Radiometric Surveys

Radiometric surveys identify and chart natural radioactive emanations, known as gamma rays, originating from rocks and soils. The detectable gamma radiation from earth materials is solely due to the natural decay products of three elements: uranium (U), thorium (Th), and potassium (K). Similar to the magnetic method, which can identify and map only magnetite (and sometimes pyrrhotite) in soils and rocks, the radiometric method can detect the presence of U, Th, and K on the earth surface.

The primary goal of airborne radiometric surveys is to assess either the absolute or relative quantities of U, Th, and K in surface rocks and soils. No other geophysical or likely remote sensing method demands consideration of as many variables to transform observational data into a format useful for geological interpretation. Factors such as meteorological conditions, the area's topography, the impact of the Earth's cosmic environment, the sensor's altitude above ground, and the aircraft's speed are just some of the variables influencing radiometric measurements. These factors can skew an analysis if not meticulously addressed. Gamma-ray sensors, once typically used in small aircraft for geophysics, can now be mounted on drones. These sensors offer crucial insights into the Earth's subsurface composition and structure, allowing geologists to detect, map, and address various minerals and elements. This advancement significantly enhances mineral exploration and the remediation of contaminated sites.