ESTIMATION OF THERMAL-CONDUCTIVITY FROM THE MINERAL-COMPOSITION - INFLUENCE OF FABRIC AND ANISOTROPY

Measured values of thermal conductivity from crystalline rocks are com pared with values calculated from the mineral content using the layere d model. First, thermal conductivity is estimated using data based on quasi-isotropic mixtures of fragments or powder. Second, the approach is applied on core data considering the anisotropy of some rock formin g minerals. The numerical value of estimated thermal conductivity is c ontrolled by the quartz content. Sheet-silicates control anisotropy an d fabric in gneisses and their thermal consequences. If information ab out the fabric of the rock is available, the anisotropy of minerals ca n be considered in a layered model and this improves the estimation of thermal conductivity from mineral contents.