The latest merged airborne Thorium data from the Tellus project, managed by the Geological Survey Ireland. The survey was conducted using an from a survey aircraft flying at an altitude of 59 meters.
The Thorium data is recorded at 1 Hz map in parts per million (ppm) along survey lines orientated 165 degrees and line spacing of 200m. Data is gridded using a minimum curvature algorithm. Data is diurnally and IGRF corrected and control line levelled. Different datasets grids were stitched together using the Geosoft suture method and then re-sampled to a master database. Data is recorded in Irish Transverse Mercator (ITM) and latitude and longitude. The latest merged Thorium data has been collected on a seasonal basis and quality controlled before being merged. Each seasonal survey block are available to download on an individual basis and are available at tellus.ie. The survey block names, year and area they cover is as follows: Charlestown survey block (2006 – Area surrounding Charlestown, Co Cavan, Monaghan) (Industry funded) Tellus Border survey block (2001-2013, Co Donegal, Sligo, Leitrim, Cavan, Monaghan, Louth) Tellus North Midlands survey block (2014, Parts of Co Roscommon, Longford and Westmeath) Tellus A1 survey block (2015, covering parts of Co Meath, Kildare, Offaly rural Dublin and parts of Laois, Wicklow) Tellus A2 block (2016, Co Galway. Including parts of Mayo, Tipperary and Offaly) Tellus Waterford survey block (2016,Eastern Waterford, parts of southern Tipperary, Kilkenny and western Wexford) Tellus A3 block (2017, Co Mayo, including parts of Galway) Tellus A4 block (2017, Co Donegal) Also available: Mine site airborne surveys (2006, Charlestown block, Silvermines (Co Tipperary) and Castleisland(Co Kerry)) this data was reprocessed and technical report available in 2016.Hunting Geology and Geophysics Ltd, low resolution Magnetic Intensity survey (1979-1981, across central Ireland).