Radiogenic Heat Generation in Western Australia — Implications for Geothermal Energy

Abstract

The chapter reviews heat generation in crystalline rocks and influences on overlying sedimentary basins in Western Australia (WA). Regions of elevated thorium and uranium will cause elevated heat generation, which in turn can cause elevated heat flow. Western Australia hosts several large sedimentary basins with the potential for hot sedimentary aquifers (HSAs). These include the Perth, Carnarvon, and Canning basins. Parts of these basins are underlain by crystalline rocks that contain high levels of heat-generating elements, such as uranium, thorium, and potassium. Also, the Pilbara Craton, which contains both sedimentary and crystalline rocks, that entertains a number of active mines, which may benefit from geothermal energy, is investigated. Further, the southern part of the Perth Basin (Vasse Shelf), which is underlain by crystalline rocks with elevated concentrations of thorium and uranium, is shown to possess higher than usual temperatures. From observations, and geothermal modeling, it is concluded that the Perth Basin has a high potential for medium-to low-temperature geothermal energy developments. In other parts of Western Australia, the Carnarvon Basin has elevated temperatures in artesian groundwater. Heat flow in the Canning Basin is briefly reviewed; this basin has some geothermal potential, but it is far from the major population centers.

Strength variations of the Australian continent: Effects of temperature, strain rate, and rheological changes

“…Western Australia shows large variability of the surface HF values (20-70 mWm −2 ), although its Archean crystalline crust is expected to be depleted of radiogenic elements. However, this area hosts several large sedimentary basins, including the Perth, Carnarvon, and Canning basin, which are partly underlain by the crystalline rocks with a high concentration of heat-generating elements (Haynes et al, 2015;Middleton, 2016). We can observe a sharp difference between the western part of the Yilgarn and Pilbara craton, characterized by moderate HF values, with respect to the eastern part of the WAC, Officer and Eucla basin, where the low HF values (< 40 mWm −2 ) suppose the presence of a more mafic crust.…”