Volcanic Rock Petrochemistry as an Exploration Technique for Geothermal Energy

Abstract

Large level silicic magma chambers offer a high potential for economically viable geothermal systems. While purely basic volcanic system rarely form thermal anomalies, they may prove the necessary long term heat input to silicic systems, by underplating, to sustain a high temperature geothermal system. Petrographic and microprobe, geochemical, geochronologic, and isotopic data on young volcanic rocks in west central Nevada indicate compositions that may result from magmatic differentiation, crystal fractionating, variation in magmatic source regions and in particular, magma mixing. Analysis of the petrochemisty and the recognition of magma mixing textures of extrusive rocks may indicate interacting mafic magma with buried shallow silicic magma systems. These systems may provide a shallow heat source for development of geothermal resources.