Experimental study on the detection of metal sulfide under seafloor environment using time domain induced polarization

The induced polarization (IP) method can play an important role in the exploration of seafloor polymetallic sulfide deposits. Compared to frequency-domain IP, time-domain IP (TDIP) requires a simpler apparatus configuration and can be more widely and economically deployed for operations in seafloor environments. To investigate the effect of the seafloor environment on the TDIP measurement and find suitable parameters to characterize metallic bodies, laboratory experiments on synthetic samples were carried out based on a special electrical experimental system. The time-domain Cole–Cole model and relaxation time distribution (RTD) method were combined to process and interpret the measured data. The results show that the volume content of metallic minerals in ore-bearing rocks can be directly quantified by the total chargeability. The sizes of metallic particles can be approximately determined by the relaxation time defined from the peak of the RTD. The RTD method was used to distinguish multiple polarizable sources, such as sulfide and basalt. TDIP surveying in the marine environment is more efficient than surveying in the terrestrial environment. A short time delay used before starting secondary voltage measurements is more suitable for a successful TDIP survey in a high-salinity environment. In addition, the chargeability is shown to be more sensitive to the variation in the volume content of metallic minerals than the direct current resistivity.