Methods and systems are provided for investigating a rock sample, in which wideband electromagnetic response data are obtained and processed by inversion in order to determine values for a plurality of parameters of the rock sample. The wideband electromagnetic response data is derived from electromagnetic measurements of the rock sample at frequencies that fall within a wideband of frequencies, wherein the wideband of frequencies includes a low frequency sub-band that is sensitive to conductivity of the rock sample and a high frequency sub-band that is sensitive to the permittivity of the rock sample. In one embodiment, the inversion can employ a wideband model that accounts for two different polarization mechanisms. The wideband model can be used to describe predicted electromagnetic response of the rock sample at frequencies that fall within the wideband of frequencies.