Radiometric equipment is used to measure gamma ray emissions from the natural radioactive decay of elements within rocks and soil, in particular the emissions from isotopes of Potassium, Thorium and Uranium.
Radiometric measurements can be taken simultaneously with the Dual EM collection. The gamma radiometric results complement Dual EM data, determining with greater accuracy changes in soil type where low electrical conductivity levels exist.
In general, a low total gamma count is typical of sandy saline soils. High total gamma counts are indicative of soils with high amounts of rock, whilst gravelly soils exhibit high thorium counts.
Soils types that benefit from the additional GR measurement are those with predominately sandy to sandy gravel soils, very low clay content and those that do not have high water holding capacity.