Australian National Radiometric Data Collection

This data collection is comprised of radiometric (gamma-ray spectrometric) surveys acquired across Australia by Commonwealth, State and Northern Territory governments and the private sector with project management and quality control undertaken by Geoscience Australia.

The radiometric method measures naturally occurring radioactivity arising from gamma-rays. In particular, the method is able to identify the presence of the radioactive isotopes potassium (K), uranium (U) and thorium (Th). The measured radioactivity is then converted into concentrations of the radioelements K, U and Th in the ground.

Radiometric surveys have a limited ability to see into the subsurface with the measured radioactivity originating from top few centimetres of the ground. These surveys are primarily used as a geological mapping tool as changes in rock and soil type are often accompanied by changes in the concentrations of the radioactive isotopes of K, U and Th. The method is also capable of directly detecting mineral deposits. For example, K alteration can be detected using the radiometric method and is often associated with hydrothermal ore deposits. Similarly, the method is also used for U and Th exploration, heat flow studies, and environmental mapping purposes such as characterising surface drainage features. The instrument used in radiometric surveys is a gamma-ray spectrometer.

This instrument measures the number of radioactive emissions (measured in counts per second) and their energies (measured in electron volts (eV)).

Radiometric data are simultaneously acquired with magnetic data during airborne surveys and are a non-invasive method for investigating near-surface geology and regolith.