The frequency spectrum of electrical properties of seawater-saturated oceanic crust and oceanic island basalts has been studied. All samples showed at least two of three possible polarization mechanisms: dielectric, membrane, and electrode. The membrane polarization appears to result from the presence of clay minerals, which frequently line or block pores and cracks in the samples. The dominant conduction mechanism in the samples is pore fluid (seawater) conduction, but the electrical properties of samples containing clay are modified by the clay. The results support the suggestion by Drury that a model of three conduction mechanisms acting approximately in parallel—pore fluid, clay mineral, and metallic mineral conduction—describes the electrical properties of seawater-saturated basalts.

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