Electrical properties of two-component mixtures and their application to high-frequency IP exploration of permafrost
We investigate the problem of determination of the volumetric ratio between the two components of a heterogeneous mixture with unknown internal structure. If both resistivity and permittivity of one component are known to be much higher than those of the other within a sufficiently wide frequency range, the volumetric ratio may be roughly estimated from measured electromagnetic response of the mixture by making use of the variational approach. Otherwise, such estimation requires the exact knowledge of the inherent electrical properties of the mixed materials and application of some universal mixing model, such as the weighted power mean formula. The high-frequency induced polarization measurements are strongly influenced by the presence of ice inclusions in an investigated rock formation, which is commonly used for mapping of frozen ground within the permafrost regions. We show that for sedimentary rocks with low clay content, it is also possible to roughly estimate the ice concentration from broadband induced polarization data by using the two-component, weighted power mean model, which is confirmed by a lab experiment on a frozen core sample with known ice content.