Distribution of Radioactivity in Rocks and Minerals, and the Effect of Weathering on Determinations of Uranium

Abstract

IN determining the uranium content of a series of rocks for the purpose of studying its geochemical behaviour, difficulties are often encountered because of the loss of uranium by leaching. In some cases it is almost impossible to ascertain whether or not a rock has been affected by leaching. Late-stage hydrothermal activity will remove (by solution) some uranium, but in addition to this a certain amount is removed by weathering. Because of the heterogenous distribution of uranium in acid rocks (for example, granites), the effect of hydrothermal solutions, mineralization and variations in uranium and thorium ratios, the geochemical behaviour of uranium is best approached by studying more homogeneous rocks, in particular basaltic types.