Sources of Late Cenozoic Deposits from the Aeolian “Sands” Massif in the Chara Basin of the Baikal Rift Zone: First Results of U–Th–Pb (LA-ICP-MS)-Geochronological Study of Detrital Zircon

The results of U–Th–Pb (LA-ICP-MS) geochronological studies of detrital zircon (fraction >50 µm) from the Late Cenozoic deposits of the large aeolian “Sands” massif of the Chara Basin in the eastern flank of the Baikal Rift Zone show that they are dominated by detrital zircon aged 263–265 and 1861–1864 Ma. Archean ages have been obtained only for individual zircon grains. This might be due to the fact that zircon of this age is present in “fine” fractions, the study of which is hardly possible due to the technological features of the method of geochronological studies in use. Based on the geological situation, granites of the Kodar Complex can be considered as the sole source of Early Proterozoic detrital zircon. The source of detrital zircon aged 263–265 Ma remains a mystery. Granitoid massifs of this age are not known on the territory of the Aldan Shield. They are widespread in its western margin.