A geophysical reconnaissance of Pilgrim Springs, Alaska

Abstract

A geophysical survey of Pilgrim Springs, Alaska, including seismic refraction, geomagnetic, microseismic background and water temperature studies indicates that the springs deserve further exploration as a potential geothermal resource. Seismic profiling indicates possible Tertiary reservoir rocks or hydrothermally cemented cap rock at a depth of 205 ft. Subsurface probes detected water temperatures up to 80°C, and local temperature inversions caused by the mixing of spring and groundwater and convective circulation in coarse, permeable sands. Less diluted spring water, when sampled at depth, will probably be more saline and siliceous than that previously sampled at the surface; and estimated reservoir temperatures, based on geothermometry, will probably be increased. A modest exploration program, involving additional geophysical and geochemical studies and the drilling of a test hole, is recommended.