Heat-flow values from the precambrian shield of western Australia

The geothermal flux has been determined for three points on the Western Australian Precambrian shield from temperature measurements in depressed drilled holes and laboratory determinations of thermal conductivity of core samples from the holes. The values (in μcal/cm2 sec) are: for Kalgoorlie 0.96, for Coolgardie, 0.90, and for Norseman 1.01, with a precision of better than 10 per cent. The temperature measurements show that, in semiarid areas, the intermittent presence of water in a salt lake bed has an appreciable effect on temperatures measured in drilled holes in the immediate vicinity of the lake. Although surface geology varies among the three localities there is no great variation in heat-flow values, which differ by a factor of 2 from published values for eastern Australia. Comparison with other results confirms the world pattern of relatively lower heat flows from Precambrian shield areas than from areas lying off shields.