Behaviour and spatial distribution of radioactive elements in Megrin pluton intrusive complexes

The gamma spectrometry method was used to study the content of uranium, thorium and potassium, and the fragment radiography method to study the spatial distribution of uranium in the process of the igneous complex formation of the Megrin plutonium. Enhancement has been established of average contents of radioactive elements starting with early igneous phases to later ones, with the early oligocenic igneous complex to the early miocenic complex, and with the rocks of major igneous phases to veined derivatives. In the apical constituent of the rock there is a distinct increase of radioactivity. In holocrystalline rocks the major portion of uranium is concentrated in accessory minerals, and in andesite-dacites-in the groundmass. The rock-making mineral insets in andesite-dacites have little or no uranium whose content increases only in their substitution by secondary products. The multidifferentiated Megrin plutonium was used to exemplify and to reveal the ore-forming capacity of magmatic melts manifested as the accumulation of uranium in the apical constituents of the rock, in its late differentiates, and in the portions of concentration of volatile components