The geophysics of Northern Ireland: the Tellus effect

Abstract

In the UK, prior to the onset of revised high-resolution airborne surveying in the late 1990s, the national onshore magnetic data set comprised 430,238 line km acquired in the late 1950s and early 1960s. These data were acquired at wide flight-line separations of between 2 and 10 km (tie-lines) and at an elevation of about 1000 ft, and with a previous generation of fluxgate magnetometers. Northern Ireland was the first part of the UK to conduct an independent cost-benefit analysis and recognize the benefits of modern, high-resolution aerogeophysical surveying. The Tellus project was conceived as a resource and environmental survey for the benefit of both public and private development sectors. The project also included detailed geochemical sampling surveys of soils and streams. These datasets are being used both to promote mineral exploration and to provide environmental baselines that support government planning in economic and sustainable development, social infrastructure, environment, and health. The three main geophysical measurements (magnetic, radiometric, and electromagnetic) contribute to different aspects of these broad objectives. A major Tellus concept and effect (the naming itself was significant) was the apportioning of a significant part of the project budget to public awareness, outreach, and understanding of science. A very obvious and prolonged low-level airborne survey is an ideal platform for a public outreach campaign, which proved highly effective. Tellus, and the fact that it was about ‘Understanding Underground’, provided a bridge of understanding between science and everyday culture in the local population and it continues to do so