Geothermal resource analysis in the Big Wood River Valley, Blaine County, Idaho.

摘要

A geochemical investigation of both thermal and nonthermal springs in the Wood River area was conducted to determine possible flowpaths, ages of the waters, and environmental implications. Seven thermal springs and five cold springs were sampled for major cations and anions along with arsenic, lithium, boron, deuterium and oxygen-18. Eight rocks, representative of outcrops at or near the thermal occurrences were sampled and analyzed for major and trace elements. The Wood River area hydrothermal springs are dilute Na-HCO(sub 3)-SiO(sub 2) type waters. Calculated reservoir temperatures do not exceed 100(degree)C, except for Magic Hot Springs Landing well (108(degree)C with Mg correction). The isotope data suggest that the thermal water is not derived from present-day precipitation, but from precipitation when the climate was much colder and wetter. Intrusive igneous rocks of the Idaho batholith have reacted with the hydrothermal fluids at depth. The co-location of the thermal springs and mining districts suggests that the structures acting as conduits for the present-day hydrothermal fluids were also active during the emplacement of the ore bodies.