3-D Magnetotelluric Assessment of the Geo-resources Potential of the Irish Crust

Quantifying and de-risking the exploration for geo-resources require knowledge of the subsurface. This is true for example for both mineral and geothermal exploration. Often that knowledge is built up by local geophysical studies on areas of interest but the broad deeper context and controls for the system are often missing due to a lack of appropriate deep (e.g., >2 km) geophysical imagery. The primary goal of this project is to develop a deep (range 5-100 km) 3-D electrical conductivity model of Ireland’s crust and uppermost mantle using magnetotelluric (MT) method. Deep probing MT imaging yields information on the structure, composition and temperature of Earth’s crust and upper mantle, and can detect processes associated with mineralisation and areas of high temperature and or permeability related to promising geothermal targets. It will also help better illuminate the deep geology of Ireland, particularly in the context of the mechanisms of the Caledonian and Variscan Orogenies that formed Ireland, the emplacement of its sizable granites, and the intraplate basaltic volcanism that followed the opening of the North Atlantic and created the famous Giant’s Causeway and other features. MT experiments have been conducted in Ireland since 1980s. These include the Irish Magnetotelluric Profile in the late 1980s, and the Irish Magnetotelluric Lithospheric Experiment ISLE-MT in the mid-2000s. In the framework of Space Weather ElectroMagnetic Database for Ireland, long-period MT (LMT) data were acquired at over twenty stations in 2018. Since June 2019, new LMT data have been acquired at twelve stations. The recent project HIbernian Regional GeoElectrical Structure Hi-RES aims to complete an all-island dataset of LMT soundings by acquiring an additional 22 sites across Ireland, expanding on previous MT campaigns. This contribution will present analysis and 3-D modelling results of these datasets.