracture zones Close

• 24. [Image] Packer injection test data from sites on fractured rock

  	Packer tests conducted in drill holes in fractured rocks at dam and tunnel sites are the primary data for characterizing permeabilities, fracture spacings, apertures, and porosities. A collection of data, ...
  	Citation × Citation Citation Abstract Copy Title: Packer injection test data from sites on fractured rock Author: Snow, D.T. Year: 1979 Packer tests conducted in drill holes in fractured rocks at dam and tunnel sites are the primary data for characterizing permeabilities, fracture spacings, apertures, and porosities. A collection of data, numbering 5862 tests at 41 sites between the surface and 200 m depth in 12 different fractured crystalline rock types is reported on microfiche. In addition to the discharge and collar pressure, each entry records the angle and size of drill hole, the inclined depths to the top and bottom of the test interval, the depth to the static water level and the bottom of overburden. A summary of computed permeabilities, porosities, fracture spacings, and apertures averaged for several depth zons at each site are tabulated, and publications derived from the data are referenced; LBL-10080 Title: Packer injection test data from sites on fractured rock Author: Snow, D.T. Year: 1979 Packer tests conducted in drill holes in fractured rocks at dam and tunnel sites are the primary data for characterizing permeabilities, fracture spacings, apertures, and porosities. A collection of data, numbering 5862 tests at 41 sites between the surface and 200 m depth in 12 different fractured crystalline rock types is reported on microfiche. In addition to the discharge and collar pressure, each entry records the angle and size of drill hole, the inclined depths to the top and bottom of the test interval, the depth to the static water level and the bottom of overburden. A summary of computed permeabilities, porosities, fracture spacings, and apertures averaged for several depth zons at each site are tabulated, and publications derived from the data are referenced; LBL-10080 Close

• 25. [Image] The Cody Hydrothermal System

  	The hot springs of Colter's Hell are the surface manifestations of a much larger hydrothermal system. That system has been studied to define its extent, maximum temperature, and mechanism of operation. ...
  	Citation × Citation Citation Abstract Copy Title: The Cody Hydrothermal System Author: Heasler, H.P. Year: 1982 The hot springs of Colter's Hell are the surface manifestations of a much larger hydrothermal system. That system has been studied to define its extent, maximum temperature, and mechanism of operation. The study area covers 2700 km/sup 2/ (1040 mi/sup 2/) in northwest Wyoming. Research and field work included locating and sampling the hot springs, geologic mapping, thermal logging of available wells, measuring thermal conductivities, analyzing over 200 oil and gas well bottom-hole temperatures, and compiling and analyzing hydrologic data. These data were used to generate a model for the hydrothermal system Title: The Cody Hydrothermal System Author: Heasler, H.P. Year: 1982 The hot springs of Colter's Hell are the surface manifestations of a much larger hydrothermal system. That system has been studied to define its extent, maximum temperature, and mechanism of operation. The study area covers 2700 km/sup 2/ (1040 mi/sup 2/) in northwest Wyoming. Research and field work included locating and sampling the hot springs, geologic mapping, thermal logging of available wells, measuring thermal conductivities, analyzing over 200 oil and gas well bottom-hole temperatures, and compiling and analyzing hydrologic data. These data were used to generate a model for the hydrothermal system Close

• 26. [Image] Geothermal energy enhancement by thermal fracture. [REX (Rock Energy Extraction)]

  	A large, vertical, circular fracture created deep within hot rock is connected to the surface through two holes. The inlet provides a source of cold water and the outlet extracts heated water. Cooling ...
  	Citation × Citation Citation Abstract Copy Title: Geothermal energy enhancement by thermal fracture. [REX (Rock Energy Extraction)] Author: Demuth, R.B. Year: 1980 A large, vertical, circular fracture created deep within hot rock is connected to the surface through two holes. The inlet provides a source of cold water and the outlet extracts heated water. Cooling of the rock produces thermal stresses that fracture the rock adjacent to the primary crack, thereby enhancing the heat extraction rate by means of convective transport. The properties of the thermal fracture network vary with position and time. The REX code for high-speed computer was written and used to study the coupled processes of primary-crack flow and lateral thermal fracture heat transport. Calculations for elapsed times of 100 y show that thermal fracture enhancement can double the heat extraction rate over the results from conduction alone. Long-term enhancement predictions depend on data from rock-mechanics studies, which the REX code is prepared to accept as they become available.; LA-8428 Title: Geothermal energy enhancement by thermal fracture. [REX (Rock Energy Extraction)] Author: Demuth, R.B. Year: 1980 A large, vertical, circular fracture created deep within hot rock is connected to the surface through two holes. The inlet provides a source of cold water and the outlet extracts heated water. Cooling of the rock produces thermal stresses that fracture the rock adjacent to the primary crack, thereby enhancing the heat extraction rate by means of convective transport. The properties of the thermal fracture network vary with position and time. The REX code for high-speed computer was written and used to study the coupled processes of primary-crack flow and lateral thermal fracture heat transport. Calculations for elapsed times of 100 y show that thermal fracture enhancement can double the heat extraction rate over the results from conduction alone. Long-term enhancement predictions depend on data from rock-mechanics studies, which the REX code is prepared to accept as they become available.; LA-8428 Close

• 27. [Image] Dipole-Dipole Resistivity Survey of a Portion of the Coso Hot Springs KGRA, Inyo County, California

  	A detailed electrical resistivity survey of 54 line-km was completed at the Coso Hot Springs KGRA in September 1977. This survey has defined a bedrock resistivity low at least 4 sq mi (10 sq km) in extent ...
  	Citation × Citation Citation Abstract Copy Title: Dipole-Dipole Resistivity Survey of a Portion of the Coso Hot Springs KGRA, Inyo County, California Author: Fox, R.C. Year: 1978 A detailed electrical resistivity survey of 54 line-km was completed at the Coso Hot Springs KGRA in September 1977. This survey has defined a bedrock resistivity low at least 4 sq mi (10 sq km) in extent associated with the geothermal system at Coso. The boundaries of this low are generally well defined to the north and west but not as well to the south where an approximate southern limit has been determined. The bedrock resistivity low merges with an observed resistivity low over gravel fill east of Coso Hot Springs. A complex horizontal and vertical resistivity structure of the surveyed area has been defined which precludes the use of layered-earth or two-dimensional interpretive models for much of the surveyed area. In general the survey data indicate that a 10 to 20 ohm-meter zone extends from near surface to a depth greater than 750 meters within the geothermal system. This zone is bordered to the north and west by bedrock resistivities greater than 200 ohm-meters and to the south by bedrock resistivities greater than 50 ohm-meters. A combination of observed increases in: (1) fracture density (higher permeability), (2) alteration (high clay content), and (3) temperatures (higher dissolved solid content of ground water) within the bedrock low explain its presence Title: Dipole-Dipole Resistivity Survey of a Portion of the Coso Hot Springs KGRA, Inyo County, California Author: Fox, R.C. Year: 1978 A detailed electrical resistivity survey of 54 line-km was completed at the Coso Hot Springs KGRA in September 1977. This survey has defined a bedrock resistivity low at least 4 sq mi (10 sq km) in extent associated with the geothermal system at Coso. The boundaries of this low are generally well defined to the north and west but not as well to the south where an approximate southern limit has been determined. The bedrock resistivity low merges with an observed resistivity low over gravel fill east of Coso Hot Springs. A complex horizontal and vertical resistivity structure of the surveyed area has been defined which precludes the use of layered-earth or two-dimensional interpretive models for much of the surveyed area. In general the survey data indicate that a 10 to 20 ohm-meter zone extends from near surface to a depth greater than 750 meters within the geothermal system. This zone is bordered to the north and west by bedrock resistivities greater than 200 ohm-meters and to the south by bedrock resistivities greater than 50 ohm-meters. A combination of observed increases in: (1) fracture density (higher permeability), (2) alteration (high clay content), and (3) temperatures (higher dissolved solid content of ground water) within the bedrock low explain its presence Close

• 28. [Image] Hot Dry Rock Geothermal Energy Development Program: Annual Report, Fiscal Year 1987

  	During fiscal year 1987, emphasis in the Hot Dry Rock Geothermal Energy Development Program was on preparations for a " Long-Term Flow Test " of the "Phase II" or "Engineering" hot dry rock energy system ...
  	Citation × Citation Citation Abstract Copy Title: Hot Dry Rock Geothermal Energy Development Program: Annual Report, Fiscal Year 1987 Author: Smith, M.C. Year: 1989 During fiscal year 1987, emphasis in the Hot Dry Rock Geothermal Energy Development Program was on preparations for a " Long-Term Flow Test " of the "Phase II" or "Engineering" hot dry rock energy system at Fenton Hill, New Mexico. A successful 30 day flow test of the system during FY86 indicated that such a system would produce heat at at temperature and rate that could support operation of a commercial electrical power plant. However, it did not answer certain questions basic to the economics of long-term operation, including the rate of depletion of the thermal reservoir, the rate of water loss from the system, and the possibility of operating problems during extended continuous operation. Preparations for a one year flow test of the system to answer these and more fundamental questions concerning hot dry rock systems were made in FY87: design of the required surface facilities; procurement and installation of some of their components; development and testing of slim line logging tools for use through small-diameter production tubing; research on temperature-sensitive reactive chemical tracers to monitor thermal depletion of the reservoir; and computer simulations of the 30-day test, extended to modeling the planned Long-Term Flow Test Title: Hot Dry Rock Geothermal Energy Development Program: Annual Report, Fiscal Year 1987 Author: Smith, M.C. Year: 1989 During fiscal year 1987, emphasis in the Hot Dry Rock Geothermal Energy Development Program was on preparations for a " Long-Term Flow Test " of the "Phase II" or "Engineering" hot dry rock energy system at Fenton Hill, New Mexico. A successful 30 day flow test of the system during FY86 indicated that such a system would produce heat at at temperature and rate that could support operation of a commercial electrical power plant. However, it did not answer certain questions basic to the economics of long-term operation, including the rate of depletion of the thermal reservoir, the rate of water loss from the system, and the possibility of operating problems during extended continuous operation. Preparations for a one year flow test of the system to answer these and more fundamental questions concerning hot dry rock systems were made in FY87: design of the required surface facilities; procurement and installation of some of their components; development and testing of slim line logging tools for use through small-diameter production tubing; research on temperature-sensitive reactive chemical tracers to monitor thermal depletion of the reservoir; and computer simulations of the 30-day test, extended to modeling the planned Long-Term Flow Test Close

• 29. [Image] Initial Investigation of Soil Mercury Geochemistry as an Aid to Drill Site Selection in Geothermal Systems

  	A mercury-in-soil survey was conducted at the Roosevelt Hot Springs Known Geothermal Resource Area (KGRA), Utah, to evaluate mercury soil geochemistry as a method of selecting exploration well sites in ...
  	Citation × Citation Citation Abstract Copy Title: Initial Investigation of Soil Mercury Geochemistry as an Aid to Drill Site Selection in Geothermal Systems Author: Capuano, R.M. Year: 1978 A mercury-in-soil survey was conducted at the Roosevelt Hot Springs Known Geothermal Resource Area (KGRA), Utah, to evaluate mercury soil geochemistry as a method of selecting exploration well sites in a hot-water geothermal system. Samples of -80 mesh soil were collected at 30.5 m intervals along traverses crossing known structures, surficial geothermal alteration, and exploration well sites, and were analyzed using a Gold Film Mercury Detector. Strong mercury anomalies occur at locations along known structures in close proximity to subsurface thermal activity; examples include areas over hot spring deposits and near a shallow producing well. In contrast, background mercury concentrations are present in nearby locations with little or no indication of subsurface thermal activity, such as areas around deep marginal producing wells and dry wells, and areas lacking hot spring deposits. These results indicate that mercury geochemical surveys can be useful for identifying and mapping structures controlling fluid flow in geothermal systems and for delineating areas overlying near-surface thermal activity. Soil mercury geochemistry thus provides information which may aid in the cost-effective selection of exploratory well sites Title: Initial Investigation of Soil Mercury Geochemistry as an Aid to Drill Site Selection in Geothermal Systems Author: Capuano, R.M. Year: 1978 A mercury-in-soil survey was conducted at the Roosevelt Hot Springs Known Geothermal Resource Area (KGRA), Utah, to evaluate mercury soil geochemistry as a method of selecting exploration well sites in a hot-water geothermal system. Samples of -80 mesh soil were collected at 30.5 m intervals along traverses crossing known structures, surficial geothermal alteration, and exploration well sites, and were analyzed using a Gold Film Mercury Detector. Strong mercury anomalies occur at locations along known structures in close proximity to subsurface thermal activity; examples include areas over hot spring deposits and near a shallow producing well. In contrast, background mercury concentrations are present in nearby locations with little or no indication of subsurface thermal activity, such as areas around deep marginal producing wells and dry wells, and areas lacking hot spring deposits. These results indicate that mercury geochemical surveys can be useful for identifying and mapping structures controlling fluid flow in geothermal systems and for delineating areas overlying near-surface thermal activity. Soil mercury geochemistry thus provides information which may aid in the cost-effective selection of exploratory well sites Close

• 30. [Image] Evaluation and Targeting of Geothermal Energy Resources in the Southeastern United States. Progress Report, May 1, 1976--October 31, 1976

  	Progress is reported in the development of procedures for the evaluation of low-temperature radiogenically-derived geothermal resources in the eastern United States utilizing geological geochemical, and ...
  	Citation × Citation Citation Abstract Copy Title: Evaluation and Targeting of Geothermal Energy Resources in the Southeastern United States. Progress Report, May 1, 1976--October 31, 1976 Author: Costain, J.K. Year: 1976 Progress is reported in the development of procedures for the evaluation of low-temperature radiogenically-derived geothermal resources in the eastern United States utilizing geological geochemical, and geophysical data. An optimum site for geothermal development in the tectonically stable eastern United States will probably be associated with crustal igneous rocks containing relatively high concentrations of radiogenic heat-producing elements buried beneath an insulating blanket of sediments of low thermal conductivity. Evaluation of plutonic rocks exposed in the Piedmont will aid in the interpretation of gravity and magnetic data for the Atlantic Coastal Plain. Initial results of determination of heat generation from surface samples in South Caroline are encouraging, especially if granitic igneous rocks of similar heat generation can be found beneath sedimentary insulation. Continues logging of existing wells in Coastal Plain sediments supports earlier conclusion that these sediments do behave as efficient sedimentary insulators. Higher temperatures appear to be reached at shallower depths for wells drilled in Coastal Plain sediments in the vicinity of the Georgetown, South Carolina gravity law. Detailed structural mapping in the vicinity of the warm springs in northwestern Virginia has confirmed structural control of the warm springs, and has revealed the existence of kink bands. The kink bands could be related to the development of zones of vertical permeability which serve as conduits in sedimentary rocks for ascending hot water. Title: Evaluation and Targeting of Geothermal Energy Resources in the Southeastern United States. Progress Report, May 1, 1976--October 31, 1976 Author: Costain, J.K. Year: 1976 Progress is reported in the development of procedures for the evaluation of low-temperature radiogenically-derived geothermal resources in the eastern United States utilizing geological geochemical, and geophysical data. An optimum site for geothermal development in the tectonically stable eastern United States will probably be associated with crustal igneous rocks containing relatively high concentrations of radiogenic heat-producing elements buried beneath an insulating blanket of sediments of low thermal conductivity. Evaluation of plutonic rocks exposed in the Piedmont will aid in the interpretation of gravity and magnetic data for the Atlantic Coastal Plain. Initial results of determination of heat generation from surface samples in South Caroline are encouraging, especially if granitic igneous rocks of similar heat generation can be found beneath sedimentary insulation. Continues logging of existing wells in Coastal Plain sediments supports earlier conclusion that these sediments do behave as efficient sedimentary insulators. Higher temperatures appear to be reached at shallower depths for wells drilled in Coastal Plain sediments in the vicinity of the Georgetown, South Carolina gravity law. Detailed structural mapping in the vicinity of the warm springs in northwestern Virginia has confirmed structural control of the warm springs, and has revealed the existence of kink bands. The kink bands could be related to the development of zones of vertical permeability which serve as conduits in sedimentary rocks for ascending hot water. Close