Multidisciplinary Assessment of a Potential Hidden Geothermal System: Insights from Northeastern Reese River Valley, North-Central Nevada

Abstract

The Great Basin region of the western United States hosts numerous geothermal resources, yet a substantial portion are "hidden" systems lacking surface manifestations. The Argenta Rise study area, within the northeastern Reese River basin of Nevada, was identified as a high-priority blind prospect through regional play fairway analysis (PFA) due to its favorable structural setting, including a major pull-apart between the Argenta Rim and northern Shoshone Range faults. This study, part of the broader INnovative Geothermal Exploration through Novel Investigations Of Undiscovered Systems (INGENIOUS) project, applies detailed geological and geophysical investigations to characterize the hidden geothermal potential at Argenta Rise. Our integrated approach combined geological mapping and structural analysis, geophysical surveys (gravity, magnetics, magnetotellurics, and seismic reflection), a shallow (2-m) temperature survey, and temperature-gradient (TG) drilling. Results confirm the presence of complex, interacting fault systems conducive to fluid flow and identify geophysical anomalies, including low-resistivity zones at ~1.5 km depth, aligned with some of these structures. However, no clear thermal anomalies were detected in the shallow subsurface by the 2-m survey or in ten TG wells drilled to ~244 m depth. This discrepancy highlights the challenge of exploring truly blind systems, where favorable structural and geophysical indicators are decoupled from shallow thermal signatures. We conclude that the geothermal potential at Argenta Rise remains prospective but unresolved; if present, a potential resource may be localized outside the drilled array, masked by cool groundwater from aquifers, or confined to a deeper reservoir.