Thorium, uranium and potassium concentrations in granites and gneisses of the Rum Jungle complex, Northern Territory, Australia

Rich uranium-copper mineralization occurs in metasediments adjacent to and mantling the older granites and gneisses of the Rum Jungle complex. The uranium and thorium content of these older rocks, measured by gamma-ray spectrometry, is more than twice the average for silicic igneous rocks in general. Younger granites of the area also have high concentrations, suggesting that this is a uranium-thorium-rich province. During low-grade metamorphism, mobilization of these elements in the older complex or in the sediments derived from it may have led to formation of the ore deposits.