The Tellus Project is the most concentrated geological mapping project ever undertaken in Northern Ireland. The project, managed by the Geological Survey of Northern Ireland (GSNI), has produced new geochemical and geophysical maps that will extend and deepen our knowledge of the geology, soils, natural resources and environment of Northern Ireland. This information supports the exploration for, and development of, mineral and hydrocarbon resources, informs land-use planning and provides a country-wide environmental baseline.
The British Geological Survey (BGS), in partnership with the Geological Survey of Finland (GTK), flew a low-level airborne geophysical survey over the country in 2005–6. The survey aircraft, one of several scientific aircraft owned by NERC, flew a total distance of 86,000 km at a height of 56 m and collected magnetic field, electrical conductivity and terrestrial gamma-radiation measurements. The results provide new insights into Northern Ireland’s geology, particularly where bedrock is obscured by glacial cover and peat. Delineation of faults, dykes and the major volcanic complexes has been greatly improved. The complementary imagery of magnetics, electrical conductivity and radioactivity facilitate mapping of soils and rock types.
On the ground, GSNI and BGS teams collected nearly 30 000 soil, stream-sediment and stream-water samples for analysis, at a nominal interval of one soil and one stream site per 2 km2. The geochemical results provide a new and consistent baseline standard for some 60 elements and compounds across rural Northern Ireland and in the main metropolitan centres. The extensive range of new geochemical maps of soils and streams provides a standard against which to monitor change and a means of identifying abnormally depleted or potentially toxic levels of key elements or compounds. With this information government can identify areas for remediation or control, particularly in the context of the Soil Guideline Values, which define safe levels of certain toxic elements.
The improved geophysical mapping and new regional geochemical maps have prompted renewed interest in mineral prospecting, and new prospecting permits for precious and base metals have been issued as a result.
Improved mapping by airborne magnetics and gamma-ray spectrometry has encouraged a new interest in the potential for geothermal resources. Granitic components of the radioactive Palaeogene intrusive complexes in the south-east show potential for radiogenic heat production.
Terrestrial radiation has been mapped in detail, providing an improved means of mapping the potential distribution of the naturally occurring radioactive gas radon, a principal cause of lung cancer. The first map of the distribution in Northern Ireland of the artificial radionuclide, Cs-137 has also been generated, showing current levels of historic radioactive fallout from global nuclear accidents and weapons testing.
Tellus also provides tools for mapping contamination from terrestrial activities. The airborne systems have mapped changes in electrical conductivity, magnetisation and radioactivity over man-made structures, landfills and industrial sites. The survey offers a rapid method of screening such sites, in conjunction with other remotely sensed data.
These data are a major resource for industry, regulatory authorities and researchers. The Tellus Project is encouraging economic development by promoting investment in mineral exploration, by providing contextual, baseline geoscience information for managing development sustainably, and by stimulating research into a range of applied geological and environmental and land-use issues.
The Tellus Project has been funded by the Department of Enterprise Trade and Investment and by the Rural Development Programme through the Northern Ireland Programme for Building Sustainable Prosperity.