REVIEW OF SELECTED GEOTHERMAL AREAS IN SOUTHWESTERN UTAH

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REVIEW OF SELECTED GEOTHERMAL AREAS IN
SOUTHWESTERN UTAH

• Robert Blackett
• Utah Geological Survey
• Cedar City, Utah

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Sevier Thermal Area

• Located in SW Utah
• Eastern BR province and BR-CP Transition Zone
• Most identified moderate and high-temperature
  systems in Utah
• Several geothermal areas situated near
  transverse zones of Rowley and Dixon (2001)

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Sevier Thermal Area

• Abundant late Cenozoic normal faults
• Tertiary plutonic and volcanic rocks
• Quaternary (bimodal) basalt and rhyolite
• High regional heat flow
• Complex structural history
• Active seismicity (ISB)
• transverse zones Rowley and Dixon (2001)

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Sevier Thermal Area

• Centered on RHS and CFS geothermal power
  projects
• Drum Mtns. WWV - Crater Springs prospect
• Neels RR Siding Well - prospect
• Meadow-Hatton undeveloped
• Monroe-Joseph resort
• Thermo HS undeveloped
• Beryl-Woods Ranch prospect
• Newcastle large, commercial greenhouses

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Drum Mountains - Whirlwind Valley

• Geothermal prospect (?) at head of Whirlwind
  Valley
• No surface manifestations
• Includes parts of the Drum and Little Drum
  Mountains
• Quaternary eruptive center at Crater Bench
  Fumarole Butte
• Little Drum Mountains are Eocene-Oligocene
  intermediate volcanics
• Within the Ely-Tintic igneous belt
• Near the Payson - Sand Pass transverse zones
• Later overprinting of BR faulting produced the
  north-south oriented DMFZ

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Drum Mountains - Whirlwind Valley

• Temperature-depth data from shallow boreholes
  drilled during the 1970s and 1980s (INL, USGS,
  SMU)
• Highest BHT - 70C at 150 m (310C/km)

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Crater Springs Geothermal Area

• Surrounds Pleistocene basaltic volcano - Fumarole
  Butte
• NNE-trending DMFZ offsets basalt on west-central
  side of Crater Bench at Fumarole Butte
• Warm vapor rises from several fissures in the
  vicinity of Fumarole Butte
• Abraham (Crater, Baker) hot springs issues 4
  miles east of Fumarole Butte along the east
  margin of Crater Bench

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Abraham Hot Springs

• Temperatures up to 87C
• Flows up to 8400 L/min (40 spring orifices)
• Na-Ca-Cl type, TDS from 3590 to 4060 mg/L
• 20 MWt discharge

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Crater Springs Geothermal Area

• Mabey Budding (1987) suggest gravity high
  trending NNW with axis through AHS is a possible
  buried horst block, and vapor at FB and water at
  AHS are part of same geothermal system
• Rush, 1983 suggests possible high-density
  volcanic rocks or hydrothermal mineralization
  used silica-enthalpy mixing model 50
  non-thermal water hot water component could be
  140C

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Meadow-Hatton Geothermal Area
Meadow-Hatton Geothermal Area
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Meadow-Hatton Geothermal Area
Young Geologic Features

• Pavant Butte basalts 15,500 yrs
• Tabernacle Hill basalt 14,300 yrs
• Ice Springs basalt - less than 1,000 yrs
• White Mountain rhyolite dome 400,000
• NNE Quaternary faults

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Meadow-Hatton Geothermal Area

• Hatton Hot Spring issues 63C (145F) at south
  end of large travertine mound
• Meadow Hot Springs issues 41C (106F) located
  NW of Hatton travertine mound
• Springs coupled to the regional ground-water flow
  system

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Meadow-Hatton Geothermal Area

• SP surveys reveal 3 minima near southern part of
  travertine mound
• Lowest (most distinct) minimum (-120 mV) lies 300
  m (1000 ft) northeast of Hatton Hot Spring
• Water chemistry appears to vary temporally over
  years/seasons (K, Si, F)
• Standard geothermometers 86C (187F) -
  Na-K-Ca-Mg), 108C (226F) - quartz conductive
  111C (232F) K/Mg

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Meadow-Hatton Geothermal Area
Meadow-Hatton Geothermal Area

• Large area of travertine (CaCO3 tufa) associated
  with hot springs
• Tufa as much as 30 meters thick

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Meadow-Hatton Geothermal Area

• Tufa accumulated along a NE-SW fracture system
  parallel to Q-faults to the west
• In places, tufa has accumulated along secondary
  fractures, radiating from central points (Oviatt,
  1991)

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Neels RR Well Area
Neels Railroad Well
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Neels Railroad Well

• Water Well Drilled in 1906 for SP-LA-SL RR
• Described by W.T. Lee (1908)
• Several hot water horizons
• Steam vented continuously
• Some oil
• Gas at 549 m (1802 ft)
• Drilling abandoned
• Water sample from 426 m (1398 ft) yielded TDS of
  3345 ppm and 370 ppm of siliceous matter
• Silica geothermometers temp 205C 226C
• Two other samples yielded normal silica values

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Neels RR Well Area

• In 1980, Cominco American, Inc. completed a deep
  test well (2 Beaver River) to a depth of 4021 m
  (13,193 ft) near the old Neels siding.
• Utah DOGM records report an unconformity at 610 m
  (2000 ft) and Precambrian rocks at 756 m (2480
  ft)
• Thrust fault at 2557 m (8390 ft), continued in
  lower Paleozoic rocks to total depth, and
  probably bottomed in the Cambrian Tintic
  Quartzite
• Geophysical logs indicate a BHT of 153C (308F)
  measured five hours after circulation stopped
• Well later plugged to 180 m (600 ft), converted
  to a water well

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Thermo Hot Springs

• NE Escalante Desert

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Thermo Hot Springs

• Two large spring mounds along axial drainage
• Shauntie Hills and Black Mountains - intermediate
  volcanics from Oligocene-Miocene (29 -19 Ma)
  stratovolcanos
• Rhyolite dome 2 mi east of mounds 10.3 Ma
  (Rowley, 1978)
• Young faults, mapped near spring mounds, displace
  Q-units

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Thermo Hot Springs

• Older faults in Tv-units have dominant NW
  orientation
• Structural intersection localizes the geothermal
  system (Rowley Lipman, 1975)
• Mabey Budding (1987) suggest from gravity data,
  a buried fault with several hundred feet
  displacement (down to west) passes through the
  hot springs area

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Thermo Hot Springs

• Spring temperatures range to 89.5C (193.1F)
• Quartz (cond.) GTH range from 128 to 131C (262
  - 268F)
• K-Mg GTH range from 110 to 115C (230 239F)
• Production test and temperature data from a deep
  (2221 m 7288 ft) exploratory well TE 57-29
  171C (339F) at 2048 m (6719 ft)

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Thermo Hot Springs

• SP survey (Ross et al., 1991) covered an area of
  approximately 4.0 mi2
• No outstanding anomalies across the two spring
  mounds
• Broad, complex SP low in SE part of area on
  alluvial fan (stipple pattern -30 mV contour)
• Several stations -90 to -116 mV
• No deep drilling, geophysical data available in
  immediate area to indicate source (geothermal??)
• On U/T side of mapped NE Q-fault

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Thermo Hot Springs

• Buried fault intersections (?)
• NW-oriented drainage patterns
• Similarly oriented bedrock faults to the S and SE
• Suggest geothermal source controlled by
  intersecting structures

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Beryl Woods Ranch Area

• Southwestern extension of Escalante Valley
• South of Wah Wah Mtns. Indian Peak Range
• 10 miles NW of Beryl-Enterprise-Newcastle

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Beryl Woods Ranch Area

• Goode (1978) reported temp of 149 (300F) from
  7000 ft in a 12,295 ft well he termed De Armand
  1
• Goode also reported, upon testing, the well
• Flowed at 1000 gpm
• Water contained lt 4000 ppm TDS
• No flowing temperature reported

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Beryl Woods Ranch Area

• Utah DWR reported MCR Geothermal Corp., GKI, and
  UPL completed a well referred to as
  MCO-GKI-UPL-DeArman 1 in the spring of 1976
• Did not comply with abandonment procedures
  (remained open)

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Beryl Woods Ranch Area

• Klauk and Gourley (1983) reported a temperature
  of 284F (140C) at a depth of 8072 ft in a well
  drilled by MCR Geothermal Corp. (MCR State 1)

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Beryl Woods Ranch Area

• At Woods Ranch, one of two wells, 200-ft-deep
  water well produces 98F water
• No hot springs
• SP survey (Ross et al., 1991) showed broad, neg.,
  anomaly
• Geothermometers suggest equilibrium temps 212
  - 239F (100 - 115C)
• May be a mixture of thermal water and non-thermal
  ground water from the Escalante Valley aquifer

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SUMMARY

• STA in SW Utah contains most of the states
  higher quality, identified geothermal systems
• Power generation geothermal systems in the STA
  are either undeveloped or under-developed
• Direct use systems are remote and pose some
  transportation or access challenges
• Six prospective geothermal sites reviewed here
  probably reflect only a fraction of the
  geothermal endowment in the region
• Additional exploration, a considerable but
  necessary up-front investment, will be required
  to assess the economic viability of these systems

Thank You!