A Case Study on Resistivity and Spectral IP Properties of Modern Seafloor Hydrothermal Deposits in Japan

Summary Resistivity and induced polarization (IP) rock properties are effectively used in the exploration of massive sulphide deposits, formed by ancient seafloor hydrothermal activity. The present study has investigated these properties using sulphide-bearing drill core samples taken from the Ihaya North Knoll and the Iheya-Small Ridge, the location of modern seafloor hydrothermal deposits in Japan. Overall, the results showed that resistivity of sulphide-bearing sediments correlates with porosity, rather than sulphide content. Furthermore, the intensity of spectral IP (phase) was found to depend on the amount of the sulphide minerals, which has a peak at a high frequency range (several kHz). These features are similar to that of typical fine-grained disseminated sulphides. In contrast to the sediments, a massive sulphide sample was found to have unique IP property, possibly due to its large sulphide mineral particles.