Geothermal resources evaluation Pro G ram of the eastern san francisco volcanic field , arizona

The Geothermal Resource Evaluation Program of the Eastern San Francisco Volcanic Field, Arizona, has been a fifteen-month study collecting and evaluating geological and geophysical data to assess the potential for a geothermal resource in this region. The San Francisco Volcanic Field has been recognized as a target for geothermal exploration for more than thirty years, primarily based on the volume and youth of volcanic rocks in the field. Interest has never progressed to the stage of drilling, however, because the field lacks surface geothermal manifestations, such as geysers, hot springs, or fumaroles. Cold water springs are also absent in the field because it is a recharge area for the regional aquifer system, and a working hypothesis at the beginning of this project was that a deep thermal system was masked beneath the shallow recharge system. Previous studies have provided strong evidence that there is heat, and perhaps partial melt from the eruption of the San Francisco Peaks in the deep crust.