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• 1. [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

• 2. [Image] Assessment of geothermal resources of Caliente, Nevada

  	An assessment of the geothermal resources of Caliente, Nevada was made to provide information on resource characteristics and to site 2 (two) 500 ft (152 m) test wells to confirm the resource. The strategy ...
  	Citation × Citation Citation Abstract Copy Title: Assessment of geothermal resources of Caliente, Nevada Author: Trexler, D.T. Year: 1980 An assessment of the geothermal resources of Caliente, Nevada was made to provide information on resource characteristics and to site 2 (two) 500 ft (152 m) test wells to confirm the resource. The strategy used in the resource assessment employed a logical sequence of work elements that included 1) baseline data collection, 2) field investigations, 3) laboratory analyses and 4) data interpretation and synthesis. Airphoto interpretation indicated that a series of normal faults produced a stepped arrangement in the canyon walls on the west side of Meadow Valley Wash north of downtown Caiente. This area coincides with the area of known geothermal occurrences. Temperature measurements in existing wells indicate a rapid cooling of the geothermal waters as they mix with cold groundwater flows in Meadow Valley Wash. Soil mercury analyses range from 15 ppB to as high as 120 ppB. Trends in soil mercury content may indicate the presence of buried faults. Temperature measured in 2-meter deep auger holes indicated temperatures as high as 40/sup 0/C in an area north of the Lincoln County Medical Facility. Interpretation of chemical analyses, both major and minor, of waters collected from wells and streams in the area failed to conclusively show any mechanisms for the mixing of thermal and nonthermal waters. The selection of sites for the 2 (two) 500 ft (152 m) reservoir confirmation wells was made using the results of temperature surveys, geologic structure and historic observations; DOE/NV/10039-1 Title: Assessment of geothermal resources of Caliente, Nevada Author: Trexler, D.T. Year: 1980 An assessment of the geothermal resources of Caliente, Nevada was made to provide information on resource characteristics and to site 2 (two) 500 ft (152 m) test wells to confirm the resource. The strategy used in the resource assessment employed a logical sequence of work elements that included 1) baseline data collection, 2) field investigations, 3) laboratory analyses and 4) data interpretation and synthesis. Airphoto interpretation indicated that a series of normal faults produced a stepped arrangement in the canyon walls on the west side of Meadow Valley Wash north of downtown Caiente. This area coincides with the area of known geothermal occurrences. Temperature measurements in existing wells indicate a rapid cooling of the geothermal waters as they mix with cold groundwater flows in Meadow Valley Wash. Soil mercury analyses range from 15 ppB to as high as 120 ppB. Trends in soil mercury content may indicate the presence of buried faults. Temperature measured in 2-meter deep auger holes indicated temperatures as high as 40/sup 0/C in an area north of the Lincoln County Medical Facility. Interpretation of chemical analyses, both major and minor, of waters collected from wells and streams in the area failed to conclusively show any mechanisms for the mixing of thermal and nonthermal waters. The selection of sites for the 2 (two) 500 ft (152 m) reservoir confirmation wells was made using the results of temperature surveys, geologic structure and historic observations; DOE/NV/10039-1 Close

• 3. [Image] Low-Temperature Geothermal Potential of the Ojo Caliente Warm Springs Area, Northern New Mexico

  	A detailed geochemical investigation of 17 waters (thermal and cold, mineralized and dilute) was performed in the Ojo Caliente-La Madera area. Two types of thermomineral waters have separate and distinctive ...
  	Citation × Citation Citation Abstract Copy Title: Low-Temperature Geothermal Potential of the Ojo Caliente Warm Springs Area, Northern New Mexico Author: Vuataz, F.D. Year: 1984 A detailed geochemical investigation of 17 waters (thermal and cold, mineralized and dilute) was performed in the Ojo Caliente-La Madera area. Two types of thermomineral waters have separate and distinctive geologic, geochemical, and geothermal characteristics. The water from Ojo Caliente Resort emerges with temperatures less than or equal to 54/sup 0/C from a Precambrian metarhyolite. Its chemistry, typically Na-HCO/sub 3/, has a total mineralization of 3600 mg/l. Isotopic studies have shown that the thermal water emerges from the springs and a hot well without significant mixing with the cold shallow aquifer of the valley alluvium. However, the cold aquifer adjacent to the resort does contain varying amounts of thermal water that originates from the warm spring system. Geothermometry calculations indicate that the thermal water may be as hot as 85/sup 0/C at depth before its ascent toward surface. Thermodynamic computations on the reaction states of numerous mineral phases suggest that the thermal water will not cause major scaling problems if the hot water is utilized for direct-use geothermal applications. By means of a network of very shallow holes, temperature and electrical conductivity anomalies have been found elsewhere in the valley around Ojo Caliente, and resistivity soundings have confirmed the presence of a plume of thermal water entering the shallow aquifer. The group of lukewarm springs around La Madera, with temperatures less than or equal to 29/sup 0/C, chemical type of NaCaMg-HCO/sub 3/Cl and with a total mineralization less than or equal to 1500 mg/l behaves as a different system without any Apparent relation to the Ojo Caliente system. Its temperature at depth is not believed to exceed 35 to 40/sup 0/C Title: Low-Temperature Geothermal Potential of the Ojo Caliente Warm Springs Area, Northern New Mexico Author: Vuataz, F.D. Year: 1984 A detailed geochemical investigation of 17 waters (thermal and cold, mineralized and dilute) was performed in the Ojo Caliente-La Madera area. Two types of thermomineral waters have separate and distinctive geologic, geochemical, and geothermal characteristics. The water from Ojo Caliente Resort emerges with temperatures less than or equal to 54/sup 0/C from a Precambrian metarhyolite. Its chemistry, typically Na-HCO/sub 3/, has a total mineralization of 3600 mg/l. Isotopic studies have shown that the thermal water emerges from the springs and a hot well without significant mixing with the cold shallow aquifer of the valley alluvium. However, the cold aquifer adjacent to the resort does contain varying amounts of thermal water that originates from the warm spring system. Geothermometry calculations indicate that the thermal water may be as hot as 85/sup 0/C at depth before its ascent toward surface. Thermodynamic computations on the reaction states of numerous mineral phases suggest that the thermal water will not cause major scaling problems if the hot water is utilized for direct-use geothermal applications. By means of a network of very shallow holes, temperature and electrical conductivity anomalies have been found elsewhere in the valley around Ojo Caliente, and resistivity soundings have confirmed the presence of a plume of thermal water entering the shallow aquifer. The group of lukewarm springs around La Madera, with temperatures less than or equal to 29/sup 0/C, chemical type of NaCaMg-HCO/sub 3/Cl and with a total mineralization less than or equal to 1500 mg/l behaves as a different system without any Apparent relation to the Ojo Caliente system. Its temperature at depth is not believed to exceed 35 to 40/sup 0/C Close

• 4. [Image] Geotechnical Studies of Geothermal Reservoirs

  	Maximum temperatures found in the reservoir were approximately 700°F in the Imperial Valley, California, but drill bit temperatures may be considerably higher in the Geysers geothermal area. Temperatures ...
  	Citation × Citation Citation Abstract Copy Title: Geotechnical Studies of Geothermal Reservoirs Author: Pratt, H. R. Year: 1976 Maximum temperatures found in the reservoir were approximately 700°F in the Imperial Valley, California, but drill bit temperatures may be considerably higher in the Geysers geothermal area. Temperatures reached up to 900°F because of frictional heating and possibly inefficient cooling. Rock types found in the high temperature environments range from hard abrasive granites and metamorphosed sandstones to unconsolidated sediments and friable sandstones. The rocks are highly fractured at reservoir depths Title: Geotechnical Studies of Geothermal Reservoirs Author: Pratt, H. R. Year: 1976 Maximum temperatures found in the reservoir were approximately 700°F in the Imperial Valley, California, but drill bit temperatures may be considerably higher in the Geysers geothermal area. Temperatures reached up to 900°F because of frictional heating and possibly inefficient cooling. Rock types found in the high temperature environments range from hard abrasive granites and metamorphosed sandstones to unconsolidated sediments and friable sandstones. The rocks are highly fractured at reservoir depths Close

• 5. [Image] Geological and Geophysical Analysis of Coso Geothermal Exploration Hole No. 1 (CGEH-1), Coso Hot Springs KGRA, California

  	The Coso Geothermal Exploration Hole number one (CGEH-1) was drilled in the Coso Hot Springs KGRA, California from September 2 to December 2, 1977. Chip samples were collected at ten foot intervals and ...
  	Citation × Citation Citation Abstract Copy Title: Geological and Geophysical Analysis of Coso Geothermal Exploration Hole No. 1 (CGEH-1), Coso Hot Springs KGRA, California Author: Galbraith, R.M. Year: 1978 The Coso Geothermal Exploration Hole number one (CGEH-1) was drilled in the Coso Hot Springs KGRA, California from September 2 to December 2, 1977. Chip samples were collected at ten foot intervals and extensive geophysical logging surveys were conducted to document the geologic character of the geothermal system as penetrated by CGEH-1. The major rock units encountered include a mafic metamorphic sequence and a leucogranite which intruded the metamorphic rocks. Only weak hydrothermal alteration was noted in these rocks. Drillhole surveys and drilling rate data indicate that the geothermal system is structurally controlled and that the drillhole itself was strongly influenced by structural zones. Water chemistry indicates that this geothermal resource is a hot-water rather than a vapor-dominated system. Several geophysical logs were employed to characterize the drillhole geology. The natural gamma and neutron porosity logs indicate gross rock type and the acoustic logs indicate fractured rock and potentially permeable zones. A series of temperature logs run as a function of time during and after the completion of Drilling were most Useful in delineating the zones of maximum heat flux. Convective heat flow and temperatures greater than 350/sup 0/F appear to occur only along an open fracture system encountered between depths of 1850 and 2775 feet. Temperature logs indicate a negative thermal gradient below 3000 feet Title: Geological and Geophysical Analysis of Coso Geothermal Exploration Hole No. 1 (CGEH-1), Coso Hot Springs KGRA, California Author: Galbraith, R.M. Year: 1978 The Coso Geothermal Exploration Hole number one (CGEH-1) was drilled in the Coso Hot Springs KGRA, California from September 2 to December 2, 1977. Chip samples were collected at ten foot intervals and extensive geophysical logging surveys were conducted to document the geologic character of the geothermal system as penetrated by CGEH-1. The major rock units encountered include a mafic metamorphic sequence and a leucogranite which intruded the metamorphic rocks. Only weak hydrothermal alteration was noted in these rocks. Drillhole surveys and drilling rate data indicate that the geothermal system is structurally controlled and that the drillhole itself was strongly influenced by structural zones. Water chemistry indicates that this geothermal resource is a hot-water rather than a vapor-dominated system. Several geophysical logs were employed to characterize the drillhole geology. The natural gamma and neutron porosity logs indicate gross rock type and the acoustic logs indicate fractured rock and potentially permeable zones. A series of temperature logs run as a function of time during and after the completion of Drilling were most Useful in delineating the zones of maximum heat flux. Convective heat flow and temperatures greater than 350/sup 0/F appear to occur only along an open fracture system encountered between depths of 1850 and 2775 feet. Temperature logs indicate a negative thermal gradient below 3000 feet Close

• 6. [Image] Report of the Geophysical Measurements in Geothermal Wells Workshop, Airport Marina Hotel, Albuquerque, New Mexico, September 17--19, 1975

  	This report presents results of a Workshop on Geophysical Measurements in Geothermal Wells, hosted in Albuquerque, September 17-19, by Sandia Laboratories and jointly sponsored by the United States Geological ...
  	Citation × Citation Citation Abstract Copy Title: Report of the Geophysical Measurements in Geothermal Wells Workshop, Airport Marina Hotel, Albuquerque, New Mexico, September 17--19, 1975 Author: Baker, L.E. Year: 1975 This report presents results of a Workshop on Geophysical Measurements in Geothermal Wells, hosted in Albuquerque, September 17-19, by Sandia Laboratories and jointly sponsored by the United States Geological Survey and the Energy Research and Development Administration. During the workshop, tutorial papers dealing with the geothermal resource, geothermal logging, and high temperature technology were followed by working panel sessions. Three panels deliberated, respectively, well and reservoir parameters, log interpretation, and high temperature technology. In a final session, the reports of the panels were heard and discussed by the full workshop. A summary of the workshop conclusions and recommendations, as well as the complete panel statements, are presented. (auth) Title: Report of the Geophysical Measurements in Geothermal Wells Workshop, Airport Marina Hotel, Albuquerque, New Mexico, September 17--19, 1975 Author: Baker, L.E. Year: 1975 This report presents results of a Workshop on Geophysical Measurements in Geothermal Wells, hosted in Albuquerque, September 17-19, by Sandia Laboratories and jointly sponsored by the United States Geological Survey and the Energy Research and Development Administration. During the workshop, tutorial papers dealing with the geothermal resource, geothermal logging, and high temperature technology were followed by working panel sessions. Three panels deliberated, respectively, well and reservoir parameters, log interpretation, and high temperature technology. In a final session, the reports of the panels were heard and discussed by the full workshop. A summary of the workshop conclusions and recommendations, as well as the complete panel statements, are presented. (auth) Close

• 7. [Image] Low-Temperature Geothermal Reservoir Site Evaluation in Arizona. Quarterly Progress Report, November 1, 1977--January 31, 1978

  	The Department of Energy, Division of Geothermal Energy, has charged the Bureau of Geology and Mineral Technology, Geological Survey Branch with development of a cost-effective exploration program for ...
  	Citation × Citation Citation Abstract Copy Title: Low-Temperature Geothermal Reservoir Site Evaluation in Arizona. Quarterly Progress Report, November 1, 1977--January 31, 1978 Author: Hahman, W.R. Sr. Year: 1978 The Department of Energy, Division of Geothermal Energy, has charged the Bureau of Geology and Mineral Technology, Geological Survey Branch with development of a cost-effective exploration program for low- to moderate-temperature geothermal resources. As part of this program two or three demonstration projects in Arizona will be brought on stream. The site-specific exploration, evaluation and development program as well as the state wide reconnaissance exploration program is continuing. The compilation of data for the 1 : 500,000 geothermal energy resource map is continuing. Drafting and data collection for the 1 : 1,000,000 Preliminary map, Geothermal Energy Resources of Arizona, Geothermal Map No. 1, requested the first week in January by DOE/DGE is nearing completion. This preliminary map should be published in March, 1978. All outside projects are either complete or on schedule Title: Low-Temperature Geothermal Reservoir Site Evaluation in Arizona. Quarterly Progress Report, November 1, 1977--January 31, 1978 Author: Hahman, W.R. Sr. Year: 1978 The Department of Energy, Division of Geothermal Energy, has charged the Bureau of Geology and Mineral Technology, Geological Survey Branch with development of a cost-effective exploration program for low- to moderate-temperature geothermal resources. As part of this program two or three demonstration projects in Arizona will be brought on stream. The site-specific exploration, evaluation and development program as well as the state wide reconnaissance exploration program is continuing. The compilation of data for the 1 : 500,000 geothermal energy resource map is continuing. Drafting and data collection for the 1 : 1,000,000 Preliminary map, Geothermal Energy Resources of Arizona, Geothermal Map No. 1, requested the first week in January by DOE/DGE is nearing completion. This preliminary map should be published in March, 1978. All outside projects are either complete or on schedule Close

• 8. [Image] Research on the Physical Properties of Geothermal Reservoir Rock. Quarterly Report, March 1978

  	A laboratory study of the P-wave velocity and electric Resistivity was undertaken on Cenozoic Volcanic Rocks collected from the Columbia Plateau Volcanic basin (C) and the Jemez Volcanic field (NM). Electric ...
  	Citation × Citation Citation Abstract Copy Title: Research on the Physical Properties of Geothermal Reservoir Rock. Quarterly Report, March 1978 Author: Keller, G.V. Year: 1978 A laboratory study of the P-wave velocity and electric Resistivity was undertaken on Cenozoic Volcanic Rocks collected from the Columbia Plateau Volcanic basin (C) and the Jemez Volcanic field (NM). Electric resistivities of cylindrical samples saturated with 0.1 N NaCl solution were measured using a four electrode system and a 1.0 KHz frequency source. Seismic P-wave velocities were calculated from measured transit time of mechanical pulses generated and received by piezoelectric transducers. The electric Resistivity of water saturated Samples decreased as temperature increased to the boiling point of water. Above boiling point, Resistivity increased rapidly as water changed to vapor. Resistivity is most sensitive to temperature changes between 35/sup 0/C to 65/sup 0/C. Resistivities of samples increased with decrease in saturation. The effect is more pronounced at lower temperatures. No dependence of seismic P-wave velocities on temperature was observed. Both Resistivity and P-wave velocity depend on porosity. The increase in porosity results in a decrease in the Resistivity formation factor. Assuming a relationship FF = a phi/sup -m/ (Archie's Law), where FF and phi represent the formation factor and porosity respectively, least squares indicate a variation of a between .5 and 2.0. The value of m varied between 1.2 to 1.7. Seismic velocities (v) decrease as porosity increases. Porosity appears to be linearly related to log v. Several Samples show anomalous relationship between porosity and Resistivity. Most of these samples also show anomalous seismic velocities. The majority of these samples have coarse grains or large pores. The effect of saturation on P-wave velocity is small and can be observed in few samples. In these samples, seismic velocities decrease with increase in saturation at high saturation (100% to 85%), and show a reverse relationship at low saturation. Between 15% and 85% saturation in velocity is constant Title: Research on the Physical Properties of Geothermal Reservoir Rock. Quarterly Report, March 1978 Author: Keller, G.V. Year: 1978 A laboratory study of the P-wave velocity and electric Resistivity was undertaken on Cenozoic Volcanic Rocks collected from the Columbia Plateau Volcanic basin (C) and the Jemez Volcanic field (NM). Electric resistivities of cylindrical samples saturated with 0.1 N NaCl solution were measured using a four electrode system and a 1.0 KHz frequency source. Seismic P-wave velocities were calculated from measured transit time of mechanical pulses generated and received by piezoelectric transducers. The electric Resistivity of water saturated Samples decreased as temperature increased to the boiling point of water. Above boiling point, Resistivity increased rapidly as water changed to vapor. Resistivity is most sensitive to temperature changes between 35/sup 0/C to 65/sup 0/C. Resistivities of samples increased with decrease in saturation. The effect is more pronounced at lower temperatures. No dependence of seismic P-wave velocities on temperature was observed. Both Resistivity and P-wave velocity depend on porosity. The increase in porosity results in a decrease in the Resistivity formation factor. Assuming a relationship FF = a phi/sup -m/ (Archie's Law), where FF and phi represent the formation factor and porosity respectively, least squares indicate a variation of a between .5 and 2.0. The value of m varied between 1.2 to 1.7. Seismic velocities (v) decrease as porosity increases. Porosity appears to be linearly related to log v. Several Samples show anomalous relationship between porosity and Resistivity. Most of these samples also show anomalous seismic velocities. The majority of these samples have coarse grains or large pores. The effect of saturation on P-wave velocity is small and can be observed in few samples. In these samples, seismic velocities decrease with increase in saturation at high saturation (100% to 85%), and show a reverse relationship at low saturation. Between 15% and 85% saturation in velocity is constant Close

• 9. [Image] Evaluation and Targeting of Geothermal Energy Resources in the Southeastern United States. Progress Report, October 1--December 31, 1977

  	Progress in the evaluation of low-temperature geothermal resources in the eastern United States utilizing geological, geochemical, and geophysical data is reported. Primary programmatic emphasis is now ...
  	Citation × Citation Citation Abstract Copy Title: Evaluation and Targeting of Geothermal Energy Resources in the Southeastern United States. Progress Report, October 1--December 31, 1977 Author: Costain, J.K. Year: 1978 Progress in the evaluation of low-temperature geothermal resources in the eastern United States utilizing geological, geochemical, and geophysical data is reported. Primary programmatic emphasis is now being placed on the confirmation of radiogenic resources beneath sediments of the Atlantic Coastal Plain. Collation of existing gravity and magnetic data available for the Atlantic Coastal Plain is complete, and modeling of selected negative gravity anomalies of the Cuffytown Creek (Edgefield) pluton, S.C., the Rolesville batholith, N.C., and the Petersburg granite, Va., is in progress. Maps showing the distribution of gravity stations for the states of Georgia, South Carolina, and North Carolina were prepared. A reconnaissance geologic map is being prepared of the Raleigh belt and Carolina slate belt rocks. The purpose of this study is to determine the relationship of the Rolesville batholith to the surrounding country rocks, and to provide a geologic base for the geophysical interpretation of Piedmont stratigraphy underlying Atlantic Coastal Plain sediments to the east Title: Evaluation and Targeting of Geothermal Energy Resources in the Southeastern United States. Progress Report, October 1--December 31, 1977 Author: Costain, J.K. Year: 1978 Progress in the evaluation of low-temperature geothermal resources in the eastern United States utilizing geological, geochemical, and geophysical data is reported. Primary programmatic emphasis is now being placed on the confirmation of radiogenic resources beneath sediments of the Atlantic Coastal Plain. Collation of existing gravity and magnetic data available for the Atlantic Coastal Plain is complete, and modeling of selected negative gravity anomalies of the Cuffytown Creek (Edgefield) pluton, S.C., the Rolesville batholith, N.C., and the Petersburg granite, Va., is in progress. Maps showing the distribution of gravity stations for the states of Georgia, South Carolina, and North Carolina were prepared. A reconnaissance geologic map is being prepared of the Raleigh belt and Carolina slate belt rocks. The purpose of this study is to determine the relationship of the Rolesville batholith to the surrounding country rocks, and to provide a geologic base for the geophysical interpretation of Piedmont stratigraphy underlying Atlantic Coastal Plain sediments to the east Close

• 10. [Image] Geothermal exploration assessment and interpretation, Upper Klamath Lake Area, Klamath Basin, Oregon

  	Data from public and private sources on the Klamath Basin geothermal resource are reviewed, synthesized, and reinterpreted. In this, the second and final phase of the work, geological, remote sensing, ...
  	Citation × Citation Citation Abstract Copy Title: Geothermal exploration assessment and interpretation, Upper Klamath Lake Area, Klamath Basin, Oregon Author: Stark, M. Year: 1980 Data from public and private sources on the Klamath Basin geothermal resource are reviewed, synthesized, and reinterpreted. In this, the second and final phase of the work, geological, remote sensing, geochemical, temperature gradient, gravity, aeromagnetic, and electrical resistivity data sets are examined. These data were derived from surveys concentrated on the east and west shores of Upper Klamath Lake. The geological, remote sensing, and potential field data suggest a few northeast-trending discontinuities, which cross the regional north-westerly strike. The near-surface distribution of warm water appears to be related to the intersections of these lineaments and northwest-trending faults. The groundwater geochemical data are reviewed and the various reservoir temperature estimates compared. Particular attention is given to specific electrical conductivities of waters as an interpretational aid to the subsurface resistivity results. A clear trend emerges in the Klamath Falls/Olene Gap area; hotter waters are associated with higher specific conductivities. In the Nuss Lake/Stukel Mountain area the opposite trend prevails, although the relationship is somewhat equivocal; LBL-10140 Title: Geothermal exploration assessment and interpretation, Upper Klamath Lake Area, Klamath Basin, Oregon Author: Stark, M. Year: 1980 Data from public and private sources on the Klamath Basin geothermal resource are reviewed, synthesized, and reinterpreted. In this, the second and final phase of the work, geological, remote sensing, geochemical, temperature gradient, gravity, aeromagnetic, and electrical resistivity data sets are examined. These data were derived from surveys concentrated on the east and west shores of Upper Klamath Lake. The geological, remote sensing, and potential field data suggest a few northeast-trending discontinuities, which cross the regional north-westerly strike. The near-surface distribution of warm water appears to be related to the intersections of these lineaments and northwest-trending faults. The groundwater geochemical data are reviewed and the various reservoir temperature estimates compared. Particular attention is given to specific electrical conductivities of waters as an interpretational aid to the subsurface resistivity results. A clear trend emerges in the Klamath Falls/Olene Gap area; hotter waters are associated with higher specific conductivities. In the Nuss Lake/Stukel Mountain area the opposite trend prevails, although the relationship is somewhat equivocal; LBL-10140 Close