Geological Sciences Seminar: Elizabeth Miller and Jason Craig, Stanford University

Exploring for (blind) normal fault-hosted geothermal systems using low temperature thermochronology 

Geothermal energy serves a critical role in the transition to a carbon-free energy future. As a low-emissions source of baseload power it can complement sources like wind and solar. A major uncertainty when exploring for geothermal systems is whether an active fault is permeable at depth and acts as a pathway for ascending hydrothermal fluids. Tools that can assess the fluid flow history and present behavior of faults before drilling are critical to reducing risk and accelerating geothermal development.

In this overview talk, we introduce the Basin and Range province, a vast region of extension and higher than average temperatures at depth. We review current exploration strategies for geothermal and suggest that high-resolution thermochronology from rocks close to the surface trace of major faults is a promising means for determining recent hydrothermal activity. Low temperature thermochronology such as the U-Th/He and fission track systems in apatite are sensitive to short-lived thermal disturbances and thus offer low cost potential to quantify transient hydrothermal events along a fault system.

We will test these methods and further assess the geothermal potential of an active regional fault system in western Alaska, the Kigluaik normal fault system near the Pilgrim Hot Springs. Combined with 3D geologic modeling, results are anticipated to add to our understanding of whether the geothermal anomaly (whose exploration is currently on hold) is fault controlled at depth. Arctic communities such as nearby Nome spend ~ $8M/year on diesel generated electricity.

Funding is from the TomKat Center for Sustainable Energy at Stanford University and Zanskar Geothermal and Minerals Inc,building on prior NSF-funded geologic studies in the Kigluaik Mts. by Miller’s research team. We are collaborating with Dr. Carl Hoiland of Zanskar and leaning on the expertise of Jason Craig who holds an MS degree in geothermal exploration from UNR.

Email Kelly Wells, kcwells7@stanford.edu, for Zoom link and password.