ASSESSING GEOTHERMAL ENERGY POTENTIAL IN SOUTHERN UTAH USING THE TRACE ELEMENT CHEMISTRY OF GRANITIC INTRUSIONS

Enhanced Geothermal Systems (EGS) have been recognized by geothermal energy experts as a very large potential alternative energy source to help meet growing energy demands. The benefits of EGS are vast, not solely limited to energy production alone, that can be exploited for industrial and residential purposes. This project aims to advance the development of geothermal systems by analyzing the major and trace element geochemistry of the Mineral Mountains in Utah to determine the cause of the elevated geothermal gradient and consequent favorable geothermal setting of the region. The Roosevelt Geothermal Area is a designated geothermal resource area surrounding the Mineral Mountains. Several natural hot springs and the Blundell geothermal power plant are within the Roosevelt Geothermal Area. Additionally, a deep EGS experiment laboratory, the Frontier Observatory for Research in Geothermal Energy (FORGE), has been proposed for placement within the geothermal area. Many studies over the course of several decades have provided extensive geochemical, structural, hydrologic, and thermal data to compare to. Samples were taken across competent outcrops of the major granitic units in the Mineral Mountains and analyzed by XRF. Radiogenic heat generation produced by decay of the unstable isotopes ²³⁸U, ²³²Th, and ⁴⁰K in Tertiary granites has been calculated from XRF and the results are favorable in certain units. Average radiogenic heat production at the surface is 2.86 microwatts/m³ with several units approaching or slightly exceeding 4 microwatts/m³. The strongly speculated presence of an active magma chamber in the region combined with favorable amounts of radioactive heat decay in granitic plutons are very likely the sources of heat in the Mineral Mountains.