Thermal conductivity of rocks for accurate estimation of geothermal heat flux is important. Here we introduce the desgin and
construction of a newly built system based on the principle of steady state heat conduction using divided bars method.
The system is computer controlled and has been calibrated using standard quartz samples. Typical error in the system is about one
percent which is mainly due to the way the sample is positioned in the system. For proper positioning, one must use a conductive greace
to generate good contacts between the sample and the rods.
Measurements of a few rock samples from Iran, give thermal conductivites which are within the reported values by others. The geothermal heat flux based on these measurements and the geothermal gradients from different parts of Iran, show that its mean value varies between 45 and 70 mW/m2, for these regions.
Variations in geothermal gradient along the depth of same wells may also indicate the variations in rock with different thermal conductvities.