Induced polarization effect in time domain: theory, modeling, and applications

A new theoretical and experimental method of induced polarization (IP) in the time domain is tested with resistivity data and detailed mineralogy of rock samples. The Generalized Effective Medium Theory of Induced Polarization (GEMTIP) was originally developed in the frequency domain for explaining the structure-property relationship of rocks. The geoelectrical parameters of this model are determined by the intrinsic petrophysical and geometric characteristics of composite media: the mineralization and/or fluid content of rocks and the matrix composition, porosity, anisotropy, and polarizability of formations. The physical properties of rock samples from exploration or mining sites are often used to assist in planning geological surveys or interpretation of geophysical results. However, electrical property data are often recorded in the time domain. In this paper, the Generalized Efective Medium Theory of Induced Polarization (GEMTIP) is tested with the time domain resistivity data transformed from complex resistivity data. It is demonstrated that the time-domain GEMTIP method can be used to study the induced polarization (IP) effect. Results indicate that the time domain resistivity data from laboratory measurements can be used in inversion routines. With advances in the understanding of the IP effect through the GEMTIP model and wide application of the time domain measurements, detection, and discrimination capability will improve for porphyry systems and other geologic targets, leading to greater efficiency in mineral exploration.