Heat-producing crust regulation of subsurface temperatures: A stochastic model re-evaluation of the geothermal potential in southwestern Queensland, Australia

Abstract

A large subsurface, elevated temperature anomaly is well documented in Central Australia. High heat producing granites (HHPGs) intersected by drilling at Innamincka are often assumed to be the dominant cause of the elevated subsurface temperatures, although their presence in other parts of the temperature anomaly has not been confirmed. Geological controls on the temperature anomaly remain poorly understood. Additionally, methods previously used to predict temperature at 5km depth in this area are simplistic and possibly do not give an accurate representation of the true distribution and magnitude of the temperature anomaly. Here we re-evaluate the geological controls on geothermal potential in the Queensland part of the temperature anomaly using a stochastic thermal model. The results illustrate that the temperature distribution is most sensitive to the thermal conductivity structure of the top 5km. Furthermore, the results indicate the presence of silicic crust enriched in heat producing elements between 5 and 40km.