hese data show the intensity of gamma rays released by Uranium, Thorium and Potassium in different soils and rocks in Ireland. Different soils and rock types can then be mapped. The data were collected between 2005 and 2021.

Several surveys were merged to create this dataset.

(1) Tellus Northern Ireland 2005-2006

(2) Cavan-Monaghan, 2006

(3) Tellus Border, 2011-2012

(4) Tellus North Midlands, 2014-2015

(5) Block A1, 2015

(6) Block A2, 2016

(7) Waterford, 2016

(8) Block A3, 2017

(9) Block A4, 2017

(10) Block A5, 2018-2019

(11) Block A6, 2018-2019

(12) Block A7, 2019

(13) Block A8 2020-2021

(14) Block A9 2021

The data were collected using an airplane. The airplane flies at 60 m flight height along lines that are 200 m apart. Gamma ray spectrometer data are recorded at around 60 m intervals along the flight lines. The spectrometer system mounted on the airplane records the number of gamma rays emitted per second by rocks and soils. The gamma ray intensity changes depending on the amount of Uranium, Thorium and Potassium in rocks and soil beneath the aircraft. For example, rocks such as granite contain a large amount of Uranium, Thorium and Potassium, while limestone rocks contain low amounts of these elements.

The data are collected as points in XYZ format. X and Y are the airplane coordinates. Z is the different recorded data, which include gamma ray intensity and aircraft flight height. The XYZ data for each line contains thousands of points. The data from separate lines are merged to create grids of gamma ray counts and Uranium, Thorium and Potassium contents for each survey block. All the survey blocks are then merged to create final grids for Ireland.

This data shows the total radioactivity contained in the ground which can then be mapped.

Colours are used to show gamma ray counts, Uranium, Thorium and Potassium concentration ranges. The values are defined in counts-per-second for gamma ray counts, parts per million for Uranium and Thorium concentrations and percent for Potassium concentration. Pinks and reds show the highest values. Greens and blues show lowest values.

This is a raster dataset. Raster data stores information in a cell-based manner and consists of a matrix of cells (or pixels) arranged into rows and columns. The format of the raster is a grid. The grid cell size is 50 m by 50 m. This means that each cell (pixel) represents an area on the ground of 50 metres squared. Each cell has a value which is the average value of all the points located within that cell.

The Tellus project is a national survey which collects geochemical and geophysical data across Ireland. It allows us to study the chemical and physical properties of our soil, rocks and water. It is managed by the Geological Survey Ireland.