AEM surveys in the UK

Most countries would regard National Scale Mapping of magnetic and gravity data as a required geoscientific asset baseline. Airborne magnetic data were acquired in the UK over 45 years ago and our gravity data were obtained in accumulated ground surveys. It is possible therefore to make a case that there is geoscientific knowledge gap in terms of modern, high-resolution geophysical data. Assessment of priority items has lead to the joint acquisition of radiometric, active electromagnetic (EM) and magnetic data as a practical means of providing a cost-effective scientific framework of value to a wide range of stakeholders. Our multi-parameter surveys, follow a lead set by the Geological Survey of Finland (GTK) in their long-established national airborne mapping program. In the UK, these High resolution Resource and Environmental Surveys (HiRES) have been carried out at a preferred line-spacing of 200 m. We have formed a shared capability (JAC) with GTK to perform airborne geophysical survey work, processing and interpretation. The JAC capability together with the current AEM system are described by Leväniemi et al. (2008). Regulatory CAA airborne activity permits typically restrict UK surveys to twin-engine operation and elevations of between 100´ and 180´, with mandatory fly-high (800´) above conurbations.