Application of (U-Th)/He Thermochronometry as a Geothermal Exploration Tool in Extensional Tectonic Settings: The Wassuk Range, Hawthorne, Nevada

Abstract

Geothermal exploration in the Basin and Range Province is often focused in extended terrains where heat has been transferred to the surface through advection in the footwall rocks of normal faults. Low temperature (U-Th)/He apatite ages of such footwall rocks can determine which areas have experienced the most recent, significant extension or have interacted with hot geothermal fluids. Apatite cooling ages from the footwall of the Wassuk Range, Hawthorne, Nevada have identified the presence of a known geothermal anomaly and associated structural complexities. The most recent pulse of exhumation along the Wassuk Range front occurred around 4-5 Ma. Range front apatite ages that deviate from this age range correspond to the location of the geothermal anomaly or highlight fault displaced blocks of Wassuk Range footwall. Constraints on the geometry and thermal evolution of the footwall can better focus exploration efforts therefore lowering the associated risks and costs of geothermal exploration.