A 3D Conductivity Model of the Isle of Wight, UK, from Airborne EM Data

This study reports the first airborne electromagnetic (AEM) survey in southern England. An airborne geophysical survey incorporating magnetic, radiometric and electromagnetic observations was carried out in 2007 over a 36 x 22 km area incorporating the Isle of Wight. The island is of significant geological interest due to the nature of the reactivated Variscan thrust faulting causing near vertical bedding along a central monocline. Of primary interest to this study was a first chance to deploy AEM over a significant chalk deposit and to assess the accuracy and resolution of the final 3D models in regions of significantly dipping, but well mapped, sedimentary beds. The results of multi-layer inversion are displayed across a 3D conductivity volume. The conductive Gault clay/mudstone is highly resolved against the more resistive Upper Greensand and Chalk and provides a detailed mapping of the concealed geological structure.