Complex conductivity and surface conductivity of kimberlites: first results of lab investigation

Kimberlites are of interest for both Earth scientists and mining engineers because (i) they are produced at very large depth and, so, provide information about the deep Earth composition and also (ii) because they are sources of diamonds. This is why, kimberlites are prospected in all continents. It is well known, electrical methods usually provide useful information to delineate kimberlite pipes, which typically show small apparent resistivity values.

However, to the best of our knowledge, nobody studied, why intrusive rock like kimberlite is a good conductor.  We carried out multi-salinity experiments with kimberlite samples taken in Arkhangelsk region (Deposit Lomonosova). We saturated samples with water of different electrical conductivity values, and we measured the complex electrical conductivity of the samples. We obtained surprisingly large values of both real and imaginary conductivities, which can be explained by anomalously large surface conductivity.