Numerical Simulation Study on the Relationships between Mineralized Structures and Induced Polarization Properties of Seafloor Polymetallic Sulfide Rocks

Abstract

The induced polarization (IP) method plays an important role in the detection of seafloor polymetallic sulfide deposits. Numerical simulations based on the Poisson–Nernst–Planck equation and the Maxwell equation were performed. The effects of mineralized structures on the IP and electrical conductivity properties of seafloor sulfide-bearing rocks were investigated. The results show that total chargeability increases linearly as the volume content of disseminated metal sulfides increases when the volume content is below 20%. However, total chargeability increases nonlinearly with increasing volume content in vein and massive metal sulfides when the volume content is below 30%. The electrical resistivity of disseminated metal sulfides mainly depends on the conductivity of pore water. The electrical resistivity of vein and massive sulfides mainly depends on the volume content and the length of sulfides. Increase in the aspect ratio (0.36 to 0.93) of seafloor massive sulfides causes relaxation time constants and total chargeability to decrease. Relaxation time constants and total chargeability also decrease with increase in the tortuosity of seafloor vein sulfides from 1.0 to 1.38. This study is of great value for the electrical survey of seafloor polymetallic sulfide deposits.

Correlation between induced polarization and sulfide content of rock samples obtained from seafloor hydrothermal mounds in the Okinawa Trough, Japan

“…( 11), which is 0.063. Wu et al (2022) reported related results to this; through numerical simulation, they calculated the chargeability for 0.7 with φ m = 0.1 of massive sulfide ore. The observed discrepancy between the chargeability values calculated using Eq.…”

“…Equation ( 11) assumes spherical sulfide grains (e.g., Revil et al 2018 ;Revil and Gresse 2021), but real sulfides often have varied shapes like flattened ellipsoids, influencing the IP effect (Zhdanov et al 2008;2012). Moreover, Wu et al (2022) indicates that massive and veined sulfides in rocks create extended electron paths, thereby enhancing conductivity. Nevertheless, the low-frequency polarization of these sulfides obstructs the primary current, leading to significant conductivity losses and an increase in chargeability.…”