Induced polarization spectra of sands and clays measured in the time domain

Time domain induced polarization (IP) responses of pure clay, pure sieved sand, and two sand<br>mixtures were measured and inverted to relaxation time distributions (RTD) and pore characteristic length<br>distributions (CLD) representing IP spectra. For the clay the CLD was found to be similar to the pore size<br>distribution obtained on the basis of scanning microscope imaging. For the sand mixtures the CLD was<br>found to be sensitive to the proportion of particles of different sizes. In both cases the form of the CLD is<br>practically independent of water conductivity.