VLF surface impedance measurements at Zeehan, Tasmania

Abstract

One dimensional very low frequency surface impedance measurements were made in an area with a number of mineralization bands. The results compare favourably with soil geochemistry and drill core analysis in the location of this mineralization in an environment with a relatively shallow overburden. The dependence of surface impedance on measurement direction over an anisotropic earth plane agrees well with theory. The horizontal electric field component was found to be elliptically polarized while the horizontal magnetic field component was linearly polarized. Curve fitting of the electric and magnetic field components independently as a function of measurement angle allowed the magnitude and direction of the maximum and minimum resistivity values to be determined.