Airborne Inductive Induced Polarization Chargeability Mapping of VTEM Data

Abstract

Airborne inductive induced polarization (AIIP) effect has been widely recognized in airborne time domain EM system data. AIIP chargeability mapping opens new and exciting areas in mineral exploration for airborne time domain EM systems in the search for sulphides and clay minerals. An AIIP chargeability mapping tool based on CSIRO/AMIRA Airbeo is created for VTEM data, with examples from Mt Milligan, British Columbia, Canada and Tullah, Tasmania. Using the Cole-Cole frequency dependent resistivity, the tool examines the VTEM decay data spectrally and selects the decay associated with the lowest RMS error from a set of decays generated by varying chargeability m and time constant within specific ranges, giving a constant frequency factor c, while the background resistivity is inverted. The parameter mo used to generate the decay is the AIIP apparent chargeability.