A new look at geothermal energy potential of the eastern Snake River Plain, Idaho
- EG and G Idaho, Inc., Idaho Falls (USA)
- Idaho State Univ., Pocatello (USA)
Passage of the Yellowstone plume beneath the Eastern Snake River Plain (ESRP) left a wake of silicic batholiths and associated 4 to 6 Ma rhyolitic tuffs, a 1 km thick sequence of post 4 Ma basalt lava flows, and high heat flow comparable to that of the Basin-and-Range province. U.S.G.S. (United States Geological Survey) Circular 790 estimates that accessible resources are one-third larger than those of the Cascades, but geothermal exploration and research activities on the ESRP have quietly perished. The authors believe that the ESRP merits further attention as a geothermal exploration target. In this article, the first of several by their group, they identify relevant geological and geophysical features of the ESRP, the first step toward a meaningful exploration strategy. Although exploration is hindered by the heat-sapping effects of the overlying SRP aquifer, several geological features of the ESRP suggest that viable exploration targets exist beneath the aquifer: (1) the fracture zones of buried, Neogene silicic calderas; (2) Quaternary basaltic rift zones (several NW-trending ones and an axial one), which have been persistent zones of fissuring, minor faulting, and magma transport; (3) high-angle faults and fractures around the margin of the downwarped ESRP, including NW-trending basin-and-range faults and NE-trending marginal faults; and (4) fractured or brecciated zones near Pleistocene rhyolite domes and silicic intrusions. Existing geophysical data also constrain exploration targets. Aeromagnetic surveys show NW-trending highs that intersect a NE-trending axial high; rhyolite domes and youthful basaltic volcanism are localized along the highs and at intersections. Although the ESRP is remarkably aseismic, recently installed local seismic networks have identified contemporary microearthquakes that could preserve fracture permeability to depths of several kilometers.
- OSTI ID:
- 6363166
- Report Number(s):
- CONF-900702--
- Journal Information:
- AAPG Bulletin (American Association of Petroleum Geologists); (USA), Journal Name: AAPG Bulletin (American Association of Petroleum Geologists); (USA) Vol. 74:6; ISSN AABUD; ISSN 0149-1423
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
150100* -- Geothermal Energy-- Resources & Availability
AQUIFERS
BASALT
CENOZOIC ERA
EXPLORATION
FEDERAL REGION X
GEOLOGIC AGES
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOTHERMAL SYSTEMS
IDAHO
IGNEOUS ROCKS
NATIONAL ORGANIZATIONS
NORTH AMERICA
QUATERNARY PERIOD
RESEARCH PROGRAMS
RESOURCE POTENTIAL
RIFT ZONES
ROCKS
US DOI
US ORGANIZATIONS
USA
VOLCANIC ROCKS