Induced polarization effects in fixed-wing airborne EM: the TEMPESTTM system—Part B, field data inversion from regional targeting to deposit-scale characterization

This paper is the second part of a series examining the effects of ground polarization in airborne electromagnetic (AEM) data collected with fixed-wing platforms. Induced polarization (IP) effects can be detected using airborne electromagnetic methods; however, most geophysical studies have focused on helicopter-borne systems whose sensitivity to subsurface polarizable features is well established. In contrast, the potential of fixed-wing AEM systems for IP detection remains largely unexplored, and their effects have not yet been modelled. Building on Part A of this series, which examined the sensitivity of TEMPEST™ system to ground chargeability with numerical analysis and dataspace inspection, we extend the study using field survey data to model subsurface IP effects in inversion. This study is defined at three different exploration scales: deposit scale, survey-line and regional scale. The first experiment focuses on a comparative modelling analysis between the TEMPEST™ and SkyTEM312FAST helicopter-borne system along two overlapping survey lines. The results show highly comparable chargeability and resistivity distributions, with consistent outcomes across the TEMPEST™ measured components (X and Z) and with geological interpretation of the area. These findings demonstrate that fixed-wing AEM can effectively resolve IP anomalies with resolution and depth penetration similar to helicopter-borne systems, despite differences in acquisition geometry and system design. Then, to assess regional-scale applicability, the entire Musgrave Province in South Australia was inverted incorporating IP effects and comparing the results with the non-IP modelling of the area. The IP modelling show a systematically reduction of inversion misfit, when compared with non-AIP modelling with differences between the resistivity models higher than 100 per cent. To conclude, the ground truthing of regional modelling has been carried over the well-characterized Nemo-Babel mineralization. This confirmed that TEMPEST™ derived chargeability anomalies align closely with known mineralized zones, validating both spatial accuracy and correspondence with mineralization of the modelled resistivity and chargeability. Overall, this study demonstrates that fixed-wing AEM platforms, such as TEMPEST™, can detect and quantify ground chargeability from regional to deposit scale, providing a valuable tool to target exploration and to characterize mineralized bodies.