Distribution of Uranium in the Water-rock System within the Ob-Zaisan Orogen

The distribution of uranium in the water-rock system in contrast hydrogeological conditions of granitoid massifs, contact zones and different-aged sedimentary complexes of the Ob-Zaisan orogen is considered. It was revealed that the uranium content in waters varies from 6.71・10 -4 to 1162.81 μg/dm3, and γ ( 234 U/ 238 U) values range from 1.3 to 18.0. The maximum values of 234 Ue were recorded in waters sampled within the granitoids of the Ob and Barlak complexes, which are the main sources of uranium in natural waters of the studied region. It is shown that the data on waterbearing rocks confirm these facts, namely, the average uranium concentrations vary from 2.6 g/t in sedimentary rocks to 9.6 g/t in magmatic rocks. At the same time, intrusive complexes of the Kolyvan granitoid massif are the most enriched with uranium (up to 65.1 g/t).