Radiometric Grid of Australia (Radmap) v4 2019 ratio uranium over potassium

Brief description

This record was harvested by RDA at 2026-09-17T11:58:12.611638+10:00 from NCI's Data Catalogue where it was last modified at 2018-04-20T05:51:54.

Full description

The uranium over potassium grid is a derivative of the 2019 radiometric or gamma-ray grid of Australia comprising over 600 airborne gamma-ray spectrometric surveys. The radiometric, or gamma-ray spectrometric method, measures the natural variations in the gamma-rays detected near the Earth's surface as the result of the natural radioactive decay of potassium (K), uranium (U) and thorium (Th). The data are collected on airborne geophysical surveys conducted by Commonwealth, State and Northern Territory Governments and the private sector. The 2019 uranium over potassium grid has a cell size of about 100 m (0.001 degrees) and is derived from the filtered uranium and potassium grids. -- This record represents data published by NCI. It uses catalogue metadata modified from Geoscience Australia. See our Record Lineage Information for more details.

Lineage

The uranium over potassium ratio grid is a derivative of the 2019 radiometric or gamma-ray grid of Australia. The radiometric grid of Australia is derived by merging over 600 airborne gamma-ray spectrometric surveys by the Commonwealth, State and Territory Governments and held in the national radioelement database of Australia. The cell sizes of the original survey grids range from 50 m through 800 m, but most have a cell size of about 100 m. The original survey grids are levelled to each other, and to the Australia Wide Airborne Geophysical Survey (AWAGS). The grids were then re-sampled to generate the Radiometric Map of Australia Grids with a cell size of about 100m (0.001 degrees). The survey grids are levelled to each other, and to the Australia Wide Airborne Geophysical Survey (AWAGS). The AWAGS traverses were funded under the Australian Government’s Onshore Energy Security Program in 2007. They comprise N-S flight lines spaced 75 km apart and E-W tie lines spaced 400 km apart across the entire continent. The AWAGS survey was designed to serve as a baseline for both airborne gamma-ray spectrometric and magnetic surveys. Since the AWAGS traverses are consistent with the International Atomic Energy Agency’s (IAEA) radioelement datum, the new continental merges are level to this datum as well. The data quality varies depending on the survey. The data are processed via standard methods to ensure the response recorded is that due only to the rocks in the ground. The results produce datasets that can be interpreted to reveal the geological structure of the sub-surface.The final grid is checked for quality by GA geophysicists to ensure that the final data released by GA are fit-for-purpose. Uranium over potassium ratio grid was calculated after first applying a low value 'clip' to the uranium and potassium grid values - i.e. any values less than 0.1 are set to 0.1 prior to ratioing. This clipping will necessarily introduce some artefacts into the ratio grids in areas of very low radioelement concentrations.