Hotspot: the Snake River Geothermal Drilling Project--initial report
The Snake River volcanic province (SRP) overlies a thermal anomaly that extends deep into the mantle; it represents one of the highest heat flow provinces in North America. The primary goal of this project is to evaluate geothermal potential in three distinct settings: (1) Kimama site: inferred high sub-aquifer geothermal gradient associated with the intrusion of mafic magmas, (2) Kimberly site: a valley-margin setting where surface heat flow may be driven by the up-flow of hot fluids along buried caldera ringfault complexes, and (3) Mountain Home site: a more traditional fault-bounded basin with thick sedimentary cover. The Kimama hole, on the axial volcanic zone, penetrated 1912 m of basalt with minor intercalated sediment; no rhyolite basement was encountered. Temperatures are isothermal through the aquifer (to 960 m), then rise steeply on a super-conductive gradient to an estimated bottom hole temperature of ~98°C. The Kimberly hole is on the inferred margin of a buried rhyolite eruptive center, penetrated rhyolite with intercalated basalt and sediment to a TD of 1958 m. Temperatures are isothermal at 55-60°C below 400 m, suggesting an immense passive geothermal resource. The Mountain Home hole is located above the margin of a buried gravity high in the western SRP. It penetrates a thick section of basalt and lacustrine sediment overlying altered basalt flows, hyaloclastites, and volcanic sediments, with a TD of 1821 m. Artesian flow of geothermal water from 1745 m depth documents a power-grade resource that is now being explored in more detail. In-depth studies continue at all three sites, complemented by high-resolution gravity, magnetic, and seismic surveys, and by downhole geophysical logging.
Citation Information
Publication Year | 2012 |
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Title | Hotspot: the Snake River Geothermal Drilling Project--initial report |
Authors | J.W. Shervais, D. Nielson, T. Lachmar, E. H. Christiansen, L. Morgan, Wayne C. Shanks, C. Delahunty, D.R. Schmitt, L.M. Liberty, D.D. Blackwell, J. M. Glen, J.A. Kessler, K.E. Potter, M.M. Jean, C.J. Sant, T. Freeman |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Geothermal Resources Council Transactions |
Index ID | 70042904 |
Record Source | USGS Publications Warehouse |
USGS Organization | Central Mineral and Environmental Resources Science Center |