Coolbaugh DOE Peer Review 2003

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Geothermal Potential of the Pyramid Lake Paiute
Reservation, Nevada, USA Evidence of Previously
Unrecognized Moderate-Temperature (130-170C)
Geothermal Systems
Mark Coolbaugh, Jim Faulds, Chris Kratt, Gary
Oppliger, Lisa Shevenell, Wendy Calvin, William
Ehni, Rick Zehner Great Basin Center for
Geothermal Energy University of Nevada, Reno
Key assistance from John Jackson, Donna Noel,
PLPT Shuman Moore, Mack Shelor
Funded by GeoPowering the West Grant
DE-PS36-04GO94006
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Newberry Crater
Geothermal Systems in Nevada Great Basin, USA
Big Southern Butte
China Hat
Borax Lake
Medicine Lake
Pyramid Lake
Roosevelt/ Cove Fort
Mammoth
Current GB Geothermal Power Plant Capacity is
600 MWe
Coso
Boundary of Great Basin
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Pyramid Lake Paiute Reservation (1400 km2 not
including lake)
NE margin Walker Lane
Nevada
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Reconnaissance Assessment and Exploration The
First in Series of Steps to Develop Geothermal
Resources

• 1) Reconnaissance Exploration
• 2) Detailed Exploration and Assessment
• 3) Resource Development and Utilization

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Reconnaissance Exploration

• 1) Compilation of existing data (computer GIS)
• 2) Hyperspectral remote sensing
• 3) Regional assessment of structures and faults
• 4) Field examinations
• - spring and well sampling
• - check areas of potential interest

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• DATA General Sources of Information plus Water
  temperatures, depths, geochemistry

Geothermal Resources Council http//www.geother
mal.org/ Great Basin Center for Geothermal
Energy http//www.unr.edu/geothermal/ Nevada
Bureau of Mines and Geology http//www.nbmg.unr.
edu/geothermal/ Nevada Well Drillers Database
http//water.nv.gov/Engineering/welldrill.htm
NWIS http//waterdata.usgs.gov/nwis Geo-Heat
Center http//geoheat.oit.edu/ Tribal Databases
and People
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• Data Geothermal Wells
• Southern Methodist University
• http//www.smu.edu/geothermal/
• United States Geological Survey
• http//pubs.usgs.gov/of/1999/of99-425/webma
  ps/home.html
• http//pubs.usgs.gov/of/2005/1207/
• Nevada Division of Minerals
• http//minerals.state.nv.us/
• Exploration Companies and Consultants

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• DATA Geophysics
• Great Basin Center for Geothermal Energy
• http//www.unr.edu/geothermal/
• (gravity and magnetics compilations)
• Southern Methodist University
• http//geoheat.oit.edu/
• (for heat flow and temperature gradient data)
• United States Geological Survey
• http//pubs.usgs.gov/of/1999/of99-425/webmap
  s/home.html
• http//pubs.usgs.gov/of/2005/1207/
• (for heat flow and temperature gradient data)

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• DATA Remote Sensing
• ASTER, LANDSAT Multispectral
• NASA EOS Data Gateway
• http//edcimswww.cr.usgs.gov/pub/imswelcome/
  
• AVIRIS Hyperspectral Imagery
• Jet Propulsion Laboratory (JPL)
• http//aviris.jpl.nasa.gov/html/aviris.task.htm
  l
• Other Hyperspectral Imagery
• Remote Sensing Companies (recently used by
  UNR)
• HyVista Corp http//www.hyvista.com/
• SpecTIR http//www.spectir.com/
• there are many other remote sensing providers
  

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Reconnaissance Exploration

• 1) Compilation of existing data (computer GIS)
• 2) Hyperspectral remote sensing
• 3) Regional assessment of structures and faults
• 4) Field examinations
• - spring and well sampling
• - check areas of potential interest

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Reconnaissance Exploration

• 1) Compilation of existing data (computer GIS)
• 2) Hyperspectral remote sensing
• 3) Regional assessment of structures and faults
• 4) Field examinations
• - spring and well sampling
• - check areas of potential interest

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Silicified sediments (opal)
All blind geothermal systems in Nevada that are
currently producing electricity have surface
geothermal signatures
Carbonate tufa/travertine
Clay alteration
Borate and sulfate evaporites
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Diagnostic Spectral Features
siliceous sinter carbonaceous travertine/tufa sulf
ate and borate evaporites hydrothermal alteration
(clay) thermal anomalies
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Remote Sensing for mapping mineralogy and thermal
anomalies
Hymap 3-5 meter
Nixon, NV
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Olinghouse Pyramid Lake faults
Truckee River
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Reconnaissance Exploration

• 1) Compilation of existing data (computer GIS)
• 2) Hyperspectral remote sensing
• 3) Regional assessment of structures and faults
• 4) Field examinations
• - spring and well sampling
• - check areas of potential interest

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Favorable Structural Environments

• 1) Step Overs in Normal Faults
• 2) Step Overs in Strike-slip Faults
• 3) Changes in Dip of Normal Faults
• 4) Northeast-striking young faults
• 5) Rotational Block Terminations in Strike-Slip
  Fault Zones
• 6) Fault Intersections

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Reconnaissance Exploration

• 1) Compilation of existing data (computer GIS)
• 2) Hyperspectral remote sensing
• 3) Regional assessment of structures and faults
• 4) Field examinations
• - spring and well sampling
• - temperatures/geochemistry
• - check areas of potential interest

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Spring and well sampling for temperatures and
geochemistry
160 sites visited
2000 ft cable for well temperatures
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For measurement of temperatures in existing
wells, this equipment pays for itself very quickly
Depth meter
Down-hole temperature probe with 2,000 ft of wire
cable and platinum RTD with temperature-resistant
seals
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Hand augers were used to obtain temperatures at a
depth of 2.1 meters below surface
Valuable for pinpointing zones of thermal
upwelling Helps minimize the number of
temperature gradient wells
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RESULTS Pyramid Lake Paiute Reservation
- identification of 3 previously unknown
moderate- temperature geothermal systems
(?130C) with surface thermal features
supportive geothermometry
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Pyramid Lake Paiute Reservation
Pyramid Rock - boiling spring - 153C
geothermometers ( 15 miles from Needle Rocks)
There are other poorly documented occurrences of
hot water in the Great Basin that have not been
evaluated
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Tufa tower near Astor Pass, Pyramid Lake Paiute
Reservation - near-boiling water (94C) at 200
ft depth beneath tower - other than the tufa,
there are no other surface geothermal
indicators - a strong shallow temperature
anomaly is present
Needle Rocks 6 km away
Discovered during reconnaissance geothermal
exploration - young northwest-striking
faults extending from Needle Rocks -
argillic alteration in adjacent Terraced Hills
- tufa tower
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Detailed gravity and magnetic surveys were used
for specific drill-hole targeting and played a
key role in the discovery
Temperatures in 2-meter-deep auger holes were
used to minimize the number of temperature
gradient wells drilled
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Smoke Creek Desert, Pyramid Lake Paiute
Reservation - discovered during
reconnaissance geothermal exploration
large sulfate anomaly detected with
hyperspectral imagery
systematic spring and well sampling program
Estimates of geothermal reservoir temperature
148-165C
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Shallow temperature measurements at 2-meter depth
helped pinpoint possible upwelling zone near
tufas at step-over in range front fault (orange
ellipse)
Smoke Creek Desert
Warmer colored squares indicate warmer
temperatures at a 2-meter depth
Purple remotely sensed gypsum anomaly
Yellow, orange, and red stars are warm and hot
wells and springs
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Tufa towers form by reaction of Ca in groundwater
with CO2 in lake water (in this case, former Lake
Lahontan, western NV)
Astor Pass
Smoke Creek Desert
Pyramid Rock
Needle Rocks
Tufa towers, Pyramid Lake Reservation Reservoir
temps 130-170 C
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Travertine forms around some thermal springs but
it can also form around non-thermal springs.
Sou Hot Springs, NV
Dianas Punch Bowl, NV
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Tufa towers form by reaction of Ca in groundwater
with CO2 in lake water (in this case, former Lake
Lahontan, western NV)
Astor Pass
Smoke Creek Desert
Pyramid Rock
Needle Rocks
Tufa towers, Pyramid Lake Reservation Reservoir
temps 130-170 C
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Tufa waters have higher calcium to bicarbonate
ratios, consistent with the different mechanism
of formation of tufas vs travertines
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Tufa waters have chloride contents typical of
Na-Cl geothermal waters, and have higher silica
contents and higher geothermometer temperatures
compared to travertine waters
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CONCLUSIONS
1) New grass-roots geothermal targets can still
be found in the Great Basin with systematic
reconnaissance exploration programs 2) With the
help of digital databases, technology, and
computers it is possible to design and implement
rapid and effective reconnaissance exploration
programs 3) More geothermal systems are likely
to be found beneath unexplored tufas in the Great
Basin
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The End